1 // layout.cc -- lay out output file sections for gold
3 // Copyright (C) 2006-2019 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
34 #include "libiberty.h"
42 #include "parameters.h"
46 #include "script-sections.h"
51 #include "gdb-index.h"
52 #include "compressed_output.h"
53 #include "reduced_debug_output.h"
56 #include "descriptors.h"
58 #include "incremental.h"
66 // The total number of free lists used.
67 unsigned int Free_list::num_lists
= 0;
68 // The total number of free list nodes used.
69 unsigned int Free_list::num_nodes
= 0;
70 // The total number of calls to Free_list::remove.
71 unsigned int Free_list::num_removes
= 0;
72 // The total number of nodes visited during calls to Free_list::remove.
73 unsigned int Free_list::num_remove_visits
= 0;
74 // The total number of calls to Free_list::allocate.
75 unsigned int Free_list::num_allocates
= 0;
76 // The total number of nodes visited during calls to Free_list::allocate.
77 unsigned int Free_list::num_allocate_visits
= 0;
79 // Initialize the free list. Creates a single free list node that
80 // describes the entire region of length LEN. If EXTEND is true,
81 // allocate() is allowed to extend the region beyond its initial
85 Free_list::init(off_t len
, bool extend
)
87 this->list_
.push_front(Free_list_node(0, len
));
88 this->last_remove_
= this->list_
.begin();
89 this->extend_
= extend
;
91 ++Free_list::num_lists
;
92 ++Free_list::num_nodes
;
95 // Remove a chunk from the free list. Because we start with a single
96 // node that covers the entire section, and remove chunks from it one
97 // at a time, we do not need to coalesce chunks or handle cases that
98 // span more than one free node. We expect to remove chunks from the
99 // free list in order, and we expect to have only a few chunks of free
100 // space left (corresponding to files that have changed since the last
101 // incremental link), so a simple linear list should provide sufficient
105 Free_list::remove(off_t start
, off_t end
)
109 gold_assert(start
< end
);
111 ++Free_list::num_removes
;
113 Iterator p
= this->last_remove_
;
114 if (p
->start_
> start
)
115 p
= this->list_
.begin();
117 for (; p
!= this->list_
.end(); ++p
)
119 ++Free_list::num_remove_visits
;
120 // Find a node that wholly contains the indicated region.
121 if (p
->start_
<= start
&& p
->end_
>= end
)
123 // Case 1: the indicated region spans the whole node.
124 // Add some fuzz to avoid creating tiny free chunks.
125 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
126 p
= this->list_
.erase(p
);
127 // Case 2: remove a chunk from the start of the node.
128 else if (p
->start_
+ 3 >= start
)
130 // Case 3: remove a chunk from the end of the node.
131 else if (p
->end_
<= end
+ 3)
133 // Case 4: remove a chunk from the middle, and split
134 // the node into two.
137 Free_list_node
newnode(p
->start_
, start
);
139 this->list_
.insert(p
, newnode
);
140 ++Free_list::num_nodes
;
142 this->last_remove_
= p
;
147 // Did not find a node containing the given chunk. This could happen
148 // because a small chunk was already removed due to the fuzz.
149 gold_debug(DEBUG_INCREMENTAL
,
150 "Free_list::remove(%d,%d) not found",
151 static_cast<int>(start
), static_cast<int>(end
));
154 // Allocate a chunk of size LEN from the free list. Returns -1ULL
155 // if a sufficiently large chunk of free space is not found.
156 // We use a simple first-fit algorithm.
159 Free_list::allocate(off_t len
, uint64_t align
, off_t minoff
)
161 gold_debug(DEBUG_INCREMENTAL
,
162 "Free_list::allocate(%08lx, %d, %08lx)",
163 static_cast<long>(len
), static_cast<int>(align
),
164 static_cast<long>(minoff
));
166 return align_address(minoff
, align
);
168 ++Free_list::num_allocates
;
170 // We usually want to drop free chunks smaller than 4 bytes.
171 // If we need to guarantee a minimum hole size, though, we need
172 // to keep track of all free chunks.
173 const int fuzz
= this->min_hole_
> 0 ? 0 : 3;
175 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
177 ++Free_list::num_allocate_visits
;
178 off_t start
= p
->start_
> minoff
? p
->start_
: minoff
;
179 start
= align_address(start
, align
);
180 off_t end
= start
+ len
;
181 if (end
> p
->end_
&& p
->end_
== this->length_
&& this->extend_
)
186 if (end
== p
->end_
|| (end
<= p
->end_
- this->min_hole_
))
188 if (p
->start_
+ fuzz
>= start
&& p
->end_
<= end
+ fuzz
)
189 this->list_
.erase(p
);
190 else if (p
->start_
+ fuzz
>= start
)
192 else if (p
->end_
<= end
+ fuzz
)
196 Free_list_node
newnode(p
->start_
, start
);
198 this->list_
.insert(p
, newnode
);
199 ++Free_list::num_nodes
;
206 off_t start
= align_address(this->length_
, align
);
207 this->length_
= start
+ len
;
213 // Dump the free list (for debugging).
217 gold_info("Free list:\n start end length\n");
218 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
219 gold_info(" %08lx %08lx %08lx", static_cast<long>(p
->start_
),
220 static_cast<long>(p
->end_
),
221 static_cast<long>(p
->end_
- p
->start_
));
224 // Print the statistics for the free lists.
226 Free_list::print_stats()
228 fprintf(stderr
, _("%s: total free lists: %u\n"),
229 program_name
, Free_list::num_lists
);
230 fprintf(stderr
, _("%s: total free list nodes: %u\n"),
231 program_name
, Free_list::num_nodes
);
232 fprintf(stderr
, _("%s: calls to Free_list::remove: %u\n"),
233 program_name
, Free_list::num_removes
);
234 fprintf(stderr
, _("%s: nodes visited: %u\n"),
235 program_name
, Free_list::num_remove_visits
);
236 fprintf(stderr
, _("%s: calls to Free_list::allocate: %u\n"),
237 program_name
, Free_list::num_allocates
);
238 fprintf(stderr
, _("%s: nodes visited: %u\n"),
239 program_name
, Free_list::num_allocate_visits
);
242 // A Hash_task computes the MD5 checksum of an array of char.
244 class Hash_task
: public Task
247 Hash_task(Output_file
* of
,
251 Task_token
* final_blocker
)
252 : of_(of
), offset_(offset
), size_(size
), dst_(dst
),
253 final_blocker_(final_blocker
)
259 const unsigned char* iv
=
260 this->of_
->get_input_view(this->offset_
, this->size_
);
261 md5_buffer(reinterpret_cast<const char*>(iv
), this->size_
, this->dst_
);
262 this->of_
->free_input_view(this->offset_
, this->size_
, iv
);
269 // Unblock FINAL_BLOCKER_ when done.
271 locks(Task_locker
* tl
)
272 { tl
->add(this, this->final_blocker_
); }
276 { return "Hash_task"; }
280 const size_t offset_
;
282 unsigned char* const dst_
;
283 Task_token
* const final_blocker_
;
286 // Layout::Relaxation_debug_check methods.
288 // Check that sections and special data are in reset states.
289 // We do not save states for Output_sections and special Output_data.
290 // So we check that they have not assigned any addresses or offsets.
291 // clean_up_after_relaxation simply resets their addresses and offsets.
293 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
294 const Layout::Section_list
& sections
,
295 const Layout::Data_list
& special_outputs
,
296 const Layout::Data_list
& relax_outputs
)
298 for(Layout::Section_list::const_iterator p
= sections
.begin();
301 gold_assert((*p
)->address_and_file_offset_have_reset_values());
303 for(Layout::Data_list::const_iterator p
= special_outputs
.begin();
304 p
!= special_outputs
.end();
306 gold_assert((*p
)->address_and_file_offset_have_reset_values());
308 gold_assert(relax_outputs
.empty());
311 // Save information of SECTIONS for checking later.
314 Layout::Relaxation_debug_check::read_sections(
315 const Layout::Section_list
& sections
)
317 for(Layout::Section_list::const_iterator p
= sections
.begin();
321 Output_section
* os
= *p
;
323 info
.output_section
= os
;
324 info
.address
= os
->is_address_valid() ? os
->address() : 0;
325 info
.data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
326 info
.offset
= os
->is_offset_valid()? os
->offset() : -1 ;
327 this->section_infos_
.push_back(info
);
331 // Verify SECTIONS using previously recorded information.
334 Layout::Relaxation_debug_check::verify_sections(
335 const Layout::Section_list
& sections
)
338 for(Layout::Section_list::const_iterator p
= sections
.begin();
342 Output_section
* os
= *p
;
343 uint64_t address
= os
->is_address_valid() ? os
->address() : 0;
344 off_t data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
345 off_t offset
= os
->is_offset_valid()? os
->offset() : -1 ;
347 if (i
>= this->section_infos_
.size())
349 gold_fatal("Section_info of %s missing.\n", os
->name());
351 const Section_info
& info
= this->section_infos_
[i
];
352 if (os
!= info
.output_section
)
353 gold_fatal("Section order changed. Expecting %s but see %s\n",
354 info
.output_section
->name(), os
->name());
355 if (address
!= info
.address
356 || data_size
!= info
.data_size
357 || offset
!= info
.offset
)
358 gold_fatal("Section %s changed.\n", os
->name());
362 // Layout_task_runner methods.
364 // Lay out the sections. This is called after all the input objects
368 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
370 // See if any of the input definitions violate the One Definition Rule.
371 // TODO: if this is too slow, do this as a task, rather than inline.
372 this->symtab_
->detect_odr_violations(task
, this->options_
.output_file_name());
374 Layout
* layout
= this->layout_
;
375 off_t file_size
= layout
->finalize(this->input_objects_
,
380 // Now we know the final size of the output file and we know where
381 // each piece of information goes.
383 if (this->mapfile_
!= NULL
)
385 this->mapfile_
->print_discarded_sections(this->input_objects_
);
386 layout
->print_to_mapfile(this->mapfile_
);
390 if (layout
->incremental_base() == NULL
)
392 of
= new Output_file(parameters
->options().output_file_name());
393 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
394 of
->set_is_temporary();
399 of
= layout
->incremental_base()->output_file();
401 // Apply the incremental relocations for symbols whose values
402 // have changed. We do this before we resize the file and start
403 // writing anything else to it, so that we can read the old
404 // incremental information from the file before (possibly)
406 if (parameters
->incremental_update())
407 layout
->incremental_base()->apply_incremental_relocs(this->symtab_
,
411 of
->resize(file_size
);
414 // Queue up the final set of tasks.
415 gold::queue_final_tasks(this->options_
, this->input_objects_
,
416 this->symtab_
, layout
, workqueue
, of
);
421 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
422 : number_of_input_files_(number_of_input_files
),
423 script_options_(script_options
),
431 unattached_section_list_(),
432 special_output_list_(),
433 relax_output_list_(),
434 section_headers_(NULL
),
436 relro_segment_(NULL
),
437 interp_segment_(NULL
),
439 symtab_section_(NULL
),
440 symtab_xindex_(NULL
),
441 dynsym_section_(NULL
),
442 dynsym_xindex_(NULL
),
443 dynamic_section_(NULL
),
444 dynamic_symbol_(NULL
),
446 eh_frame_section_(NULL
),
447 eh_frame_data_(NULL
),
448 added_eh_frame_data_(false),
449 eh_frame_hdr_section_(NULL
),
450 gdb_index_data_(NULL
),
451 build_id_note_(NULL
),
455 output_file_size_(-1),
456 have_added_input_section_(false),
457 sections_are_attached_(false),
458 input_requires_executable_stack_(false),
459 input_with_gnu_stack_note_(false),
460 input_without_gnu_stack_note_(false),
461 has_static_tls_(false),
462 any_postprocessing_sections_(false),
463 resized_signatures_(false),
464 have_stabstr_section_(false),
465 section_ordering_specified_(false),
466 unique_segment_for_sections_specified_(false),
467 incremental_inputs_(NULL
),
468 record_output_section_data_from_script_(false),
469 script_output_section_data_list_(),
470 segment_states_(NULL
),
471 relaxation_debug_check_(NULL
),
472 section_order_map_(),
473 section_segment_map_(),
474 input_section_position_(),
475 input_section_glob_(),
476 incremental_base_(NULL
),
480 // Make space for more than enough segments for a typical file.
481 // This is just for efficiency--it's OK if we wind up needing more.
482 this->segment_list_
.reserve(12);
484 // We expect two unattached Output_data objects: the file header and
485 // the segment headers.
486 this->special_output_list_
.reserve(2);
488 // Initialize structure needed for an incremental build.
489 if (parameters
->incremental())
490 this->incremental_inputs_
= new Incremental_inputs
;
492 // The section name pool is worth optimizing in all cases, because
493 // it is small, but there are often overlaps due to .rel sections.
494 this->namepool_
.set_optimize();
497 // For incremental links, record the base file to be modified.
500 Layout::set_incremental_base(Incremental_binary
* base
)
502 this->incremental_base_
= base
;
503 this->free_list_
.init(base
->output_file()->filesize(), true);
506 // Hash a key we use to look up an output section mapping.
509 Layout::Hash_key::operator()(const Layout::Key
& k
) const
511 return k
.first
+ k
.second
.first
+ k
.second
.second
;
514 // These are the debug sections that are actually used by gdb.
515 // Currently, we've checked versions of gdb up to and including 7.4.
516 // We only check the part of the name that follows ".debug_" or
519 static const char* gdb_sections
[] =
522 "addr", // Fission extension
523 // "aranges", // not used by gdb as of 7.4
532 // "pubnames", // not used by gdb as of 7.4
533 // "pubtypes", // not used by gdb as of 7.4
534 // "gnu_pubnames", // Fission extension
535 // "gnu_pubtypes", // Fission extension
541 // This is the minimum set of sections needed for line numbers.
543 static const char* lines_only_debug_sections
[] =
546 // "addr", // Fission extension
547 // "aranges", // not used by gdb as of 7.4
556 // "pubnames", // not used by gdb as of 7.4
557 // "pubtypes", // not used by gdb as of 7.4
558 // "gnu_pubnames", // Fission extension
559 // "gnu_pubtypes", // Fission extension
562 "str_offsets", // Fission extension
565 // These sections are the DWARF fast-lookup tables, and are not needed
566 // when building a .gdb_index section.
568 static const char* gdb_fast_lookup_sections
[] =
577 // Returns whether the given debug section is in the list of
578 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
579 // portion of the name following ".debug_" or ".zdebug_".
582 is_gdb_debug_section(const char* suffix
)
584 // We can do this faster: binary search or a hashtable. But why bother?
585 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
586 if (strcmp(suffix
, gdb_sections
[i
]) == 0)
591 // Returns whether the given section is needed for lines-only debugging.
594 is_lines_only_debug_section(const char* suffix
)
596 // We can do this faster: binary search or a hashtable. But why bother?
598 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
600 if (strcmp(suffix
, lines_only_debug_sections
[i
]) == 0)
605 // Returns whether the given section is a fast-lookup section that
606 // will not be needed when building a .gdb_index section.
609 is_gdb_fast_lookup_section(const char* suffix
)
611 // We can do this faster: binary search or a hashtable. But why bother?
613 i
< sizeof(gdb_fast_lookup_sections
)/sizeof(*gdb_fast_lookup_sections
);
615 if (strcmp(suffix
, gdb_fast_lookup_sections
[i
]) == 0)
620 // Sometimes we compress sections. This is typically done for
621 // sections that are not part of normal program execution (such as
622 // .debug_* sections), and where the readers of these sections know
623 // how to deal with compressed sections. This routine doesn't say for
624 // certain whether we'll compress -- it depends on commandline options
625 // as well -- just whether this section is a candidate for compression.
626 // (The Output_compressed_section class decides whether to compress
627 // a given section, and picks the name of the compressed section.)
630 is_compressible_debug_section(const char* secname
)
632 return (is_prefix_of(".debug", secname
));
635 // We may see compressed debug sections in input files. Return TRUE
636 // if this is the name of a compressed debug section.
639 is_compressed_debug_section(const char* secname
)
641 return (is_prefix_of(".zdebug", secname
));
645 corresponding_uncompressed_section_name(std::string secname
)
647 gold_assert(secname
[0] == '.' && secname
[1] == 'z');
648 std::string
ret(".");
649 ret
.append(secname
, 2, std::string::npos
);
653 // Whether to include this section in the link.
655 template<int size
, bool big_endian
>
657 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
658 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
660 if (!parameters
->options().relocatable()
661 && (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
))
664 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
666 if ((sh_type
>= elfcpp::SHT_LOOS
&& sh_type
<= elfcpp::SHT_HIOS
)
667 || (sh_type
>= elfcpp::SHT_LOPROC
&& sh_type
<= elfcpp::SHT_HIPROC
))
668 return parameters
->target().should_include_section(sh_type
);
672 case elfcpp::SHT_NULL
:
673 case elfcpp::SHT_SYMTAB
:
674 case elfcpp::SHT_DYNSYM
:
675 case elfcpp::SHT_HASH
:
676 case elfcpp::SHT_DYNAMIC
:
677 case elfcpp::SHT_SYMTAB_SHNDX
:
680 case elfcpp::SHT_STRTAB
:
681 // Discard the sections which have special meanings in the ELF
682 // ABI. Keep others (e.g., .stabstr). We could also do this by
683 // checking the sh_link fields of the appropriate sections.
684 return (strcmp(name
, ".dynstr") != 0
685 && strcmp(name
, ".strtab") != 0
686 && strcmp(name
, ".shstrtab") != 0);
688 case elfcpp::SHT_RELA
:
689 case elfcpp::SHT_REL
:
690 case elfcpp::SHT_GROUP
:
691 // If we are emitting relocations these should be handled
693 gold_assert(!parameters
->options().relocatable());
696 case elfcpp::SHT_PROGBITS
:
697 if (parameters
->options().strip_debug()
698 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
700 if (is_debug_info_section(name
))
703 if (parameters
->options().strip_debug_non_line()
704 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
706 // Debugging sections can only be recognized by name.
707 if (is_prefix_of(".debug_", name
)
708 && !is_lines_only_debug_section(name
+ 7))
710 if (is_prefix_of(".zdebug_", name
)
711 && !is_lines_only_debug_section(name
+ 8))
714 if (parameters
->options().strip_debug_gdb()
715 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
717 // Debugging sections can only be recognized by name.
718 if (is_prefix_of(".debug_", name
)
719 && !is_gdb_debug_section(name
+ 7))
721 if (is_prefix_of(".zdebug_", name
)
722 && !is_gdb_debug_section(name
+ 8))
725 if (parameters
->options().gdb_index()
726 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
728 // When building .gdb_index, we can strip .debug_pubnames,
729 // .debug_pubtypes, and .debug_aranges sections.
730 if (is_prefix_of(".debug_", name
)
731 && is_gdb_fast_lookup_section(name
+ 7))
733 if (is_prefix_of(".zdebug_", name
)
734 && is_gdb_fast_lookup_section(name
+ 8))
737 if (parameters
->options().strip_lto_sections()
738 && !parameters
->options().relocatable()
739 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
741 // Ignore LTO sections containing intermediate code.
742 if (is_prefix_of(".gnu.lto_", name
))
745 // The GNU linker strips .gnu_debuglink sections, so we do too.
746 // This is a feature used to keep debugging information in
748 if (strcmp(name
, ".gnu_debuglink") == 0)
757 // Return an output section named NAME, or NULL if there is none.
760 Layout::find_output_section(const char* name
) const
762 for (Section_list::const_iterator p
= this->section_list_
.begin();
763 p
!= this->section_list_
.end();
765 if (strcmp((*p
)->name(), name
) == 0)
770 // Return an output segment of type TYPE, with segment flags SET set
771 // and segment flags CLEAR clear. Return NULL if there is none.
774 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
775 elfcpp::Elf_Word clear
) const
777 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
778 p
!= this->segment_list_
.end();
780 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
781 && ((*p
)->flags() & set
) == set
782 && ((*p
)->flags() & clear
) == 0)
787 // When we put a .ctors or .dtors section with more than one word into
788 // a .init_array or .fini_array section, we need to reverse the words
789 // in the .ctors/.dtors section. This is because .init_array executes
790 // constructors front to back, where .ctors executes them back to
791 // front, and vice-versa for .fini_array/.dtors. Although we do want
792 // to remap .ctors/.dtors into .init_array/.fini_array because it can
793 // be more efficient, we don't want to change the order in which
794 // constructors/destructors are run. This set just keeps track of
795 // these sections which need to be reversed. It is only changed by
796 // Layout::layout. It should be a private member of Layout, but that
797 // would require layout.h to #include object.h to get the definition
799 static Unordered_set
<Section_id
, Section_id_hash
> ctors_sections_in_init_array
;
801 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
802 // .init_array/.fini_array section.
