1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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 "compressed_output.h"
48 #include "reduced_debug_output.h"
51 #include "descriptors.h"
53 #include "incremental.h"
61 // The total number of free lists used.
62 unsigned int Free_list::num_lists = 0;
63 // The total number of free list nodes used.
64 unsigned int Free_list::num_nodes = 0;
65 // The total number of calls to Free_list::remove.
66 unsigned int Free_list::num_removes = 0;
67 // The total number of nodes visited during calls to Free_list::remove.
68 unsigned int Free_list::num_remove_visits = 0;
69 // The total number of calls to Free_list::allocate.
70 unsigned int Free_list::num_allocates = 0;
71 // The total number of nodes visited during calls to Free_list::allocate.
72 unsigned int Free_list::num_allocate_visits = 0;
74 // Initialize the free list. Creates a single free list node that
75 // describes the entire region of length LEN. If EXTEND is true,
76 // allocate() is allowed to extend the region beyond its initial
80 Free_list::init(off_t len, bool extend)
82 this->list_.push_front(Free_list_node(0, len));
83 this->last_remove_ = this->list_.begin();
84 this->extend_ = extend;
86 ++Free_list::num_lists;
87 ++Free_list::num_nodes;
90 // Remove a chunk from the free list. Because we start with a single
91 // node that covers the entire section, and remove chunks from it one
92 // at a time, we do not need to coalesce chunks or handle cases that
93 // span more than one free node. We expect to remove chunks from the
94 // free list in order, and we expect to have only a few chunks of free
95 // space left (corresponding to files that have changed since the last
96 // incremental link), so a simple linear list should provide sufficient
100 Free_list::remove(off_t start, off_t end)
104 gold_assert(start < end);
106 ++Free_list::num_removes;
108 Iterator p = this->last_remove_;
109 if (p->start_ > start)
110 p = this->list_.begin();
112 for (; p != this->list_.end(); ++p)
114 ++Free_list::num_remove_visits;
115 // Find a node that wholly contains the indicated region.
116 if (p->start_ <= start && p->end_ >= end)
118 // Case 1: the indicated region spans the whole node.
119 // Add some fuzz to avoid creating tiny free chunks.
120 if (p->start_ + 3 >= start && p->end_ <= end + 3)
121 p = this->list_.erase(p);
122 // Case 2: remove a chunk from the start of the node.
123 else if (p->start_ + 3 >= start)
125 // Case 3: remove a chunk from the end of the node.
126 else if (p->end_ <= end + 3)
128 // Case 4: remove a chunk from the middle, and split
129 // the node into two.
132 Free_list_node newnode(p->start_, start);
134 this->list_.insert(p, newnode);
135 ++Free_list::num_nodes;
137 this->last_remove_ = p;
142 // Did not find a node containing the given chunk. This could happen
143 // because a small chunk was already removed due to the fuzz.
144 gold_debug(DEBUG_INCREMENTAL,
145 "Free_list::remove(%d,%d) not found",
146 static_cast<int>(start), static_cast<int>(end));
149 // Allocate a chunk of size LEN from the free list. Returns -1ULL
150 // if a sufficiently large chunk of free space is not found.
151 // We use a simple first-fit algorithm.
154 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
156 gold_debug(DEBUG_INCREMENTAL,
157 "Free_list::allocate(%08lx, %d, %08lx)",
158 static_cast<long>(len), static_cast<int>(align),
159 static_cast<long>(minoff));
161 return align_address(minoff, align);
163 ++Free_list::num_allocates;
165 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
167 ++Free_list::num_allocate_visits;
168 off_t start = p->start_ > minoff ? p->start_ : minoff;
169 start = align_address(start, align);
170 off_t end = start + len;
173 if (p->start_ + 3 >= start && p->end_ <= end + 3)
174 this->list_.erase(p);
175 else if (p->start_ + 3 >= start)
177 else if (p->end_ <= end + 3)
181 Free_list_node newnode(p->start_, start);
183 this->list_.insert(p, newnode);
184 ++Free_list::num_nodes;
192 // Dump the free list (for debugging).
196 gold_info("Free list:\n start end length\n");
197 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
198 gold_info(" %08lx %08lx %08lx", static_cast<long>(p->start_),
199 static_cast<long>(p->end_),
200 static_cast<long>(p->end_ - p->start_));
203 // Print the statistics for the free lists.
205 Free_list::print_stats()
207 fprintf(stderr, _("%s: total free lists: %u\n"),
208 program_name, Free_list::num_lists);
209 fprintf(stderr, _("%s: total free list nodes: %u\n"),
210 program_name, Free_list::num_nodes);
211 fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
212 program_name, Free_list::num_removes);
213 fprintf(stderr, _("%s: nodes visited: %u\n"),
214 program_name, Free_list::num_remove_visits);
215 fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
216 program_name, Free_list::num_allocates);
217 fprintf(stderr, _("%s: nodes visited: %u\n"),
218 program_name, Free_list::num_allocate_visits);
221 // Layout::Relaxation_debug_check methods.
223 // Check that sections and special data are in reset states.
224 // We do not save states for Output_sections and special Output_data.
225 // So we check that they have not assigned any addresses or offsets.
226 // clean_up_after_relaxation simply resets their addresses and offsets.
228 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
229 const Layout::Section_list& sections,
230 const Layout::Data_list& special_outputs)
232 for(Layout::Section_list::const_iterator p = sections.begin();
235 gold_assert((*p)->address_and_file_offset_have_reset_values());
237 for(Layout::Data_list::const_iterator p = special_outputs.begin();
238 p != special_outputs.end();
240 gold_assert((*p)->address_and_file_offset_have_reset_values());
243 // Save information of SECTIONS for checking later.
246 Layout::Relaxation_debug_check::read_sections(
247 const Layout::Section_list& sections)
249 for(Layout::Section_list::const_iterator p = sections.begin();
253 Output_section* os = *p;
255 info.output_section = os;
256 info.address = os->is_address_valid() ? os->address() : 0;
257 info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
258 info.offset = os->is_offset_valid()? os->offset() : -1 ;
259 this->section_infos_.push_back(info);
263 // Verify SECTIONS using previously recorded information.
266 Layout::Relaxation_debug_check::verify_sections(
267 const Layout::Section_list& sections)
270 for(Layout::Section_list::const_iterator p = sections.begin();
274 Output_section* os = *p;
275 uint64_t address = os->is_address_valid() ? os->address() : 0;
276 off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
277 off_t offset = os->is_offset_valid()? os->offset() : -1 ;
279 if (i >= this->section_infos_.size())
281 gold_fatal("Section_info of %s missing.\n", os->name());
283 const Section_info& info = this->section_infos_[i];
284 if (os != info.output_section)
285 gold_fatal("Section order changed. Expecting %s but see %s\n",
286 info.output_section->name(), os->name());
287 if (address != info.address
288 || data_size != info.data_size
289 || offset != info.offset)
290 gold_fatal("Section %s changed.\n", os->name());
294 // Layout_task_runner methods.
296 // Lay out the sections. This is called after all the input objects
300 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
302 Layout* layout = this->layout_;
303 off_t file_size = layout->finalize(this->input_objects_,
308 // Now we know the final size of the output file and we know where
309 // each piece of information goes.
311 if (this->mapfile_ != NULL)
313 this->mapfile_->print_discarded_sections(this->input_objects_);
314 layout->print_to_mapfile(this->mapfile_);
318 if (layout->incremental_base() == NULL)
320 of = new Output_file(parameters->options().output_file_name());
321 if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
322 of->set_is_temporary();
327 of = layout->incremental_base()->output_file();
329 // Apply the incremental relocations for symbols whose values
330 // have changed. We do this before we resize the file and start
331 // writing anything else to it, so that we can read the old
332 // incremental information from the file before (possibly)
334 if (parameters->incremental_update())
335 layout->incremental_base()->apply_incremental_relocs(this->symtab_,
339 of->resize(file_size);
342 // Queue up the final set of tasks.
343 gold::queue_final_tasks(this->options_, this->input_objects_,
344 this->symtab_, layout, workqueue, of);
349 Layout::Layout(int number_of_input_files, Script_options* script_options)
350 : number_of_input_files_(number_of_input_files),
351 script_options_(script_options),
359 unattached_section_list_(),
360 special_output_list_(),
361 section_headers_(NULL),
363 relro_segment_(NULL),
364 interp_segment_(NULL),
366 symtab_section_(NULL),
367 symtab_xindex_(NULL),
368 dynsym_section_(NULL),
369 dynsym_xindex_(NULL),
370 dynamic_section_(NULL),
371 dynamic_symbol_(NULL),
373 eh_frame_section_(NULL),
374 eh_frame_data_(NULL),
375 added_eh_frame_data_(false),
376 eh_frame_hdr_section_(NULL),
377 build_id_note_(NULL),
381 output_file_size_(-1),
382 have_added_input_section_(false),
383 sections_are_attached_(false),
384 input_requires_executable_stack_(false),
385 input_with_gnu_stack_note_(false),
386 input_without_gnu_stack_note_(false),
387 has_static_tls_(false),
388 any_postprocessing_sections_(false),
389 resized_signatures_(false),
390 have_stabstr_section_(false),
391 incremental_inputs_(NULL),
392 record_output_section_data_from_script_(false),
393 script_output_section_data_list_(),
394 segment_states_(NULL),
395 relaxation_debug_check_(NULL),
396 incremental_base_(NULL),
399 // Make space for more than enough segments for a typical file.
400 // This is just for efficiency--it's OK if we wind up needing more.
401 this->segment_list_.reserve(12);
403 // We expect two unattached Output_data objects: the file header and
404 // the segment headers.
405 this->special_output_list_.reserve(2);
407 // Initialize structure needed for an incremental build.
408 if (parameters->incremental())
409 this->incremental_inputs_ = new Incremental_inputs;
411 // The section name pool is worth optimizing in all cases, because
412 // it is small, but there are often overlaps due to .rel sections.
413 this->namepool_.set_optimize();
416 // For incremental links, record the base file to be modified.
419 Layout::set_incremental_base(Incremental_binary* base)
421 this->incremental_base_ = base;
422 this->free_list_.init(base->output_file()->filesize(), true);
425 // Hash a key we use to look up an output section mapping.
428 Layout::Hash_key::operator()(const Layout::Key& k) const
430 return k.first + k.second.first + k.second.second;
433 // Returns whether the given section is in the list of
434 // debug-sections-used-by-some-version-of-gdb. Currently,
435 // we've checked versions of gdb up to and including 6.7.1.
437 static const char* gdb_sections[] =
439 // ".debug_aranges", // not used by gdb as of 6.7.1
446 // ".debug_pubnames", // not used by gdb as of 6.7.1
451 static const char* lines_only_debug_sections[] =
453 // ".debug_aranges", // not used by gdb as of 6.7.1
460 // ".debug_pubnames", // not used by gdb as of 6.7.1
466 is_gdb_debug_section(const char* str)
468 // We can do this faster: binary search or a hashtable. But why bother?
469 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
470 if (strcmp(str, gdb_sections[i]) == 0)
476 is_lines_only_debug_section(const char* str)
478 // We can do this faster: binary search or a hashtable. But why bother?
480 i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
482 if (strcmp(str, lines_only_debug_sections[i]) == 0)
487 // Sometimes we compress sections. This is typically done for
488 // sections that are not part of normal program execution (such as
489 // .debug_* sections), and where the readers of these sections know
490 // how to deal with compressed sections. This routine doesn't say for
491 // certain whether we'll compress -- it depends on commandline options
492 // as well -- just whether this section is a candidate for compression.
493 // (The Output_compressed_section class decides whether to compress
494 // a given section, and picks the name of the compressed section.)
497 is_compressible_debug_section(const char* secname)
499 return (is_prefix_of(".debug", secname));
502 // We may see compressed debug sections in input files. Return TRUE
503 // if this is the name of a compressed debug section.
506 is_compressed_debug_section(const char* secname)
508 return (is_prefix_of(".zdebug", secname));
511 // Whether to include this section in the link.
513 template<int size, bool big_endian>
515 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
516 const elfcpp::Shdr<size, big_endian>& shdr)
518 if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
521 switch (shdr.get_sh_type())
523 case elfcpp::SHT_NULL:
524 case elfcpp::SHT_SYMTAB:
525 case elfcpp::SHT_DYNSYM:
526 case elfcpp::SHT_HASH:
527 case elfcpp::SHT_DYNAMIC:
528 case elfcpp::SHT_SYMTAB_SHNDX:
531 case elfcpp::SHT_STRTAB:
532 // Discard the sections which have special meanings in the ELF
533 // ABI. Keep others (e.g., .stabstr). We could also do this by
534 // checking the sh_link fields of the appropriate sections.
535 return (strcmp(name, ".dynstr") != 0
536 && strcmp(name, ".strtab") != 0
537 && strcmp(name, ".shstrtab") != 0);
539 case elfcpp::SHT_RELA:
540 case elfcpp::SHT_REL:
541 case elfcpp::SHT_GROUP:
542 // If we are emitting relocations these should be handled
544 gold_assert(!parameters->options().relocatable()
545 && !parameters->options().emit_relocs());
548 case elfcpp::SHT_PROGBITS:
549 if (parameters->options().strip_debug()
550 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
552 if (is_debug_info_section(name))
555 if (parameters->options().strip_debug_non_line()
556 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
558 // Debugging sections can only be recognized by name.
559 if (is_prefix_of(".debug", name)
560 && !is_lines_only_debug_section(name))
563 if (parameters->options().strip_debug_gdb()
564 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
566 // Debugging sections can only be recognized by name.
567 if (is_prefix_of(".debug", name)
568 && !is_gdb_debug_section(name))
571 if (parameters->options().strip_lto_sections()
572 && !parameters->options().relocatable()
573 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
575 // Ignore LTO sections containing intermediate code.
576 if (is_prefix_of(".gnu.lto_", name))
579 // The GNU linker strips .gnu_debuglink sections, so we do too.
580 // This is a feature used to keep debugging information in
582 if (strcmp(name, ".gnu_debuglink") == 0)
591 // Return an output section named NAME, or NULL if there is none.
594 Layout::find_output_section(const char* name) const
596 for (Section_list::const_iterator p = this->section_list_.begin();
597 p != this->section_list_.end();
599 if (strcmp((*p)->name(), name) == 0)
604 // Return an output segment of type TYPE, with segment flags SET set
605 // and segment flags CLEAR clear. Return NULL if there is none.
608 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
609 elfcpp::Elf_Word clear) const
611 for (Segment_list::const_iterator p = this->segment_list_.begin();
612 p != this->segment_list_.end();
614 if (static_cast<elfcpp::PT>((*p)->type()) == type
615 && ((*p)->flags() & set) == set
616 && ((*p)->flags() & clear) == 0)
621 // When we put a .ctors or .dtors section with more than one word into
622 // a .init_array or .fini_array section, we need to reverse the words
623 // in the .ctors/.dtors section. This is because .init_array executes
624 // constructors front to back, where .ctors executes them back to
625 // front, and vice-versa for .fini_array/.dtors. Although we do want
626 // to remap .ctors/.dtors into .init_array/.fini_array because it can
627 // be more efficient, we don't want to change the order in which
628 // constructors/destructors are run. This set just keeps track of
629 // these sections which need to be reversed. It is only changed by
630 // Layout::layout. It should be a private member of Layout, but that
631 // would require layout.h to #include object.h to get the definition
633 static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array;
635 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
636 // .init_array/.fini_array section.
639 Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const
641 return (ctors_sections_in_init_array.find(Section_id(relobj, shndx))
642 != ctors_sections_in_init_array.end());
645 // Return the output section to use for section NAME with type TYPE
646 // and section flags FLAGS. NAME must be canonicalized in the string
647 // pool, and NAME_KEY is the key. ORDER is where this should appear
648 // in the output sections. IS_RELRO is true for a relro section.
651 Layout::get_output_section(const char* name, Stringpool::Key name_key,
652 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
653 Output_section_order order, bool is_relro)
655 elfcpp::Elf_Word lookup_type = type;
657 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
658 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
659 // .init_array, .fini_array, and .preinit_array sections by name
660 // whatever their type in the input file. We do this because the
661 // types are not always right in the input files.
662 if (lookup_type == elfcpp::SHT_INIT_ARRAY
663 || lookup_type == elfcpp::SHT_FINI_ARRAY
664 || lookup_type == elfcpp::SHT_PREINIT_ARRAY)
665 lookup_type = elfcpp::SHT_PROGBITS;
667 elfcpp::Elf_Xword lookup_flags = flags;
669 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
670 // read-write with read-only sections. Some other ELF linkers do
671 // not do this. FIXME: Perhaps there should be an option
673 lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
675 const Key key(name_key, std::make_pair(lookup_type, lookup_flags));
676 const std::pair<Key, Output_section*> v(key, NULL);
677 std::pair<Section_name_map::iterator, bool> ins(
678 this->section_name_map_.insert(v));
681 return ins.first->second;
684 // This is the first time we've seen this name/type/flags
685 // combination. For compatibility with the GNU linker, we
686 // combine sections with contents and zero flags with sections
687 // with non-zero flags. This is a workaround for cases where
688 // assembler code forgets to set section flags. FIXME: Perhaps
689 // there should be an option to control this.
690 Output_section* os = NULL;
692 if (lookup_type == elfcpp::SHT_PROGBITS)
696 Output_section* same_name = this->find_output_section(name);
697 if (same_name != NULL
698 && (same_name->type() == elfcpp::SHT_PROGBITS
699 || same_name->type() == elfcpp::SHT_INIT_ARRAY
700 || same_name->type() == elfcpp::SHT_FINI_ARRAY
701 || same_name->type() == elfcpp::SHT_PREINIT_ARRAY)
702 && (same_name->flags() & elfcpp::SHF_TLS) == 0)
705 else if ((flags & elfcpp::SHF_TLS) == 0)
707 elfcpp::Elf_Xword zero_flags = 0;
708 const Key zero_key(name_key, std::make_pair(lookup_type,
710 Section_name_map::iterator p =
711 this->section_name_map_.find(zero_key);
712 if (p != this->section_name_map_.end())
718 os = this->make_output_section(name, type, flags, order, is_relro);
720 ins.first->second = os;
725 // Pick the output section to use for section NAME, in input file
726 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
727 // linker created section. IS_INPUT_SECTION is true if we are
728 // choosing an output section for an input section found in a input
729 // file. ORDER is where this section should appear in the output
730 // sections. IS_RELRO is true for a relro section. This will return
731 // NULL if the input section should be discarded.
734 Layout::choose_output_section(const Relobj* relobj, const char* name,
735 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
736 bool is_input_section, Output_section_order order,
739 // We should not see any input sections after we have attached
740 // sections to segments.
741 gold_assert(!is_input_section || !this->sections_are_attached_);
743 // Some flags in the input section should not be automatically
744 // copied to the output section.
745 flags &= ~ (elfcpp::SHF_INFO_LINK
748 | elfcpp::SHF_STRINGS);
750 // We only clear the SHF_LINK_ORDER flag in for
751 // a non-relocatable link.
752 if (!parameters->options().relocatable())
753 flags &= ~elfcpp::SHF_LINK_ORDER;
755 if (this->script_options_->saw_sections_clause())
757 // We are using a SECTIONS clause, so the output section is
758 // chosen based only on the name.
760 Script_sections* ss = this->script_options_->script_sections();
761 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
762 Output_section** output_section_slot;
763 Script_sections::Section_type script_section_type;
764 const char* orig_name = name;
765 name = ss->output_section_name(file_name, name, &output_section_slot,
766 &script_section_type);
769 gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
770 "because it is not allowed by the "
771 "SECTIONS clause of the linker script"),
773 // The SECTIONS clause says to discard this input section.
777 // We can only handle script section types ST_NONE and ST_NOLOAD.
778 switch (script_section_type)
780 case Script_sections::ST_NONE:
782 case Script_sections::ST_NOLOAD:
783 flags &= elfcpp::SHF_ALLOC;
789 // If this is an orphan section--one not mentioned in the linker
790 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
791 // default processing below.
793 if (output_section_slot != NULL)
795 if (*output_section_slot != NULL)
797 (*output_section_slot)->update_flags_for_input_section(flags);
798 return *output_section_slot;
801 // We don't put sections found in the linker script into
802 // SECTION_NAME_MAP_. That keeps us from getting confused
803 // if an orphan section is mapped to a section with the same
804 // name as one in the linker script.
806 name = this->namepool_.add(name, false, NULL);
808 Output_section* os = this->make_output_section(name, type, flags,
811 os->set_found_in_sections_clause();
813 // Special handling for NOLOAD sections.
814 if (script_section_type == Script_sections::ST_NOLOAD)
818 // The constructor of Output_section sets addresses of non-ALLOC
819 // sections to 0 by default. We don't want that for NOLOAD
820 // sections even if they have no SHF_ALLOC flag.
821 if ((os->flags() & elfcpp::SHF_ALLOC) == 0
822 && os->is_address_valid())
824 gold_assert(os->address() == 0
825 && !os->is_offset_valid()
826 && !os->is_data_size_valid());
827 os->reset_address_and_file_offset();
831 *output_section_slot = os;
836 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
838 size_t len = strlen(name);
839 char* uncompressed_name = NULL;
841 // Compressed debug sections should be mapped to the corresponding
842 // uncompressed section.
843 if (is_compressed_debug_section(name))
845 uncompressed_name = new char[len];
846 uncompressed_name[0] = '.';
847 gold_assert(name[0] == '.' && name[1] == 'z');
848 strncpy(&uncompressed_name[1], &name[2], len - 2);
849 uncompressed_name[len - 1] = '\0';
851 name = uncompressed_name;
854 // Turn NAME from the name of the input section into the name of the
857 && !this->script_options_->saw_sections_clause()
858 && !parameters->options().relocatable())
859 name = Layout::output_section_name(relobj, name, &len);
861 Stringpool::Key name_key;
862 name = this->namepool_.add_with_length(name, len, true, &name_key);
864 if (uncompressed_name != NULL)
865 delete[] uncompressed_name;
867 // Find or make the output section. The output section is selected
868 // based on the section name, type, and flags.
869 return this->get_output_section(name, name_key, type, flags, order, is_relro);
872 // For incremental links, record the initial fixed layout of a section
873 // from the base file, and return a pointer to the Output_section.
875 template<int size, bool big_endian>
877 Layout::init_fixed_output_section(const char* name,
878 elfcpp::Shdr<size, big_endian>& shdr)
880 unsigned int sh_type = shdr.get_sh_type();
882 // We preserve the layout of PROGBITS, NOBITS, and NOTE sections.
883 // All others will be created from scratch and reallocated.
884 if (sh_type != elfcpp::SHT_PROGBITS
885 && sh_type != elfcpp::SHT_NOBITS
886 && sh_type != elfcpp::SHT_NOTE)
889 typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
890 typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
891 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
892 typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
893 typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
894 shdr.get_sh_addralign();
896 // Make the output section.
897 Stringpool::Key name_key;
898 name = this->namepool_.add(name, true, &name_key);
899 Output_section* os = this->get_output_section(name, name_key, sh_type,
900 sh_flags, ORDER_INVALID, false);
901 os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
902 if (sh_type != elfcpp::SHT_NOBITS)
903 this->free_list_.remove(sh_offset, sh_offset + sh_size);
907 // Return the output section to use for input section SHNDX, with name
908 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
909 // index of a relocation section which applies to this section, or 0
910 // if none, or -1U if more than one. RELOC_TYPE is the type of the
911 // relocation section if there is one. Set *OFF to the offset of this
912 // input section without the output section. Return NULL if the
913 // section should be discarded. Set *OFF to -1 if the section
914 // contents should not be written directly to the output file, but
915 // will instead receive special handling.
917 template<int size, bool big_endian>
919 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
920 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
921 unsigned int reloc_shndx, unsigned int, off_t* off)
925 if (!this->include_section(object, name, shdr))
928 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
930 // In a relocatable link a grouped section must not be combined with
931 // any other sections.
933 if (parameters->options().relocatable()
934 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
936 name = this->namepool_.add(name, true, NULL);
937 os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
938 ORDER_INVALID, false);
942 os = this->choose_output_section(object, name, sh_type,
943 shdr.get_sh_flags(), true,
944 ORDER_INVALID, false);
949 // By default the GNU linker sorts input sections whose names match
950 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
951 // sections are sorted by name. This is used to implement
952 // constructor priority ordering. We are compatible. When we put
953 // .ctor sections in .init_array and .dtor sections in .fini_array,
954 // we must also sort plain .ctor and .dtor sections.
955 if (!this->script_options_->saw_sections_clause()
956 && !parameters->options().relocatable()
957 && (is_prefix_of(".ctors.", name)
958 || is_prefix_of(".dtors.", name)
959 || is_prefix_of(".init_array.", name)
960 || is_prefix_of(".fini_array.", name)
961 || (parameters->options().ctors_in_init_array()
962 && (strcmp(name, ".ctors") == 0
963 || strcmp(name, ".dtors") == 0))))
964 os->set_must_sort_attached_input_sections();
966 // If this is a .ctors or .ctors.* section being mapped to a
967 // .init_array section, or a .dtors or .dtors.* section being mapped
968 // to a .fini_array section, we will need to reverse the words if
969 // there is more than one. Record this section for later. See
970 // ctors_sections_in_init_array above.
971 if (!this->script_options_->saw_sections_clause()
972 && !parameters->options().relocatable()
973 && shdr.get_sh_size() > size / 8
974 && (((strcmp(name, ".ctors") == 0
975 || is_prefix_of(".ctors.", name))
976 && strcmp(os->name(), ".init_array") == 0)
977 || ((strcmp(name, ".dtors") == 0
978 || is_prefix_of(".dtors.", name))
979 && strcmp(os->name(), ".fini_array") == 0)))
980 ctors_sections_in_init_array.insert(Section_id(object, shndx));
982 // FIXME: Handle SHF_LINK_ORDER somewhere.
984 elfcpp::Elf_Xword orig_flags = os->flags();
986 *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
987 this->script_options_->saw_sections_clause());
989 // If the flags changed, we may have to change the order.
990 if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
992 orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
993 elfcpp::Elf_Xword new_flags =
994 os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
995 if (orig_flags != new_flags)
996 os->set_order(this->default_section_order(os, false));
999 this->have_added_input_section_ = true;
1004 // Handle a relocation section when doing a relocatable link.
1006 template<int size, bool big_endian>
1008 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
1010 const elfcpp::Shdr<size, big_endian>& shdr,
1011 Output_section* data_section,
1012 Relocatable_relocs* rr)
1014 gold_assert(parameters->options().relocatable()
1015 || parameters->options().emit_relocs());
1017 int sh_type = shdr.get_sh_type();
1020 if (sh_type == elfcpp::SHT_REL)
1022 else if (sh_type == elfcpp::SHT_RELA)
1026 name += data_section->name();
1028 // In a relocatable link relocs for a grouped section must not be
1029 // combined with other reloc sections.
1031 if (!parameters->options().relocatable()
1032 || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
1033 os = this->choose_output_section(object, name.c_str(), sh_type,
1034 shdr.get_sh_flags(), false,
1035 ORDER_INVALID, false);
1038 const char* n = this->namepool_.add(name.c_str(), true, NULL);
1039 os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1040 ORDER_INVALID, false);
1043 os->set_should_link_to_symtab();
1044 os->set_info_section(data_section);
1046 Output_section_data* posd;
1047 if (sh_type == elfcpp::SHT_REL)
1049 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1050 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1054 else if (sh_type == elfcpp::SHT_RELA)
1056 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1057 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1064 os->add_output_section_data(posd);
1065 rr->set_output_data(posd);
1070 // Handle a group section when doing a relocatable link.
1072 template<int size, bool big_endian>
1074 Layout::layout_group(Symbol_table* symtab,
1075 Sized_relobj_file<size, big_endian>* object,
1077 const char* group_section_name,
1078 const char* signature,
1079 const elfcpp::Shdr<size, big_endian>& shdr,
1080 elfcpp::Elf_Word flags,
1081 std::vector<unsigned int>* shndxes)
1083 gold_assert(parameters->options().relocatable());
1084 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1085 group_section_name = this->namepool_.add(group_section_name, true, NULL);
1086 Output_section* os = this->make_output_section(group_section_name,
1088 shdr.get_sh_flags(),
1089 ORDER_INVALID, false);
1091 // We need to find a symbol with the signature in the symbol table.
1092 // If we don't find one now, we need to look again later.
1093 Symbol* sym = symtab->lookup(signature, NULL);
1095 os->set_info_symndx(sym);
1098 // Reserve some space to minimize reallocations.
1099 if (this->group_signatures_.empty())
1100 this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1102 // We will wind up using a symbol whose name is the signature.
1103 // So just put the signature in the symbol name pool to save it.
1104 signature = symtab->canonicalize_name(signature);
1105 this->group_signatures_.push_back(Group_signature(os, signature));
1108 os->set_should_link_to_symtab();
1111 section_size_type entry_count =
1112 convert_to_section_size_type(shdr.get_sh_size() / 4);
1113 Output_section_data* posd =
1114 new Output_data_group<size, big_endian>(object, entry_count, flags,
1116 os->add_output_section_data(posd);
1119 // Special GNU handling of sections name .eh_frame. They will
1120 // normally hold exception frame data as defined by the C++ ABI
1121 // (http://codesourcery.com/cxx-abi/).
1123 template<int size, bool big_endian>
1125 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1126 const unsigned char* symbols,
1128 const unsigned char* symbol_names,
1129 off_t symbol_names_size,
1131 const elfcpp::Shdr<size, big_endian>& shdr,
1132 unsigned int reloc_shndx, unsigned int reloc_type,
1135 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
1136 || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
1137 gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1139 const char* const name = ".eh_frame";
1140 Output_section* os = this->choose_output_section(object, name,
1141 elfcpp::SHT_PROGBITS,
1142 elfcpp::SHF_ALLOC, false,
1143 ORDER_EHFRAME, false);
1147 if (this->eh_frame_section_ == NULL)
1149 this->eh_frame_section_ = os;
1150 this->eh_frame_data_ = new Eh_frame();
1152 // For incremental linking, we do not optimize .eh_frame sections
1153 // or create a .eh_frame_hdr section.
1154 if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1156 Output_section* hdr_os =
1157 this->choose_output_section(NULL, ".eh_frame_hdr",
1158 elfcpp::SHT_PROGBITS,
1159 elfcpp::SHF_ALLOC, false,
1160 ORDER_EHFRAME, false);
1164 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1165 this->eh_frame_data_);
1166 hdr_os->add_output_section_data(hdr_posd);
1168 hdr_os->set_after_input_sections();
1170 if (!this->script_options_->saw_phdrs_clause())
1172 Output_segment* hdr_oseg;
1173 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1175 hdr_oseg->add_output_section_to_nonload(hdr_os,
1179 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1184 gold_assert(this->eh_frame_section_ == os);
1186 elfcpp::Elf_Xword orig_flags = os->flags();
1188 if (!parameters->incremental()
1189 && this->eh_frame_data_->add_ehframe_input_section(object,
1198 os->update_flags_for_input_section(shdr.get_sh_flags());
1200 // A writable .eh_frame section is a RELRO section.
1201 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1202 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1205 os->set_order(ORDER_RELRO);
1208 // We found a .eh_frame section we are going to optimize, so now
1209 // we can add the set of optimized sections to the output
1210 // section. We need to postpone adding this until we've found a
1211 // section we can optimize so that the .eh_frame section in
1212 // crtbegin.o winds up at the start of the output section.
1213 if (!this->added_eh_frame_data_)
1215 os->add_output_section_data(this->eh_frame_data_);
1216 this->added_eh_frame_data_ = true;
1222 // We couldn't handle this .eh_frame section for some reason.
1223 // Add it as a normal section.
1224 bool saw_sections_clause = this->script_options_->saw_sections_clause();
1225 *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1226 saw_sections_clause);
1227 this->have_added_input_section_ = true;
1229 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1230 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1231 os->set_order(this->default_section_order(os, false));
1237 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1238 // the output section.
1241 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1242 elfcpp::Elf_Xword flags,
1243 Output_section_data* posd,
1244 Output_section_order order, bool is_relro)
1246 Output_section* os = this->choose_output_section(NULL, name, type, flags,
1247 false, order, is_relro);
1249 os->add_output_section_data(posd);
1253 // Map section flags to segment flags.
1256 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1258 elfcpp::Elf_Word ret = elfcpp::PF_R;
1259 if ((flags & elfcpp::SHF_WRITE) != 0)
1260 ret |= elfcpp::PF_W;
1261 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1262 ret |= elfcpp::PF_X;
1266 // Make a new Output_section, and attach it to segments as
1267 // appropriate. ORDER is the order in which this section should
1268 // appear in the output segment. IS_RELRO is true if this is a relro
1269 // (read-only after relocations) section.
1272 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1273 elfcpp::Elf_Xword flags,
1274 Output_section_order order, bool is_relro)
1277 if ((flags & elfcpp::SHF_ALLOC) == 0
1278 && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1279 && is_compressible_debug_section(name))
1280 os = new Output_compressed_section(¶meters->options(), name, type,
1282 else if ((flags & elfcpp::SHF_ALLOC) == 0
1283 && parameters->options().strip_debug_non_line()
1284 && strcmp(".debug_abbrev", name) == 0)
1286 os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1288 if (this->debug_info_)
1289 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1291 else if ((flags & elfcpp::SHF_ALLOC) == 0
1292 && parameters->options().strip_debug_non_line()
1293 && strcmp(".debug_info", name) == 0)
1295 os = this->debug_info_ = new Output_reduced_debug_info_section(
1297 if (this->debug_abbrev_)
1298 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1302 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1303 // not have correct section types. Force them here.