805 Layout::is_ctors_in_init_array(Relobj
* relobj
, unsigned int shndx
) const
807 return (ctors_sections_in_init_array
.find(Section_id(relobj
, shndx
))
808 != ctors_sections_in_init_array
.end());
811 // Return the output section to use for section NAME with type TYPE
812 // and section flags FLAGS. NAME must be canonicalized in the string
813 // pool, and NAME_KEY is the key. ORDER is where this should appear
814 // in the output sections. IS_RELRO is true for a relro section.
817 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
818 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
819 Output_section_order order
, bool is_relro
)
821 elfcpp::Elf_Word lookup_type
= type
;
823 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
824 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
825 // .init_array, .fini_array, and .preinit_array sections by name
826 // whatever their type in the input file. We do this because the
827 // types are not always right in the input files.
828 if (lookup_type
== elfcpp::SHT_INIT_ARRAY
829 || lookup_type
== elfcpp::SHT_FINI_ARRAY
830 || lookup_type
== elfcpp::SHT_PREINIT_ARRAY
)
831 lookup_type
= elfcpp::SHT_PROGBITS
;
833 elfcpp::Elf_Xword lookup_flags
= flags
;
835 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
836 // read-write with read-only sections. Some other ELF linkers do
837 // not do this. FIXME: Perhaps there should be an option
839 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
841 const Key
key(name_key
, std::make_pair(lookup_type
, lookup_flags
));
842 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
843 std::pair
<Section_name_map::iterator
, bool> ins(
844 this->section_name_map_
.insert(v
));
847 return ins
.first
->second
;
850 // This is the first time we've seen this name/type/flags
851 // combination. For compatibility with the GNU linker, we
852 // combine sections with contents and zero flags with sections
853 // with non-zero flags. This is a workaround for cases where
854 // assembler code forgets to set section flags. FIXME: Perhaps
855 // there should be an option to control this.
856 Output_section
* os
= NULL
;
858 if (lookup_type
== elfcpp::SHT_PROGBITS
)
862 Output_section
* same_name
= this->find_output_section(name
);
863 if (same_name
!= NULL
864 && (same_name
->type() == elfcpp::SHT_PROGBITS
865 || same_name
->type() == elfcpp::SHT_INIT_ARRAY
866 || same_name
->type() == elfcpp::SHT_FINI_ARRAY
867 || same_name
->type() == elfcpp::SHT_PREINIT_ARRAY
)
868 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
871 else if ((flags
& elfcpp::SHF_TLS
) == 0)
873 elfcpp::Elf_Xword zero_flags
= 0;
874 const Key
zero_key(name_key
, std::make_pair(lookup_type
,
876 Section_name_map::iterator p
=
877 this->section_name_map_
.find(zero_key
);
878 if (p
!= this->section_name_map_
.end())
884 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
886 ins
.first
->second
= os
;
891 // Returns TRUE iff NAME (an input section from RELOBJ) will
892 // be mapped to an output section that should be KEPT.
895 Layout::keep_input_section(const Relobj
* relobj
, const char* name
)
897 if (! this->script_options_
->saw_sections_clause())
900 Script_sections
* ss
= this->script_options_
->script_sections();
901 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
902 Output_section
** output_section_slot
;
903 Script_sections::Section_type script_section_type
;
906 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
907 &script_section_type
, &keep
, true);
908 return name
!= NULL
&& keep
;
911 // Clear the input section flags that should not be copied to the
915 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags
)
917 // Some flags in the input section should not be automatically
918 // copied to the output section.
919 input_section_flags
&= ~ (elfcpp::SHF_INFO_LINK
921 | elfcpp::SHF_COMPRESSED
923 | elfcpp::SHF_STRINGS
);
925 // We only clear the SHF_LINK_ORDER flag in for
926 // a non-relocatable link.
927 if (!parameters
->options().relocatable())
928 input_section_flags
&= ~elfcpp::SHF_LINK_ORDER
;
930 return input_section_flags
;
933 // Pick the output section to use for section NAME, in input file
934 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
935 // linker created section. IS_INPUT_SECTION is true if we are
936 // choosing an output section for an input section found in a input
937 // file. ORDER is where this section should appear in the output
938 // sections. IS_RELRO is true for a relro section. This will return
939 // NULL if the input section should be discarded. MATCH_INPUT_SPEC
940 // is true if the section name should be matched against input specs
941 // in a linker script.
944 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
945 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
946 bool is_input_section
, Output_section_order order
,
947 bool is_relro
, bool is_reloc
,
948 bool match_input_spec
)
950 // We should not see any input sections after we have attached
951 // sections to segments.
952 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
954 flags
= this->get_output_section_flags(flags
);
956 if (this->script_options_
->saw_sections_clause() && !is_reloc
)
958 // We are using a SECTIONS clause, so the output section is
959 // chosen based only on the name.
961 Script_sections
* ss
= this->script_options_
->script_sections();
962 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
963 Output_section
** output_section_slot
;
964 Script_sections::Section_type script_section_type
;
965 const char* orig_name
= name
;
967 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
968 &script_section_type
, &keep
,
973 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
974 "because it is not allowed by the "
975 "SECTIONS clause of the linker script"),
977 // The SECTIONS clause says to discard this input section.
981 // We can only handle script section types ST_NONE and ST_NOLOAD.
982 switch (script_section_type
)
984 case Script_sections::ST_NONE
:
986 case Script_sections::ST_NOLOAD
:
987 flags
&= elfcpp::SHF_ALLOC
;
993 // If this is an orphan section--one not mentioned in the linker
994 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
995 // default processing below.
997 if (output_section_slot
!= NULL
)
999 if (*output_section_slot
!= NULL
)
1001 (*output_section_slot
)->update_flags_for_input_section(flags
);
1002 return *output_section_slot
;
1005 // We don't put sections found in the linker script into
1006 // SECTION_NAME_MAP_. That keeps us from getting confused
1007 // if an orphan section is mapped to a section with the same
1008 // name as one in the linker script.
1010 name
= this->namepool_
.add(name
, false, NULL
);
1012 Output_section
* os
= this->make_output_section(name
, type
, flags
,
1015 os
->set_found_in_sections_clause();
1017 // Special handling for NOLOAD sections.
1018 if (script_section_type
== Script_sections::ST_NOLOAD
)
1020 os
->set_is_noload();
1022 // The constructor of Output_section sets addresses of non-ALLOC
1023 // sections to 0 by default. We don't want that for NOLOAD
1024 // sections even if they have no SHF_ALLOC flag.
1025 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
1026 && os
->is_address_valid())
1028 gold_assert(os
->address() == 0
1029 && !os
->is_offset_valid()
1030 && !os
->is_data_size_valid());
1031 os
->reset_address_and_file_offset();
1035 *output_section_slot
= os
;
1040 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1042 size_t len
= strlen(name
);
1043 std::string uncompressed_name
;
1045 // Compressed debug sections should be mapped to the corresponding
1046 // uncompressed section.
1047 if (is_compressed_debug_section(name
))
1050 corresponding_uncompressed_section_name(std::string(name
, len
));
1051 name
= uncompressed_name
.c_str();
1052 len
= uncompressed_name
.length();
1055 // Turn NAME from the name of the input section into the name of the
1057 if (is_input_section
1058 && !this->script_options_
->saw_sections_clause()
1059 && !parameters
->options().relocatable())
1061 const char *orig_name
= name
;
1062 name
= parameters
->target().output_section_name(relobj
, name
, &len
);
1064 name
= Layout::output_section_name(relobj
, orig_name
, &len
);
1067 Stringpool::Key name_key
;
1068 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
1070 // Find or make the output section. The output section is selected
1071 // based on the section name, type, and flags.
1072 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
1075 // For incremental links, record the initial fixed layout of a section
1076 // from the base file, and return a pointer to the Output_section.
1078 template<int size
, bool big_endian
>
1080 Layout::init_fixed_output_section(const char* name
,
1081 elfcpp::Shdr
<size
, big_endian
>& shdr
)
1083 unsigned int sh_type
= shdr
.get_sh_type();
1085 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1086 // PRE_INIT_ARRAY, and NOTE sections.
1087 // All others will be created from scratch and reallocated.
1088 if (!can_incremental_update(sh_type
))
1091 // If we're generating a .gdb_index section, we need to regenerate
1093 if (parameters
->options().gdb_index()
1094 && sh_type
== elfcpp::SHT_PROGBITS
1095 && strcmp(name
, ".gdb_index") == 0)
1098 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
1099 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
1100 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
1101 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
1102 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
1103 shdr
.get_sh_addralign();
1105 // Make the output section.
1106 Stringpool::Key name_key
;
1107 name
= this->namepool_
.add(name
, true, &name_key
);
1108 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
1109 sh_flags
, ORDER_INVALID
, false);
1110 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
1111 if (sh_type
!= elfcpp::SHT_NOBITS
)
1112 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
1116 // Return the index by which an input section should be ordered. This
1117 // is used to sort some .text sections, for compatibility with GNU ld.
1120 Layout::special_ordering_of_input_section(const char* name
)
1122 // The GNU linker has some special handling for some sections that
1123 // wind up in the .text section. Sections that start with these
1124 // prefixes must appear first, and must appear in the order listed
1126 static const char* const text_section_sort
[] =
1135 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1137 if (is_prefix_of(text_section_sort
[i
], name
))
1143 // Return the output section to use for input section SHNDX, with name
1144 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1145 // index of a relocation section which applies to this section, or 0
1146 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1147 // relocation section if there is one. Set *OFF to the offset of this
1148 // input section without the output section. Return NULL if the
1149 // section should be discarded. Set *OFF to -1 if the section
1150 // contents should not be written directly to the output file, but
1151 // will instead receive special handling.
1153 template<int size
, bool big_endian
>
1155 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1156 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1157 unsigned int sh_type
, unsigned int reloc_shndx
,
1158 unsigned int, off_t
* off
)
1162 if (!this->include_section(object
, name
, shdr
))
1165 // In a relocatable link a grouped section must not be combined with
1166 // any other sections.
1168 if (parameters
->options().relocatable()
1169 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1171 // Some flags in the input section should not be automatically
1172 // copied to the output section.
1173 elfcpp::Elf_Xword flags
= (shdr
.get_sh_flags()
1174 & ~ elfcpp::SHF_COMPRESSED
);
1175 name
= this->namepool_
.add(name
, true, NULL
);
1176 os
= this->make_output_section(name
, sh_type
, flags
,
1177 ORDER_INVALID
, false);
1181 // All ".text.unlikely.*" sections can be moved to a unique
1182 // segment with --text-unlikely-segment option.
1183 bool text_unlikely_segment
1184 = (parameters
->options().text_unlikely_segment()
1185 && is_prefix_of(".text.unlikely",
1186 object
->section_name(shndx
).c_str()));
1187 if (text_unlikely_segment
)
1189 elfcpp::Elf_Xword flags
1190 = this->get_output_section_flags(shdr
.get_sh_flags());
1192 Stringpool::Key name_key
;
1193 const char* os_name
= this->namepool_
.add(".text.unlikely", true,
1195 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1196 ORDER_INVALID
, false);
1197 // Map this output section to a unique segment. This is done to
1198 // separate "text" that is not likely to be executed from "text"
1199 // that is likely executed.
1200 os
->set_is_unique_segment();
1204 // Plugins can choose to place one or more subsets of sections in
1205 // unique segments and this is done by mapping these section subsets
1206 // to unique output sections. Check if this section needs to be
1207 // remapped to a unique output section.
1208 Section_segment_map::iterator it
1209 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1210 if (it
== this->section_segment_map_
.end())
1212 os
= this->choose_output_section(object
, name
, sh_type
,
1213 shdr
.get_sh_flags(), true,
1214 ORDER_INVALID
, false, false,
1219 // We know the name of the output section, directly call
1220 // get_output_section here by-passing choose_output_section.
1221 elfcpp::Elf_Xword flags
1222 = this->get_output_section_flags(shdr
.get_sh_flags());
1224 const char* os_name
= it
->second
->name
;
1225 Stringpool::Key name_key
;
1226 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1227 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1228 ORDER_INVALID
, false);
1229 if (!os
->is_unique_segment())
1231 os
->set_is_unique_segment();
1232 os
->set_extra_segment_flags(it
->second
->flags
);
1233 os
->set_segment_alignment(it
->second
->align
);
1241 // By default the GNU linker sorts input sections whose names match
1242 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1243 // sections are sorted by name. This is used to implement
1244 // constructor priority ordering. We are compatible. When we put
1245 // .ctor sections in .init_array and .dtor sections in .fini_array,
1246 // we must also sort plain .ctor and .dtor sections.
1247 if (!this->script_options_
->saw_sections_clause()
1248 && !parameters
->options().relocatable()
1249 && (is_prefix_of(".ctors.", name
)
1250 || is_prefix_of(".dtors.", name
)
1251 || is_prefix_of(".init_array.", name
)
1252 || is_prefix_of(".fini_array.", name
)
1253 || (parameters
->options().ctors_in_init_array()
1254 && (strcmp(name
, ".ctors") == 0
1255 || strcmp(name
, ".dtors") == 0))))
1256 os
->set_must_sort_attached_input_sections();
1258 // By default the GNU linker sorts some special text sections ahead
1259 // of others. We are compatible.
1260 if (parameters
->options().text_reorder()
1261 && !this->script_options_
->saw_sections_clause()
1262 && !this->is_section_ordering_specified()
1263 && !parameters
->options().relocatable()
1264 && Layout::special_ordering_of_input_section(name
) >= 0)
1265 os
->set_must_sort_attached_input_sections();
1267 // If this is a .ctors or .ctors.* section being mapped to a
1268 // .init_array section, or a .dtors or .dtors.* section being mapped
1269 // to a .fini_array section, we will need to reverse the words if
1270 // there is more than one. Record this section for later. See
1271 // ctors_sections_in_init_array above.
1272 if (!this->script_options_
->saw_sections_clause()
1273 && !parameters
->options().relocatable()
1274 && shdr
.get_sh_size() > size
/ 8
1275 && (((strcmp(name
, ".ctors") == 0
1276 || is_prefix_of(".ctors.", name
))
1277 && strcmp(os
->name(), ".init_array") == 0)
1278 || ((strcmp(name
, ".dtors") == 0
1279 || is_prefix_of(".dtors.", name
))
1280 && strcmp(os
->name(), ".fini_array") == 0)))
1281 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1283 // FIXME: Handle SHF_LINK_ORDER somewhere.
1285 elfcpp::Elf_Xword orig_flags
= os
->flags();
1287 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1288 this->script_options_
->saw_sections_clause());
1290 // If the flags changed, we may have to change the order.
1291 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1293 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1294 elfcpp::Elf_Xword new_flags
=
1295 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1296 if (orig_flags
!= new_flags
)
1297 os
->set_order(this->default_section_order(os
, false));
1300 this->have_added_input_section_
= true;
1305 // Maps section SECN to SEGMENT s.
1307 Layout::insert_section_segment_map(Const_section_id secn
,
1308 Unique_segment_info
*s
)
1310 gold_assert(this->unique_segment_for_sections_specified_
);
1311 this->section_segment_map_
[secn
] = s
;
1314 // Handle a relocation section when doing a relocatable link.
1316 template<int size
, bool big_endian
>
1318 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>*,
1320 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1321 Output_section
* data_section
,
1322 Relocatable_relocs
* rr
)
1324 gold_assert(parameters
->options().relocatable()
1325 || parameters
->options().emit_relocs());
1327 int sh_type
= shdr
.get_sh_type();
1330 if (sh_type
== elfcpp::SHT_REL
)
1332 else if (sh_type
== elfcpp::SHT_RELA
)
1336 name
+= data_section
->name();
1338 // If the output data section already has a reloc section, use that;
1339 // otherwise, make a new one.
1340 Output_section
* os
= data_section
->reloc_section();
1343 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1344 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1345 ORDER_INVALID
, false);
1346 os
->set_should_link_to_symtab();
1347 os
->set_info_section(data_section
);
1348 data_section
->set_reloc_section(os
);
1351 Output_section_data
* posd
;
1352 if (sh_type
== elfcpp::SHT_REL
)
1354 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1355 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1359 else if (sh_type
== elfcpp::SHT_RELA
)
1361 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1362 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1369 os
->add_output_section_data(posd
);
1370 rr
->set_output_data(posd
);
1375 // Handle a group section when doing a relocatable link.
1377 template<int size
, bool big_endian
>
1379 Layout::layout_group(Symbol_table
* symtab
,
1380 Sized_relobj_file
<size
, big_endian
>* object
,
1382 const char* group_section_name
,
1383 const char* signature
,
1384 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1385 elfcpp::Elf_Word flags
,
1386 std::vector
<unsigned int>* shndxes
)
1388 gold_assert(parameters
->options().relocatable());
1389 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1390 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1391 Output_section
* os
= this->make_output_section(group_section_name
,
1393 shdr
.get_sh_flags(),
1394 ORDER_INVALID
, false);
1396 // We need to find a symbol with the signature in the symbol table.
1397 // If we don't find one now, we need to look again later.
1398 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1400 os
->set_info_symndx(sym
);
1403 // Reserve some space to minimize reallocations.
1404 if (this->group_signatures_
.empty())
1405 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1407 // We will wind up using a symbol whose name is the signature.
1408 // So just put the signature in the symbol name pool to save it.
1409 signature
= symtab
->canonicalize_name(signature
);
1410 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1413 os
->set_should_link_to_symtab();
1416 section_size_type entry_count
=
1417 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1418 Output_section_data
* posd
=
1419 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1421 os
->add_output_section_data(posd
);
1424 // Special GNU handling of sections name .eh_frame. They will
1425 // normally hold exception frame data as defined by the C++ ABI
1426 // (http://codesourcery.com/cxx-abi/).
1428 template<int size
, bool big_endian
>
1430 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1431 const unsigned char* symbols
,
1433 const unsigned char* symbol_names
,
1434 off_t symbol_names_size
,
1436 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1437 unsigned int reloc_shndx
, unsigned int reloc_type
,
1440 const unsigned int unwind_section_type
=
1441 parameters
->target().unwind_section_type();
1443 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1444 || shdr
.get_sh_type() == unwind_section_type
);
1445 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1447 Output_section
* os
= this->make_eh_frame_section(object
);
1451 gold_assert(this->eh_frame_section_
== os
);
1453 elfcpp::Elf_Xword orig_flags
= os
->flags();
1455 Eh_frame::Eh_frame_section_disposition disp
=
1456 Eh_frame::EH_UNRECOGNIZED_SECTION
;
1457 if (!parameters
->incremental())
1459 disp
= this->eh_frame_data_
->add_ehframe_input_section(object
,
1469 if (disp
== Eh_frame::EH_OPTIMIZABLE_SECTION
)
1471 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1473 // A writable .eh_frame section is a RELRO section.
1474 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1475 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1478 os
->set_order(ORDER_RELRO
);
1485 if (disp
== Eh_frame::EH_END_MARKER_SECTION
&& !this->added_eh_frame_data_
)
1487 // We found the end marker section, so now we can add the set of
1488 // optimized sections to the output section. We need to postpone
1489 // adding this until we've found a section we can optimize so that
1490 // the .eh_frame section in crtbeginT.o winds up at the start of
1491 // the output section.
1492 os
->add_output_section_data(this->eh_frame_data_
);
1493 this->added_eh_frame_data_
= true;
1496 // We couldn't handle this .eh_frame section for some reason.
1497 // Add it as a normal section.
1498 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1499 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1500 reloc_shndx
, saw_sections_clause
);
1501 this->have_added_input_section_
= true;
1503 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1504 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1505 os
->set_order(this->default_section_order(os
, false));
1511 Layout::finalize_eh_frame_section()
1513 // If we never found an end marker section, we need to add the
1514 // optimized eh sections to the output section now.
1515 if (!parameters
->incremental()
1516 && this->eh_frame_section_
!= NULL
1517 && !this->added_eh_frame_data_
)
1519 this->eh_frame_section_
->add_output_section_data(this->eh_frame_data_
);
1520 this->added_eh_frame_data_
= true;
1524 // Create and return the magic .eh_frame section. Create
1525 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1526 // input .eh_frame section; it may be NULL.
1529 Layout::make_eh_frame_section(const Relobj
* object
)
1531 const unsigned int unwind_section_type
=
1532 parameters
->target().unwind_section_type();
1534 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1535 unwind_section_type
,
1536 elfcpp::SHF_ALLOC
, false,
1537 ORDER_EHFRAME
, false, false,
1542 if (this->eh_frame_section_
== NULL
)
1544 this->eh_frame_section_
= os
;
1545 this->eh_frame_data_
= new Eh_frame();
1547 // For incremental linking, we do not optimize .eh_frame sections
1548 // or create a .eh_frame_hdr section.