1304 if (type == elfcpp::SHT_PROGBITS)
1306 if (is_prefix_of(".init_array", name))
1307 type = elfcpp::SHT_INIT_ARRAY;
1308 else if (is_prefix_of(".preinit_array", name))
1309 type = elfcpp::SHT_PREINIT_ARRAY;
1310 else if (is_prefix_of(".fini_array", name))
1311 type = elfcpp::SHT_FINI_ARRAY;
1314 // FIXME: const_cast is ugly.
1315 Target* target = const_cast<Target*>(¶meters->target());
1316 os = target->make_output_section(name, type, flags);
1319 // With -z relro, we have to recognize the special sections by name.
1320 // There is no other way.
1321 bool is_relro_local = false;
1322 if (!this->script_options_->saw_sections_clause()
1323 && parameters->options().relro()
1324 && type == elfcpp::SHT_PROGBITS
1325 && (flags & elfcpp::SHF_ALLOC) != 0
1326 && (flags & elfcpp::SHF_WRITE) != 0)
1328 if (strcmp(name, ".data.rel.ro") == 0)
1330 else if (strcmp(name, ".data.rel.ro.local") == 0)
1333 is_relro_local = true;
1335 else if (type == elfcpp::SHT_INIT_ARRAY
1336 || type == elfcpp::SHT_FINI_ARRAY
1337 || type == elfcpp::SHT_PREINIT_ARRAY)
1339 else if (strcmp(name, ".ctors") == 0
1340 || strcmp(name, ".dtors") == 0
1341 || strcmp(name, ".jcr") == 0)
1348 if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1349 order = this->default_section_order(os, is_relro_local);
1351 os->set_order(order);
1353 parameters->target().new_output_section(os);
1355 this->section_list_.push_back(os);
1357 // The GNU linker by default sorts some sections by priority, so we
1358 // do the same. We need to know that this might happen before we
1359 // attach any input sections.
1360 if (!this->script_options_->saw_sections_clause()
1361 && !parameters->options().relocatable()
1362 && (strcmp(name, ".init_array") == 0
1363 || strcmp(name, ".fini_array") == 0
1364 || (!parameters->options().ctors_in_init_array()
1365 && (strcmp(name, ".ctors") == 0
1366 || strcmp(name, ".dtors") == 0))))
1367 os->set_may_sort_attached_input_sections();
1369 // Check for .stab*str sections, as .stab* sections need to link to
1371 if (type == elfcpp::SHT_STRTAB
1372 && !this->have_stabstr_section_
1373 && strncmp(name, ".stab", 5) == 0
1374 && strcmp(name + strlen(name) - 3, "str") == 0)
1375 this->have_stabstr_section_ = true;
1377 // If we have already attached the sections to segments, then we
1378 // need to attach this one now. This happens for sections created
1379 // directly by the linker.
1380 if (this->sections_are_attached_)
1381 this->attach_section_to_segment(os);
1386 // Return the default order in which a section should be placed in an
1387 // output segment. This function captures a lot of the ideas in
1388 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1389 // linker created section is normally set when the section is created;
1390 // this function is used for input sections.
1392 Output_section_order
1393 Layout::default_section_order(Output_section* os, bool is_relro_local)
1395 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1396 bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1397 bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1398 bool is_bss = false;
1403 case elfcpp::SHT_PROGBITS:
1405 case elfcpp::SHT_NOBITS:
1408 case elfcpp::SHT_RELA:
1409 case elfcpp::SHT_REL:
1411 return ORDER_DYNAMIC_RELOCS;
1413 case elfcpp::SHT_HASH:
1414 case elfcpp::SHT_DYNAMIC:
1415 case elfcpp::SHT_SHLIB:
1416 case elfcpp::SHT_DYNSYM:
1417 case elfcpp::SHT_GNU_HASH:
1418 case elfcpp::SHT_GNU_verdef:
1419 case elfcpp::SHT_GNU_verneed:
1420 case elfcpp::SHT_GNU_versym:
1422 return ORDER_DYNAMIC_LINKER;
1424 case elfcpp::SHT_NOTE:
1425 return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1428 if ((os->flags() & elfcpp::SHF_TLS) != 0)
1429 return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1431 if (!is_bss && !is_write)
1435 if (strcmp(os->name(), ".init") == 0)
1437 else if (strcmp(os->name(), ".fini") == 0)
1440 return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1444 return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1446 if (os->is_small_section())
1447 return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1448 if (os->is_large_section())
1449 return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1451 return is_bss ? ORDER_BSS : ORDER_DATA;
1454 // Attach output sections to segments. This is called after we have
1455 // seen all the input sections.
1458 Layout::attach_sections_to_segments()
1460 for (Section_list::iterator p = this->section_list_.begin();
1461 p != this->section_list_.end();
1463 this->attach_section_to_segment(*p);
1465 this->sections_are_attached_ = true;
1468 // Attach an output section to a segment.
1471 Layout::attach_section_to_segment(Output_section* os)
1473 if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1474 this->unattached_section_list_.push_back(os);
1476 this->attach_allocated_section_to_segment(os);
1479 // Attach an allocated output section to a segment.
1482 Layout::attach_allocated_section_to_segment(Output_section* os)
1484 elfcpp::Elf_Xword flags = os->flags();
1485 gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1487 if (parameters->options().relocatable())
1490 // If we have a SECTIONS clause, we can't handle the attachment to
1491 // segments until after we've seen all the sections.
1492 if (this->script_options_->saw_sections_clause())
1495 gold_assert(!this->script_options_->saw_phdrs_clause());
1497 // This output section goes into a PT_LOAD segment.
1499 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1501 // Check for --section-start.
1503 bool is_address_set = parameters->options().section_start(os->name(), &addr);
1505 // In general the only thing we really care about for PT_LOAD
1506 // segments is whether or not they are writable or executable,
1507 // so that is how we search for them.
1508 // Large data sections also go into their own PT_LOAD segment.
1509 // People who need segments sorted on some other basis will
1510 // have to use a linker script.
1512 Segment_list::const_iterator p;
1513 for (p = this->segment_list_.begin();
1514 p != this->segment_list_.end();
1517 if ((*p)->type() != elfcpp::PT_LOAD)
1519 if (!parameters->options().omagic()
1520 && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1522 if (parameters->options().rosegment()
1523 && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1525 // If -Tbss was specified, we need to separate the data and BSS
1527 if (parameters->options().user_set_Tbss())
1529 if ((os->type() == elfcpp::SHT_NOBITS)
1530 == (*p)->has_any_data_sections())
1533 if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1538 if ((*p)->are_addresses_set())
1541 (*p)->add_initial_output_data(os);
1542 (*p)->update_flags_for_output_section(seg_flags);
1543 (*p)->set_addresses(addr, addr);
1547 (*p)->add_output_section_to_load(this, os, seg_flags);
1551 if (p == this->segment_list_.end())
1553 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1555 if (os->is_large_data_section())
1556 oseg->set_is_large_data_segment();
1557 oseg->add_output_section_to_load(this, os, seg_flags);
1559 oseg->set_addresses(addr, addr);
1562 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1564 if (os->type() == elfcpp::SHT_NOTE)
1566 // See if we already have an equivalent PT_NOTE segment.
1567 for (p = this->segment_list_.begin();
1568 p != segment_list_.end();
1571 if ((*p)->type() == elfcpp::PT_NOTE
1572 && (((*p)->flags() & elfcpp::PF_W)
1573 == (seg_flags & elfcpp::PF_W)))
1575 (*p)->add_output_section_to_nonload(os, seg_flags);
1580 if (p == this->segment_list_.end())
1582 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
1584 oseg->add_output_section_to_nonload(os, seg_flags);
1588 // If we see a loadable SHF_TLS section, we create a PT_TLS
1589 // segment. There can only be one such segment.
1590 if ((flags & elfcpp::SHF_TLS) != 0)
1592 if (this->tls_segment_ == NULL)
1593 this->make_output_segment(elfcpp::PT_TLS, seg_flags);
1594 this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
1597 // If -z relro is in effect, and we see a relro section, we create a
1598 // PT_GNU_RELRO segment. There can only be one such segment.
1599 if (os->is_relro() && parameters->options().relro())
1601 gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
1602 if (this->relro_segment_ == NULL)
1603 this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
1604 this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
1607 // If we see a section named .interp, put it into a PT_INTERP
1608 // segment. This seems broken to me, but this is what GNU ld does,
1609 // and glibc expects it.
1610 if (strcmp(os->name(), ".interp") == 0
1611 && !this->script_options_->saw_phdrs_clause())
1613 if (this->interp_segment_ == NULL)
1614 this->make_output_segment(elfcpp::PT_INTERP, seg_flags);
1616 gold_warning(_("multiple '.interp' sections in input files "
1617 "may cause confusing PT_INTERP segment"));
1618 this->interp_segment_->add_output_section_to_nonload(os, seg_flags);
1622 // Make an output section for a script.
1625 Layout::make_output_section_for_script(
1627 Script_sections::Section_type section_type)
1629 name = this->namepool_.add(name, false, NULL);
1630 elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
1631 if (section_type == Script_sections::ST_NOLOAD)
1633 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
1634 sh_flags, ORDER_INVALID,
1636 os->set_found_in_sections_clause();
1637 if (section_type == Script_sections::ST_NOLOAD)
1638 os->set_is_noload();
1642 // Return the number of segments we expect to see.
1645 Layout::expected_segment_count() const
1647 size_t ret = this->segment_list_.size();
1649 // If we didn't see a SECTIONS clause in a linker script, we should
1650 // already have the complete list of segments. Otherwise we ask the
1651 // SECTIONS clause how many segments it expects, and add in the ones
1652 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1654 if (!this->script_options_->saw_sections_clause())
1658 const Script_sections* ss = this->script_options_->script_sections();
1659 return ret + ss->expected_segment_count(this);
1663 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
1664 // is whether we saw a .note.GNU-stack section in the object file.
1665 // GNU_STACK_FLAGS is the section flags. The flags give the
1666 // protection required for stack memory. We record this in an
1667 // executable as a PT_GNU_STACK segment. If an object file does not
1668 // have a .note.GNU-stack segment, we must assume that it is an old
1669 // object. On some targets that will force an executable stack.
1672 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
1675 if (!seen_gnu_stack)
1677 this->input_without_gnu_stack_note_ = true;
1678 if (parameters->options().warn_execstack()
1679 && parameters->target().is_default_stack_executable())
1680 gold_warning(_("%s: missing .note.GNU-stack section"
1681 " implies executable stack"),
1682 obj->name().c_str());
1686 this->input_with_gnu_stack_note_ = true;
1687 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
1689 this->input_requires_executable_stack_ = true;
1690 if (parameters->options().warn_execstack()
1691 || parameters->options().is_stack_executable())
1692 gold_warning(_("%s: requires executable stack"),
1693 obj->name().c_str());
1698 // Create automatic note sections.
1701 Layout::create_notes()
1703 this->create_gold_note();
1704 this->create_executable_stack_info();
1705 this->create_build_id();
1708 // Create the dynamic sections which are needed before we read the
1712 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
1714 if (parameters->doing_static_link())
1717 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
1718 elfcpp::SHT_DYNAMIC,
1720 | elfcpp::SHF_WRITE),
1724 this->dynamic_symbol_ =
1725 symtab->define_in_output_data("_DYNAMIC", NULL, Symbol_table::PREDEFINED,
1726 this->dynamic_section_, 0, 0,
1727 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
1728 elfcpp::STV_HIDDEN, 0, false, false);
1730 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
1732 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
1735 // For each output section whose name can be represented as C symbol,
1736 // define __start and __stop symbols for the section. This is a GNU
1740 Layout::define_section_symbols(Symbol_table* symtab)
1742 for (Section_list::const_iterator p = this->section_list_.begin();
1743 p != this->section_list_.end();
1746 const char* const name = (*p)->name();
1747 if (is_cident(name))
1749 const std::string name_string(name);
1750 const std::string start_name(cident_section_start_prefix
1752 const std::string stop_name(cident_section_stop_prefix
1755 symtab->define_in_output_data(start_name.c_str(),
1757 Symbol_table::PREDEFINED,
1763 elfcpp::STV_DEFAULT,
1765 false, // offset_is_from_end
1766 true); // only_if_ref
1768 symtab->define_in_output_data(stop_name.c_str(),
1770 Symbol_table::PREDEFINED,
1776 elfcpp::STV_DEFAULT,
1778 true, // offset_is_from_end
1779 true); // only_if_ref
1784 // Define symbols for group signatures.
1787 Layout::define_group_signatures(Symbol_table* symtab)
1789 for (Group_signatures::iterator p = this->group_signatures_.begin();
1790 p != this->group_signatures_.end();
1793 Symbol* sym = symtab->lookup(p->signature, NULL);
1795 p->section->set_info_symndx(sym);
1798 // Force the name of the group section to the group
1799 // signature, and use the group's section symbol as the
1800 // signature symbol.
1801 if (strcmp(p->section->name(), p->signature) != 0)
1803 const char* name = this->namepool_.add(p->signature,
1805 p->section->set_name(name);
1807 p->section->set_needs_symtab_index();
1808 p->section->set_info_section_symndx(p->section);
1812 this->group_signatures_.clear();
1815 // Find the first read-only PT_LOAD segment, creating one if
1819 Layout::find_first_load_seg()
1821 Output_segment* best = NULL;
1822 for (Segment_list::const_iterator p = this->segment_list_.begin();
1823 p != this->segment_list_.end();
1826 if ((*p)->type() == elfcpp::PT_LOAD
1827 && ((*p)->flags() & elfcpp::PF_R) != 0
1828 && (parameters->options().omagic()
1829 || ((*p)->flags() & elfcpp::PF_W) == 0))
1831 if (best == NULL || this->segment_precedes(*p, best))
1838 gold_assert(!this->script_options_->saw_phdrs_clause());
1840 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
1845 // Save states of all current output segments. Store saved states
1846 // in SEGMENT_STATES.
1849 Layout::save_segments(Segment_states* segment_states)
1851 for (Segment_list::const_iterator p = this->segment_list_.begin();
1852 p != this->segment_list_.end();
1855 Output_segment* segment = *p;
1857 Output_segment* copy = new Output_segment(*segment);
1858 (*segment_states)[segment] = copy;
1862 // Restore states of output segments and delete any segment not found in
1866 Layout::restore_segments(const Segment_states* segment_states)
1868 // Go through the segment list and remove any segment added in the
1870 this->tls_segment_ = NULL;
1871 this->relro_segment_ = NULL;
1872 Segment_list::iterator list_iter = this->segment_list_.begin();
1873 while (list_iter != this->segment_list_.end())
1875 Output_segment* segment = *list_iter;
1876 Segment_states::const_iterator states_iter =
1877 segment_states->find(segment);
1878 if (states_iter != segment_states->end())
1880 const Output_segment* copy = states_iter->second;
1881 // Shallow copy to restore states.
1884 // Also fix up TLS and RELRO segment pointers as appropriate.
1885 if (segment->type() == elfcpp::PT_TLS)
1886 this->tls_segment_ = segment;
1887 else if (segment->type() == elfcpp::PT_GNU_RELRO)
1888 this->relro_segment_ = segment;
1894 list_iter = this->segment_list_.erase(list_iter);
1895 // This is a segment created during section layout. It should be
1896 // safe to remove it since we should have removed all pointers to it.
1902 // Clean up after relaxation so that sections can be laid out again.
1905 Layout::clean_up_after_relaxation()
1907 // Restore the segments to point state just prior to the relaxation loop.
1908 Script_sections* script_section = this->script_options_->script_sections();
1909 script_section->release_segments();
1910 this->restore_segments(this->segment_states_);
1912 // Reset section addresses and file offsets
1913 for (Section_list::iterator p = this->section_list_.begin();
1914 p != this->section_list_.end();
1917 (*p)->restore_states();
1919 // If an input section changes size because of relaxation,
1920 // we need to adjust the section offsets of all input sections.
1921 // after such a section.
1922 if ((*p)->section_offsets_need_adjustment())
1923 (*p)->adjust_section_offsets();
1925 (*p)->reset_address_and_file_offset();
1928 // Reset special output object address and file offsets.
1929 for (Data_list::iterator p = this->special_output_list_.begin();
1930 p != this->special_output_list_.end();
1932 (*p)->reset_address_and_file_offset();
1934 // A linker script may have created some output section data objects.