1549 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1551 Output_section
* hdr_os
=
1552 this->choose_output_section(NULL
, ".eh_frame_hdr",
1553 unwind_section_type
,
1554 elfcpp::SHF_ALLOC
, false,
1555 ORDER_EHFRAME
, false, false,
1560 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1561 this->eh_frame_data_
);
1562 hdr_os
->add_output_section_data(hdr_posd
);
1564 hdr_os
->set_after_input_sections();
1566 if (!this->script_options_
->saw_phdrs_clause())
1568 Output_segment
* hdr_oseg
;
1569 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1571 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1575 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1583 // Add an exception frame for a PLT. This is called from target code.
1586 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1587 size_t cie_length
, const unsigned char* fde_data
,
1590 if (parameters
->incremental())
1592 // FIXME: Maybe this could work some day....
1595 Output_section
* os
= this->make_eh_frame_section(NULL
);
1598 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1599 fde_data
, fde_length
);
1600 if (!this->added_eh_frame_data_
)
1602 os
->add_output_section_data(this->eh_frame_data_
);
1603 this->added_eh_frame_data_
= true;
1607 // Remove all post-map .eh_frame information for a PLT.
1610 Layout::remove_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1613 if (parameters
->incremental())
1615 // FIXME: Maybe this could work some day....
1618 this->eh_frame_data_
->remove_ehframe_for_plt(plt
, cie_data
, cie_length
);
1621 // Scan a .debug_info or .debug_types section, and add summary
1622 // information to the .gdb_index section.
1624 template<int size
, bool big_endian
>
1626 Layout::add_to_gdb_index(bool is_type_unit
,
1627 Sized_relobj
<size
, big_endian
>* object
,
1628 const unsigned char* symbols
,
1631 unsigned int reloc_shndx
,
1632 unsigned int reloc_type
)
1634 if (this->gdb_index_data_
== NULL
)
1636 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1637 elfcpp::SHT_PROGBITS
, 0,
1638 false, ORDER_INVALID
,
1639 false, false, false);
1643 this->gdb_index_data_
= new Gdb_index(os
);
1644 os
->add_output_section_data(this->gdb_index_data_
);
1645 os
->set_after_input_sections();
1648 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1649 symbols_size
, shndx
, reloc_shndx
,
1653 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1654 // the output section.
1657 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1658 elfcpp::Elf_Xword flags
,
1659 Output_section_data
* posd
,
1660 Output_section_order order
, bool is_relro
)
1662 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1663 false, order
, is_relro
,
1666 os
->add_output_section_data(posd
);
1670 // Map section flags to segment flags.
1673 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1675 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1676 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1677 ret
|= elfcpp::PF_W
;
1678 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1679 ret
|= elfcpp::PF_X
;
1683 // Make a new Output_section, and attach it to segments as
1684 // appropriate. ORDER is the order in which this section should
1685 // appear in the output segment. IS_RELRO is true if this is a relro
1686 // (read-only after relocations) section.
1689 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1690 elfcpp::Elf_Xword flags
,
1691 Output_section_order order
, bool is_relro
)
1694 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1695 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1696 && is_compressible_debug_section(name
))
1697 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1699 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1700 && parameters
->options().strip_debug_non_line()
1701 && strcmp(".debug_abbrev", name
) == 0)
1703 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1705 if (this->debug_info_
)
1706 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1708 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1709 && parameters
->options().strip_debug_non_line()
1710 && strcmp(".debug_info", name
) == 0)
1712 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1714 if (this->debug_abbrev_
)
1715 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1719 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1720 // not have correct section types. Force them here.
1721 if (type
== elfcpp::SHT_PROGBITS
)
1723 if (is_prefix_of(".init_array", name
))
1724 type
= elfcpp::SHT_INIT_ARRAY
;
1725 else if (is_prefix_of(".preinit_array", name
))
1726 type
= elfcpp::SHT_PREINIT_ARRAY
;
1727 else if (is_prefix_of(".fini_array", name
))
1728 type
= elfcpp::SHT_FINI_ARRAY
;
1731 // FIXME: const_cast is ugly.
1732 Target
* target
= const_cast<Target
*>(¶meters
->target());
1733 os
= target
->make_output_section(name
, type
, flags
);
1736 // With -z relro, we have to recognize the special sections by name.
1737 // There is no other way.
1738 bool is_relro_local
= false;
1739 if (!this->script_options_
->saw_sections_clause()
1740 && parameters
->options().relro()
1741 && (flags
& elfcpp::SHF_ALLOC
) != 0
1742 && (flags
& elfcpp::SHF_WRITE
) != 0)
1744 if (type
== elfcpp::SHT_PROGBITS
)
1746 if ((flags
& elfcpp::SHF_TLS
) != 0)
1748 else if (strcmp(name
, ".data.rel.ro") == 0)
1750 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1753 is_relro_local
= true;
1755 else if (strcmp(name
, ".ctors") == 0
1756 || strcmp(name
, ".dtors") == 0
1757 || strcmp(name
, ".jcr") == 0)
1760 else if (type
== elfcpp::SHT_INIT_ARRAY
1761 || type
== elfcpp::SHT_FINI_ARRAY
1762 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1769 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1770 order
= this->default_section_order(os
, is_relro_local
);
1772 os
->set_order(order
);
1774 parameters
->target().new_output_section(os
);
1776 this->section_list_
.push_back(os
);
1778 // The GNU linker by default sorts some sections by priority, so we
1779 // do the same. We need to know that this might happen before we
1780 // attach any input sections.
1781 if (!this->script_options_
->saw_sections_clause()
1782 && !parameters
->options().relocatable()
1783 && (strcmp(name
, ".init_array") == 0
1784 || strcmp(name
, ".fini_array") == 0
1785 || (!parameters
->options().ctors_in_init_array()
1786 && (strcmp(name
, ".ctors") == 0
1787 || strcmp(name
, ".dtors") == 0))))
1788 os
->set_may_sort_attached_input_sections();
1790 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1791 // sections before other .text sections. We are compatible. We
1792 // need to know that this might happen before we attach any input
1794 if (parameters
->options().text_reorder()
1795 && !this->script_options_
->saw_sections_clause()
1796 && !this->is_section_ordering_specified()
1797 && !parameters
->options().relocatable()
1798 && strcmp(name
, ".text") == 0)
1799 os
->set_may_sort_attached_input_sections();
1801 // GNU linker sorts section by name with --sort-section=name.
1802 if (strcmp(parameters
->options().sort_section(), "name") == 0)
1803 os
->set_must_sort_attached_input_sections();
1805 // Check for .stab*str sections, as .stab* sections need to link to
1807 if (type
== elfcpp::SHT_STRTAB
1808 && !this->have_stabstr_section_
1809 && strncmp(name
, ".stab", 5) == 0
1810 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1811 this->have_stabstr_section_
= true;
1813 // During a full incremental link, we add patch space to most
1814 // PROGBITS and NOBITS sections. Flag those that may be
1815 // arbitrarily padded.
1816 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1817 && order
!= ORDER_INTERP
1818 && order
!= ORDER_INIT
1819 && order
!= ORDER_PLT
1820 && order
!= ORDER_FINI
1821 && order
!= ORDER_RELRO_LAST
1822 && order
!= ORDER_NON_RELRO_FIRST
1823 && strcmp(name
, ".eh_frame") != 0
1824 && strcmp(name
, ".ctors") != 0
1825 && strcmp(name
, ".dtors") != 0
1826 && strcmp(name
, ".jcr") != 0)
1828 os
->set_is_patch_space_allowed();
1830 // Certain sections require "holes" to be filled with
1831 // specific fill patterns. These fill patterns may have
1832 // a minimum size, so we must prevent allocations from the
1833 // free list that leave a hole smaller than the minimum.
1834 if (strcmp(name
, ".debug_info") == 0)
1835 os
->set_free_space_fill(new Output_fill_debug_info(false));
1836 else if (strcmp(name
, ".debug_types") == 0)
1837 os
->set_free_space_fill(new Output_fill_debug_info(true));
1838 else if (strcmp(name
, ".debug_line") == 0)
1839 os
->set_free_space_fill(new Output_fill_debug_line());
1842 // If we have already attached the sections to segments, then we
1843 // need to attach this one now. This happens for sections created
1844 // directly by the linker.
1845 if (this->sections_are_attached_
)
1846 this->attach_section_to_segment(¶meters
->target(), os
);
1851 // Return the default order in which a section should be placed in an
1852 // output segment. This function captures a lot of the ideas in
1853 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1854 // linker created section is normally set when the section is created;
1855 // this function is used for input sections.
1857 Output_section_order
1858 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1860 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1861 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1862 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1863 bool is_bss
= false;
1868 case elfcpp::SHT_PROGBITS
:
1870 case elfcpp::SHT_NOBITS
:
1873 case elfcpp::SHT_RELA
:
1874 case elfcpp::SHT_REL
:
1876 return ORDER_DYNAMIC_RELOCS
;
1878 case elfcpp::SHT_HASH
:
1879 case elfcpp::SHT_DYNAMIC
:
1880 case elfcpp::SHT_SHLIB
:
1881 case elfcpp::SHT_DYNSYM
:
1882 case elfcpp::SHT_GNU_HASH
:
1883 case elfcpp::SHT_GNU_verdef
:
1884 case elfcpp::SHT_GNU_verneed
:
1885 case elfcpp::SHT_GNU_versym
:
1887 return ORDER_DYNAMIC_LINKER
;
1889 case elfcpp::SHT_NOTE
:
1890 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1893 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1894 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1896 if (!is_bss
&& !is_write
)
1900 if (strcmp(os
->name(), ".init") == 0)
1902 else if (strcmp(os
->name(), ".fini") == 0)
1904 else if (parameters
->options().keep_text_section_prefix())
1906 // -z,keep-text-section-prefix introduces additional
1908 if (strcmp(os
->name(), ".text.hot") == 0)
1909 return ORDER_TEXT_HOT
;
1910 else if (strcmp(os
->name(), ".text.startup") == 0)
1911 return ORDER_TEXT_STARTUP
;
1912 else if (strcmp(os
->name(), ".text.exit") == 0)
1913 return ORDER_TEXT_EXIT
;
1914 else if (strcmp(os
->name(), ".text.unlikely") == 0)
1915 return ORDER_TEXT_UNLIKELY
;
1918 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1922 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1924 if (os
->is_small_section())
1925 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1926 if (os
->is_large_section())
1927 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1929 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1932 // Attach output sections to segments. This is called after we have
1933 // seen all the input sections.
1936 Layout::attach_sections_to_segments(const Target
* target
)
1938 for (Section_list::iterator p
= this->section_list_
.begin();
1939 p
!= this->section_list_
.end();
1941 this->attach_section_to_segment(target
, *p
);
1943 this->sections_are_attached_
= true;
1946 // Attach an output section to a segment.
1949 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1951 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1952 this->unattached_section_list_
.push_back(os
);
1954 this->attach_allocated_section_to_segment(target
, os
);
1957 // Attach an allocated output section to a segment.
1960 Layout::attach_allocated_section_to_segment(const Target
* target
,
1963 elfcpp::Elf_Xword flags
= os
->flags();
1964 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1966 if (parameters
->options().relocatable())
1969 // If we have a SECTIONS clause, we can't handle the attachment to
1970 // segments until after we've seen all the sections.
1971 if (this->script_options_
->saw_sections_clause())
1974 gold_assert(!this->script_options_
->saw_phdrs_clause());
1976 // This output section goes into a PT_LOAD segment.
1978 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1980 // If this output section's segment has extra flags that need to be set,
1981 // coming from a linker plugin, do that.
1982 seg_flags
|= os
->extra_segment_flags();
1984 // Check for --section-start.
1986 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1988 // In general the only thing we really care about for PT_LOAD
1989 // segments is whether or not they are writable or executable,
1990 // so that is how we search for them.
1991 // Large data sections also go into their own PT_LOAD segment.
1992 // People who need segments sorted on some other basis will
1993 // have to use a linker script.
1995 Segment_list::const_iterator p
;
1996 if (!os
->is_unique_segment())
1998 for (p
= this->segment_list_
.begin();
1999 p
!= this->segment_list_
.end();
2002 if ((*p
)->type() != elfcpp::PT_LOAD
)
2004 if ((*p
)->is_unique_segment())
2006 if (!parameters
->options().omagic()
2007 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
2009 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
2010 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
2012 // If -Tbss was specified, we need to separate the data and BSS
2014 if (parameters
->options().user_set_Tbss())
2016 if ((os
->type() == elfcpp::SHT_NOBITS
)
2017 == (*p
)->has_any_data_sections())
2020 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
2025 if ((*p
)->are_addresses_set())
2028 (*p
)->add_initial_output_data(os
);
2029 (*p
)->update_flags_for_output_section(seg_flags
);
2030 (*p
)->set_addresses(addr
, addr
);
2034 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
2039 if (p
== this->segment_list_
.end()
2040 || os
->is_unique_segment())
2042 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
2044 if (os
->is_large_data_section())
2045 oseg
->set_is_large_data_segment();
2046 oseg
->add_output_section_to_load(this, os
, seg_flags
);
2048 oseg
->set_addresses(addr
, addr
);
2049 // Check if segment should be marked unique. For segments marked
2050 // unique by linker plugins, set the new alignment if specified.
2051 if (os
->is_unique_segment())
2053 oseg
->set_is_unique_segment();
2054 if (os
->segment_alignment() != 0)
2055 oseg
->set_minimum_p_align(os
->segment_alignment());
2059 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
2061 if (os
->type() == elfcpp::SHT_NOTE
)
2063 // See if we already have an equivalent PT_NOTE segment.
2064 for (p
= this->segment_list_
.begin();
2065 p
!= segment_list_
.end();
2068 if ((*p
)->type() == elfcpp::PT_NOTE
2069 && (((*p
)->flags() & elfcpp::PF_W
)
2070 == (seg_flags
& elfcpp::PF_W
)))
2072 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
2077 if (p
== this->segment_list_
.end())
2079 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
2081 oseg
->add_output_section_to_nonload(os
, seg_flags
);
2085 // If we see a loadable SHF_TLS section, we create a PT_TLS
2086 // segment. There can only be one such segment.
2087 if ((flags
& elfcpp::SHF_TLS
) != 0)
2089 if (this->tls_segment_
== NULL
)
2090 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
2091 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2094 // If -z relro is in effect, and we see a relro section, we create a
2095 // PT_GNU_RELRO segment. There can only be one such segment.
2096 if (os
->is_relro() && parameters
->options().relro())
2098 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
2099 if (this->relro_segment_
== NULL
)
2100 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
2101 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2104 // If we see a section named .interp, put it into a PT_INTERP
2105 // segment. This seems broken to me, but this is what GNU ld does,
2106 // and glibc expects it.
2107 if (strcmp(os
->name(), ".interp") == 0
2108 && !this->script_options_
->saw_phdrs_clause())
2110 if (this->interp_segment_
== NULL
)
2111 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
2113 gold_warning(_("multiple '.interp' sections in input files "
2114 "may cause confusing PT_INTERP segment"));
2115 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2119 // Make an output section for a script.
2122 Layout::make_output_section_for_script(
2124 Script_sections::Section_type section_type
)
2126 name
= this->namepool_
.add(name
, false, NULL
);
2127 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
2128 if (section_type
== Script_sections::ST_NOLOAD
)
2130 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
2131 sh_flags
, ORDER_INVALID
,
2133 os
->set_found_in_sections_clause();
2134 if (section_type
== Script_sections::ST_NOLOAD
)
2135 os
->set_is_noload();
2139 // Return the number of segments we expect to see.
2142 Layout::expected_segment_count() const
2144 size_t ret
= this->segment_list_
.size();
2146 // If we didn't see a SECTIONS clause in a linker script, we should
2147 // already have the complete list of segments. Otherwise we ask the
2148 // SECTIONS clause how many segments it expects, and add in the ones
2149 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2151 if (!this->script_options_
->saw_sections_clause())
2155 const Script_sections
* ss
= this->script_options_
->script_sections();
2156 return ret
+ ss
->expected_segment_count(this);
2160 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2161 // is whether we saw a .note.GNU-stack section in the object file.
2162 // GNU_STACK_FLAGS is the section flags. The flags give the
2163 // protection required for stack memory. We record this in an
2164 // executable as a PT_GNU_STACK segment. If an object file does not
2165 // have a .note.GNU-stack segment, we must assume that it is an old
2166 // object. On some targets that will force an executable stack.
2169 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2172 if (!seen_gnu_stack
)
2174 this->input_without_gnu_stack_note_
= true;
2175 if (parameters
->options().warn_execstack()
2176 && parameters
->target().is_default_stack_executable())
2177 gold_warning(_("%s: missing .note.GNU-stack section"
2178 " implies executable stack"),
2179 obj
->name().c_str());
2183 this->input_with_gnu_stack_note_
= true;
2184 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2186 this->input_requires_executable_stack_
= true;
2187 if (parameters
->options().warn_execstack())
2188 gold_warning(_("%s: requires executable stack"),
2189 obj
->name().c_str());
2194 // Read a value with given size and endianness.
2196 static inline uint64_t
2197 read_sized_value(size_t size
, const unsigned char* buf
, bool is_big_endian
,
2198 const Object
* object
)
2204 val
= elfcpp::Swap
<32, true>::readval(buf
);
2206 val
= elfcpp::Swap
<32, false>::readval(buf
);
2211 val
= elfcpp::Swap
<64, true>::readval(buf
);
2213 val
= elfcpp::Swap
<64, false>::readval(buf
);
2217 gold_warning(_("%s: in .note.gnu.property section, "
2218 "pr_datasz must be 4 or 8"),
2219 object
->name().c_str());
2224 // Write a value with given size and endianness.
2227 write_sized_value(uint64_t value
, size_t size
, unsigned char* buf
,
2233 elfcpp::Swap
<32, true>::writeval(buf
, static_cast<uint32_t>(value
));
2235 elfcpp::Swap
<32, false>::writeval(buf
, static_cast<uint32_t>(value
));
2240 elfcpp::Swap
<64, true>::writeval(buf
, value
);
2242 elfcpp::Swap
<64, false>::writeval(buf
, value
);
2246 // We will have already complained about this.
2250 // Handle the .note.gnu.property section at layout time.
2253 Layout::layout_gnu_property(unsigned int note_type
,
2254 unsigned int pr_type
,
2256 const unsigned char* pr_data
,
2257 const Object
* object
)
2259 // We currently support only the one note type.
2260 gold_assert(note_type
== elfcpp::NT_GNU_PROPERTY_TYPE_0
);
2262 if (pr_type
>= elfcpp::GNU_PROPERTY_LOPROC
2263 && pr_type
< elfcpp::GNU_PROPERTY_HIPROC
)
2265 // Target-dependent property value; call the target to record.
2266 const int size
= parameters
->target().get_size();
2267 const bool is_big_endian
= parameters
->target().is_big_endian();
2272 #ifdef HAVE_TARGET_32_BIG
2273 parameters
->sized_target
<32, true>()->
2274 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2282 #ifdef HAVE_TARGET_32_LITTLE
2283 parameters
->sized_target
<32, false>()->
2284 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2291 else if (size
== 64)
2295 #ifdef HAVE_TARGET_64_BIG
2296 parameters
->sized_target
<64, true>()->
2297 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2305 #ifdef HAVE_TARGET_64_LITTLE
2306 parameters
->sized_target
<64, false>()->
2307 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2319 Gnu_properties::iterator pprop
= this->gnu_properties_
.find(pr_type
);
2320 if (pprop
== this->gnu_properties_
.end())
2323 prop
.pr_datasz
= pr_datasz
;
2324 prop
.pr_data
= new unsigned char[pr_datasz
];
2325 memcpy(prop
.pr_data
, pr_data
, pr_datasz
);
2326 this->gnu_properties_
[pr_type
] = prop
;
2330 const bool is_big_endian
= parameters
->target().is_big_endian();
2333 case elfcpp::GNU_PROPERTY_STACK_SIZE
:
2334 // Record the maximum value seen.
2336 uint64_t val1
= read_sized_value(pprop
->second
.pr_datasz
,
2337 pprop
->second
.pr_data
,
2338 is_big_endian
, object
);
2339 uint64_t val2
= read_sized_value(pr_datasz
, pr_data
,
2340 is_big_endian
, object
);
2342 write_sized_value(val2
, pprop
->second
.pr_datasz
,
2343 pprop
->second
.pr_data
, is_big_endian
);
2346 case elfcpp::GNU_PROPERTY_NO_COPY_ON_PROTECTED
:
2347 // No data to merge.
2350 gold_warning(_("%s: unknown program property type %d "
2351 "in .note.gnu.property section"),
2352 object
->name().c_str(), pr_type
);
2357 // Merge per-object properties with program properties.
2358 // This lets the target identify objects that are missing certain
2359 // properties, in cases where properties must be ANDed together.
2362 Layout::merge_gnu_properties(const Object
* object
)
2364 const int size
= parameters
->target().get_size();
2365 const bool is_big_endian
= parameters
->target().is_big_endian();
2370 #ifdef HAVE_TARGET_32_BIG
2371 parameters
->sized_target
<32, true>()->merge_gnu_properties(object
);
2378 #ifdef HAVE_TARGET_32_LITTLE
2379 parameters
->sized_target
<32, false>()->merge_gnu_properties(object
);
2385 else if (size
== 64)
2389 #ifdef HAVE_TARGET_64_BIG
2390 parameters
->sized_target
<64, true>()->merge_gnu_properties(object
);
2397 #ifdef HAVE_TARGET_64_LITTLE
2398 parameters
->sized_target
<64, false>()->merge_gnu_properties(object
);
2408 // Add a target-specific property for the output .note.gnu.property section.
2411 Layout::add_gnu_property(unsigned int note_type
,
2412 unsigned int pr_type
,
2414 const unsigned char* pr_data
)
2416 gold_assert(note_type
== elfcpp::NT_GNU_PROPERTY_TYPE_0
);
2419 prop
.pr_datasz
= pr_datasz
;
2420 prop
.pr_data
= new unsigned char[pr_datasz
];
2421 memcpy(prop
.pr_data
, pr_data
, pr_datasz
);
2422 this->gnu_properties_
[pr_type
] = prop
;
2425 // Create automatic note sections.
2428 Layout::create_notes()
2430 this->create_gnu_properties_note();
2431 this->create_gold_note();
2432 this->create_stack_segment();
2433 this->create_build_id();
2436 // Create the dynamic sections which are needed before we read the
2440 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2442 if (parameters
->doing_static_link())
2445 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2446 elfcpp::SHT_DYNAMIC
,
2448 | elfcpp::SHF_WRITE
),
2450 true, false, false);
2452 // A linker script may discard .dynamic, so check for NULL.
2453 if (this->dynamic_section_
!= NULL
)
2455 this->dynamic_symbol_
=
2456 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2457 Symbol_table::PREDEFINED
,
2458 this->dynamic_section_
, 0, 0,
2459 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2460 elfcpp::STV_HIDDEN
, 0, false, false);
2462 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2464 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2468 // For each output section whose name can be represented as C symbol,
2469 // define __start and __stop symbols for the section. This is a GNU
2473 Layout::define_section_symbols(Symbol_table
* symtab
)
2475 for (Section_list::const_iterator p
= this->section_list_
.begin();
2476 p
!= this->section_list_
.end();
2479 const char* const name
= (*p
)->name();
2480 if (is_cident(name
))
2482 const std::string
name_string(name
);
2483 const std::string
start_name(cident_section_start_prefix
2485 const std::string
stop_name(cident_section_stop_prefix
2488 symtab
->define_in_output_data(start_name
.c_str(),
2490 Symbol_table::PREDEFINED
,
2496 elfcpp::STV_PROTECTED
,
2498 false, // offset_is_from_end
2499 true); // only_if_ref
2501 symtab
->define_in_output_data(stop_name
.c_str(),
2503 Symbol_table::PREDEFINED
,
2509 elfcpp::STV_PROTECTED
,
2511 true, // offset_is_from_end
2512 true); // only_if_ref
2517 // Define symbols for group signatures.
2520 Layout::define_group_signatures(Symbol_table
* symtab
)
2522 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2523 p
!= this->group_signatures_
.end();
2526 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2528 p
->section
->set_info_symndx(sym
);
2531 // Force the name of the group section to the group
2532 // signature, and use the group's section symbol as the
2533 // signature symbol.
2534 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2536 const char* name
= this->namepool_
.add(p
->signature
,
2538 p
->section
->set_name(name
);
2540 p
->section
->set_needs_symtab_index();
2541 p
->section
->set_info_section_symndx(p
->section
);
2545 this->group_signatures_
.clear();
2548 // Find the first read-only PT_LOAD segment, creating one if
2552 Layout::find_first_load_seg(const Target
* target
)
2554 Output_segment
* best
= NULL
;
2555 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2556 p
!= this->segment_list_
.end();
2559 if ((*p
)->type() == elfcpp::PT_LOAD
2560 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2561 && (parameters
->options().omagic()
2562 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2563 && (!target
->isolate_execinstr()
2564 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2566 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2573 gold_assert(!this->script_options_
->saw_phdrs_clause());
2575 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2580 // Save states of all current output segments. Store saved states
2581 // in SEGMENT_STATES.
2584 Layout::save_segments(Segment_states
* segment_states
)
2586 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2587 p
!= this->segment_list_
.end();
2590 Output_segment
* segment
= *p
;
2592 Output_segment
* copy
= new Output_segment(*segment
);
2593 (*segment_states
)[segment
] = copy
;
2597 // Restore states of output segments and delete any segment not found in
2601 Layout::restore_segments(const Segment_states
* segment_states
)
2603 // Go through the segment list and remove any segment added in the
2605 this->tls_segment_
= NULL
;
2606 this->relro_segment_
= NULL
;
2607 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2608 while (list_iter
!= this->segment_list_
.end())
2610 Output_segment
* segment
= *list_iter
;
2611 Segment_states::const_iterator states_iter
=
2612 segment_states
->find(segment
);
2613 if (states_iter
!= segment_states
->end())
2615 const Output_segment
* copy
= states_iter
->second
;
2616 // Shallow copy to restore states.
2619 // Also fix up TLS and RELRO segment pointers as appropriate.
2620 if (segment
->type() == elfcpp::PT_TLS
)
2621 this->tls_segment_
= segment
;
2622 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2623 this->relro_segment_
= segment
;
2629 list_iter
= this->segment_list_
.erase(list_iter
);
2630 // This is a segment created during section layout. It should be
2631 // safe to remove it since we should have removed all pointers to it.
2637 // Clean up after relaxation so that sections can be laid out again.
2640 Layout::clean_up_after_relaxation()
2642 // Restore the segments to point state just prior to the relaxation loop.
2643 Script_sections
* script_section
= this->script_options_
->script_sections();
2644 script_section
->release_segments();
2645 this->restore_segments(this->segment_states_
);
2647 // Reset section addresses and file offsets
2648 for (Section_list::iterator p
= this->section_list_
.begin();
2649 p
!= this->section_list_
.end();
2652 (*p
)->restore_states();
2654 // If an input section changes size because of relaxation,
2655 // we need to adjust the section offsets of all input sections.
2656 // after such a section.
2657 if ((*p
)->section_offsets_need_adjustment())
2658 (*p
)->adjust_section_offsets();
2660 (*p
)->reset_address_and_file_offset();
2663 // Reset special output object address and file offsets.
2664 for (Data_list::iterator p
= this->special_output_list_
.begin();
2665 p
!= this->special_output_list_
.end();
2667 (*p
)->reset_address_and_file_offset();
2669 // A linker script may have created some output section data objects.
2670 // They are useless now.
2671 for (Output_section_data_list::const_iterator p
=
2672 this->script_output_section_data_list_
.begin();
2673 p
!= this->script_output_section_data_list_
.end();
2676 this->script_output_section_data_list_
.clear();
2678 // Special-case fill output objects are recreated each time through
2679 // the relaxation loop.
2680 this->reset_relax_output();
2684 Layout::reset_relax_output()
2686 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
2687 p
!= this->relax_output_list_
.end();
2690 this->relax_output_list_
.clear();
2693 // Prepare for relaxation.
2696 Layout::prepare_for_relaxation()
2698 // Create an relaxation debug check if in debugging mode.
2699 if (is_debugging_enabled(DEBUG_RELAXATION
))
2700 this->relaxation_debug_check_
= new Relaxation_debug_check();
2702 // Save segment states.
2703 this->segment_states_
= new Segment_states();
2704 this->save_segments(this->segment_states_
);
2706 for(Section_list::const_iterator p
= this->section_list_
.begin();
2707 p
!= this->section_list_
.end();
2709 (*p
)->save_states();
2711 if (is_debugging_enabled(DEBUG_RELAXATION
))
2712 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2713 this->section_list_
, this->special_output_list_
,
2714 this->relax_output_list_
);
2716 // Also enable recording of output section data from scripts.
2717 this->record_output_section_data_from_script_
= true;
2720 // If the user set the address of the text segment, that may not be
2721 // compatible with putting the segment headers and file headers into
2722 // that segment. For isolate_execinstr() targets, it's the rodata
2723 // segment rather than text where we might put the headers.
2725 load_seg_unusable_for_headers(const Target
* target
)
2727 const General_options
& options
= parameters
->options();
2728 if (target
->isolate_execinstr())
2729 return (options
.user_set_Trodata_segment()
2730 && options
.Trodata_segment() % target
->abi_pagesize() != 0);
2732 return (options
.user_set_Ttext()
2733 && options
.Ttext() % target
->abi_pagesize() != 0);
2736 // Relaxation loop body: If target has no relaxation, this runs only once
2737 // Otherwise, the target relaxation hook is called at the end of
2738 // each iteration. If the hook returns true, it means re-layout of
2739 // section is required.
2741 // The number of segments created by a linking script without a PHDRS
2742 // clause may be affected by section sizes and alignments. There is
2743 // a remote chance that relaxation causes different number of PT_LOAD
2744 // segments are created and sections are attached to different segments.
2745 // Therefore, we always throw away all segments created during section
2746 // layout. In order to be able to restart the section layout, we keep
2747 // a copy of the segment list right before the relaxation loop and use
2748 // that to restore the segments.
2750 // PASS is the current relaxation pass number.
2751 // SYMTAB is a symbol table.
2752 // PLOAD_SEG is the address of a pointer for the load segment.
2753 // PHDR_SEG is a pointer to the PHDR segment.
2754 // SEGMENT_HEADERS points to the output segment header.
2755 // FILE_HEADER points to the output file header.
2756 // PSHNDX is the address to store the output section index.
2759 Layout::relaxation_loop_body(
2762 Symbol_table
* symtab
,
2763 Output_segment
** pload_seg
,
2764 Output_segment
* phdr_seg
,
2765 Output_segment_headers
* segment_headers
,
2766 Output_file_header
* file_header
,
2767 unsigned int* pshndx
)
2769 // If this is not the first iteration, we need to clean up after
2770 // relaxation so that we can lay out the sections again.
2772 this->clean_up_after_relaxation();
2774 // If there is a SECTIONS clause, put all the input sections into
2775 // the required order.
2776 Output_segment
* load_seg
;
2777 if (this->script_options_
->saw_sections_clause())
2778 load_seg
= this->set_section_addresses_from_script(symtab
);
2779 else if (parameters
->options().relocatable())
2782 load_seg
= this->find_first_load_seg(target
);
2784 if (parameters
->options().oformat_enum()
2785 != General_options::OBJECT_FORMAT_ELF
)
2788 if (load_seg_unusable_for_headers(target
))
2794 gold_assert(phdr_seg
== NULL
2796 || this->script_options_
->saw_sections_clause());
2798 // If the address of the load segment we found has been set by
2799 // --section-start rather than by a script, then adjust the VMA and
2800 // LMA downward if possible to include the file and section headers.
2801 uint64_t header_gap
= 0;
2802 if (load_seg
!= NULL
2803 && load_seg
->are_addresses_set()
2804 && !this->script_options_
->saw_sections_clause()
2805 && !parameters
->options().relocatable())
2807 file_header
->finalize_data_size();
2808 segment_headers
->finalize_data_size();
2809 size_t sizeof_headers
= (file_header
->data_size()
2810 + segment_headers
->data_size());
2811 const uint64_t abi_pagesize
= target
->abi_pagesize();
2812 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2813 hdr_paddr
&= ~(abi_pagesize
- 1);
2814 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2815 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2819 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2820 load_seg
->paddr() - subtract
);
2821 header_gap
= subtract
- sizeof_headers
;
2825 // Lay out the segment headers.
2826 if (!parameters
->options().relocatable())
2828 gold_assert(segment_headers
!= NULL
);
2829 if (header_gap
!= 0 && load_seg
!= NULL
)
2831 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2832 load_seg
->add_initial_output_data(z
);
2834 if (load_seg
!= NULL
)
2835 load_seg
->add_initial_output_data(segment_headers
);
2836 if (phdr_seg
!= NULL
)
2837 phdr_seg
->add_initial_output_data(segment_headers
);
2840 // Lay out the file header.
2841 if (load_seg
!= NULL
)
2842 load_seg
->add_initial_output_data(file_header
);
2844 if (this->script_options_
->saw_phdrs_clause()
2845 && !parameters
->options().relocatable())
2847 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2848 // clause in a linker script.
2849 Script_sections
* ss
= this->script_options_
->script_sections();
2850 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2853 // We set the output section indexes in set_segment_offsets and
2854 // set_section_indexes.
2857 // Set the file offsets of all the segments, and all the sections
2860 if (!parameters
->options().relocatable())
2861 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2863 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2865 // Verify that the dummy relaxation does not change anything.
2866 if (is_debugging_enabled(DEBUG_RELAXATION
))
2869 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2871 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2874 *pload_seg
= load_seg
;
2878 // Search the list of patterns and find the position of the given section
2879 // name in the output section. If the section name matches a glob
2880 // pattern and a non-glob name, then the non-glob position takes
2881 // precedence. Return 0 if no match is found.
2884 Layout::find_section_order_index(const std::string
& section_name
)
2886 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2887 map_it
= this->input_section_position_
.find(section_name
);
2888 if (map_it
!= this->input_section_position_
.end())
2889 return map_it
->second
;
2891 // Absolute match failed. Linear search the glob patterns.
2892 std::vector
<std::string
>::iterator it
;
2893 for (it
= this->input_section_glob_
.begin();
2894 it
!= this->input_section_glob_
.end();
2897 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2899 map_it
= this->input_section_position_
.find(*it
);
2900 gold_assert(map_it
!= this->input_section_position_
.end());
2901 return map_it
->second
;
2907 // Read the sequence of input sections from the file specified with
2908 // option --section-ordering-file.
2911 Layout::read_layout_from_file()
2913 const char* filename
= parameters
->options().section_ordering_file();
2919 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2920 filename
, strerror(errno
));
2922 std::getline(in
, line
); // this chops off the trailing \n, if any
2923 unsigned int position
= 1;
2924 this->set_section_ordering_specified();
2928 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2929 line
.resize(line
.length() - 1);
2930 // Ignore comments, beginning with '#'
2933 std::getline(in
, line
);
2936 this->input_section_position_
[line
] = position
;
2937 // Store all glob patterns in a vector.
2938 if (is_wildcard_string(line
.c_str()))
2939 this->input_section_glob_
.push_back(line
);
2941 std::getline(in
, line
);
2945 // Finalize the layout. When this is called, we have created all the
2946 // output sections and all the output segments which are based on
2947 // input sections. We have several things to do, and we have to do
2948 // them in the right order, so that we get the right results correctly
2951 // 1) Finalize the list of output segments and create the segment
2954 // 2) Finalize the dynamic symbol table and associated sections.
2956 // 3) Determine the final file offset of all the output segments.
2958 // 4) Determine the final file offset of all the SHF_ALLOC output
2961 // 5) Create the symbol table sections and the section name table
2964 // 6) Finalize the symbol table: set symbol values to their final
2965 // value and make a final determination of which symbols are going
2966 // into the output symbol table.
2968 // 7) Create the section table header.
2970 // 8) Determine the final file offset of all the output sections which
2971 // are not SHF_ALLOC, including the section table header.
2973 // 9) Finalize the ELF file header.
2975 // This function returns the size of the output file.
2978 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2979 Target
* target
, const Task
* task
)
2981 unsigned int local_dynamic_count
= 0;
2982 unsigned int forced_local_dynamic_count
= 0;
2984 target
->finalize_sections(this, input_objects
, symtab
);
2986 this->count_local_symbols(task
, input_objects
);
2988 this->link_stabs_sections();
2990 Output_segment
* phdr_seg
= NULL
;
2991 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2993 // There was a dynamic object in the link. We need to create
2994 // some information for the dynamic linker.
2996 // Create the PT_PHDR segment which will hold the program
2998 if (!this->script_options_
->saw_phdrs_clause())
2999 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
3001 // Create the dynamic symbol table, including the hash table.
3002 Output_section
* dynstr
;
3003 std::vector
<Symbol
*> dynamic_symbols
;
3004 Versions
versions(*this->script_options()->version_script_info(),
3006 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
3007 &local_dynamic_count
,
3008 &forced_local_dynamic_count
,
3012 // Create the .interp section to hold the name of the
3013 // interpreter, and put it in a PT_INTERP segment. Don't do it
3014 // if we saw a .interp section in an input file.
3015 if ((!parameters
->options().shared()
3016 || parameters
->options().dynamic_linker() != NULL
)
3017 && this->interp_segment_
== NULL
)
3018 this->create_interp(target
);
3020 // Finish the .dynamic section to hold the dynamic data, and put
3021 // it in a PT_DYNAMIC segment.
3022 this->finish_dynamic_section(input_objects
, symtab
);
3024 // We should have added everything we need to the dynamic string
3026 this->dynpool_
.set_string_offsets();
3028 // Create the version sections. We can't do this until the
3029 // dynamic string table is complete.
3030 this->create_version_sections(&versions
, symtab
,
3031 (local_dynamic_count
3032 + forced_local_dynamic_count
),
3033 dynamic_symbols
, dynstr
);
3035 // Set the size of the _DYNAMIC symbol. We can't do this until
3036 // after we call create_version_sections.
3037 this->set_dynamic_symbol_size(symtab
);
3040 // Create segment headers.
3041 Output_segment_headers
* segment_headers
=
3042 (parameters
->options().relocatable()
3044 : new Output_segment_headers(this->segment_list_
));
3046 // Lay out the file header.
3047 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
3050 this->special_output_list_
.push_back(file_header
);
3051 if (segment_headers
!= NULL
)
3052 this->special_output_list_
.push_back(segment_headers
);
3054 // Find approriate places for orphan output sections if we are using
3056 if (this->script_options_
->saw_sections_clause())
3057 this->place_orphan_sections_in_script();
3059 Output_segment
* load_seg
;
3064 // Take a snapshot of the section layout as needed.
3065 if (target
->may_relax())
3066 this->prepare_for_relaxation();
3068 // Run the relaxation loop to lay out sections.
3071 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
3072 phdr_seg
, segment_headers
, file_header
,
3076 while (target
->may_relax()
3077 && target
->relax(pass
, input_objects
, symtab
, this, task
));
3079 // If there is a load segment that contains the file and program headers,
3080 // provide a symbol __ehdr_start pointing there.
3081 // A program can use this to examine itself robustly.
3082 Symbol
*ehdr_start
= symtab
->lookup("__ehdr_start");
3083 if (ehdr_start
!= NULL
&& ehdr_start
->is_predefined())
3085 if (load_seg
!= NULL
)
3086 ehdr_start
->set_output_segment(load_seg
, Symbol::SEGMENT_START
);
3088 ehdr_start
->set_undefined();
3091 // Set the file offsets of all the non-data sections we've seen so
3092 // far which don't have to wait for the input sections. We need
3093 // this in order to finalize local symbols in non-allocated
3095 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
3097 // Set the section indexes of all unallocated sections seen so far,
3098 // in case any of them are somehow referenced by a symbol.
3099 shndx
= this->set_section_indexes(shndx
);
3101 // Create the symbol table sections.
3102 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
,
3103 local_dynamic_count
);
3104 if (!parameters
->doing_static_link())
3105 this->assign_local_dynsym_offsets(input_objects
);
3107 // Process any symbol assignments from a linker script. This must
3108 // be called after the symbol table has been finalized.
3109 this->script_options_
->finalize_symbols(symtab
, this);
3111 // Create the incremental inputs sections.
3112 if (this->incremental_inputs_
)
3114 this->incremental_inputs_
->finalize();
3115 this->create_incremental_info_sections(symtab
);
3118 // Create the .shstrtab section.
3119 Output_section
* shstrtab_section
= this->create_shstrtab();
3121 // Set the file offsets of the rest of the non-data sections which
3122 // don't have to wait for the input sections.
3123 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
3125 // Now that all sections have been created, set the section indexes
3126 // for any sections which haven't been done yet.
3127 shndx
= this->set_section_indexes(shndx
);
3129 // Create the section table header.
3130 this->create_shdrs(shstrtab_section
, &off
);
3132 // If there are no sections which require postprocessing, we can
3133 // handle the section names now, and avoid a resize later.
3134 if (!this->any_postprocessing_sections_
)
3136 off
= this->set_section_offsets(off
,
3137 POSTPROCESSING_SECTIONS_PASS
);
3139 this->set_section_offsets(off
,
3140 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
3143 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
3145 // Now we know exactly where everything goes in the output file
3146 // (except for non-allocated sections which require postprocessing).
3147 Output_data::layout_complete();
3149 this->output_file_size_
= off
;
3154 // Create a note header following the format defined in the ELF ABI.