1935 // They are useless now.
1936 for (Output_section_data_list::const_iterator p =
1937 this->script_output_section_data_list_.begin();
1938 p != this->script_output_section_data_list_.end();
1941 this->script_output_section_data_list_.clear();
1944 // Prepare for relaxation.
1947 Layout::prepare_for_relaxation()
1949 // Create an relaxation debug check if in debugging mode.
1950 if (is_debugging_enabled(DEBUG_RELAXATION))
1951 this->relaxation_debug_check_ = new Relaxation_debug_check();
1953 // Save segment states.
1954 this->segment_states_ = new Segment_states();
1955 this->save_segments(this->segment_states_);
1957 for(Section_list::const_iterator p = this->section_list_.begin();
1958 p != this->section_list_.end();
1960 (*p)->save_states();
1962 if (is_debugging_enabled(DEBUG_RELAXATION))
1963 this->relaxation_debug_check_->check_output_data_for_reset_values(
1964 this->section_list_, this->special_output_list_);
1966 // Also enable recording of output section data from scripts.
1967 this->record_output_section_data_from_script_ = true;
1970 // Relaxation loop body: If target has no relaxation, this runs only once
1971 // Otherwise, the target relaxation hook is called at the end of
1972 // each iteration. If the hook returns true, it means re-layout of
1973 // section is required.
1975 // The number of segments created by a linking script without a PHDRS
1976 // clause may be affected by section sizes and alignments. There is
1977 // a remote chance that relaxation causes different number of PT_LOAD
1978 // segments are created and sections are attached to different segments.
1979 // Therefore, we always throw away all segments created during section
1980 // layout. In order to be able to restart the section layout, we keep
1981 // a copy of the segment list right before the relaxation loop and use
1982 // that to restore the segments.
1984 // PASS is the current relaxation pass number.
1985 // SYMTAB is a symbol table.
1986 // PLOAD_SEG is the address of a pointer for the load segment.
1987 // PHDR_SEG is a pointer to the PHDR segment.
1988 // SEGMENT_HEADERS points to the output segment header.
1989 // FILE_HEADER points to the output file header.
1990 // PSHNDX is the address to store the output section index.
1993 Layout::relaxation_loop_body(
1996 Symbol_table* symtab,
1997 Output_segment** pload_seg,
1998 Output_segment* phdr_seg,
1999 Output_segment_headers* segment_headers,
2000 Output_file_header* file_header,
2001 unsigned int* pshndx)
2003 // If this is not the first iteration, we need to clean up after
2004 // relaxation so that we can lay out the sections again.
2006 this->clean_up_after_relaxation();
2008 // If there is a SECTIONS clause, put all the input sections into
2009 // the required order.
2010 Output_segment* load_seg;
2011 if (this->script_options_->saw_sections_clause())
2012 load_seg = this->set_section_addresses_from_script(symtab);
2013 else if (parameters->options().relocatable())
2016 load_seg = this->find_first_load_seg();
2018 if (parameters->options().oformat_enum()
2019 != General_options::OBJECT_FORMAT_ELF)
2022 // If the user set the address of the text segment, that may not be
2023 // compatible with putting the segment headers and file headers into
2025 if (parameters->options().user_set_Ttext())
2028 gold_assert(phdr_seg == NULL
2030 || this->script_options_->saw_sections_clause());
2032 // If the address of the load segment we found has been set by
2033 // --section-start rather than by a script, then adjust the VMA and
2034 // LMA downward if possible to include the file and section headers.
2035 uint64_t header_gap = 0;
2036 if (load_seg != NULL
2037 && load_seg->are_addresses_set()
2038 && !this->script_options_->saw_sections_clause()
2039 && !parameters->options().relocatable())
2041 file_header->finalize_data_size();
2042 segment_headers->finalize_data_size();
2043 size_t sizeof_headers = (file_header->data_size()
2044 + segment_headers->data_size());
2045 const uint64_t abi_pagesize = target->abi_pagesize();
2046 uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
2047 hdr_paddr &= ~(abi_pagesize - 1);
2048 uint64_t subtract = load_seg->paddr() - hdr_paddr;
2049 if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
2053 load_seg->set_addresses(load_seg->vaddr() - subtract,
2054 load_seg->paddr() - subtract);
2055 header_gap = subtract - sizeof_headers;
2059 // Lay out the segment headers.
2060 if (!parameters->options().relocatable())
2062 gold_assert(segment_headers != NULL);
2063 if (header_gap != 0 && load_seg != NULL)
2065 Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
2066 load_seg->add_initial_output_data(z);
2068 if (load_seg != NULL)
2069 load_seg->add_initial_output_data(segment_headers);
2070 if (phdr_seg != NULL)
2071 phdr_seg->add_initial_output_data(segment_headers);
2074 // Lay out the file header.
2075 if (load_seg != NULL)
2076 load_seg->add_initial_output_data(file_header);
2078 if (this->script_options_->saw_phdrs_clause()
2079 && !parameters->options().relocatable())
2081 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2082 // clause in a linker script.
2083 Script_sections* ss = this->script_options_->script_sections();
2084 ss->put_headers_in_phdrs(file_header, segment_headers);
2087 // We set the output section indexes in set_segment_offsets and
2088 // set_section_indexes.
2091 // Set the file offsets of all the segments, and all the sections
2094 if (!parameters->options().relocatable())
2095 off = this->set_segment_offsets(target, load_seg, pshndx);
2097 off = this->set_relocatable_section_offsets(file_header, pshndx);
2099 // Verify that the dummy relaxation does not change anything.
2100 if (is_debugging_enabled(DEBUG_RELAXATION))
2103 this->relaxation_debug_check_->read_sections(this->section_list_);
2105 this->relaxation_debug_check_->verify_sections(this->section_list_);
2108 *pload_seg = load_seg;
2112 // Search the list of patterns and find the postion of the given section
2113 // name in the output section. If the section name matches a glob
2114 // pattern and a non-glob name, then the non-glob position takes
2115 // precedence. Return 0 if no match is found.
2118 Layout::find_section_order_index(const std::string& section_name)
2120 Unordered_map<std::string, unsigned int>::iterator map_it;
2121 map_it = this->input_section_position_.find(section_name);
2122 if (map_it != this->input_section_position_.end())
2123 return map_it->second;
2125 // Absolute match failed. Linear search the glob patterns.
2126 std::vector<std::string>::iterator it;
2127 for (it = this->input_section_glob_.begin();
2128 it != this->input_section_glob_.end();
2131 if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2133 map_it = this->input_section_position_.find(*it);
2134 gold_assert(map_it != this->input_section_position_.end());
2135 return map_it->second;
2141 // Read the sequence of input sections from the file specified with
2142 // --section-ordering-file.
2145 Layout::read_layout_from_file()
2147 const char* filename = parameters->options().section_ordering_file();
2153 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2154 filename, strerror(errno));
2156 std::getline(in, line); // this chops off the trailing \n, if any
2157 unsigned int position = 1;
2161 if (!line.empty() && line[line.length() - 1] == '\r') // Windows
2162 line.resize(line.length() - 1);
2163 // Ignore comments, beginning with '#'
2166 std::getline(in, line);
2169 this->input_section_position_[line] = position;
2170 // Store all glob patterns in a vector.
2171 if (is_wildcard_string(line.c_str()))
2172 this->input_section_glob_.push_back(line);
2174 std::getline(in, line);
2178 // Finalize the layout. When this is called, we have created all the
2179 // output sections and all the output segments which are based on
2180 // input sections. We have several things to do, and we have to do
2181 // them in the right order, so that we get the right results correctly
2184 // 1) Finalize the list of output segments and create the segment
2187 // 2) Finalize the dynamic symbol table and associated sections.
2189 // 3) Determine the final file offset of all the output segments.
2191 // 4) Determine the final file offset of all the SHF_ALLOC output
2194 // 5) Create the symbol table sections and the section name table
2197 // 6) Finalize the symbol table: set symbol values to their final
2198 // value and make a final determination of which symbols are going
2199 // into the output symbol table.
2201 // 7) Create the section table header.
2203 // 8) Determine the final file offset of all the output sections which
2204 // are not SHF_ALLOC, including the section table header.
2206 // 9) Finalize the ELF file header.
2208 // This function returns the size of the output file.
2211 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2212 Target* target, const Task* task)
2214 target->finalize_sections(this, input_objects, symtab);
2216 this->count_local_symbols(task, input_objects);
2218 this->link_stabs_sections();
2220 Output_segment* phdr_seg = NULL;
2221 if (!parameters->options().relocatable() && !parameters->doing_static_link())
2223 // There was a dynamic object in the link. We need to create
2224 // some information for the dynamic linker.
2226 // Create the PT_PHDR segment which will hold the program
2228 if (!this->script_options_->saw_phdrs_clause())
2229 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2231 // Create the dynamic symbol table, including the hash table.
2232 Output_section* dynstr;
2233 std::vector<Symbol*> dynamic_symbols;
2234 unsigned int local_dynamic_count;
2235 Versions versions(*this->script_options()->version_script_info(),
2237 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2238 &local_dynamic_count, &dynamic_symbols,
2241 // Create the .interp section to hold the name of the
2242 // interpreter, and put it in a PT_INTERP segment. Don't do it
2243 // if we saw a .interp section in an input file.
2244 if ((!parameters->options().shared()
2245 || parameters->options().dynamic_linker() != NULL)
2246 && this->interp_segment_ == NULL)
2247 this->create_interp(target);
2249 // Finish the .dynamic section to hold the dynamic data, and put
2250 // it in a PT_DYNAMIC segment.
2251 this->finish_dynamic_section(input_objects, symtab);
2253 // We should have added everything we need to the dynamic string
2255 this->dynpool_.set_string_offsets();
2257 // Create the version sections. We can't do this until the
2258 // dynamic string table is complete.
2259 this->create_version_sections(&versions, symtab, local_dynamic_count,
2260 dynamic_symbols, dynstr);
2262 // Set the size of the _DYNAMIC symbol. We can't do this until
2263 // after we call create_version_sections.
2264 this->set_dynamic_symbol_size(symtab);
2267 // Create segment headers.
2268 Output_segment_headers* segment_headers =
2269 (parameters->options().relocatable()
2271 : new Output_segment_headers(this->segment_list_));
2273 // Lay out the file header.
2274 Output_file_header* file_header = new Output_file_header(target, symtab,
2277 this->special_output_list_.push_back(file_header);
2278 if (segment_headers != NULL)
2279 this->special_output_list_.push_back(segment_headers);
2281 // Find approriate places for orphan output sections if we are using
2283 if (this->script_options_->saw_sections_clause())
2284 this->place_orphan_sections_in_script();
2286 Output_segment* load_seg;
2291 // Take a snapshot of the section layout as needed.
2292 if (target->may_relax())
2293 this->prepare_for_relaxation();
2295 // Run the relaxation loop to lay out sections.
2298 off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2299 phdr_seg, segment_headers, file_header,
2303 while (target->may_relax()
2304 && target->relax(pass, input_objects, symtab, this, task));
2306 // Set the file offsets of all the non-data sections we've seen so
2307 // far which don't have to wait for the input sections. We need
2308 // this in order to finalize local symbols in non-allocated
2310 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2312 // Set the section indexes of all unallocated sections seen so far,
2313 // in case any of them are somehow referenced by a symbol.
2314 shndx = this->set_section_indexes(shndx);
2316 // Create the symbol table sections.
2317 this->create_symtab_sections(input_objects, symtab, shndx, &off);
2318 if (!parameters->doing_static_link())
2319 this->assign_local_dynsym_offsets(input_objects);
2321 // Process any symbol assignments from a linker script. This must
2322 // be called after the symbol table has been finalized.
2323 this->script_options_->finalize_symbols(symtab, this);
2325 // Create the incremental inputs sections.
2326 if (this->incremental_inputs_)
2328 this->incremental_inputs_->finalize();
2329 this->create_incremental_info_sections(symtab);
2332 // Create the .shstrtab section.
2333 Output_section* shstrtab_section = this->create_shstrtab();
2335 // Set the file offsets of the rest of the non-data sections which
2336 // don't have to wait for the input sections.
2337 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2339 // Now that all sections have been created, set the section indexes
2340 // for any sections which haven't been done yet.
2341 shndx = this->set_section_indexes(shndx);
2343 // Create the section table header.
2344 this->create_shdrs(shstrtab_section, &off);
2346 // If there are no sections which require postprocessing, we can
2347 // handle the section names now, and avoid a resize later.
2348 if (!this->any_postprocessing_sections_)
2350 off = this->set_section_offsets(off,
2351 POSTPROCESSING_SECTIONS_PASS);
2353 this->set_section_offsets(off,
2354 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2357 file_header->set_section_info(this->section_headers_, shstrtab_section);
2359 // Now we know exactly where everything goes in the output file
2360 // (except for non-allocated sections which require postprocessing).
2361 Output_data::layout_complete();
2363 this->output_file_size_ = off;
2368 // Create a note header following the format defined in the ELF ABI.
2369 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2370 // of the section to create, DESCSZ is the size of the descriptor.
2371 // ALLOCATE is true if the section should be allocated in memory.
2372 // This returns the new note section. It sets *TRAILING_PADDING to
2373 // the number of trailing zero bytes required.
2376 Layout::create_note(const char* name, int note_type,
2377 const char* section_name, size_t descsz,
2378 bool allocate, size_t* trailing_padding)
2380 // Authorities all agree that the values in a .note field should
2381 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2382 // they differ on what the alignment is for 64-bit binaries.
2383 // The GABI says unambiguously they take 8-byte alignment:
2384 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2385 // Other documentation says alignment should always be 4 bytes:
2386 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2387 // GNU ld and GNU readelf both support the latter (at least as of
2388 // version 2.16.91), and glibc always generates the latter for
2389 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2391 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2392 const int size = parameters->target().get_size();
2394 const int size = 32;
2397 // The contents of the .note section.
2398 size_t namesz = strlen(name) + 1;
2399 size_t aligned_namesz = align_address(namesz, size / 8);
2400 size_t aligned_descsz = align_address(descsz, size / 8);
2402 size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2404 unsigned char* buffer = new unsigned char[notehdrsz];
2405 memset(buffer, 0, notehdrsz);
2407 bool is_big_endian = parameters->target().is_big_endian();
2413 elfcpp::Swap<32, false>::writeval(buffer, namesz);
2414 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2415 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2419 elfcpp::Swap<32, true>::writeval(buffer, namesz);
2420 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2421 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2424 else if (size == 64)
2428 elfcpp::Swap<64, false>::writeval(buffer, namesz);
2429 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2430 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2434 elfcpp::Swap<64, true>::writeval(buffer, namesz);
2435 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2436 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2442 memcpy(buffer + 3 * (size / 8), name, namesz);
2444 elfcpp::Elf_Xword flags = 0;
2445 Output_section_order order = ORDER_INVALID;
2448 flags = elfcpp::SHF_ALLOC;
2449 order = ORDER_RO_NOTE;
2451 Output_section* os = this->choose_output_section(NULL, section_name,
2453 flags, false, order, false);
2457 Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2460 os->add_output_section_data(posd);
2462 *trailing_padding = aligned_descsz - descsz;
2467 // For an executable or shared library, create a note to record the
2468 // version of gold used to create the binary.
2471 Layout::create_gold_note()
2473 if (parameters->options().relocatable()
2474 || parameters->incremental_update())
2477 std::string desc = std::string("gold ") + gold::get_version_string();
2479 size_t trailing_padding;
2480 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2481 ".note.gnu.gold-version", desc.size(),
2482 false, &trailing_padding);
2486 Output_section_data* posd = new Output_data_const(desc, 4);
2487 os->add_output_section_data(posd);
2489 if (trailing_padding > 0)
2491 posd = new Output_data_zero_fill(trailing_padding, 0);
2492 os->add_output_section_data(posd);
2496 // Record whether the stack should be executable. This can be set
2497 // from the command line using the -z execstack or -z noexecstack
2498 // options. Otherwise, if any input file has a .note.GNU-stack
2499 // section with the SHF_EXECINSTR flag set, the stack should be
2500 // executable. Otherwise, if at least one input file a
2501 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2502 // section, we use the target default for whether the stack should be
2503 // executable. Otherwise, we don't generate a stack note. When
2504 // generating a object file, we create a .note.GNU-stack section with
2505 // the appropriate marking. When generating an executable or shared
2506 // library, we create a PT_GNU_STACK segment.