3155 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
3156 // of the section to create, DESCSZ is the size of the descriptor.
3157 // ALLOCATE is true if the section should be allocated in memory.
3158 // This returns the new note section. It sets *TRAILING_PADDING to
3159 // the number of trailing zero bytes required.
3162 Layout::create_note(const char* name
, int note_type
,
3163 const char* section_name
, size_t descsz
,
3164 bool allocate
, size_t* trailing_padding
)
3166 // Authorities all agree that the values in a .note field should
3167 // be aligned on 4-byte boundaries for 32-bit binaries. However,
3168 // they differ on what the alignment is for 64-bit binaries.
3169 // The GABI says unambiguously they take 8-byte alignment:
3170 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
3171 // Other documentation says alignment should always be 4 bytes:
3172 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
3173 // GNU ld and GNU readelf both support the latter (at least as of
3174 // version 2.16.91), and glibc always generates the latter for
3175 // .note.ABI-tag (as of version 1.6), so that's the one we go with
3177 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
3178 const int size
= parameters
->target().get_size();
3180 const int size
= 32;
3183 // The contents of the .note section.
3184 size_t namesz
= strlen(name
) + 1;
3185 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
3186 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
3188 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
3190 unsigned char* buffer
= new unsigned char[notehdrsz
];
3191 memset(buffer
, 0, notehdrsz
);
3193 bool is_big_endian
= parameters
->target().is_big_endian();
3199 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
3200 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
3201 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
3205 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
3206 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
3207 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
3210 else if (size
== 64)
3214 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
3215 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
3216 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
3220 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
3221 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
3222 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
3228 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
3230 elfcpp::Elf_Xword flags
= 0;
3231 Output_section_order order
= ORDER_INVALID
;
3234 flags
= elfcpp::SHF_ALLOC
;
3235 order
= ORDER_RO_NOTE
;
3237 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
3239 flags
, false, order
, false,
3244 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
3247 os
->add_output_section_data(posd
);
3249 *trailing_padding
= aligned_descsz
- descsz
;
3254 // Create a .note.gnu.property section to record program properties
3255 // accumulated from the input files.
3258 Layout::create_gnu_properties_note()
3260 parameters
->target().finalize_gnu_properties(this);
3262 if (this->gnu_properties_
.empty())
3265 const unsigned int size
= parameters
->target().get_size();
3266 const bool is_big_endian
= parameters
->target().is_big_endian();
3268 // Compute the total size of the properties array.
3270 for (Gnu_properties::const_iterator prop
= this->gnu_properties_
.begin();
3271 prop
!= this->gnu_properties_
.end();
3274 descsz
= align_address(descsz
+ 8 + prop
->second
.pr_datasz
, size
/ 8);
3277 // Create the note section.
3278 size_t trailing_padding
;
3279 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_PROPERTY_TYPE_0
,
3280 ".note.gnu.property", descsz
,
3281 true, &trailing_padding
);
3284 gold_assert(trailing_padding
== 0);
3286 // Allocate and fill the properties array.
3287 unsigned char* desc
= new unsigned char[descsz
];
3288 unsigned char* p
= desc
;
3289 for (Gnu_properties::const_iterator prop
= this->gnu_properties_
.begin();
3290 prop
!= this->gnu_properties_
.end();
3293 size_t datasz
= prop
->second
.pr_datasz
;
3294 size_t aligned_datasz
= align_address(prop
->second
.pr_datasz
, size
/ 8);
3295 write_sized_value(prop
->first
, 4, p
, is_big_endian
);
3296 write_sized_value(datasz
, 4, p
+ 4, is_big_endian
);
3297 memcpy(p
+ 8, prop
->second
.pr_data
, datasz
);
3298 if (aligned_datasz
> datasz
)
3299 memset(p
+ 8 + datasz
, 0, aligned_datasz
- datasz
);
3300 p
+= 8 + aligned_datasz
;
3302 Output_section_data
* posd
= new Output_data_const(desc
, descsz
, 4);
3303 os
->add_output_section_data(posd
);
3306 // For an executable or shared library, create a note to record the
3307 // version of gold used to create the binary.
3310 Layout::create_gold_note()
3312 if (parameters
->options().relocatable()
3313 || parameters
->incremental_update())
3316 std::string desc
= std::string("gold ") + gold::get_version_string();
3318 size_t trailing_padding
;
3319 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
3320 ".note.gnu.gold-version", desc
.size(),
3321 false, &trailing_padding
);
3325 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3326 os
->add_output_section_data(posd
);
3328 if (trailing_padding
> 0)
3330 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3331 os
->add_output_section_data(posd
);
3335 // Record whether the stack should be executable. This can be set
3336 // from the command line using the -z execstack or -z noexecstack
3337 // options. Otherwise, if any input file has a .note.GNU-stack
3338 // section with the SHF_EXECINSTR flag set, the stack should be
3339 // executable. Otherwise, if at least one input file a
3340 // .note.GNU-stack section, and some input file has no .note.GNU-stack
3341 // section, we use the target default for whether the stack should be
3342 // executable. If -z stack-size was used to set a p_memsz value for
3343 // PT_GNU_STACK, we generate the segment regardless. Otherwise, we
3344 // don't generate a stack note. When generating a object file, we
3345 // create a .note.GNU-stack section with the appropriate marking.
3346 // When generating an executable or shared library, we create a
3347 // PT_GNU_STACK segment.
3350 Layout::create_stack_segment()
3352 bool is_stack_executable
;
3353 if (parameters
->options().is_execstack_set())
3355 is_stack_executable
= parameters
->options().is_stack_executable();
3356 if (!is_stack_executable
3357 && this->input_requires_executable_stack_
3358 && parameters
->options().warn_execstack())
3359 gold_warning(_("one or more inputs require executable stack, "
3360 "but -z noexecstack was given"));
3362 else if (!this->input_with_gnu_stack_note_
3363 && (!parameters
->options().user_set_stack_size()
3364 || parameters
->options().relocatable()))
3368 if (this->input_requires_executable_stack_
)
3369 is_stack_executable
= true;
3370 else if (this->input_without_gnu_stack_note_
)
3371 is_stack_executable
=
3372 parameters
->target().is_default_stack_executable();
3374 is_stack_executable
= false;
3377 if (parameters
->options().relocatable())
3379 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
3380 elfcpp::Elf_Xword flags
= 0;
3381 if (is_stack_executable
)
3382 flags
|= elfcpp::SHF_EXECINSTR
;
3383 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
3384 ORDER_INVALID
, false);
3388 if (this->script_options_
->saw_phdrs_clause())
3390 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
3391 if (is_stack_executable
)
3392 flags
|= elfcpp::PF_X
;
3393 Output_segment
* seg
=
3394 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
3395 seg
->set_size(parameters
->options().stack_size());
3396 // BFD lets targets override this default alignment, but the only
3397 // targets that do so are ones that Gold does not support so far.
3398 seg
->set_minimum_p_align(16);
3402 // If --build-id was used, set up the build ID note.
3405 Layout::create_build_id()
3407 if (!parameters
->options().user_set_build_id())
3410 const char* style
= parameters
->options().build_id();
3411 if (strcmp(style
, "none") == 0)
3414 // Set DESCSZ to the size of the note descriptor. When possible,
3415 // set DESC to the note descriptor contents.
3418 if (strcmp(style
, "md5") == 0)
3420 else if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
3422 else if (strcmp(style
, "uuid") == 0)
3425 const size_t uuidsz
= 128 / 8;
3427 char buffer
[uuidsz
];
3428 memset(buffer
, 0, uuidsz
);
3430 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
3432 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3436 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
3437 release_descriptor(descriptor
, true);
3439 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
3440 else if (static_cast<size_t>(got
) != uuidsz
)
3441 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3445 desc
.assign(buffer
, uuidsz
);
3447 #else // __MINGW32__
3449 typedef RPC_STATUS (RPC_ENTRY
*UuidCreateFn
)(UUID
*Uuid
);
3451 HMODULE rpc_library
= LoadLibrary("rpcrt4.dll");
3453 gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll"));
3456 UuidCreateFn uuid_create
= reinterpret_cast<UuidCreateFn
>(
3457 GetProcAddress(rpc_library
, "UuidCreate"));
3459 gold_error(_("--build-id=uuid failed: could not find UuidCreate"));
3460 else if (uuid_create(&uuid
) != RPC_S_OK
)
3461 gold_error(_("__build_id=uuid failed: call UuidCreate() failed"));
3462 FreeLibrary(rpc_library
);
3464 desc
.assign(reinterpret_cast<const char *>(&uuid
), sizeof(UUID
));
3465 descsz
= sizeof(UUID
);
3466 #endif // __MINGW32__
3468 else if (strncmp(style
, "0x", 2) == 0)
3471 const char* p
= style
+ 2;
3474 if (hex_p(p
[0]) && hex_p(p
[1]))
3476 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
3480 else if (*p
== '-' || *p
== ':')
3483 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3486 descsz
= desc
.size();
3489 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
3492 size_t trailing_padding
;
3493 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
3494 ".note.gnu.build-id", descsz
, true,
3501 // We know the value already, so we fill it in now.
3502 gold_assert(desc
.size() == descsz
);
3504 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3505 os
->add_output_section_data(posd
);
3507 if (trailing_padding
!= 0)
3509 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3510 os
->add_output_section_data(posd
);
3515 // We need to compute a checksum after we have completed the
3517 gold_assert(trailing_padding
== 0);
3518 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3519 os
->add_output_section_data(this->build_id_note_
);
3523 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3524 // field of the former should point to the latter. I'm not sure who
3525 // started this, but the GNU linker does it, and some tools depend
3529 Layout::link_stabs_sections()
3531 if (!this->have_stabstr_section_
)
3534 for (Section_list::iterator p
= this->section_list_
.begin();
3535 p
!= this->section_list_
.end();
3538 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3541 const char* name
= (*p
)->name();
3542 if (strncmp(name
, ".stab", 5) != 0)
3545 size_t len
= strlen(name
);
3546 if (strcmp(name
+ len
- 3, "str") != 0)
3549 std::string
stab_name(name
, len
- 3);
3550 Output_section
* stab_sec
;
3551 stab_sec
= this->find_output_section(stab_name
.c_str());
3552 if (stab_sec
!= NULL
)
3553 stab_sec
->set_link_section(*p
);
3557 // Create .gnu_incremental_inputs and related sections needed
3558 // for the next run of incremental linking to check what has changed.
3561 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3563 Incremental_inputs
* incr
= this->incremental_inputs_
;
3565 gold_assert(incr
!= NULL
);
3567 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3568 incr
->create_data_sections(symtab
);
3570 // Add the .gnu_incremental_inputs section.
3571 const char* incremental_inputs_name
=
3572 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3573 Output_section
* incremental_inputs_os
=
3574 this->make_output_section(incremental_inputs_name
,
3575 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3576 ORDER_INVALID
, false);
3577 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3579 // Add the .gnu_incremental_symtab section.
3580 const char* incremental_symtab_name
=
3581 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3582 Output_section
* incremental_symtab_os
=
3583 this->make_output_section(incremental_symtab_name
,
3584 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3585 ORDER_INVALID
, false);
3586 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3587 incremental_symtab_os
->set_entsize(4);
3589 // Add the .gnu_incremental_relocs section.
3590 const char* incremental_relocs_name
=
3591 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3592 Output_section
* incremental_relocs_os
=
3593 this->make_output_section(incremental_relocs_name
,
3594 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3595 ORDER_INVALID
, false);
3596 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3597 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3599 // Add the .gnu_incremental_got_plt section.
3600 const char* incremental_got_plt_name
=
3601 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3602 Output_section
* incremental_got_plt_os
=
3603 this->make_output_section(incremental_got_plt_name
,
3604 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3605 ORDER_INVALID
, false);
3606 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3608 // Add the .gnu_incremental_strtab section.
3609 const char* incremental_strtab_name
=
3610 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3611 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3612 elfcpp::SHT_STRTAB
, 0,
3613 ORDER_INVALID
, false);
3614 Output_data_strtab
* strtab_data
=
3615 new Output_data_strtab(incr
->get_stringpool());
3616 incremental_strtab_os
->add_output_section_data(strtab_data
);
3618 incremental_inputs_os
->set_after_input_sections();
3619 incremental_symtab_os
->set_after_input_sections();
3620 incremental_relocs_os
->set_after_input_sections();
3621 incremental_got_plt_os
->set_after_input_sections();
3623 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3624 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3625 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3626 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3629 // Return whether SEG1 should be before SEG2 in the output file. This
3630 // is based entirely on the segment type and flags. When this is
3631 // called the segment addresses have normally not yet been set.
3634 Layout::segment_precedes(const Output_segment
* seg1
,
3635 const Output_segment
* seg2
)
3637 // In order to produce a stable ordering if we're called with the same pointer
3642 elfcpp::Elf_Word type1
= seg1
->type();
3643 elfcpp::Elf_Word type2
= seg2
->type();
3645 // The single PT_PHDR segment is required to precede any loadable
3646 // segment. We simply make it always first.
3647 if (type1
== elfcpp::PT_PHDR
)
3649 gold_assert(type2
!= elfcpp::PT_PHDR
);
3652 if (type2
== elfcpp::PT_PHDR
)
3655 // The single PT_INTERP segment is required to precede any loadable
3656 // segment. We simply make it always second.
3657 if (type1
== elfcpp::PT_INTERP
)
3659 gold_assert(type2
!= elfcpp::PT_INTERP
);
3662 if (type2
== elfcpp::PT_INTERP
)
3665 // We then put PT_LOAD segments before any other segments.
3666 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3668 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3671 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3672 // segment, because that is where the dynamic linker expects to find
3673 // it (this is just for efficiency; other positions would also work
3675 if (type1
== elfcpp::PT_TLS
3676 && type2
!= elfcpp::PT_TLS
3677 && type2
!= elfcpp::PT_GNU_RELRO
)
3679 if (type2
== elfcpp::PT_TLS
3680 && type1
!= elfcpp::PT_TLS
3681 && type1
!= elfcpp::PT_GNU_RELRO
)
3684 // We put the PT_GNU_RELRO segment last, because that is where the
3685 // dynamic linker expects to find it (as with PT_TLS, this is just
3687 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3689 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3692 const elfcpp::Elf_Word flags1
= seg1
->flags();
3693 const elfcpp::Elf_Word flags2
= seg2
->flags();
3695 // The order of non-PT_LOAD segments is unimportant. We simply sort
3696 // by the numeric segment type and flags values. There should not
3697 // be more than one segment with the same type and flags, except
3698 // when a linker script specifies such.
3699 if (type1
!= elfcpp::PT_LOAD
)
3702 return type1
< type2
;
3703 gold_assert(flags1
!= flags2
3704 || this->script_options_
->saw_phdrs_clause());
3705 return flags1
< flags2
;
3708 // If the addresses are set already, sort by load address.
3709 if (seg1
->are_addresses_set())
3711 if (!seg2
->are_addresses_set())
3714 unsigned int section_count1
= seg1
->output_section_count();
3715 unsigned int section_count2
= seg2
->output_section_count();
3716 if (section_count1
== 0 && section_count2
> 0)
3718 if (section_count1
> 0 && section_count2
== 0)
3721 uint64_t paddr1
= (seg1
->are_addresses_set()
3723 : seg1
->first_section_load_address());
3724 uint64_t paddr2
= (seg2
->are_addresses_set()
3726 : seg2
->first_section_load_address());
3728 if (paddr1
!= paddr2
)
3729 return paddr1
< paddr2
;
3731 else if (seg2
->are_addresses_set())
3734 // A segment which holds large data comes after a segment which does
3735 // not hold large data.
3736 if (seg1
->is_large_data_segment())
3738 if (!seg2
->is_large_data_segment())
3741 else if (seg2
->is_large_data_segment())
3744 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3745 // segments come before writable segments. Then writable segments
3746 // with data come before writable segments without data. Then
3747 // executable segments come before non-executable segments. Then
3748 // the unlikely case of a non-readable segment comes before the
3749 // normal case of a readable segment. If there are multiple
3750 // segments with the same type and flags, we require that the
3751 // address be set, and we sort by virtual address and then physical
3753 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3754 return (flags1
& elfcpp::PF_W
) == 0;
3755 if ((flags1
& elfcpp::PF_W
) != 0
3756 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3757 return seg1
->has_any_data_sections();
3758 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3759 return (flags1
& elfcpp::PF_X
) != 0;
3760 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3761 return (flags1
& elfcpp::PF_R
) == 0;
3763 // We shouldn't get here--we shouldn't create segments which we
3764 // can't distinguish. Unless of course we are using a weird linker
3765 // script or overlapping --section-start options. We could also get
3766 // here if plugins want unique segments for subsets of sections.
3767 gold_assert(this->script_options_
->saw_phdrs_clause()
3768 || parameters
->options().any_section_start()
3769 || this->is_unique_segment_for_sections_specified()
3770 || parameters
->options().text_unlikely_segment());
3774 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3777 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3779 uint64_t unsigned_off
= off
;
3780 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3781 | (addr
& (abi_pagesize
- 1)));
3782 if (aligned_off
< unsigned_off
)
3783 aligned_off
+= abi_pagesize
;
3787 // On targets where the text segment contains only executable code,
3788 // a non-executable segment is never the text segment.
3791 is_text_segment(const Target
* target
, const Output_segment
* seg
)
3793 elfcpp::Elf_Xword flags
= seg
->flags();
3794 if ((flags
& elfcpp::PF_W
) != 0)
3796 if ((flags
& elfcpp::PF_X
) == 0)
3797 return !target
->isolate_execinstr();
3801 // Set the file offsets of all the segments, and all the sections they
3802 // contain. They have all been created. LOAD_SEG must be laid out
3803 // first. Return the offset of the data to follow.
3806 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3807 unsigned int* pshndx
)
3809 // Sort them into the final order. We use a stable sort so that we
3810 // don't randomize the order of indistinguishable segments created
3811 // by linker scripts.
3812 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3813 Layout::Compare_segments(this));
3815 // Find the PT_LOAD segments, and set their addresses and offsets
3816 // and their section's addresses and offsets.
3817 uint64_t start_addr
;
3818 if (parameters
->options().user_set_Ttext())
3819 start_addr
= parameters
->options().Ttext();
3820 else if (parameters
->options().output_is_position_independent())
3823 start_addr
= target
->default_text_segment_address();
3825 uint64_t addr
= start_addr
;
3828 // If LOAD_SEG is NULL, then the file header and segment headers
3829 // will not be loadable. But they still need to be at offset 0 in
3830 // the file. Set their offsets now.
3831 if (load_seg
== NULL
)
3833 for (Data_list::iterator p
= this->special_output_list_
.begin();
3834 p
!= this->special_output_list_
.end();
3837 off
= align_address(off
, (*p
)->addralign());
3838 (*p
)->set_address_and_file_offset(0, off
);
3839 off
+= (*p
)->data_size();
3843 unsigned int increase_relro
= this->increase_relro_
;
3844 if (this->script_options_
->saw_sections_clause())
3847 const bool check_sections
= parameters
->options().check_sections();
3848 Output_segment
* last_load_segment
= NULL
;
3850 unsigned int shndx_begin
= *pshndx
;
3851 unsigned int shndx_load_seg
= *pshndx
;
3853 for (Segment_list::iterator p
= this->segment_list_
.begin();
3854 p
!= this->segment_list_
.end();
3857 if ((*p
)->type() == elfcpp::PT_LOAD
)
3859 if (target
->isolate_execinstr())
3861 // When we hit the segment that should contain the
3862 // file headers, reset the file offset so we place
3863 // it and subsequent segments appropriately.
3864 // We'll fix up the preceding segments below.
3872 shndx_load_seg
= *pshndx
;
3878 // Verify that the file headers fall into the first segment.
3879 if (load_seg
!= NULL
&& load_seg
!= *p
)
3884 bool are_addresses_set
= (*p
)->are_addresses_set();
3885 if (are_addresses_set
)
3887 // When it comes to setting file offsets, we care about
3888 // the physical address.
3889 addr
= (*p
)->paddr();
3891 else if (parameters
->options().user_set_Ttext()
3892 && (parameters
->options().omagic()
3893 || is_text_segment(target
, *p
)))
3895 are_addresses_set
= true;
3897 else if (parameters
->options().user_set_Trodata_segment()
3898 && ((*p
)->flags() & (elfcpp::PF_W
| elfcpp::PF_X
)) == 0)
3900 addr
= parameters
->options().Trodata_segment();
3901 are_addresses_set
= true;
3903 else if (parameters
->options().user_set_Tdata()
3904 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3905 && (!parameters
->options().user_set_Tbss()
3906 || (*p
)->has_any_data_sections()))
3908 addr
= parameters
->options().Tdata();
3909 are_addresses_set
= true;
3911 else if (parameters
->options().user_set_Tbss()
3912 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3913 && !(*p
)->has_any_data_sections())
3915 addr
= parameters
->options().Tbss();
3916 are_addresses_set
= true;
3919 uint64_t orig_addr
= addr
;
3920 uint64_t orig_off
= off
;
3922 uint64_t aligned_addr
= 0;
3923 uint64_t abi_pagesize
= target
->abi_pagesize();
3924 uint64_t common_pagesize
= target
->common_pagesize();
3926 if (!parameters
->options().nmagic()
3927 && !parameters
->options().omagic())
3928 (*p
)->set_minimum_p_align(abi_pagesize
);
3930 if (!are_addresses_set
)
3932 // Skip the address forward one page, maintaining the same
3933 // position within the page. This lets us store both segments
3934 // overlapping on a single page in the file, but the loader will
3935 // put them on different pages in memory. We will revisit this
3936 // decision once we know the size of the segment.