2509 Layout::create_executable_stack_info()
2511 bool is_stack_executable;
2512 if (parameters->options().is_execstack_set())
2513 is_stack_executable = parameters->options().is_stack_executable();
2514 else if (!this->input_with_gnu_stack_note_)
2518 if (this->input_requires_executable_stack_)
2519 is_stack_executable = true;
2520 else if (this->input_without_gnu_stack_note_)
2521 is_stack_executable =
2522 parameters->target().is_default_stack_executable();
2524 is_stack_executable = false;
2527 if (parameters->options().relocatable())
2529 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
2530 elfcpp::Elf_Xword flags = 0;
2531 if (is_stack_executable)
2532 flags |= elfcpp::SHF_EXECINSTR;
2533 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
2534 ORDER_INVALID, false);
2538 if (this->script_options_->saw_phdrs_clause())
2540 int flags = elfcpp::PF_R | elfcpp::PF_W;
2541 if (is_stack_executable)
2542 flags |= elfcpp::PF_X;
2543 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
2547 // If --build-id was used, set up the build ID note.
2550 Layout::create_build_id()
2552 if (!parameters->options().user_set_build_id())
2555 const char* style = parameters->options().build_id();
2556 if (strcmp(style, "none") == 0)
2559 // Set DESCSZ to the size of the note descriptor. When possible,
2560 // set DESC to the note descriptor contents.
2563 if (strcmp(style, "md5") == 0)
2565 else if (strcmp(style, "sha1") == 0)
2567 else if (strcmp(style, "uuid") == 0)
2569 const size_t uuidsz = 128 / 8;
2571 char buffer[uuidsz];
2572 memset(buffer, 0, uuidsz);
2574 int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
2576 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2580 ssize_t got = ::read(descriptor, buffer, uuidsz);
2581 release_descriptor(descriptor, true);
2583 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
2584 else if (static_cast<size_t>(got) != uuidsz)
2585 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2589 desc.assign(buffer, uuidsz);
2592 else if (strncmp(style, "0x", 2) == 0)
2595 const char* p = style + 2;
2598 if (hex_p(p[0]) && hex_p(p[1]))
2600 char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
2604 else if (*p == '-' || *p == ':')
2607 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2610 descsz = desc.size();
2613 gold_fatal(_("unrecognized --build-id argument '%s'"), style);
2616 size_t trailing_padding;
2617 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
2618 ".note.gnu.build-id", descsz, true,
2625 // We know the value already, so we fill it in now.
2626 gold_assert(desc.size() == descsz);
2628 Output_section_data* posd = new Output_data_const(desc, 4);
2629 os->add_output_section_data(posd);
2631 if (trailing_padding != 0)
2633 posd = new Output_data_zero_fill(trailing_padding, 0);
2634 os->add_output_section_data(posd);
2639 // We need to compute a checksum after we have completed the
2641 gold_assert(trailing_padding == 0);
2642 this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
2643 os->add_output_section_data(this->build_id_note_);
2647 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2648 // field of the former should point to the latter. I'm not sure who
2649 // started this, but the GNU linker does it, and some tools depend
2653 Layout::link_stabs_sections()
2655 if (!this->have_stabstr_section_)
2658 for (Section_list::iterator p = this->section_list_.begin();
2659 p != this->section_list_.end();
2662 if ((*p)->type() != elfcpp::SHT_STRTAB)
2665 const char* name = (*p)->name();
2666 if (strncmp(name, ".stab", 5) != 0)
2669 size_t len = strlen(name);
2670 if (strcmp(name + len - 3, "str") != 0)
2673 std::string stab_name(name, len - 3);
2674 Output_section* stab_sec;
2675 stab_sec = this->find_output_section(stab_name.c_str());
2676 if (stab_sec != NULL)
2677 stab_sec->set_link_section(*p);
2681 // Create .gnu_incremental_inputs and related sections needed
2682 // for the next run of incremental linking to check what has changed.
2685 Layout::create_incremental_info_sections(Symbol_table* symtab)
2687 Incremental_inputs* incr = this->incremental_inputs_;
2689 gold_assert(incr != NULL);
2691 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2692 incr->create_data_sections(symtab);
2694 // Add the .gnu_incremental_inputs section.
2695 const char* incremental_inputs_name =
2696 this->namepool_.add(".gnu_incremental_inputs", false, NULL);
2697 Output_section* incremental_inputs_os =
2698 this->make_output_section(incremental_inputs_name,
2699 elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
2700 ORDER_INVALID, false);
2701 incremental_inputs_os->add_output_section_data(incr->inputs_section());
2703 // Add the .gnu_incremental_symtab section.
2704 const char* incremental_symtab_name =
2705 this->namepool_.add(".gnu_incremental_symtab", false, NULL);
2706 Output_section* incremental_symtab_os =
2707 this->make_output_section(incremental_symtab_name,
2708 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
2709 ORDER_INVALID, false);
2710 incremental_symtab_os->add_output_section_data(incr->symtab_section());
2711 incremental_symtab_os->set_entsize(4);
2713 // Add the .gnu_incremental_relocs section.
2714 const char* incremental_relocs_name =
2715 this->namepool_.add(".gnu_incremental_relocs", false, NULL);
2716 Output_section* incremental_relocs_os =
2717 this->make_output_section(incremental_relocs_name,
2718 elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
2719 ORDER_INVALID, false);
2720 incremental_relocs_os->add_output_section_data(incr->relocs_section());
2721 incremental_relocs_os->set_entsize(incr->relocs_entsize());
2723 // Add the .gnu_incremental_got_plt section.
2724 const char* incremental_got_plt_name =
2725 this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
2726 Output_section* incremental_got_plt_os =
2727 this->make_output_section(incremental_got_plt_name,
2728 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
2729 ORDER_INVALID, false);
2730 incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
2732 // Add the .gnu_incremental_strtab section.
2733 const char* incremental_strtab_name =
2734 this->namepool_.add(".gnu_incremental_strtab", false, NULL);
2735 Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
2736 elfcpp::SHT_STRTAB, 0,
2737 ORDER_INVALID, false);
2738 Output_data_strtab* strtab_data =
2739 new Output_data_strtab(incr->get_stringpool());
2740 incremental_strtab_os->add_output_section_data(strtab_data);
2742 incremental_inputs_os->set_after_input_sections();
2743 incremental_symtab_os->set_after_input_sections();
2744 incremental_relocs_os->set_after_input_sections();
2745 incremental_got_plt_os->set_after_input_sections();
2747 incremental_inputs_os->set_link_section(incremental_strtab_os);
2748 incremental_symtab_os->set_link_section(incremental_inputs_os);
2749 incremental_relocs_os->set_link_section(incremental_inputs_os);
2750 incremental_got_plt_os->set_link_section(incremental_inputs_os);
2753 // Return whether SEG1 should be before SEG2 in the output file. This
2754 // is based entirely on the segment type and flags. When this is
2755 // called the segment addresses have normally not yet been set.
2758 Layout::segment_precedes(const Output_segment* seg1,
2759 const Output_segment* seg2)
2761 elfcpp::Elf_Word type1 = seg1->type();
2762 elfcpp::Elf_Word type2 = seg2->type();
2764 // The single PT_PHDR segment is required to precede any loadable
2765 // segment. We simply make it always first.
2766 if (type1 == elfcpp::PT_PHDR)
2768 gold_assert(type2 != elfcpp::PT_PHDR);
2771 if (type2 == elfcpp::PT_PHDR)
2774 // The single PT_INTERP segment is required to precede any loadable
2775 // segment. We simply make it always second.
2776 if (type1 == elfcpp::PT_INTERP)
2778 gold_assert(type2 != elfcpp::PT_INTERP);
2781 if (type2 == elfcpp::PT_INTERP)
2784 // We then put PT_LOAD segments before any other segments.
2785 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
2787 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
2790 // We put the PT_TLS segment last except for the PT_GNU_RELRO
2791 // segment, because that is where the dynamic linker expects to find
2792 // it (this is just for efficiency; other positions would also work
2794 if (type1 == elfcpp::PT_TLS
2795 && type2 != elfcpp::PT_TLS
2796 && type2 != elfcpp::PT_GNU_RELRO)
2798 if (type2 == elfcpp::PT_TLS
2799 && type1 != elfcpp::PT_TLS
2800 && type1 != elfcpp::PT_GNU_RELRO)
2803 // We put the PT_GNU_RELRO segment last, because that is where the
2804 // dynamic linker expects to find it (as with PT_TLS, this is just
2806 if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
2808 if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
2811 const elfcpp::Elf_Word flags1 = seg1->flags();
2812 const elfcpp::Elf_Word flags2 = seg2->flags();
2814 // The order of non-PT_LOAD segments is unimportant. We simply sort
2815 // by the numeric segment type and flags values. There should not
2816 // be more than one segment with the same type and flags.
2817 if (type1 != elfcpp::PT_LOAD)
2820 return type1 < type2;
2821 gold_assert(flags1 != flags2);
2822 return flags1 < flags2;
2825 // If the addresses are set already, sort by load address.
2826 if (seg1->are_addresses_set())
2828 if (!seg2->are_addresses_set())
2831 unsigned int section_count1 = seg1->output_section_count();
2832 unsigned int section_count2 = seg2->output_section_count();
2833 if (section_count1 == 0 && section_count2 > 0)
2835 if (section_count1 > 0 && section_count2 == 0)
2838 uint64_t paddr1 = (seg1->are_addresses_set()
2840 : seg1->first_section_load_address());
2841 uint64_t paddr2 = (seg2->are_addresses_set()
2843 : seg2->first_section_load_address());
2845 if (paddr1 != paddr2)
2846 return paddr1 < paddr2;
2848 else if (seg2->are_addresses_set())
2851 // A segment which holds large data comes after a segment which does
2852 // not hold large data.
2853 if (seg1->is_large_data_segment())
2855 if (!seg2->is_large_data_segment())
2858 else if (seg2->is_large_data_segment())
2861 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
2862 // segments come before writable segments. Then writable segments
2863 // with data come before writable segments without data. Then
2864 // executable segments come before non-executable segments. Then
2865 // the unlikely case of a non-readable segment comes before the
2866 // normal case of a readable segment. If there are multiple
2867 // segments with the same type and flags, we require that the
2868 // address be set, and we sort by virtual address and then physical
2870 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
2871 return (flags1 & elfcpp::PF_W) == 0;
2872 if ((flags1 & elfcpp::PF_W) != 0
2873 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
2874 return seg1->has_any_data_sections();
2875 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
2876 return (flags1 & elfcpp::PF_X) != 0;
2877 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
2878 return (flags1 & elfcpp::PF_R) == 0;
2880 // We shouldn't get here--we shouldn't create segments which we
2881 // can't distinguish. Unless of course we are using a weird linker
2883 gold_assert(this->script_options_->saw_phdrs_clause());
2887 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2890 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
2892 uint64_t unsigned_off = off;
2893 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
2894 | (addr & (abi_pagesize - 1)));
2895 if (aligned_off < unsigned_off)
2896 aligned_off += abi_pagesize;
2900 // Set the file offsets of all the segments, and all the sections they
2901 // contain. They have all been created. LOAD_SEG must be be laid out
2902 // first. Return the offset of the data to follow.
2905 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
2906 unsigned int* pshndx)
2908 // Sort them into the final order. We use a stable sort so that we
2909 // don't randomize the order of indistinguishable segments created
2910 // by linker scripts.
2911 std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(),
2912 Layout::Compare_segments(this));
2914 // Find the PT_LOAD segments, and set their addresses and offsets
2915 // and their section's addresses and offsets.
2917 if (parameters->options().user_set_Ttext())
2918 addr = parameters->options().Ttext();
2919 else if (parameters->options().output_is_position_independent())
2922 addr = target->default_text_segment_address();
2925 // If LOAD_SEG is NULL, then the file header and segment headers
2926 // will not be loadable. But they still need to be at offset 0 in
2927 // the file. Set their offsets now.
2928 if (load_seg == NULL)
2930 for (Data_list::iterator p = this->special_output_list_.begin();
2931 p != this->special_output_list_.end();
2934 off = align_address(off, (*p)->addralign());
2935 (*p)->set_address_and_file_offset(0, off);
2936 off += (*p)->data_size();
2940 unsigned int increase_relro = this->increase_relro_;
2941 if (this->script_options_->saw_sections_clause())
2944 const bool check_sections = parameters->options().check_sections();
2945 Output_segment* last_load_segment = NULL;
2947 for (Segment_list::iterator p = this->segment_list_.begin();
2948 p != this->segment_list_.end();
2951 if ((*p)->type() == elfcpp::PT_LOAD)
2953 if (load_seg != NULL && load_seg != *p)
2957 bool are_addresses_set = (*p)->are_addresses_set();
2958 if (are_addresses_set)
2960 // When it comes to setting file offsets, we care about
2961 // the physical address.
2962 addr = (*p)->paddr();
2964 else if (parameters->options().user_set_Tdata()
2965 && ((*p)->flags() & elfcpp::PF_W) != 0
2966 && (!parameters->options().user_set_Tbss()
2967 || (*p)->has_any_data_sections()))
2969 addr = parameters->options().Tdata();
2970 are_addresses_set = true;
2972 else if (parameters->options().user_set_Tbss()
2973 && ((*p)->flags() & elfcpp::PF_W) != 0
2974 && !(*p)->has_any_data_sections())
2976 addr = parameters->options().Tbss();
2977 are_addresses_set = true;
2980 uint64_t orig_addr = addr;
2981 uint64_t orig_off = off;
2983 uint64_t aligned_addr = 0;
2984 uint64_t abi_pagesize = target->abi_pagesize();
2985 uint64_t common_pagesize = target->common_pagesize();
2987 if (!parameters->options().nmagic()
2988 && !parameters->options().omagic())
2989 (*p)->set_minimum_p_align(common_pagesize);
2991 if (!are_addresses_set)
2993 // Skip the address forward one page, maintaining the same
2994 // position within the page. This lets us store both segments
2995 // overlapping on a single page in the file, but the loader will
2996 // put them on different pages in memory. We will revisit this
2997 // decision once we know the size of the segment.
2999 addr = align_address(addr, (*p)->maximum_alignment());
3000 aligned_addr = addr;
3002 if ((addr & (abi_pagesize - 1)) != 0)
3003 addr = addr + abi_pagesize;
3005 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3008 if (!parameters->options().nmagic()
3009 && !parameters->options().omagic())
3010 off = align_file_offset(off, addr, abi_pagesize);
3011 else if (load_seg == NULL)
3013 // This is -N or -n with a section script which prevents
3014 // us from using a load segment. We need to ensure that
3015 // the file offset is aligned to the alignment of the
3016 // segment. This is because the linker script
3017 // implicitly assumed a zero offset. If we don't align
3018 // here, then the alignment of the sections in the
3019 // linker script may not match the alignment of the
3020 // sections in the set_section_addresses call below,
3021 // causing an error about dot moving backward.
3022 off = align_address(off, (*p)->maximum_alignment());
3025 unsigned int shndx_hold = *pshndx;
3026 bool has_relro = false;
3027 uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
3032 // Now that we know the size of this segment, we may be able
3033 // to save a page in memory, at the cost of wasting some
3034 // file space, by instead aligning to the start of a new
3035 // page. Here we use the real machine page size rather than
3036 // the ABI mandated page size. If the segment has been
3037 // aligned so that the relro data ends at a page boundary,
3038 // we do not try to realign it.
3040 if (!are_addresses_set
3042 && aligned_addr != addr
3043 && !parameters->incremental())
3045 uint64_t first_off = (common_pagesize
3047 & (common_pagesize - 1)));
3048 uint64_t last_off = new_addr & (common_pagesize - 1);
3051 && ((aligned_addr & ~ (common_pagesize - 1))
3052 != (new_addr & ~ (common_pagesize - 1)))
3053 && first_off + last_off <= common_pagesize)
3055 *pshndx = shndx_hold;
3056 addr = align_address(aligned_addr, common_pagesize);
3057 addr = align_address(addr, (*p)->maximum_alignment());
3058 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3059 off = align_file_offset(off, addr, abi_pagesize);
3061 increase_relro = this->increase_relro_;
3062 if (this->script_options_->saw_sections_clause())
3066 new_addr = (*p)->set_section_addresses(this, true, addr,
3075 // Implement --check-sections. We know that the segments
3076 // are sorted by LMA.
3077 if (check_sections && last_load_segment != NULL)
3079 gold_assert(last_load_segment->paddr() <= (*p)->paddr());
3080 if (last_load_segment->paddr() + last_load_segment->memsz()
3083 unsigned long long lb1 = last_load_segment->paddr();
3084 unsigned long long le1 = lb1 + last_load_segment->memsz();
3085 unsigned long long lb2 = (*p)->paddr();
3086 unsigned long long le2 = lb2 + (*p)->memsz();
3087 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3088 "[0x%llx -> 0x%llx]"),
3089 lb1, le1, lb2, le2);
3092 last_load_segment = *p;
3096 // Handle the non-PT_LOAD segments, setting their offsets from their
3097 // section's offsets.
3098 for (Segment_list::iterator p = this->segment_list_.begin();
3099 p != this->segment_list_.end();
3102 if ((*p)->type() != elfcpp::PT_LOAD)
3103 (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
3108 // Set the TLS offsets for each section in the PT_TLS segment.
3109 if (this->tls_segment_ != NULL)
3110 this->tls_segment_->set_tls_offsets();
3115 // Set the offsets of all the allocated sections when doing a
3116 // relocatable link. This does the same jobs as set_segment_offsets,
3117 // only for a relocatable link.
3120 Layout::set_relocatable_section_offsets(Output_data* file_header,
3121 unsigned int* pshndx)
3125 file_header->set_address_and_file_offset(0, 0);
3126 off += file_header->data_size();
3128 for (Section_list::iterator p = this->section_list_.begin();
3129 p != this->section_list_.end();
3132 // We skip unallocated sections here, except that group sections
3133 // have to come first.
3134 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
3135 && (*p)->type() != elfcpp::SHT_GROUP)
3138 off = align_address(off, (*p)->addralign());
3140 // The linker script might have set the address.
3141 if (!(*p)->is_address_valid())
3142 (*p)->set_address(0);
3143 (*p)->set_file_offset(off);
3144 (*p)->finalize_data_size();
3145 off += (*p)->data_size();
3147 (*p)->set_out_shndx(*pshndx);
3154 // Set the file offset of all the sections not associated with a
3158 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
3160 off_t startoff = off;
3163 for (Section_list::iterator p = this->unattached_section_list_.begin();
3164 p != this->unattached_section_list_.end();
3167 // The symtab section is handled in create_symtab_sections.
3168 if (*p == this->symtab_section_)
3171 // If we've already set the data size, don't set it again.
3172 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
3175 if (pass == BEFORE_INPUT_SECTIONS_PASS
3176 && (*p)->requires_postprocessing())
3178 (*p)->create_postprocessing_buffer();
3179 this->any_postprocessing_sections_ = true;
3182 if (pass == BEFORE_INPUT_SECTIONS_PASS
3183 && (*p)->after_input_sections())
3185 else if (pass == POSTPROCESSING_SECTIONS_PASS
3186 && (!(*p)->after_input_sections()
3187 || (*p)->type() == elfcpp::SHT_STRTAB))
3189 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3190 && (!(*p)->after_input_sections()
3191 || (*p)->type() != elfcpp::SHT_STRTAB))
3194 if (!parameters->incremental_update())
3196 off = align_address(off, (*p)->addralign());
3197 (*p)->set_file_offset(off);
3198 (*p)->finalize_data_size();
3202 // Incremental update: allocate file space from free list.
3203 (*p)->pre_finalize_data_size();
3204 off_t current_size = (*p)->current_data_size();
3205 off = this->allocate(current_size, (*p)->addralign(), startoff);
3208 if (is_debugging_enabled(DEBUG_INCREMENTAL))
3209 this->free_list_.dump();
3210 gold_assert((*p)->output_section() != NULL);
3211 gold_fallback(_("out of patch space for section %s; "
3212 "relink with --incremental-full"),
3213 (*p)->output_section()->name());
3215 (*p)->set_file_offset(off);
3216 (*p)->finalize_data_size();
3217 if ((*p)->data_size() > current_size)
3219 gold_assert((*p)->output_section() != NULL);
3220 gold_fallback(_("%s: section changed size; "
3221 "relink with --incremental-full"),
3222 (*p)->output_section()->name());
3224 gold_debug(DEBUG_INCREMENTAL,
3225 "set_section_offsets: %08lx %08lx %s",
3226 static_cast<long>(off),
3227 static_cast<long>((*p)->data_size()),
3228 ((*p)->output_section() != NULL
3229 ? (*p)->output_section()->name() : "(special)"));
3232 off += (*p)->data_size();
3236 // At this point the name must be set.
3237 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
3238 this->namepool_.add((*p)->name(), false, NULL);
3243 // Set the section indexes of all the sections not associated with a
3247 Layout::set_section_indexes(unsigned int shndx)
3249 for (Section_list::iterator p = this->unattached_section_list_.begin();
3250 p != this->unattached_section_list_.end();
3253 if (!(*p)->has_out_shndx())
3255 (*p)->set_out_shndx(shndx);
3262 // Set the section addresses according to the linker script. This is
3263 // only called when we see a SECTIONS clause. This returns the
3264 // program segment which should hold the file header and segment
3265 // headers, if any. It will return NULL if they should not be in a
3269 Layout::set_section_addresses_from_script(Symbol_table* symtab)
3271 Script_sections* ss = this->script_options_->script_sections();
3272 gold_assert(ss->saw_sections_clause());
3273 return this->script_options_->set_section_addresses(symtab, this);
3276 // Place the orphan sections in the linker script.
3279 Layout::place_orphan_sections_in_script()
3281 Script_sections* ss = this->script_options_->script_sections();
3282 gold_assert(ss->saw_sections_clause());
3284 // Place each orphaned output section in the script.
3285 for (Section_list::iterator p = this->section_list_.begin();
3286 p != this->section_list_.end();
3289 if (!(*p)->found_in_sections_clause())
3290 ss->place_orphan(*p);
3294 // Count the local symbols in the regular symbol table and the dynamic
3295 // symbol table, and build the respective string pools.
3298 Layout::count_local_symbols(const Task* task,
3299 const Input_objects* input_objects)
3301 // First, figure out an upper bound on the number of symbols we'll
3302 // be inserting into each pool. This helps us create the pools with
3303 // the right size, to avoid unnecessary hashtable resizing.
3304 unsigned int symbol_count = 0;
3305 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3306 p != input_objects->relobj_end();
3308 symbol_count += (*p)->local_symbol_count();
3310 // Go from "upper bound" to "estimate." We overcount for two
3311 // reasons: we double-count symbols that occur in more than one
3312 // object file, and we count symbols that are dropped from the
3313 // output. Add it all together and assume we overcount by 100%.
3316 // We assume all symbols will go into both the sympool and dynpool.
3317 this->sympool_.reserve(symbol_count);
3318 this->dynpool_.reserve(symbol_count);
3320 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3321 p != input_objects->relobj_end();
3324 Task_lock_obj<Object> tlo(task, *p);
3325 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
3329 // Create the symbol table sections. Here we also set the final
3330 // values of the symbols. At this point all the loadable sections are
3331 // fully laid out. SHNUM is the number of sections so far.
3334 Layout::create_symtab_sections(const Input_objects* input_objects,
3335 Symbol_table* symtab,
3341 if (parameters->target().get_size() == 32)
3343 symsize = elfcpp::Elf_sizes<32>::sym_size;
3346 else if (parameters->target().get_size() == 64)
3348 symsize = elfcpp::Elf_sizes<64>::sym_size;
3354 // Compute file offsets relative to the start of the symtab section.
3357 // Save space for the dummy symbol at the start of the section. We
3358 // never bother to write this out--it will just be left as zero.
3360 unsigned int local_symbol_index = 1;
3362 // Add STT_SECTION symbols for each Output section which needs one.
3363 for (Section_list::iterator p = this->section_list_.begin();
3364 p != this->section_list_.end();
3367 if (!(*p)->needs_symtab_index())
3368 (*p)->set_symtab_index(-1U);
3371 (*p)->set_symtab_index(local_symbol_index);
3372 ++local_symbol_index;
3377 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3378 p != input_objects->relobj_end();
3381 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
3383 off += (index - local_symbol_index) * symsize;
3384 local_symbol_index = index;
3387 unsigned int local_symcount = local_symbol_index;
3388 gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
3391 size_t dyn_global_index;
3393 if (this->dynsym_section_ == NULL)
3396 dyn_global_index = 0;
3401 dyn_global_index = this->dynsym_section_->info();
3402 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
3403 dynoff = this->dynsym_section_->offset() + locsize;
3404 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
3405 gold_assert(static_cast<off_t>(dyncount * symsize)
3406 == this->dynsym_section_->data_size() - locsize);
3409 off_t global_off = off;
3410 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
3411 &this->sympool_, &local_symcount);
3413 if (!parameters->options().strip_all())
3415 this->sympool_.set_string_offsets();
3417 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
3418 Output_section* osymtab = this->make_output_section(symtab_name,
3422 this->symtab_section_ = osymtab;
3424 Output_section_data* pos = new Output_data_fixed_space(off, align,
3426 osymtab->add_output_section_data(pos);
3428 // We generate a .symtab_shndx section if we have more than
3429 // SHN_LORESERVE sections. Technically it is possible that we
3430 // don't need one, because it is possible that there are no
3431 // symbols in any of sections with indexes larger than
3432 // SHN_LORESERVE. That is probably unusual, though, and it is
3433 // easier to always create one than to compute section indexes
3434 // twice (once here, once when writing out the symbols).
3435 if (shnum >= elfcpp::SHN_LORESERVE)
3437 const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
3439 Output_section* osymtab_xindex =
3440 this->make_output_section(symtab_xindex_name,
3441 elfcpp::SHT_SYMTAB_SHNDX, 0,
3442 ORDER_INVALID, false);
3444 size_t symcount = off / symsize;
3445 this->symtab_xindex_ = new Output_symtab_xindex(symcount);
3447 osymtab_xindex->add_output_section_data(this->symtab_xindex_);
3449 osymtab_xindex->set_link_section(osymtab);
3450 osymtab_xindex->set_addralign(4);
3451 osymtab_xindex->set_entsize(4);
3453 osymtab_xindex->set_after_input_sections();
3455 // This tells the driver code to wait until the symbol table
3456 // has written out before writing out the postprocessing
3457 // sections, including the .symtab_shndx section.
3458 this->any_postprocessing_sections_ = true;
3461 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
3462 Output_section* ostrtab = this->make_output_section(strtab_name,
3467 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
3468 ostrtab->add_output_section_data(pstr);
3471 if (!parameters->incremental_update())
3472 symtab_off = align_address(*poff, align);
3475 symtab_off = this->allocate(off, align, *poff);
3477 gold_fallback(_("out of patch space for symbol table; "
3478 "relink with --incremental-full"));
3479 gold_debug(DEBUG_INCREMENTAL,
3480 "create_symtab_sections: %08lx %08lx .symtab",
3481 static_cast<long>(symtab_off),
3482 static_cast<long>(off));
3485 symtab->set_file_offset(symtab_off + global_off);
3486 osymtab->set_file_offset(symtab_off);
3487 osymtab->finalize_data_size();
3488 osymtab->set_link_section(ostrtab);
3489 osymtab->set_info(local_symcount);
3490 osymtab->set_entsize(symsize);
3492 if (symtab_off + off > *poff)
3493 *poff = symtab_off + off;
3497 // Create the .shstrtab section, which holds the names of the
3498 // sections. At the time this is called, we have created all the
3499 // output sections except .shstrtab itself.
3502 Layout::create_shstrtab()
3504 // FIXME: We don't need to create a .shstrtab section if we are
3505 // stripping everything.
3507 const char* name = this->namepool_.add(".shstrtab", false, NULL);
3509 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
3510 ORDER_INVALID, false);
3512 if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
3514 // We can't write out this section until we've set all the
3515 // section names, and we don't set the names of compressed
3516 // output sections until relocations are complete. FIXME: With
3517 // the current names we use, this is unnecessary.
3518 os->set_after_input_sections();
3521 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
3522 os->add_output_section_data(posd);
3527 // Create the section headers. SIZE is 32 or 64. OFF is the file
3531 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
3533 Output_section_headers* oshdrs;
3534 oshdrs = new Output_section_headers(this,
3535 &this->segment_list_,
3536 &this->section_list_,
3537 &this->unattached_section_list_,
3541 if (!parameters->incremental_update())
3542 off = align_address(*poff, oshdrs->addralign());
3545 oshdrs->pre_finalize_data_size();
3546 off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
3548 gold_fallback(_("out of patch space for section header table; "
3549 "relink with --incremental-full"));
3550 gold_debug(DEBUG_INCREMENTAL,
3551 "create_shdrs: %08lx %08lx (section header table)",
3552 static_cast<long>(off),
3553 static_cast<long>(off + oshdrs->data_size()));
3555 oshdrs->set_address_and_file_offset(0, off);
3556 off += oshdrs->data_size();
3559 this->section_headers_ = oshdrs;
3562 // Count the allocated sections.
3565 Layout::allocated_output_section_count() const
3567 size_t section_count = 0;
3568 for (Segment_list::const_iterator p = this->segment_list_.begin();
3569 p != this->segment_list_.end();
3571 section_count += (*p)->output_section_count();
3572 return section_count;
3575 // Create the dynamic symbol table.
3578 Layout::create_dynamic_symtab(const Input_objects* input_objects,
3579 Symbol_table* symtab,
3580 Output_section** pdynstr,
3581 unsigned int* plocal_dynamic_count,
3582 std::vector<Symbol*>* pdynamic_symbols,
3583 Versions* pversions)
3585 // Count all the symbols in the dynamic symbol table, and set the
3586 // dynamic symbol indexes.
3588 // Skip symbol 0, which is always all zeroes.
3589 unsigned int index = 1;
3591 // Add STT_SECTION symbols for each Output section which needs one.
3592 for (Section_list::iterator p = this->section_list_.begin();
3593 p != this->section_list_.end();
3596 if (!(*p)->needs_dynsym_index())
3597 (*p)->set_dynsym_index(-1U);
3600 (*p)->set_dynsym_index(index);
3605 // Count the local symbols that need to go in the dynamic symbol table,
3606 // and set the dynamic symbol indexes.
3607 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3608 p != input_objects->relobj_end();
3611 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
3615 unsigned int local_symcount = index;
3616 *plocal_dynamic_count = local_symcount;
3618 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
3619 &this->dynpool_, pversions);
3623 const int size = parameters->target().get_size();
3626 symsize = elfcpp::Elf_sizes<32>::sym_size;
3629 else if (size == 64)
3631 symsize = elfcpp::Elf_sizes<64>::sym_size;
3637 // Create the dynamic symbol table section.
3639 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
3643 ORDER_DYNAMIC_LINKER,
3646 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
3649 dynsym->add_output_section_data(odata);
3651 dynsym->set_info(local_symcount);
3652 dynsym->set_entsize(symsize);
3653 dynsym->set_addralign(align);
3655 this->dynsym_section_ = dynsym;
3657 Output_data_dynamic* const odyn = this->dynamic_data_;
3658 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
3659 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
3661 // If there are more than SHN_LORESERVE allocated sections, we
3662 // create a .dynsym_shndx section. It is possible that we don't
3663 // need one, because it is possible that there are no dynamic
3664 // symbols in any of the sections with indexes larger than
3665 // SHN_LORESERVE. This is probably unusual, though, and at this
3666 // time we don't know the actual section indexes so it is
3667 // inconvenient to check.
3668 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
3670 Output_section* dynsym_xindex =
3671 this->choose_output_section(NULL, ".dynsym_shndx",
3672 elfcpp::SHT_SYMTAB_SHNDX,
3674 false, ORDER_DYNAMIC_LINKER, false);
3676 this->dynsym_xindex_ = new Output_symtab_xindex(index);
3678 dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
3680 dynsym_xindex->set_link_section(dynsym);
3681 dynsym_xindex->set_addralign(4);
3682 dynsym_xindex->set_entsize(4);
3684 dynsym_xindex->set_after_input_sections();
3686 // This tells the driver code to wait until the symbol table has
3687 // written out before writing out the postprocessing sections,
3688 // including the .dynsym_shndx section.
3689 this->any_postprocessing_sections_ = true;
3692 // Create the dynamic string table section.
3694 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
3698 ORDER_DYNAMIC_LINKER,
3701 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
3702 dynstr->add_output_section_data(strdata);
3704 dynsym->set_link_section(dynstr);
3705 this->dynamic_section_->set_link_section(dynstr);
3707 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
3708 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
3712 // Create the hash tables.
3714 if (strcmp(parameters->options().hash_style(), "sysv") == 0
3715 || strcmp(parameters->options().hash_style(), "both") == 0)
3717 unsigned char* phash;
3718 unsigned int hashlen;
3719 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
3722 Output_section* hashsec =
3723 this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
3724 elfcpp::SHF_ALLOC, false,
3725 ORDER_DYNAMIC_LINKER, false);
3727 Output_section_data* hashdata = new Output_data_const_buffer(phash,
3731 hashsec->add_output_section_data(hashdata);
3733 hashsec->set_link_section(dynsym);
3734 hashsec->set_entsize(4);
3736 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
3739 if (strcmp(parameters->options().hash_style(), "gnu") == 0
3740 || strcmp(parameters->options().hash_style(), "both") == 0)
3742 unsigned char* phash;
3743 unsigned int hashlen;
3744 Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
3747 Output_section* hashsec =
3748 this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
3749 elfcpp::SHF_ALLOC, false,
3750 ORDER_DYNAMIC_LINKER, false);
3752 Output_section_data* hashdata = new Output_data_const_buffer(phash,
3756 hashsec->add_output_section_data(hashdata);
3758 hashsec->set_link_section(dynsym);
3760 // For a 64-bit target, the entries in .gnu.hash do not have a
3761 // uniform size, so we only set the entry size for a 32-bit
3763 if (parameters->target().get_size() == 32)
3764 hashsec->set_entsize(4);
3766 odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
3770 // Assign offsets to each local portion of the dynamic symbol table.