3938 uint64_t max_align
= (*p
)->maximum_alignment();
3939 if (max_align
> abi_pagesize
)
3940 addr
= align_address(addr
, max_align
);
3941 aligned_addr
= addr
;
3945 // This is the segment that will contain the file
3946 // headers, so its offset will have to be exactly zero.
3947 gold_assert(orig_off
== 0);
3949 // If the target wants a fixed minimum distance from the
3950 // text segment to the read-only segment, move up now.
3952 start_addr
+ (parameters
->options().user_set_rosegment_gap()
3953 ? parameters
->options().rosegment_gap()
3954 : target
->rosegment_gap());
3955 if (addr
< min_addr
)
3958 // But this is not the first segment! To make its
3959 // address congruent with its offset, that address better
3960 // be aligned to the ABI-mandated page size.
3961 addr
= align_address(addr
, abi_pagesize
);
3962 aligned_addr
= addr
;
3966 if ((addr
& (abi_pagesize
- 1)) != 0)
3967 addr
= addr
+ abi_pagesize
;
3969 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3973 if (!parameters
->options().nmagic()
3974 && !parameters
->options().omagic())
3976 // Here we are also taking care of the case when
3977 // the maximum segment alignment is larger than the page size.
3978 off
= align_file_offset(off
, addr
,
3979 std::max(abi_pagesize
,
3980 (*p
)->maximum_alignment()));
3984 // This is -N or -n with a section script which prevents
3985 // us from using a load segment. We need to ensure that
3986 // the file offset is aligned to the alignment of the
3987 // segment. This is because the linker script
3988 // implicitly assumed a zero offset. If we don't align
3989 // here, then the alignment of the sections in the
3990 // linker script may not match the alignment of the
3991 // sections in the set_section_addresses call below,
3992 // causing an error about dot moving backward.
3993 off
= align_address(off
, (*p
)->maximum_alignment());
3996 unsigned int shndx_hold
= *pshndx
;
3997 bool has_relro
= false;
3998 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
4004 // Now that we know the size of this segment, we may be able
4005 // to save a page in memory, at the cost of wasting some
4006 // file space, by instead aligning to the start of a new
4007 // page. Here we use the real machine page size rather than
4008 // the ABI mandated page size. If the segment has been
4009 // aligned so that the relro data ends at a page boundary,
4010 // we do not try to realign it.
4012 if (!are_addresses_set
4014 && aligned_addr
!= addr
4015 && !parameters
->incremental())
4017 uint64_t first_off
= (common_pagesize
4019 & (common_pagesize
- 1)));
4020 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
4023 && ((aligned_addr
& ~ (common_pagesize
- 1))
4024 != (new_addr
& ~ (common_pagesize
- 1)))
4025 && first_off
+ last_off
<= common_pagesize
)
4027 *pshndx
= shndx_hold
;
4028 addr
= align_address(aligned_addr
, common_pagesize
);
4029 addr
= align_address(addr
, (*p
)->maximum_alignment());
4030 if ((addr
& (abi_pagesize
- 1)) != 0)
4031 addr
= addr
+ abi_pagesize
;
4032 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
4033 off
= align_file_offset(off
, addr
, abi_pagesize
);
4035 increase_relro
= this->increase_relro_
;
4036 if (this->script_options_
->saw_sections_clause())
4040 new_addr
= (*p
)->set_section_addresses(target
, this,
4050 // Implement --check-sections. We know that the segments
4051 // are sorted by LMA.
4052 if (check_sections
&& last_load_segment
!= NULL
)
4054 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
4055 if (last_load_segment
->paddr() + last_load_segment
->memsz()
4058 unsigned long long lb1
= last_load_segment
->paddr();
4059 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
4060 unsigned long long lb2
= (*p
)->paddr();
4061 unsigned long long le2
= lb2
+ (*p
)->memsz();
4062 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
4063 "[0x%llx -> 0x%llx]"),
4064 lb1
, le1
, lb2
, le2
);
4067 last_load_segment
= *p
;
4071 if (load_seg
!= NULL
&& target
->isolate_execinstr())
4073 // Process the early segments again, setting their file offsets
4074 // so they land after the segments starting at LOAD_SEG.
4075 off
= align_file_offset(off
, 0, target
->abi_pagesize());
4077 this->reset_relax_output();
4079 for (Segment_list::iterator p
= this->segment_list_
.begin();
4083 if ((*p
)->type() == elfcpp::PT_LOAD
)
4085 // We repeat the whole job of assigning addresses and
4086 // offsets, but we really only want to change the offsets and
4087 // must ensure that the addresses all come out the same as
4088 // they did the first time through.
4089 bool has_relro
= false;
4090 const uint64_t old_addr
= (*p
)->vaddr();
4091 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
4092 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
4098 gold_assert(new_addr
== old_end
);
4102 gold_assert(shndx_begin
== shndx_load_seg
);
4105 // Handle the non-PT_LOAD segments, setting their offsets from their
4106 // section's offsets.
4107 for (Segment_list::iterator p
= this->segment_list_
.begin();
4108 p
!= this->segment_list_
.end();
4111 // PT_GNU_STACK was set up correctly when it was created.
4112 if ((*p
)->type() != elfcpp::PT_LOAD
4113 && (*p
)->type() != elfcpp::PT_GNU_STACK
)
4114 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
4119 // Set the TLS offsets for each section in the PT_TLS segment.
4120 if (this->tls_segment_
!= NULL
)
4121 this->tls_segment_
->set_tls_offsets();
4126 // Set the offsets of all the allocated sections when doing a
4127 // relocatable link. This does the same jobs as set_segment_offsets,
4128 // only for a relocatable link.
4131 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
4132 unsigned int* pshndx
)
4136 file_header
->set_address_and_file_offset(0, 0);
4137 off
+= file_header
->data_size();
4139 for (Section_list::iterator p
= this->section_list_
.begin();
4140 p
!= this->section_list_
.end();
4143 // We skip unallocated sections here, except that group sections
4144 // have to come first.
4145 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
4146 && (*p
)->type() != elfcpp::SHT_GROUP
)
4149 off
= align_address(off
, (*p
)->addralign());
4151 // The linker script might have set the address.
4152 if (!(*p
)->is_address_valid())
4153 (*p
)->set_address(0);
4154 (*p
)->set_file_offset(off
);
4155 (*p
)->finalize_data_size();
4156 if ((*p
)->type() != elfcpp::SHT_NOBITS
)
4157 off
+= (*p
)->data_size();
4159 (*p
)->set_out_shndx(*pshndx
);
4166 // Set the file offset of all the sections not associated with a
4170 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
4172 off_t startoff
= off
;
4175 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
4176 p
!= this->unattached_section_list_
.end();
4179 // The symtab section is handled in create_symtab_sections.
4180 if (*p
== this->symtab_section_
)
4183 // If we've already set the data size, don't set it again.
4184 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
4187 if (pass
== BEFORE_INPUT_SECTIONS_PASS
4188 && (*p
)->requires_postprocessing())
4190 (*p
)->create_postprocessing_buffer();
4191 this->any_postprocessing_sections_
= true;
4194 if (pass
== BEFORE_INPUT_SECTIONS_PASS
4195 && (*p
)->after_input_sections())
4197 else if (pass
== POSTPROCESSING_SECTIONS_PASS
4198 && (!(*p
)->after_input_sections()
4199 || (*p
)->type() == elfcpp::SHT_STRTAB
))
4201 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
4202 && (!(*p
)->after_input_sections()
4203 || (*p
)->type() != elfcpp::SHT_STRTAB
))
4206 if (!parameters
->incremental_update())
4208 off
= align_address(off
, (*p
)->addralign());
4209 (*p
)->set_file_offset(off
);
4210 (*p
)->finalize_data_size();
4214 // Incremental update: allocate file space from free list.
4215 (*p
)->pre_finalize_data_size();
4216 off_t current_size
= (*p
)->current_data_size();
4217 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
4220 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
4221 this->free_list_
.dump();
4222 gold_assert((*p
)->output_section() != NULL
);
4223 gold_fallback(_("out of patch space for section %s; "
4224 "relink with --incremental-full"),
4225 (*p
)->output_section()->name());
4227 (*p
)->set_file_offset(off
);
4228 (*p
)->finalize_data_size();
4229 if ((*p
)->data_size() > current_size
)
4231 gold_assert((*p
)->output_section() != NULL
);
4232 gold_fallback(_("%s: section changed size; "
4233 "relink with --incremental-full"),
4234 (*p
)->output_section()->name());
4236 gold_debug(DEBUG_INCREMENTAL
,
4237 "set_section_offsets: %08lx %08lx %s",
4238 static_cast<long>(off
),
4239 static_cast<long>((*p
)->data_size()),
4240 ((*p
)->output_section() != NULL
4241 ? (*p
)->output_section()->name() : "(special)"));
4244 off
+= (*p
)->data_size();
4248 // At this point the name must be set.
4249 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
4250 this->namepool_
.add((*p
)->name(), false, NULL
);
4255 // Set the section indexes of all the sections not associated with a
4259 Layout::set_section_indexes(unsigned int shndx
)
4261 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
4262 p
!= this->unattached_section_list_
.end();
4265 if (!(*p
)->has_out_shndx())
4267 (*p
)->set_out_shndx(shndx
);
4274 // Set the section addresses according to the linker script. This is
4275 // only called when we see a SECTIONS clause. This returns the
4276 // program segment which should hold the file header and segment
4277 // headers, if any. It will return NULL if they should not be in a
4281 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
4283 Script_sections
* ss
= this->script_options_
->script_sections();
4284 gold_assert(ss
->saw_sections_clause());
4285 return this->script_options_
->set_section_addresses(symtab
, this);
4288 // Place the orphan sections in the linker script.
4291 Layout::place_orphan_sections_in_script()
4293 Script_sections
* ss
= this->script_options_
->script_sections();
4294 gold_assert(ss
->saw_sections_clause());
4296 // Place each orphaned output section in the script.
4297 for (Section_list::iterator p
= this->section_list_
.begin();
4298 p
!= this->section_list_
.end();
4301 if (!(*p
)->found_in_sections_clause())
4302 ss
->place_orphan(*p
);
4306 // Count the local symbols in the regular symbol table and the dynamic
4307 // symbol table, and build the respective string pools.
4310 Layout::count_local_symbols(const Task
* task
,
4311 const Input_objects
* input_objects
)
4313 // First, figure out an upper bound on the number of symbols we'll
4314 // be inserting into each pool. This helps us create the pools with
4315 // the right size, to avoid unnecessary hashtable resizing.
4316 unsigned int symbol_count
= 0;
4317 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4318 p
!= input_objects
->relobj_end();
4320 symbol_count
+= (*p
)->local_symbol_count();
4322 // Go from "upper bound" to "estimate." We overcount for two
4323 // reasons: we double-count symbols that occur in more than one
4324 // object file, and we count symbols that are dropped from the
4325 // output. Add it all together and assume we overcount by 100%.
4328 // We assume all symbols will go into both the sympool and dynpool.
4329 this->sympool_
.reserve(symbol_count
);
4330 this->dynpool_
.reserve(symbol_count
);
4332 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4333 p
!= input_objects
->relobj_end();
4336 Task_lock_obj
<Object
> tlo(task
, *p
);
4337 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
4341 // Create the symbol table sections. Here we also set the final
4342 // values of the symbols. At this point all the loadable sections are
4343 // fully laid out. SHNUM is the number of sections so far.
4346 Layout::create_symtab_sections(const Input_objects
* input_objects
,
4347 Symbol_table
* symtab
,
4350 unsigned int local_dynamic_count
)
4354 if (parameters
->target().get_size() == 32)
4356 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4359 else if (parameters
->target().get_size() == 64)
4361 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4367 // Compute file offsets relative to the start of the symtab section.
4370 // Save space for the dummy symbol at the start of the section. We
4371 // never bother to write this out--it will just be left as zero.
4373 unsigned int local_symbol_index
= 1;
4375 // Add STT_SECTION symbols for each Output section which needs one.
4376 for (Section_list::iterator p
= this->section_list_
.begin();
4377 p
!= this->section_list_
.end();
4380 if (!(*p
)->needs_symtab_index())
4381 (*p
)->set_symtab_index(-1U);
4384 (*p
)->set_symtab_index(local_symbol_index
);
4385 ++local_symbol_index
;
4390 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4391 p
!= input_objects
->relobj_end();
4394 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
4396 off
+= (index
- local_symbol_index
) * symsize
;
4397 local_symbol_index
= index
;
4400 unsigned int local_symcount
= local_symbol_index
;
4401 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
4405 if (this->dynsym_section_
== NULL
)
4412 off_t locsize
= local_dynamic_count
* this->dynsym_section_
->entsize();
4413 dynoff
= this->dynsym_section_
->offset() + locsize
;
4414 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
4415 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
4416 == this->dynsym_section_
->data_size() - locsize
);
4419 off_t global_off
= off
;
4420 off
= symtab
->finalize(off
, dynoff
, local_dynamic_count
, dyncount
,
4421 &this->sympool_
, &local_symcount
);
4423 if (!parameters
->options().strip_all())
4425 this->sympool_
.set_string_offsets();
4427 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
4428 Output_section
* osymtab
= this->make_output_section(symtab_name
,
4432 this->symtab_section_
= osymtab
;
4434 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
4436 osymtab
->add_output_section_data(pos
);
4438 // We generate a .symtab_shndx section if we have more than
4439 // SHN_LORESERVE sections. Technically it is possible that we
4440 // don't need one, because it is possible that there are no
4441 // symbols in any of sections with indexes larger than
4442 // SHN_LORESERVE. That is probably unusual, though, and it is
4443 // easier to always create one than to compute section indexes
4444 // twice (once here, once when writing out the symbols).
4445 if (shnum
>= elfcpp::SHN_LORESERVE
)
4447 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
4449 Output_section
* osymtab_xindex
=
4450 this->make_output_section(symtab_xindex_name
,
4451 elfcpp::SHT_SYMTAB_SHNDX
, 0,
4452 ORDER_INVALID
, false);
4454 size_t symcount
= off
/ symsize
;
4455 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
4457 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
4459 osymtab_xindex
->set_link_section(osymtab
);
4460 osymtab_xindex
->set_addralign(4);
4461 osymtab_xindex
->set_entsize(4);
4463 osymtab_xindex
->set_after_input_sections();
4465 // This tells the driver code to wait until the symbol table
4466 // has written out before writing out the postprocessing
4467 // sections, including the .symtab_shndx section.
4468 this->any_postprocessing_sections_
= true;
4471 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
4472 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
4477 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
4478 ostrtab
->add_output_section_data(pstr
);
4481 if (!parameters
->incremental_update())
4482 symtab_off
= align_address(*poff
, align
);
4485 symtab_off
= this->allocate(off
, align
, *poff
);
4487 gold_fallback(_("out of patch space for symbol table; "
4488 "relink with --incremental-full"));
4489 gold_debug(DEBUG_INCREMENTAL
,
4490 "create_symtab_sections: %08lx %08lx .symtab",
4491 static_cast<long>(symtab_off
),
4492 static_cast<long>(off
));
4495 symtab
->set_file_offset(symtab_off
+ global_off
);
4496 osymtab
->set_file_offset(symtab_off
);
4497 osymtab
->finalize_data_size();
4498 osymtab
->set_link_section(ostrtab
);
4499 osymtab
->set_info(local_symcount
);
4500 osymtab
->set_entsize(symsize
);
4502 if (symtab_off
+ off
> *poff
)
4503 *poff
= symtab_off
+ off
;
4507 // Create the .shstrtab section, which holds the names of the
4508 // sections. At the time this is called, we have created all the
4509 // output sections except .shstrtab itself.
4512 Layout::create_shstrtab()
4514 // FIXME: We don't need to create a .shstrtab section if we are
4515 // stripping everything.
4517 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
4519 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
4520 ORDER_INVALID
, false);
4522 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
4524 // We can't write out this section until we've set all the
4525 // section names, and we don't set the names of compressed
4526 // output sections until relocations are complete. FIXME: With
4527 // the current names we use, this is unnecessary.
4528 os
->set_after_input_sections();
4531 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
4532 os
->add_output_section_data(posd
);
4537 // Create the section headers. SIZE is 32 or 64. OFF is the file
4541 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
4543 Output_section_headers
* oshdrs
;
4544 oshdrs
= new Output_section_headers(this,
4545 &this->segment_list_
,
4546 &this->section_list_
,
4547 &this->unattached_section_list_
,
4551 if (!parameters
->incremental_update())
4552 off
= align_address(*poff
, oshdrs
->addralign());
4555 oshdrs
->pre_finalize_data_size();
4556 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
4558 gold_fallback(_("out of patch space for section header table; "
4559 "relink with --incremental-full"));
4560 gold_debug(DEBUG_INCREMENTAL
,
4561 "create_shdrs: %08lx %08lx (section header table)",
4562 static_cast<long>(off
),
4563 static_cast<long>(off
+ oshdrs
->data_size()));
4565 oshdrs
->set_address_and_file_offset(0, off
);
4566 off
+= oshdrs
->data_size();
4569 this->section_headers_
= oshdrs
;
4572 // Count the allocated sections.
4575 Layout::allocated_output_section_count() const
4577 size_t section_count
= 0;
4578 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4579 p
!= this->segment_list_
.end();
4581 section_count
+= (*p
)->output_section_count();
4582 return section_count
;
4585 // Create the dynamic symbol table.
4586 // *PLOCAL_DYNAMIC_COUNT will be set to the number of local symbols
4587 // from input objects, and *PFORCED_LOCAL_DYNAMIC_COUNT will be set
4588 // to the number of global symbols that have been forced local.
4589 // We need to remember the former because the forced-local symbols are
4590 // written along with the global symbols in Symtab::write_globals().
4593 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4594 Symbol_table
* symtab
,
4595 Output_section
** pdynstr
,
4596 unsigned int* plocal_dynamic_count
,
4597 unsigned int* pforced_local_dynamic_count
,
4598 std::vector
<Symbol
*>* pdynamic_symbols
,
4599 Versions
* pversions
)
4601 // Count all the symbols in the dynamic symbol table, and set the
4602 // dynamic symbol indexes.
4604 // Skip symbol 0, which is always all zeroes.
4605 unsigned int index
= 1;
4607 // Add STT_SECTION symbols for each Output section which needs one.
4608 for (Section_list::iterator p
= this->section_list_
.begin();
4609 p
!= this->section_list_
.end();
4612 if (!(*p
)->needs_dynsym_index())
4613 (*p
)->set_dynsym_index(-1U);
4616 (*p
)->set_dynsym_index(index
);
4621 // Count the local symbols that need to go in the dynamic symbol table,
4622 // and set the dynamic symbol indexes.
4623 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4624 p
!= input_objects
->relobj_end();
4627 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4631 unsigned int local_symcount
= index
;
4632 unsigned int forced_local_count
= 0;
4634 index
= symtab
->set_dynsym_indexes(index
, &forced_local_count
,
4635 pdynamic_symbols
, &this->dynpool_
,
4638 *plocal_dynamic_count
= local_symcount
;
4639 *pforced_local_dynamic_count
= forced_local_count
;
4643 const int size
= parameters
->target().get_size();
4646 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4649 else if (size
== 64)
4651 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4657 // Create the dynamic symbol table section.
4659 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4663 ORDER_DYNAMIC_LINKER
,
4664 false, false, false);
4666 // Check for NULL as a linker script may discard .dynsym.
4669 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4672 dynsym
->add_output_section_data(odata
);
4674 dynsym
->set_info(local_symcount
+ forced_local_count
);
4675 dynsym
->set_entsize(symsize
);
4676 dynsym
->set_addralign(align
);
4678 this->dynsym_section_
= dynsym
;
4681 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4684 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4685 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4688 // If there are more than SHN_LORESERVE allocated sections, we
4689 // create a .dynsym_shndx section. It is possible that we don't
4690 // need one, because it is possible that there are no dynamic
4691 // symbols in any of the sections with indexes larger than
4692 // SHN_LORESERVE. This is probably unusual, though, and at this
4693 // time we don't know the actual section indexes so it is
4694 // inconvenient to check.