3773 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
3775 Output_section* dynsym = this->dynsym_section_;
3776 gold_assert(dynsym != NULL);
3778 off_t off = dynsym->offset();
3780 // Skip the dummy symbol at the start of the section.
3781 off += dynsym->entsize();
3783 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3784 p != input_objects->relobj_end();
3787 unsigned int count = (*p)->set_local_dynsym_offset(off);
3788 off += count * dynsym->entsize();
3792 // Create the version sections.
3795 Layout::create_version_sections(const Versions* versions,
3796 const Symbol_table* symtab,
3797 unsigned int local_symcount,
3798 const std::vector<Symbol*>& dynamic_symbols,
3799 const Output_section* dynstr)
3801 if (!versions->any_defs() && !versions->any_needs())
3804 switch (parameters->size_and_endianness())
3806 #ifdef HAVE_TARGET_32_LITTLE
3807 case Parameters::TARGET_32_LITTLE:
3808 this->sized_create_version_sections<32, false>(versions, symtab,
3810 dynamic_symbols, dynstr);
3813 #ifdef HAVE_TARGET_32_BIG
3814 case Parameters::TARGET_32_BIG:
3815 this->sized_create_version_sections<32, true>(versions, symtab,
3817 dynamic_symbols, dynstr);
3820 #ifdef HAVE_TARGET_64_LITTLE
3821 case Parameters::TARGET_64_LITTLE:
3822 this->sized_create_version_sections<64, false>(versions, symtab,
3824 dynamic_symbols, dynstr);
3827 #ifdef HAVE_TARGET_64_BIG
3828 case Parameters::TARGET_64_BIG:
3829 this->sized_create_version_sections<64, true>(versions, symtab,
3831 dynamic_symbols, dynstr);
3839 // Create the version sections, sized version.
3841 template<int size, bool big_endian>
3843 Layout::sized_create_version_sections(
3844 const Versions* versions,
3845 const Symbol_table* symtab,
3846 unsigned int local_symcount,
3847 const std::vector<Symbol*>& dynamic_symbols,
3848 const Output_section* dynstr)
3850 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
3851 elfcpp::SHT_GNU_versym,
3854 ORDER_DYNAMIC_LINKER,
3857 unsigned char* vbuf;
3859 versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
3864 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
3867 vsec->add_output_section_data(vdata);
3868 vsec->set_entsize(2);
3869 vsec->set_link_section(this->dynsym_section_);
3871 Output_data_dynamic* const odyn = this->dynamic_data_;
3872 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
3874 if (versions->any_defs())
3876 Output_section* vdsec;
3877 vdsec= this->choose_output_section(NULL, ".gnu.version_d",
3878 elfcpp::SHT_GNU_verdef,
3880 false, ORDER_DYNAMIC_LINKER, false);
3882 unsigned char* vdbuf;
3883 unsigned int vdsize;
3884 unsigned int vdentries;
3885 versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
3886 &vdsize, &vdentries);
3888 Output_section_data* vddata =
3889 new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
3891 vdsec->add_output_section_data(vddata);
3892 vdsec->set_link_section(dynstr);
3893 vdsec->set_info(vdentries);
3895 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
3896 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
3899 if (versions->any_needs())
3901 Output_section* vnsec;
3902 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
3903 elfcpp::SHT_GNU_verneed,
3905 false, ORDER_DYNAMIC_LINKER, false);
3907 unsigned char* vnbuf;
3908 unsigned int vnsize;
3909 unsigned int vnentries;
3910 versions->need_section_contents<size, big_endian>(&this->dynpool_,
3914 Output_section_data* vndata =
3915 new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
3917 vnsec->add_output_section_data(vndata);
3918 vnsec->set_link_section(dynstr);
3919 vnsec->set_info(vnentries);
3921 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
3922 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
3926 // Create the .interp section and PT_INTERP segment.
3929 Layout::create_interp(const Target* target)
3931 gold_assert(this->interp_segment_ == NULL);
3933 const char* interp = parameters->options().dynamic_linker();
3936 interp = target->dynamic_linker();
3937 gold_assert(interp != NULL);
3940 size_t len = strlen(interp) + 1;
3942 Output_section_data* odata = new Output_data_const(interp, len, 1);
3944 Output_section* osec = this->choose_output_section(NULL, ".interp",
3945 elfcpp::SHT_PROGBITS,
3947 false, ORDER_INTERP,
3949 osec->add_output_section_data(odata);
3952 // Add dynamic tags for the PLT and the dynamic relocs. This is
3953 // called by the target-specific code. This does nothing if not doing
3956 // USE_REL is true for REL relocs rather than RELA relocs.
3958 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3960 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3961 // and we also set DT_PLTREL. We use PLT_REL's output section, since
3962 // some targets have multiple reloc sections in PLT_REL.
3964 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3965 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3967 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3971 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
3972 const Output_data* plt_rel,
3973 const Output_data_reloc_generic* dyn_rel,
3974 bool add_debug, bool dynrel_includes_plt)
3976 Output_data_dynamic* odyn = this->dynamic_data_;
3980 if (plt_got != NULL && plt_got->output_section() != NULL)
3981 odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
3983 if (plt_rel != NULL && plt_rel->output_section() != NULL)
3985 odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
3986 odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
3987 odyn->add_constant(elfcpp::DT_PLTREL,
3988 use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
3991 if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
3993 odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
3995 if (plt_rel != NULL && dynrel_includes_plt)
3996 odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3999 odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
4001 const int size = parameters->target().get_size();
4006 rel_tag = elfcpp::DT_RELENT;
4008 rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
4009 else if (size == 64)
4010 rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
4016 rel_tag = elfcpp::DT_RELAENT;
4018 rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
4019 else if (size == 64)
4020 rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
4024 odyn->add_constant(rel_tag, rel_size);
4026 if (parameters->options().combreloc())
4028 size_t c = dyn_rel->relative_reloc_count();
4030 odyn->add_constant((use_rel
4031 ? elfcpp::DT_RELCOUNT
4032 : elfcpp::DT_RELACOUNT),
4037 if (add_debug && !parameters->options().shared())
4039 // The value of the DT_DEBUG tag is filled in by the dynamic
4040 // linker at run time, and used by the debugger.
4041 odyn->add_constant(elfcpp::DT_DEBUG, 0);
4045 // Finish the .dynamic section and PT_DYNAMIC segment.
4048 Layout::finish_dynamic_section(const Input_objects* input_objects,
4049 const Symbol_table* symtab)
4051 if (!this->script_options_->saw_phdrs_clause())
4053 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
4056 oseg->add_output_section_to_nonload(this->dynamic_section_,
4057 elfcpp::PF_R | elfcpp::PF_W);
4060 Output_data_dynamic* const odyn = this->dynamic_data_;
4062 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
4063 p != input_objects->dynobj_end();
4066 if (!(*p)->is_needed() && (*p)->as_needed())
4068 // This dynamic object was linked with --as-needed, but it
4073 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
4076 if (parameters->options().shared())
4078 const char* soname = parameters->options().soname();
4080 odyn->add_string(elfcpp::DT_SONAME, soname);
4083 Symbol* sym = symtab->lookup(parameters->options().init());
4084 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4085 odyn->add_symbol(elfcpp::DT_INIT, sym);
4087 sym = symtab->lookup(parameters->options().fini());
4088 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4089 odyn->add_symbol(elfcpp::DT_FINI, sym);
4091 // Look for .init_array, .preinit_array and .fini_array by checking
4093 for(Layout::Section_list::const_iterator p = this->section_list_.begin();
4094 p != this->section_list_.end();
4096 switch((*p)->type())
4098 case elfcpp::SHT_FINI_ARRAY:
4099 odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
4100 odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
4102 case elfcpp::SHT_INIT_ARRAY:
4103 odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
4104 odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
4106 case elfcpp::SHT_PREINIT_ARRAY:
4107 odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
4108 odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
4114 // Add a DT_RPATH entry if needed.
4115 const General_options::Dir_list& rpath(parameters->options().rpath());
4118 std::string rpath_val;
4119 for (General_options::Dir_list::const_iterator p = rpath.begin();
4123 if (rpath_val.empty())
4124 rpath_val = p->name();
4127 // Eliminate duplicates.
4128 General_options::Dir_list::const_iterator q;
4129 for (q = rpath.begin(); q != p; ++q)
4130 if (q->name() == p->name())
4135 rpath_val += p->name();
4140 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
4141 if (parameters->options().enable_new_dtags())
4142 odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
4145 // Look for text segments that have dynamic relocations.
4146 bool have_textrel = false;
4147 if (!this->script_options_->saw_sections_clause())
4149 for (Segment_list::const_iterator p = this->segment_list_.begin();
4150 p != this->segment_list_.end();
4153 if ((*p)->type() == elfcpp::PT_LOAD
4154 && ((*p)->flags() & elfcpp::PF_W) == 0
4155 && (*p)->has_dynamic_reloc())
4157 have_textrel = true;
4164 // We don't know the section -> segment mapping, so we are
4165 // conservative and just look for readonly sections with
4166 // relocations. If those sections wind up in writable segments,
4167 // then we have created an unnecessary DT_TEXTREL entry.
4168 for (Section_list::const_iterator p = this->section_list_.begin();
4169 p != this->section_list_.end();
4172 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
4173 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
4174 && (*p)->has_dynamic_reloc())
4176 have_textrel = true;
4182 // Add a DT_FLAGS entry. We add it even if no flags are set so that
4183 // post-link tools can easily modify these flags if desired.
4184 unsigned int flags = 0;
4187 // Add a DT_TEXTREL for compatibility with older loaders.
4188 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
4189 flags |= elfcpp::DF_TEXTREL;
4191 if (parameters->options().text())
4192 gold_error(_("read-only segment has dynamic relocations"));
4193 else if (parameters->options().warn_shared_textrel()
4194 && parameters->options().shared())
4195 gold_warning(_("shared library text segment is not shareable"));
4197 if (parameters->options().shared() && this->has_static_tls())
4198 flags |= elfcpp::DF_STATIC_TLS;
4199 if (parameters->options().origin())
4200 flags |= elfcpp::DF_ORIGIN;
4201 if (parameters->options().Bsymbolic())
4203 flags |= elfcpp::DF_SYMBOLIC;
4204 // Add DT_SYMBOLIC for compatibility with older loaders.
4205 odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
4207 if (parameters->options().now())
4208 flags |= elfcpp::DF_BIND_NOW;
4210 odyn->add_constant(elfcpp::DT_FLAGS, flags);
4213 if (parameters->options().initfirst())
4214 flags |= elfcpp::DF_1_INITFIRST;
4215 if (parameters->options().interpose())
4216 flags |= elfcpp::DF_1_INTERPOSE;
4217 if (parameters->options().loadfltr())
4218 flags |= elfcpp::DF_1_LOADFLTR;
4219 if (parameters->options().nodefaultlib())
4220 flags |= elfcpp::DF_1_NODEFLIB;
4221 if (parameters->options().nodelete())
4222 flags |= elfcpp::DF_1_NODELETE;
4223 if (parameters->options().nodlopen())
4224 flags |= elfcpp::DF_1_NOOPEN;
4225 if (parameters->options().nodump())
4226 flags |= elfcpp::DF_1_NODUMP;
4227 if (!parameters->options().shared())
4228 flags &= ~(elfcpp::DF_1_INITFIRST
4229 | elfcpp::DF_1_NODELETE
4230 | elfcpp::DF_1_NOOPEN);
4231 if (parameters->options().origin())
4232 flags |= elfcpp::DF_1_ORIGIN;
4233 if (parameters->options().now())
4234 flags |= elfcpp::DF_1_NOW;
4236 odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
4239 // Set the size of the _DYNAMIC symbol table to be the size of the
4243 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
4245 Output_data_dynamic* const odyn = this->dynamic_data_;
4246 odyn->finalize_data_size();
4247 off_t data_size = odyn->data_size();
4248 const int size = parameters->target().get_size();
4250 symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
4251 else if (size == 64)
4252 symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
4257 // The mapping of input section name prefixes to output section names.
4258 // In some cases one prefix is itself a prefix of another prefix; in
4259 // such a case the longer prefix must come first. These prefixes are
4260 // based on the GNU linker default ELF linker script.
4262 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4263 const Layout::Section_name_mapping Layout::section_name_mapping[] =
4265 MAPPING_INIT(".text.", ".text"),
4266 MAPPING_INIT(".rodata.", ".rodata"),
4267 MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
4268 MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
4269 MAPPING_INIT(".data.", ".data"),
4270 MAPPING_INIT(".bss.", ".bss"),
4271 MAPPING_INIT(".tdata.", ".tdata"),
4272 MAPPING_INIT(".tbss.", ".tbss"),
4273 MAPPING_INIT(".init_array.", ".init_array"),
4274 MAPPING_INIT(".fini_array.", ".fini_array"),
4275 MAPPING_INIT(".sdata.", ".sdata"),
4276 MAPPING_INIT(".sbss.", ".sbss"),
4277 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4278 // differently depending on whether it is creating a shared library.
4279 MAPPING_INIT(".sdata2.", ".sdata"),
4280 MAPPING_INIT(".sbss2.", ".sbss"),
4281 MAPPING_INIT(".lrodata.", ".lrodata"),
4282 MAPPING_INIT(".ldata.", ".ldata"),
4283 MAPPING_INIT(".lbss.", ".lbss"),
4284 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4285 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4286 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4287 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4288 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4289 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4290 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4291 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4292 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4293 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4294 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4295 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4296 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4297 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4298 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4299 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4300 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4301 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4302 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4303 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4304 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4308 const int Layout::section_name_mapping_count =
4309 (sizeof(Layout::section_name_mapping)
4310 / sizeof(Layout::section_name_mapping[0]));
4312 // Choose the output section name to use given an input section name.
4313 // Set *PLEN to the length of the name. *PLEN is initialized to the
4317 Layout::output_section_name(const Relobj* relobj, const char* name,
4320 // gcc 4.3 generates the following sorts of section names when it
4321 // needs a section name specific to a function:
4327 // .data.rel.local.FN
4329 // .data.rel.ro.local.FN
4336 // The GNU linker maps all of those to the part before the .FN,
4337 // except that .data.rel.local.FN is mapped to .data, and
4338 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4339 // beginning with .data.rel.ro.local are grouped together.
4341 // For an anonymous namespace, the string FN can contain a '.'.
4343 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4344 // GNU linker maps to .rodata.
4346 // The .data.rel.ro sections are used with -z relro. The sections
4347 // are recognized by name. We use the same names that the GNU
4348 // linker does for these sections.
4350 // It is hard to handle this in a principled way, so we don't even
4351 // try. We use a table of mappings. If the input section name is
4352 // not found in the table, we simply use it as the output section
4355 const Section_name_mapping* psnm = section_name_mapping;
4356 for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
4358 if (strncmp(name, psnm->from, psnm->fromlen) == 0)
4360 *plen = psnm->tolen;
4365 // As an additional complication, .ctors sections are output in
4366 // either .ctors or .init_array sections, and .dtors sections are
4367 // output in either .dtors or .fini_array sections.
4368 if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name))
4370 if (parameters->options().ctors_in_init_array())
4373 return name[1] == 'c' ? ".init_array" : ".fini_array";
4378 return name[1] == 'c' ? ".ctors" : ".dtors";
4381 if (parameters->options().ctors_in_init_array()
4382 && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0))
4384 // To make .init_array/.fini_array work with gcc we must exclude
4385 // .ctors and .dtors sections from the crtbegin and crtend
4388 || (!Layout::match_file_name(relobj, "crtbegin")
4389 && !Layout::match_file_name(relobj, "crtend")))
4392 return name[1] == 'c' ? ".init_array" : ".fini_array";
4399 // Return true if RELOBJ is an input file whose base name matches
4400 // FILE_NAME. The base name must have an extension of ".o", and must
4401 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
4402 // to match crtbegin.o as well as crtbeginS.o without getting confused
4403 // by other possibilities. Overall matching the file name this way is
4404 // a dreadful hack, but the GNU linker does it in order to better
4405 // support gcc, and we need to be compatible.
4408 Layout::match_file_name(const Relobj* relobj, const char* match)
4410 const std::string& file_name(relobj->name());
4411 const char* base_name = lbasename(file_name.c_str());
4412 size_t match_len = strlen(match);
4413 if (strncmp(base_name, match, match_len) != 0)
4415 size_t base_len = strlen(base_name);
4416 if (base_len != match_len + 2 && base_len != match_len + 3)
4418 return memcmp(base_name + base_len - 2, ".o", 2) == 0;
4421 // Check if a comdat group or .gnu.linkonce section with the given
4422 // NAME is selected for the link. If there is already a section,
4423 // *KEPT_SECTION is set to point to the existing section and the
4424 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4425 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4426 // *KEPT_SECTION is set to the internal copy and the function returns
4430 Layout::find_or_add_kept_section(const std::string& name,
4435 Kept_section** kept_section)
4437 // It's normal to see a couple of entries here, for the x86 thunk
4438 // sections. If we see more than a few, we're linking a C++
4439 // program, and we resize to get more space to minimize rehashing.
4440 if (this->signatures_.size() > 4
4441 && !this->resized_signatures_)
4443 reserve_unordered_map(&this->signatures_,
4444 this->number_of_input_files_ * 64);
4445 this->resized_signatures_ = true;
4448 Kept_section candidate;
4449 std::pair<Signatures::iterator, bool> ins =
4450 this->signatures_.insert(std::make_pair(name, candidate));
4452 if (kept_section != NULL)
4453 *kept_section = &ins.first->second;
4456 // This is the first time we've seen this signature.
4457 ins.first->second.set_object(object);
4458 ins.first->second.set_shndx(shndx);
4460 ins.first->second.set_is_comdat();
4462 ins.first->second.set_is_group_name();
4466 // We have already seen this signature.
4468 if (ins.first->second.is_group_name())
4470 // We've already seen a real section group with this signature.
4471 // If the kept group is from a plugin object, and we're in the
4472 // replacement phase, accept the new one as a replacement.
4473 if (ins.first->second.object() == NULL
4474 && parameters->options().plugins()->in_replacement_phase())
4476 ins.first->second.set_object(object);
4477 ins.first->second.set_shndx(shndx);
4482 else if (is_group_name)
4484 // This is a real section group, and we've already seen a
4485 // linkonce section with this signature. Record that we've seen
4486 // a section group, and don't include this section group.
4487 ins.first->second.set_is_group_name();
4492 // We've already seen a linkonce section and this is a linkonce
4493 // section. These don't block each other--this may be the same
4494 // symbol name with different section types.
4499 // Store the allocated sections into the section list.
4502 Layout::get_allocated_sections(Section_list* section_list) const
4504 for (Section_list::const_iterator p = this->section_list_.begin();
4505 p != this->section_list_.end();
4507 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
4508 section_list->push_back(*p);
4511 // Create an output segment.
4514 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
4516 gold_assert(!parameters->options().relocatable());
4517 Output_segment* oseg = new Output_segment(type, flags);
4518 this->segment_list_.push_back(oseg);
4520 if (type == elfcpp::PT_TLS)
4521 this->tls_segment_ = oseg;
4522 else if (type == elfcpp::PT_GNU_RELRO)
4523 this->relro_segment_ = oseg;
4524 else if (type == elfcpp::PT_INTERP)
4525 this->interp_segment_ = oseg;
4530 // Return the file offset of the normal symbol table.
4533 Layout::symtab_section_offset() const
4535 if (this->symtab_section_ != NULL)
4536 return this->symtab_section_->offset();
4540 // Return the section index of the normal symbol table. It may have
4541 // been stripped by the -s/--strip-all option.
4544 Layout::symtab_section_shndx() const
4546 if (this->symtab_section_ != NULL)
4547 return this->symtab_section_->out_shndx();
4551 // Write out the Output_sections. Most won't have anything to write,
4552 // since most of the data will come from input sections which are
4553 // handled elsewhere. But some Output_sections do have Output_data.
4556 Layout::write_output_sections(Output_file* of) const
4558 for (Section_list::const_iterator p = this->section_list_.begin();
4559 p != this->section_list_.end();
4562 if (!(*p)->after_input_sections())
4567 // Write out data not associated with a section or the symbol table.
4570 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
4572 if (!parameters->options().strip_all())
4574 const Output_section* symtab_section = this->symtab_section_;
4575 for (Section_list::const_iterator p = this->section_list_.begin();
4576 p != this->section_list_.end();
4579 if ((*p)->needs_symtab_index())
4581 gold_assert(symtab_section != NULL);
4582 unsigned int index = (*p)->symtab_index();
4583 gold_assert(index > 0 && index != -1U);
4584 off_t off = (symtab_section->offset()
4585 + index * symtab_section->entsize());
4586 symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
4591 const Output_section* dynsym_section = this->dynsym_section_;
4592 for (Section_list::const_iterator p = this->section_list_.begin();
4593 p != this->section_list_.end();
4596 if ((*p)->needs_dynsym_index())
4598 gold_assert(dynsym_section != NULL);
4599 unsigned int index = (*p)->dynsym_index();
4600 gold_assert(index > 0 && index != -1U);
4601 off_t off = (dynsym_section->offset()
4602 + index * dynsym_section->entsize());
4603 symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
4607 // Write out the Output_data which are not in an Output_section.
4608 for (Data_list::const_iterator p = this->special_output_list_.begin();
4609 p != this->special_output_list_.end();
4614 // Write out the Output_sections which can only be written after the
4615 // input sections are complete.
4618 Layout::write_sections_after_input_sections(Output_file* of)
4620 // Determine the final section offsets, and thus the final output
4621 // file size. Note we finalize the .shstrab last, to allow the
4622 // after_input_section sections to modify their section-names before
4624 if (this->any_postprocessing_sections_)
4626 off_t off = this->output_file_size_;
4627 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
4629 // Now that we've finalized the names, we can finalize the shstrab.
4631 this->set_section_offsets(off,
4632 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
4634 if (off > this->output_file_size_)
4637 this->output_file_size_ = off;
4641 for (Section_list::const_iterator p = this->section_list_.begin();
4642 p != this->section_list_.end();
4645 if ((*p)->after_input_sections())
4649 this->section_headers_->write(of);
4652 // If the build ID requires computing a checksum, do so here, and
4653 // write it out. We compute a checksum over the entire file because
4654 // that is simplest.
4657 Layout::write_build_id(Output_file* of) const
4659 if (this->build_id_note_ == NULL)
4662 const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
4664 unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
4665 this->build_id_note_->data_size());
4667 const char* style = parameters->options().build_id();
4668 if (strcmp(style, "sha1") == 0)
4671 sha1_init_ctx(&ctx);
4672 sha1_process_bytes(iv, this->output_file_size_, &ctx);
4673 sha1_finish_ctx(&ctx, ov);
4675 else if (strcmp(style, "md5") == 0)
4679 md5_process_bytes(iv, this->output_file_size_, &ctx);
4680 md5_finish_ctx(&ctx, ov);
4685 of->write_output_view(this->build_id_note_->offset(),
4686 this->build_id_note_->data_size(),
4689 of->free_input_view(0, this->output_file_size_, iv);
4692 // Write out a binary file. This is called after the link is
4693 // complete. IN is the temporary output file we used to generate the
4694 // ELF code. We simply walk through the segments, read them from
4695 // their file offset in IN, and write them to their load address in
4696 // the output file. FIXME: with a bit more work, we could support
4697 // S-records and/or Intel hex format here.
4700 Layout::write_binary(Output_file* in) const
4702 gold_assert(parameters->options().oformat_enum()
4703 == General_options::OBJECT_FORMAT_BINARY);
4705 // Get the size of the binary file.
4706 uint64_t max_load_address = 0;
4707 for (Segment_list::const_iterator p = this->segment_list_.begin();
4708 p != this->segment_list_.end();
4711 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4713 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
4714 if (max_paddr > max_load_address)
4715 max_load_address = max_paddr;
4719 Output_file out(parameters->options().output_file_name());
4720 out.open(max_load_address);
4722 for (Segment_list::const_iterator p = this->segment_list_.begin();
4723 p != this->segment_list_.end();
4726 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4728 const unsigned char* vin = in->get_input_view((*p)->offset(),
4730 unsigned char* vout = out.get_output_view((*p)->paddr(),
4732 memcpy(vout, vin, (*p)->filesz());
4733 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
4734 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
4741 // Print the output sections to the map file.
4744 Layout::print_to_mapfile(Mapfile* mapfile) const
4746 for (Segment_list::const_iterator p = this->segment_list_.begin();
4747 p != this->segment_list_.end();
4749 (*p)->print_sections_to_mapfile(mapfile);
4752 // Print statistical information to stderr. This is used for --stats.
4755 Layout::print_stats() const
4757 this->namepool_.print_stats("section name pool");
4758 this->sympool_.print_stats("output symbol name pool");
4759 this->dynpool_.print_stats("dynamic name pool");
4761 for (Section_list::const_iterator p = this->section_list_.begin();
4762 p != this->section_list_.end();
4764 (*p)->print_merge_stats();
4767 // Write_sections_task methods.
4769 // We can always run this task.
4772 Write_sections_task::is_runnable()
4777 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4781 Write_sections_task::locks(Task_locker* tl)
4783 tl->add(this, this->output_sections_blocker_);
4784 tl->add(this, this->final_blocker_);
4787 // Run the task--write out the data.
4790 Write_sections_task::run(Workqueue*)
4792 this->layout_->write_output_sections(this->of_);
4795 // Write_data_task methods.
4797 // We can always run this task.
4800 Write_data_task::is_runnable()
4805 // We need to unlock FINAL_BLOCKER when finished.
4808 Write_data_task::locks(Task_locker* tl)
4810 tl->add(this, this->final_blocker_);
4813 // Run the task--write out the data.
4816 Write_data_task::run(Workqueue*)
4818 this->layout_->write_data(this->symtab_, this->of_);
4821 // Write_symbols_task methods.
4823 // We can always run this task.
4826 Write_symbols_task::is_runnable()
4831 // We need to unlock FINAL_BLOCKER when finished.
4834 Write_symbols_task::locks(Task_locker* tl)
4836 tl->add(this, this->final_blocker_);
4839 // Run the task--write out the symbols.
4842 Write_symbols_task::run(Workqueue*)
4844 this->symtab_->write_globals(this->sympool_, this->dynpool_,
4845 this->layout_->symtab_xindex(),
4846 this->layout_->dynsym_xindex(), this->of_);
4849 // Write_after_input_sections_task methods.
4851 // We can only run this task after the input sections have completed.
4854 Write_after_input_sections_task::is_runnable()
4856 if (this->input_sections_blocker_->is_blocked())
4857 return this->input_sections_blocker_;
4861 // We need to unlock FINAL_BLOCKER when finished.
4864 Write_after_input_sections_task::locks(Task_locker* tl)
4866 tl->add(this, this->final_blocker_);
4872 Write_after_input_sections_task::run(Workqueue*)
4874 this->layout_->write_sections_after_input_sections(this->of_);
4877 // Close_task_runner methods.
4879 // Run the task--close the file.
4882 Close_task_runner::run(Workqueue*, const Task*)
4884 // If we need to compute a checksum for the BUILD if, we do so here.
4885 this->layout_->write_build_id(this->of_);
4887 // If we've been asked to create a binary file, we do so here.
4888 if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
4889 this->layout_->write_binary(this->of_);
4894 // Instantiate the templates we need. We could use the configure
4895 // script to restrict this to only the ones for implemented targets.
4897 #ifdef HAVE_TARGET_32_LITTLE
4900 Layout::init_fixed_output_section<32, false>(
4902 elfcpp::Shdr<32, false>& shdr);
4905 #ifdef HAVE_TARGET_32_BIG
4908 Layout::init_fixed_output_section<32, true>(
4910 elfcpp::Shdr<32, true>& shdr);
4913 #ifdef HAVE_TARGET_64_LITTLE
4916 Layout::init_fixed_output_section<64, false>(
4918 elfcpp::Shdr<64, false>& shdr);
4921 #ifdef HAVE_TARGET_64_BIG
4924 Layout::init_fixed_output_section<64, true>(
4926 elfcpp::Shdr<64, true>& shdr);
4929 #ifdef HAVE_TARGET_32_LITTLE
4932 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
4935 const elfcpp::Shdr<32, false>& shdr,
4936 unsigned int, unsigned int, off_t*);
4939 #ifdef HAVE_TARGET_32_BIG
4942 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
4945 const elfcpp::Shdr<32, true>& shdr,
4946 unsigned int, unsigned int, off_t*);
4949 #ifdef HAVE_TARGET_64_LITTLE
4952 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
4955 const elfcpp::Shdr<64, false>& shdr,
4956 unsigned int, unsigned int, off_t*);
4959 #ifdef HAVE_TARGET_64_BIG
4962 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
4965 const elfcpp::Shdr<64, true>& shdr,
4966 unsigned int, unsigned int, off_t*);
4969 #ifdef HAVE_TARGET_32_LITTLE
4972 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
4973 unsigned int reloc_shndx,
4974 const elfcpp::Shdr<32, false>& shdr,
4975 Output_section* data_section,
4976 Relocatable_relocs* rr);
4979 #ifdef HAVE_TARGET_32_BIG
4982 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
4983 unsigned int reloc_shndx,
4984 const elfcpp::Shdr<32, true>& shdr,
4985 Output_section* data_section,
4986 Relocatable_relocs* rr);
4989 #ifdef HAVE_TARGET_64_LITTLE
4992 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
4993 unsigned int reloc_shndx,
4994 const elfcpp::Shdr<64, false>& shdr,
4995 Output_section* data_section,
4996 Relocatable_relocs* rr);
4999 #ifdef HAVE_TARGET_64_BIG
5002 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
5003 unsigned int reloc_shndx,
5004 const elfcpp::Shdr<64, true>& shdr,
5005 Output_section* data_section,
5006 Relocatable_relocs* rr);
5009 #ifdef HAVE_TARGET_32_LITTLE
5012 Layout::layout_group<32, false>(Symbol_table* symtab,
5013 Sized_relobj_file<32, false>* object,
5015 const char* group_section_name,
5016 const char* signature,
5017 const elfcpp::Shdr<32, false>& shdr,
5018 elfcpp::Elf_Word flags,
5019 std::vector<unsigned int>* shndxes);
5022 #ifdef HAVE_TARGET_32_BIG
5025 Layout::layout_group<32, true>(Symbol_table* symtab,
5026 Sized_relobj_file<32, true>* object,
5028 const char* group_section_name,
5029 const char* signature,
5030 const elfcpp::Shdr<32, true>& shdr,
5031 elfcpp::Elf_Word flags,
5032 std::vector<unsigned int>* shndxes);
5035 #ifdef HAVE_TARGET_64_LITTLE
5038 Layout::layout_group<64, false>(Symbol_table* symtab,
5039 Sized_relobj_file<64, false>* object,
5041 const char* group_section_name,
5042 const char* signature,
5043 const elfcpp::Shdr<64, false>& shdr,
5044 elfcpp::Elf_Word flags,
5045 std::vector<unsigned int>* shndxes);
5048 #ifdef HAVE_TARGET_64_BIG
5051 Layout::layout_group<64, true>(Symbol_table* symtab,
5052 Sized_relobj_file<64, true>* object,
5054 const char* group_section_name,
5055 const char* signature,
5056 const elfcpp::Shdr<64, true>& shdr,
5057 elfcpp::Elf_Word flags,
5058 std::vector<unsigned int>* shndxes);
5061 #ifdef HAVE_TARGET_32_LITTLE
5064 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
5065 const unsigned char* symbols,
5067 const unsigned char* symbol_names,
5068 off_t symbol_names_size,
5070 const elfcpp::Shdr<32, false>& shdr,
5071 unsigned int reloc_shndx,
5072 unsigned int reloc_type,
5076 #ifdef HAVE_TARGET_32_BIG
5079 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
5080 const unsigned char* symbols,
5082 const unsigned char* symbol_names,
5083 off_t symbol_names_size,
5085 const elfcpp::Shdr<32, true>& shdr,
5086 unsigned int reloc_shndx,
5087 unsigned int reloc_type,
5091 #ifdef HAVE_TARGET_64_LITTLE
5094 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
5095 const unsigned char* symbols,
5097 const unsigned char* symbol_names,
5098 off_t symbol_names_size,
5100 const elfcpp::Shdr<64, false>& shdr,
5101 unsigned int reloc_shndx,
5102 unsigned int reloc_type,
5106 #ifdef HAVE_TARGET_64_BIG
5109 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
5110 const unsigned char* symbols,
5112 const unsigned char* symbol_names,
5113 off_t symbol_names_size,
5115 const elfcpp::Shdr<64, true>& shdr,
5116 unsigned int reloc_shndx,
5117 unsigned int reloc_type,
5121 } // End namespace gold.