4695 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4697 Output_section
* dynsym_xindex
=
4698 this->choose_output_section(NULL
, ".dynsym_shndx",
4699 elfcpp::SHT_SYMTAB_SHNDX
,
4701 false, ORDER_DYNAMIC_LINKER
, false, false,
4704 if (dynsym_xindex
!= NULL
)
4706 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4708 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4710 dynsym_xindex
->set_link_section(dynsym
);
4711 dynsym_xindex
->set_addralign(4);
4712 dynsym_xindex
->set_entsize(4);
4714 dynsym_xindex
->set_after_input_sections();
4716 // This tells the driver code to wait until the symbol table
4717 // has written out before writing out the postprocessing
4718 // sections, including the .dynsym_shndx section.
4719 this->any_postprocessing_sections_
= true;
4723 // Create the dynamic string table section.
4725 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4729 ORDER_DYNAMIC_LINKER
,
4730 false, false, false);
4734 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4735 dynstr
->add_output_section_data(strdata
);
4738 dynsym
->set_link_section(dynstr
);
4739 if (this->dynamic_section_
!= NULL
)
4740 this->dynamic_section_
->set_link_section(dynstr
);
4744 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4745 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4749 // Create the hash tables. The Gnu-style hash table must be
4750 // built first, because it changes the order of the symbols
4751 // in the dynamic symbol table.
4753 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4754 || strcmp(parameters
->options().hash_style(), "both") == 0)
4756 unsigned char* phash
;
4757 unsigned int hashlen
;
4758 Dynobj::create_gnu_hash_table(*pdynamic_symbols
,
4759 local_symcount
+ forced_local_count
,
4762 Output_section
* hashsec
=
4763 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4764 elfcpp::SHF_ALLOC
, false,
4765 ORDER_DYNAMIC_LINKER
, false, false,
4768 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4772 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4773 hashsec
->add_output_section_data(hashdata
);
4775 if (hashsec
!= NULL
)
4778 hashsec
->set_link_section(dynsym
);
4780 // For a 64-bit target, the entries in .gnu.hash do not have
4781 // a uniform size, so we only set the entry size for a
4783 if (parameters
->target().get_size() == 32)
4784 hashsec
->set_entsize(4);
4787 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4791 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4792 || strcmp(parameters
->options().hash_style(), "both") == 0)
4794 unsigned char* phash
;
4795 unsigned int hashlen
;
4796 Dynobj::create_elf_hash_table(*pdynamic_symbols
,
4797 local_symcount
+ forced_local_count
,
4800 Output_section
* hashsec
=
4801 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4802 elfcpp::SHF_ALLOC
, false,
4803 ORDER_DYNAMIC_LINKER
, false, false,
4806 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4810 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4811 hashsec
->add_output_section_data(hashdata
);
4813 if (hashsec
!= NULL
)
4816 hashsec
->set_link_section(dynsym
);
4817 hashsec
->set_entsize(parameters
->target().hash_entry_size() / 8);
4821 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4825 // Assign offsets to each local portion of the dynamic symbol table.
4828 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4830 Output_section
* dynsym
= this->dynsym_section_
;
4834 off_t off
= dynsym
->offset();
4836 // Skip the dummy symbol at the start of the section.
4837 off
+= dynsym
->entsize();
4839 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4840 p
!= input_objects
->relobj_end();
4843 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4844 off
+= count
* dynsym
->entsize();
4848 // Create the version sections.
4851 Layout::create_version_sections(const Versions
* versions
,
4852 const Symbol_table
* symtab
,
4853 unsigned int local_symcount
,
4854 const std::vector
<Symbol
*>& dynamic_symbols
,
4855 const Output_section
* dynstr
)
4857 if (!versions
->any_defs() && !versions
->any_needs())
4860 switch (parameters
->size_and_endianness())
4862 #ifdef HAVE_TARGET_32_LITTLE
4863 case Parameters::TARGET_32_LITTLE
:
4864 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4866 dynamic_symbols
, dynstr
);
4869 #ifdef HAVE_TARGET_32_BIG
4870 case Parameters::TARGET_32_BIG
:
4871 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4873 dynamic_symbols
, dynstr
);
4876 #ifdef HAVE_TARGET_64_LITTLE
4877 case Parameters::TARGET_64_LITTLE
:
4878 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4880 dynamic_symbols
, dynstr
);
4883 #ifdef HAVE_TARGET_64_BIG
4884 case Parameters::TARGET_64_BIG
:
4885 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4887 dynamic_symbols
, dynstr
);
4895 // Create the version sections, sized version.
4897 template<int size
, bool big_endian
>
4899 Layout::sized_create_version_sections(
4900 const Versions
* versions
,
4901 const Symbol_table
* symtab
,
4902 unsigned int local_symcount
,
4903 const std::vector
<Symbol
*>& dynamic_symbols
,
4904 const Output_section
* dynstr
)
4906 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4907 elfcpp::SHT_GNU_versym
,
4910 ORDER_DYNAMIC_LINKER
,
4911 false, false, false);
4913 // Check for NULL since a linker script may discard this section.
4916 unsigned char* vbuf
;
4918 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4924 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4927 vsec
->add_output_section_data(vdata
);
4928 vsec
->set_entsize(2);
4929 vsec
->set_link_section(this->dynsym_section_
);
4932 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4933 if (odyn
!= NULL
&& vsec
!= NULL
)
4934 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4936 if (versions
->any_defs())
4938 Output_section
* vdsec
;
4939 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4940 elfcpp::SHT_GNU_verdef
,
4942 false, ORDER_DYNAMIC_LINKER
, false,
4947 unsigned char* vdbuf
;
4948 unsigned int vdsize
;
4949 unsigned int vdentries
;
4950 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4954 Output_section_data
* vddata
=
4955 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4957 vdsec
->add_output_section_data(vddata
);
4958 vdsec
->set_link_section(dynstr
);
4959 vdsec
->set_info(vdentries
);
4963 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4964 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4969 if (versions
->any_needs())
4971 Output_section
* vnsec
;
4972 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4973 elfcpp::SHT_GNU_verneed
,
4975 false, ORDER_DYNAMIC_LINKER
, false,
4980 unsigned char* vnbuf
;
4981 unsigned int vnsize
;
4982 unsigned int vnentries
;
4983 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4987 Output_section_data
* vndata
=
4988 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4990 vnsec
->add_output_section_data(vndata
);
4991 vnsec
->set_link_section(dynstr
);
4992 vnsec
->set_info(vnentries
);
4996 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4997 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
5003 // Create the .interp section and PT_INTERP segment.
5006 Layout::create_interp(const Target
* target
)
5008 gold_assert(this->interp_segment_
== NULL
);
5010 const char* interp
= parameters
->options().dynamic_linker();
5013 interp
= target
->dynamic_linker();
5014 gold_assert(interp
!= NULL
);
5017 size_t len
= strlen(interp
) + 1;
5019 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
5021 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
5022 elfcpp::SHT_PROGBITS
,
5024 false, ORDER_INTERP
,
5025 false, false, false);
5027 osec
->add_output_section_data(odata
);
5030 // Add dynamic tags for the PLT and the dynamic relocs. This is
5031 // called by the target-specific code. This does nothing if not doing
5034 // USE_REL is true for REL relocs rather than RELA relocs.
5036 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
5038 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
5039 // and we also set DT_PLTREL. We use PLT_REL's output section, since
5040 // some targets have multiple reloc sections in PLT_REL.
5042 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
5043 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
5046 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
5050 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
5051 const Output_data
* plt_rel
,
5052 const Output_data_reloc_generic
* dyn_rel
,
5053 bool add_debug
, bool dynrel_includes_plt
)
5055 Output_data_dynamic
* odyn
= this->dynamic_data_
;
5059 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
5060 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
5062 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
5064 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
5065 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
5066 odyn
->add_constant(elfcpp::DT_PLTREL
,
5067 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
5070 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
5071 || (dynrel_includes_plt
5073 && plt_rel
->output_section() != NULL
))
5075 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
5076 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
5077 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
5079 ? dyn_rel
->output_section()
5080 : plt_rel
->output_section()));
5081 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
5082 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
5083 odyn
->add_section_size(size_tag
,
5084 dyn_rel
->output_section(),
5085 plt_rel
->output_section());
5086 else if (have_dyn_rel
)
5087 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
5089 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
5090 const int size
= parameters
->target().get_size();
5095 rel_tag
= elfcpp::DT_RELENT
;
5097 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
5098 else if (size
== 64)
5099 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
5105 rel_tag
= elfcpp::DT_RELAENT
;
5107 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
5108 else if (size
== 64)
5109 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
5113 odyn
->add_constant(rel_tag
, rel_size
);
5115 if (parameters
->options().combreloc() && have_dyn_rel
)
5117 size_t c
= dyn_rel
->relative_reloc_count();
5119 odyn
->add_constant((use_rel
5120 ? elfcpp::DT_RELCOUNT
5121 : elfcpp::DT_RELACOUNT
),
5126 if (add_debug
&& !parameters
->options().shared())
5128 // The value of the DT_DEBUG tag is filled in by the dynamic
5129 // linker at run time, and used by the debugger.
5130 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
5135 Layout::add_target_specific_dynamic_tag(elfcpp::DT tag
, unsigned int val
)
5137 Output_data_dynamic
* odyn
= this->dynamic_data_
;
5140 odyn
->add_constant(tag
, val
);
5143 // Finish the .dynamic section and PT_DYNAMIC segment.
5146 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
5147 const Symbol_table
* symtab
)
5149 if (!this->script_options_
->saw_phdrs_clause()
5150 && this->dynamic_section_
!= NULL
)
5152 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
5155 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
5156 elfcpp::PF_R
| elfcpp::PF_W
);
5159 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
5163 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
5164 p
!= input_objects
->dynobj_end();
5167 if (!(*p
)->is_needed() && (*p
)->as_needed())
5169 // This dynamic object was linked with --as-needed, but it
5174 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
5177 if (parameters
->options().shared())
5179 const char* soname
= parameters
->options().soname();
5181 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
5184 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
5185 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
5186 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
5188 sym
= symtab
->lookup(parameters
->options().fini());
5189 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
5190 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
5192 // Look for .init_array, .preinit_array and .fini_array by checking
5194 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
5195 p
!= this->section_list_
.end();
5197 switch((*p
)->type())
5199 case elfcpp::SHT_FINI_ARRAY
:
5200 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
5201 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
5203 case elfcpp::SHT_INIT_ARRAY
:
5204 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
5205 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
5207 case elfcpp::SHT_PREINIT_ARRAY
:
5208 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
5209 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
5215 // Add a DT_RPATH entry if needed.
5216 const General_options::Dir_list
& rpath(parameters
->options().rpath());
5219 std::string rpath_val
;
5220 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
5224 if (rpath_val
.empty())
5225 rpath_val
= p
->name();
5228 // Eliminate duplicates.
5229 General_options::Dir_list::const_iterator q
;
5230 for (q
= rpath
.begin(); q
!= p
; ++q
)
5231 if (q
->name() == p
->name())
5236 rpath_val
+= p
->name();
5241 if (!parameters
->options().enable_new_dtags())
5242 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
5244 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
5247 // Look for text segments that have dynamic relocations.
5248 bool have_textrel
= false;
5249 if (!this->script_options_
->saw_sections_clause())
5251 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5252 p
!= this->segment_list_
.end();
5255 if ((*p
)->type() == elfcpp::PT_LOAD
5256 && ((*p
)->flags() & elfcpp::PF_W
) == 0
5257 && (*p
)->has_dynamic_reloc())
5259 have_textrel
= true;
5266 // We don't know the section -> segment mapping, so we are
5267 // conservative and just look for readonly sections with
5268 // relocations. If those sections wind up in writable segments,
5269 // then we have created an unnecessary DT_TEXTREL entry.
5270 for (Section_list::const_iterator p
= this->section_list_
.begin();
5271 p
!= this->section_list_
.end();
5274 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
5275 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
5276 && (*p
)->has_dynamic_reloc())
5278 have_textrel
= true;
5284 if (parameters
->options().filter() != NULL
)
5285 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
5286 if (parameters
->options().any_auxiliary())
5288 for (options::String_set::const_iterator p
=
5289 parameters
->options().auxiliary_begin();
5290 p
!= parameters
->options().auxiliary_end();
5292 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
5295 // Add a DT_FLAGS entry if necessary.
5296 unsigned int flags
= 0;
5299 // Add a DT_TEXTREL for compatibility with older loaders.
5300 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
5301 flags
|= elfcpp::DF_TEXTREL
;
5303 if (parameters
->options().text())
5304 gold_error(_("read-only segment has dynamic relocations"));
5305 else if (parameters
->options().warn_shared_textrel()
5306 && parameters
->options().shared())
5307 gold_warning(_("shared library text segment is not shareable"));
5309 if (parameters
->options().shared() && this->has_static_tls())
5310 flags
|= elfcpp::DF_STATIC_TLS
;
5311 if (parameters
->options().origin())
5312 flags
|= elfcpp::DF_ORIGIN
;
5313 if (parameters
->options().Bsymbolic()
5314 && !parameters
->options().have_dynamic_list())
5316 flags
|= elfcpp::DF_SYMBOLIC
;
5317 // Add DT_SYMBOLIC for compatibility with older loaders.
5318 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
5320 if (parameters
->options().now())
5321 flags
|= elfcpp::DF_BIND_NOW
;
5323 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
5326 if (parameters
->options().global())
5327 flags
|= elfcpp::DF_1_GLOBAL
;
5328 if (parameters
->options().initfirst())
5329 flags
|= elfcpp::DF_1_INITFIRST
;
5330 if (parameters
->options().interpose())
5331 flags
|= elfcpp::DF_1_INTERPOSE
;
5332 if (parameters
->options().loadfltr())
5333 flags
|= elfcpp::DF_1_LOADFLTR
;
5334 if (parameters
->options().nodefaultlib())
5335 flags
|= elfcpp::DF_1_NODEFLIB
;
5336 if (parameters
->options().nodelete())
5337 flags
|= elfcpp::DF_1_NODELETE
;
5338 if (parameters
->options().nodlopen())
5339 flags
|= elfcpp::DF_1_NOOPEN
;
5340 if (parameters
->options().nodump())
5341 flags
|= elfcpp::DF_1_NODUMP
;
5342 if (!parameters
->options().shared())
5343 flags
&= ~(elfcpp::DF_1_INITFIRST
5344 | elfcpp::DF_1_NODELETE
5345 | elfcpp::DF_1_NOOPEN
);
5346 if (parameters
->options().origin())
5347 flags
|= elfcpp::DF_1_ORIGIN
;
5348 if (parameters
->options().now())
5349 flags
|= elfcpp::DF_1_NOW
;
5350 if (parameters
->options().Bgroup())
5351 flags
|= elfcpp::DF_1_GROUP
;
5353 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
5356 // Set the size of the _DYNAMIC symbol table to be the size of the
5360 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
5362 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
5365 odyn
->finalize_data_size();
5366 if (this->dynamic_symbol_
== NULL
)
5368 off_t data_size
= odyn
->data_size();
5369 const int size
= parameters
->target().get_size();
5371 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
5372 else if (size
== 64)
5373 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
5378 // The mapping of input section name prefixes to output section names.
5379 // In some cases one prefix is itself a prefix of another prefix; in
5380 // such a case the longer prefix must come first. These prefixes are
5381 // based on the GNU linker default ELF linker script.
5383 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
5384 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
5385 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
5387 MAPPING_INIT(".text.", ".text"),
5388 MAPPING_INIT(".rodata.", ".rodata"),
5389 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
5390 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
5391 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
5392 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
5393 MAPPING_INIT(".data.", ".data"),
5394 MAPPING_INIT(".bss.", ".bss"),
5395 MAPPING_INIT(".tdata.", ".tdata"),
5396 MAPPING_INIT(".tbss.", ".tbss"),
5397 MAPPING_INIT(".init_array.", ".init_array"),
5398 MAPPING_INIT(".fini_array.", ".fini_array"),
5399 MAPPING_INIT(".sdata.", ".sdata"),
5400 MAPPING_INIT(".sbss.", ".sbss"),
5401 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
5402 // differently depending on whether it is creating a shared library.
5403 MAPPING_INIT(".sdata2.", ".sdata"),
5404 MAPPING_INIT(".sbss2.", ".sbss"),
5405 MAPPING_INIT(".lrodata.", ".lrodata"),
5406 MAPPING_INIT(".ldata.", ".ldata"),
5407 MAPPING_INIT(".lbss.", ".lbss"),
5408 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
5409 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
5410 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
5411 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
5412 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
5413 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
5414 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
5415 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
5416 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
5417 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
5418 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
5419 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
5420 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
5421 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
5422 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
5423 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5424 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5425 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5426 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5427 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5428 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5429 MAPPING_INIT(".gnu.build.attributes.", ".gnu.build.attributes"),
5432 // Mapping for ".text" section prefixes with -z,keep-text-section-prefix.
5433 const Layout::Section_name_mapping
Layout::text_section_name_mapping
[] =
5435 MAPPING_INIT(".text.hot.", ".text.hot"),
5436 MAPPING_INIT_EXACT(".text.hot", ".text.hot"),
5437 MAPPING_INIT(".text.unlikely.", ".text.unlikely"),
5438 MAPPING_INIT_EXACT(".text.unlikely", ".text.unlikely"),
5439 MAPPING_INIT(".text.startup.", ".text.startup"),
5440 MAPPING_INIT_EXACT(".text.startup", ".text.startup"),
5441 MAPPING_INIT(".text.exit.", ".text.exit"),
5442 MAPPING_INIT_EXACT(".text.exit", ".text.exit"),
5443 MAPPING_INIT(".text.", ".text"),
5446 #undef MAPPING_INIT_EXACT
5448 const int Layout::section_name_mapping_count
=
5449 (sizeof(Layout::section_name_mapping
)
5450 / sizeof(Layout::section_name_mapping
[0]));
5452 const int Layout::text_section_name_mapping_count
=
5453 (sizeof(Layout::text_section_name_mapping
)
5454 / sizeof(Layout::text_section_name_mapping
[0]));
5456 // Find section name NAME in PSNM and return the mapped name if found
5457 // with the length set in PLEN.
5459 Layout::match_section_name(const Layout::Section_name_mapping
* psnm
,
5461 const char* name
, size_t* plen
)
5463 for (int i
= 0; i
< count
; ++i
, ++psnm
)
5465 if (psnm
->fromlen
> 0)
5467 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
5469 *plen
= psnm
->tolen
;
5475 if (strcmp(name
, psnm
->from
) == 0)
5477 *plen
= psnm
->tolen
;
5485 // Choose the output section name to use given an input section name.
5486 // Set *PLEN to the length of the name. *PLEN is initialized to the
5490 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
5493 // gcc 4.3 generates the following sorts of section names when it
5494 // needs a section name specific to a function:
5500 // .data.rel.local.FN
5502 // .data.rel.ro.local.FN
5509 // The GNU linker maps all of those to the part before the .FN,
5510 // except that .data.rel.local.FN is mapped to .data, and
5511 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5512 // beginning with .data.rel.ro.local are grouped together.
5514 // For an anonymous namespace, the string FN can contain a '.'.
5516 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5517 // GNU linker maps to .rodata.
5519 // The .data.rel.ro sections are used with -z relro. The sections
5520 // are recognized by name. We use the same names that the GNU
5521 // linker does for these sections.
5523 // It is hard to handle this in a principled way, so we don't even
5524 // try. We use a table of mappings. If the input section name is
5525 // not found in the table, we simply use it as the output section
5528 if (parameters
->options().keep_text_section_prefix()
5529 && is_prefix_of(".text", name
))
5531 const char* match
= match_section_name(text_section_name_mapping
,
5532 text_section_name_mapping_count
,
5538 const char* match
= match_section_name(section_name_mapping
,
5539 section_name_mapping_count
, name
, plen
);
5543 // As an additional complication, .ctors sections are output in
5544 // either .ctors or .init_array sections, and .dtors sections are
5545 // output in either .dtors or .fini_array sections.
5546 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
5548 if (parameters
->options().ctors_in_init_array())
5551 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5556 return name
[1] == 'c' ? ".ctors" : ".dtors";
5559 if (parameters
->options().ctors_in_init_array()
5560 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
5562 // To make .init_array/.fini_array work with gcc we must exclude
5563 // .ctors and .dtors sections from the crtbegin and crtend
5566 || (!Layout::match_file_name(relobj
, "crtbegin")
5567 && !Layout::match_file_name(relobj
, "crtend")))
5570 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5577 // Return true if RELOBJ is an input file whose base name matches
5578 // FILE_NAME. The base name must have an extension of ".o", and must
5579 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5580 // to match crtbegin.o as well as crtbeginS.o without getting confused
5581 // by other possibilities. Overall matching the file name this way is
5582 // a dreadful hack, but the GNU linker does it in order to better
5583 // support gcc, and we need to be compatible.
5586 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
5588 const std::string
& file_name(relobj
->name());
5589 const char* base_name
= lbasename(file_name
.c_str());
5590 size_t match_len
= strlen(match
);
5591 if (strncmp(base_name
, match
, match_len
) != 0)
5593 size_t base_len
= strlen(base_name
);
5594 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
5596 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
5599 // Check if a comdat group or .gnu.linkonce section with the given
5600 // NAME is selected for the link. If there is already a section,
5601 // *KEPT_SECTION is set to point to the existing section and the
5602 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5603 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5604 // *KEPT_SECTION is set to the internal copy and the function returns
5608 Layout::find_or_add_kept_section(const std::string
& name
,
5613 Kept_section
** kept_section
)
5615 // It's normal to see a couple of entries here, for the x86 thunk
5616 // sections. If we see more than a few, we're linking a C++
5617 // program, and we resize to get more space to minimize rehashing.
5618 if (this->signatures_
.size() > 4
5619 && !this->resized_signatures_
)
5621 reserve_unordered_map(&this->signatures_
,
5622 this->number_of_input_files_
* 64);
5623 this->resized_signatures_
= true;
5626 Kept_section candidate
;
5627 std::pair
<Signatures::iterator
, bool> ins
=
5628 this->signatures_
.insert(std::make_pair(name
, candidate
));
5630 if (kept_section
!= NULL
)
5631 *kept_section
= &ins
.first
->second
;
5634 // This is the first time we've seen this signature.
5635 ins
.first
->second
.set_object(object
);
5636 ins
.first
->second
.set_shndx(shndx
);
5638 ins
.first
->second
.set_is_comdat();
5640 ins
.first
->second
.set_is_group_name();
5644 // We have already seen this signature.
5646 if (ins
.first
->second
.is_group_name())
5648 // We've already seen a real section group with this signature.
5649 // If the kept group is from a plugin object, and we're in the
5650 // replacement phase, accept the new one as a replacement.
5651 if (ins
.first
->second
.object() == NULL
5652 && parameters
->options().plugins()->in_replacement_phase())
5654 ins
.first
->second
.set_object(object
);
5655 ins
.first
->second
.set_shndx(shndx
);
5660 else if (is_group_name
)
5662 // This is a real section group, and we've already seen a
5663 // linkonce section with this signature. Record that we've seen
5664 // a section group, and don't include this section group.
5665 ins
.first
->second
.set_is_group_name();
5670 // We've already seen a linkonce section and this is a linkonce
5671 // section. These don't block each other--this may be the same
5672 // symbol name with different section types.
5677 // Store the allocated sections into the section list.
5680 Layout::get_allocated_sections(Section_list
* section_list
) const
5682 for (Section_list::const_iterator p
= this->section_list_
.begin();
5683 p
!= this->section_list_
.end();
5685 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5686 section_list
->push_back(*p
);
5689 // Store the executable sections into the section list.
5692 Layout::get_executable_sections(Section_list
* section_list
) const
5694 for (Section_list::const_iterator p
= this->section_list_
.begin();
5695 p
!= this->section_list_
.end();
5697 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5698 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5699 section_list
->push_back(*p
);
5702 // Create an output segment.
5705 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5707 gold_assert(!parameters
->options().relocatable());
5708 Output_segment
* oseg
= new Output_segment(type
, flags
);
5709 this->segment_list_
.push_back(oseg
);
5711 if (type
== elfcpp::PT_TLS
)
5712 this->tls_segment_
= oseg
;
5713 else if (type
== elfcpp::PT_GNU_RELRO
)
5714 this->relro_segment_
= oseg
;
5715 else if (type
== elfcpp::PT_INTERP
)
5716 this->interp_segment_
= oseg
;
5721 // Return the file offset of the normal symbol table.
5724 Layout::symtab_section_offset() const
5726 if (this->symtab_section_
!= NULL
)
5727 return this->symtab_section_
->offset();
5731 // Return the section index of the normal symbol table. It may have
5732 // been stripped by the -s/--strip-all option.
5735 Layout::symtab_section_shndx() const
5737 if (this->symtab_section_
!= NULL
)
5738 return this->symtab_section_
->out_shndx();
5742 // Write out the Output_sections. Most won't have anything to write,
5743 // since most of the data will come from input sections which are
5744 // handled elsewhere. But some Output_sections do have Output_data.
5747 Layout::write_output_sections(Output_file
* of
) const
5749 for (Section_list::const_iterator p
= this->section_list_
.begin();
5750 p
!= this->section_list_
.end();
5753 if (!(*p
)->after_input_sections())
5758 // Write out data not associated with a section or the symbol table.
5761 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5763 if (!parameters
->options().strip_all())
5765 const Output_section
* symtab_section
= this->symtab_section_
;
5766 for (Section_list::const_iterator p
= this->section_list_
.begin();
5767 p
!= this->section_list_
.end();
5770 if ((*p
)->needs_symtab_index())
5772 gold_assert(symtab_section
!= NULL
);
5773 unsigned int index
= (*p
)->symtab_index();
5774 gold_assert(index
> 0 && index
!= -1U);
5775 off_t off
= (symtab_section
->offset()
5776 + index
* symtab_section
->entsize());
5777 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5782 const Output_section
* dynsym_section
= this->dynsym_section_
;
5783 for (Section_list::const_iterator p
= this->section_list_
.begin();
5784 p
!= this->section_list_
.end();
5787 if ((*p
)->needs_dynsym_index())
5789 gold_assert(dynsym_section
!= NULL
);
5790 unsigned int index
= (*p
)->dynsym_index();
5791 gold_assert(index
> 0 && index
!= -1U);
5792 off_t off
= (dynsym_section
->offset()
5793 + index
* dynsym_section
->entsize());
5794 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5798 // Write out the Output_data which are not in an Output_section.
5799 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5800 p
!= this->special_output_list_
.end();
5804 // Write out the Output_data which are not in an Output_section
5805 // and are regenerated in each iteration of relaxation.
5806 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
5807 p
!= this->relax_output_list_
.end();
5812 // Write out the Output_sections which can only be written after the
5813 // input sections are complete.
5816 Layout::write_sections_after_input_sections(Output_file
* of
)
5818 // Determine the final section offsets, and thus the final output
5819 // file size. Note we finalize the .shstrab last, to allow the
5820 // after_input_section sections to modify their section-names before
5822 if (this->any_postprocessing_sections_
)
5824 off_t off
= this->output_file_size_
;
5825 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5827 // Now that we've finalized the names, we can finalize the shstrab.
5829 this->set_section_offsets(off
,
5830 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5832 if (off
> this->output_file_size_
)
5835 this->output_file_size_
= off
;
5839 for (Section_list::const_iterator p
= this->section_list_
.begin();
5840 p
!= this->section_list_
.end();
5843 if ((*p
)->after_input_sections())
5847 this->section_headers_
->write(of
);
5850 // If a tree-style build ID was requested, the parallel part of that computation
5851 // is already done, and the final hash-of-hashes is computed here. For other
5852 // types of build IDs, all the work is done here.
5855 Layout::write_build_id(Output_file
* of
, unsigned char* array_of_hashes
,
5856 size_t size_of_hashes
) const
5858 if (this->build_id_note_
== NULL
)
5861 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5862 this->build_id_note_
->data_size());
5864 if (array_of_hashes
== NULL
)
5866 const size_t output_file_size
= this->output_file_size();
5867 const unsigned char* iv
= of
->get_input_view(0, output_file_size
);
5868 const char* style
= parameters
->options().build_id();
5870 // If we get here with style == "tree" then the output must be
5871 // too small for chunking, and we use SHA-1 in that case.
5872 if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
5873 sha1_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5874 else if (strcmp(style
, "md5") == 0)
5875 md5_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5879 of
->free_input_view(0, output_file_size
, iv
);
5883 // Non-overlapping substrings of the output file have been hashed.
5884 // Compute SHA-1 hash of the hashes.
5885 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes
),
5886 size_of_hashes
, ov
);
5887 delete[] array_of_hashes
;
5890 of
->write_output_view(this->build_id_note_
->offset(),
5891 this->build_id_note_
->data_size(),
5895 // Write out a binary file. This is called after the link is
5896 // complete. IN is the temporary output file we used to generate the
5897 // ELF code. We simply walk through the segments, read them from
5898 // their file offset in IN, and write them to their load address in
5899 // the output file. FIXME: with a bit more work, we could support
5900 // S-records and/or Intel hex format here.
5903 Layout::write_binary(Output_file
* in
) const
5905 gold_assert(parameters
->options().oformat_enum()
5906 == General_options::OBJECT_FORMAT_BINARY
);
5908 // Get the size of the binary file.
5909 uint64_t max_load_address
= 0;
5910 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5911 p
!= this->segment_list_
.end();
5914 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5916 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5917 if (max_paddr
> max_load_address
)
5918 max_load_address
= max_paddr
;
5922 Output_file
out(parameters
->options().output_file_name());
5923 out
.open(max_load_address
);
5925 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5926 p
!= this->segment_list_
.end();
5929 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5931 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5933 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5935 memcpy(vout
, vin
, (*p
)->filesz());
5936 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5937 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5944 // Print the output sections to the map file.
5947 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5949 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5950 p
!= this->segment_list_
.end();
5952 (*p
)->print_sections_to_mapfile(mapfile
);
5953 for (Section_list::const_iterator p
= this->unattached_section_list_
.begin();
5954 p
!= this->unattached_section_list_
.end();
5956 (*p
)->print_to_mapfile(mapfile
);
5959 // Print statistical information to stderr. This is used for --stats.
5962 Layout::print_stats() const
5964 this->namepool_
.print_stats("section name pool");
5965 this->sympool_
.print_stats("output symbol name pool");
5966 this->dynpool_
.print_stats("dynamic name pool");
5968 for (Section_list::const_iterator p
= this->section_list_
.begin();
5969 p
!= this->section_list_
.end();
5971 (*p
)->print_merge_stats();
5974 // Write_sections_task methods.
5976 // We can always run this task.
5979 Write_sections_task::is_runnable()
5984 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5988 Write_sections_task::locks(Task_locker
* tl
)
5990 tl
->add(this, this->output_sections_blocker_
);
5991 if (this->input_sections_blocker_
!= NULL
)
5992 tl
->add(this, this->input_sections_blocker_
);
5993 tl
->add(this, this->final_blocker_
);
5996 // Run the task--write out the data.
5999 Write_sections_task::run(Workqueue
*)
6001 this->layout_
->write_output_sections(this->of_
);
6004 // Write_data_task methods.
6006 // We can always run this task.
6009 Write_data_task::is_runnable()
6014 // We need to unlock FINAL_BLOCKER when finished.
6017 Write_data_task::locks(Task_locker
* tl
)
6019 tl
->add(this, this->final_blocker_
);
6022 // Run the task--write out the data.
6025 Write_data_task::run(Workqueue
*)
6027 this->layout_
->write_data(this->symtab_
, this->of_
);
6030 // Write_symbols_task methods.
6032 // We can always run this task.
6035 Write_symbols_task::is_runnable()
6040 // We need to unlock FINAL_BLOCKER when finished.
6043 Write_symbols_task::locks(Task_locker
* tl
)
6045 tl
->add(this, this->final_blocker_
);
6048 // Run the task--write out the symbols.
6051 Write_symbols_task::run(Workqueue
*)
6053 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
6054 this->layout_
->symtab_xindex(),
6055 this->layout_
->dynsym_xindex(), this->of_
);
6058 // Write_after_input_sections_task methods.
6060 // We can only run this task after the input sections have completed.
6063 Write_after_input_sections_task::is_runnable()
6065 if (this->input_sections_blocker_
->is_blocked())
6066 return this->input_sections_blocker_
;
6070 // We need to unlock FINAL_BLOCKER when finished.
6073 Write_after_input_sections_task::locks(Task_locker
* tl
)
6075 tl
->add(this, this->final_blocker_
);
6081 Write_after_input_sections_task::run(Workqueue
*)
6083 this->layout_
->write_sections_after_input_sections(this->of_
);
6086 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
6087 // or as a "tree" where each chunk of the string is hashed and then those
6088 // hashes are put into a (much smaller) string which is hashed with sha1.
6089 // We compute a checksum over the entire file because that is simplest.
6092 Build_id_task_runner::run(Workqueue
* workqueue
, const Task
*)
6094 Task_token
* post_hash_tasks_blocker
= new Task_token(true);
6095 const Layout
* layout
= this->layout_
;
6096 Output_file
* of
= this->of_
;
6097 const size_t filesize
= (layout
->output_file_size() <= 0 ? 0
6098 : static_cast<size_t>(layout
->output_file_size()));
6099 unsigned char* array_of_hashes
= NULL
;
6100 size_t size_of_hashes
= 0;
6102 if (strcmp(this->options_
->build_id(), "tree") == 0
6103 && this->options_
->build_id_chunk_size_for_treehash() > 0
6105 && (filesize
>= this->options_
->build_id_min_file_size_for_treehash()))
6107 static const size_t MD5_OUTPUT_SIZE_IN_BYTES
= 16;
6108 const size_t chunk_size
=
6109 this->options_
->build_id_chunk_size_for_treehash();
6110 const size_t num_hashes
= ((filesize
- 1) / chunk_size
) + 1;
6111 post_hash_tasks_blocker
->add_blockers(num_hashes
);
6112 size_of_hashes
= num_hashes
* MD5_OUTPUT_SIZE_IN_BYTES
;
6113 array_of_hashes
= new unsigned char[size_of_hashes
];
6114 unsigned char *dst
= array_of_hashes
;
6115 for (size_t i
= 0, src_offset
= 0; i
< num_hashes
;
6116 i
++, dst
+= MD5_OUTPUT_SIZE_IN_BYTES
, src_offset
+= chunk_size
)
6118 size_t size
= std::min(chunk_size
, filesize
- src_offset
);
6119 workqueue
->queue(new Hash_task(of
,
6123 post_hash_tasks_blocker
));
6127 // Queue the final task to write the build id and close the output file.
6128 workqueue
->queue(new Task_function(new Close_task_runner(this->options_
,
6133 post_hash_tasks_blocker
,
6134 "Task_function Close_task_runner"));
6137 // Close_task_runner methods.
6139 // Finish up the build ID computation, if necessary, and write a binary file,
6140 // if necessary. Then close the output file.
6143 Close_task_runner::run(Workqueue
*, const Task
*)
6145 // At this point the multi-threaded part of the build ID computation,
6146 // if any, is done. See Build_id_task_runner.
6147 this->layout_
->write_build_id(this->of_
, this->array_of_hashes_
,
6148 this->size_of_hashes_
);
6150 // If we've been asked to create a binary file, we do so here.
6151 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
6152 this->layout_
->write_binary(this->of_
);
6157 // Instantiate the templates we need. We could use the configure
6158 // script to restrict this to only the ones for implemented targets.
6160 #ifdef HAVE_TARGET_32_LITTLE
6163 Layout::init_fixed_output_section
<32, false>(
6165 elfcpp::Shdr
<32, false>& shdr
);
6168 #ifdef HAVE_TARGET_32_BIG
6171 Layout::init_fixed_output_section
<32, true>(
6173 elfcpp::Shdr
<32, true>& shdr
);
6176 #ifdef HAVE_TARGET_64_LITTLE
6179 Layout::init_fixed_output_section
<64, false>(
6181 elfcpp::Shdr
<64, false>& shdr
);
6184 #ifdef HAVE_TARGET_64_BIG
6187 Layout::init_fixed_output_section
<64, true>(
6189 elfcpp::Shdr
<64, true>& shdr
);
6192 #ifdef HAVE_TARGET_32_LITTLE
6195 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
6198 const elfcpp::Shdr
<32, false>& shdr
,
6199 unsigned int, unsigned int, unsigned int, off_t
*);
6202 #ifdef HAVE_TARGET_32_BIG
6205 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
6208 const elfcpp::Shdr
<32, true>& shdr
,
6209 unsigned int, unsigned int, unsigned int, off_t
*);
6212 #ifdef HAVE_TARGET_64_LITTLE
6215 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
6218 const elfcpp::Shdr
<64, false>& shdr
,
6219 unsigned int, unsigned int, unsigned int, off_t
*);
6222 #ifdef HAVE_TARGET_64_BIG
6225 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
6228 const elfcpp::Shdr
<64, true>& shdr
,
6229 unsigned int, unsigned int, unsigned int, off_t
*);
6232 #ifdef HAVE_TARGET_32_LITTLE
6235 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
6236 unsigned int reloc_shndx
,
6237 const elfcpp::Shdr
<32, false>& shdr
,
6238 Output_section
* data_section
,
6239 Relocatable_relocs
* rr
);
6242 #ifdef HAVE_TARGET_32_BIG
6245 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
6246 unsigned int reloc_shndx
,
6247 const elfcpp::Shdr
<32, true>& shdr
,
6248 Output_section
* data_section
,
6249 Relocatable_relocs
* rr
);
6252 #ifdef HAVE_TARGET_64_LITTLE
6255 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
6256 unsigned int reloc_shndx
,
6257 const elfcpp::Shdr
<64, false>& shdr
,
6258 Output_section
* data_section
,
6259 Relocatable_relocs
* rr
);
6262 #ifdef HAVE_TARGET_64_BIG
6265 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
6266 unsigned int reloc_shndx
,
6267 const elfcpp::Shdr
<64, true>& shdr
,
6268 Output_section
* data_section
,
6269 Relocatable_relocs
* rr
);
6272 #ifdef HAVE_TARGET_32_LITTLE
6275 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
6276 Sized_relobj_file
<32, false>* object
,
6278 const char* group_section_name
,
6279 const char* signature
,
6280 const elfcpp::Shdr
<32, false>& shdr
,
6281 elfcpp::Elf_Word flags
,
6282 std::vector
<unsigned int>* shndxes
);
6285 #ifdef HAVE_TARGET_32_BIG
6288 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
6289 Sized_relobj_file
<32, true>* object
,
6291 const char* group_section_name
,
6292 const char* signature
,
6293 const elfcpp::Shdr
<32, true>& shdr
,
6294 elfcpp::Elf_Word flags
,
6295 std::vector
<unsigned int>* shndxes
);
6298 #ifdef HAVE_TARGET_64_LITTLE
6301 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
6302 Sized_relobj_file
<64, false>* object
,
6304 const char* group_section_name
,
6305 const char* signature
,
6306 const elfcpp::Shdr
<64, false>& shdr
,
6307 elfcpp::Elf_Word flags
,
6308 std::vector
<unsigned int>* shndxes
);
6311 #ifdef HAVE_TARGET_64_BIG
6314 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
6315 Sized_relobj_file
<64, true>* object
,
6317 const char* group_section_name
,
6318 const char* signature
,
6319 const elfcpp::Shdr
<64, true>& shdr
,
6320 elfcpp::Elf_Word flags
,
6321 std::vector
<unsigned int>* shndxes
);
6324 #ifdef HAVE_TARGET_32_LITTLE
6327 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
6328 const unsigned char* symbols
,
6330 const unsigned char* symbol_names
,
6331 off_t symbol_names_size
,
6333 const elfcpp::Shdr
<32, false>& shdr
,
6334 unsigned int reloc_shndx
,
6335 unsigned int reloc_type
,
6339 #ifdef HAVE_TARGET_32_BIG
6342 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
6343 const unsigned char* symbols
,
6345 const unsigned char* symbol_names
,
6346 off_t symbol_names_size
,
6348 const elfcpp::Shdr
<32, true>& shdr
,
6349 unsigned int reloc_shndx
,
6350 unsigned int reloc_type
,
6354 #ifdef HAVE_TARGET_64_LITTLE
6357 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
6358 const unsigned char* symbols
,
6360 const unsigned char* symbol_names
,
6361 off_t symbol_names_size
,
6363 const elfcpp::Shdr
<64, false>& shdr
,
6364 unsigned int reloc_shndx
,
6365 unsigned int reloc_type
,
6369 #ifdef HAVE_TARGET_64_BIG
6372 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
6373 const unsigned char* symbols
,
6375 const unsigned char* symbol_names
,
6376 off_t symbol_names_size
,
6378 const elfcpp::Shdr
<64, true>& shdr
,
6379 unsigned int reloc_shndx
,
6380 unsigned int reloc_type
,
6384 #ifdef HAVE_TARGET_32_LITTLE
6387 Layout::add_to_gdb_index(bool is_type_unit
,
6388 Sized_relobj
<32, false>* object
,
6389 const unsigned char* symbols
,
6392 unsigned int reloc_shndx
,
6393 unsigned int reloc_type
);
6396 #ifdef HAVE_TARGET_32_BIG
6399 Layout::add_to_gdb_index(bool is_type_unit
,
6400 Sized_relobj
<32, true>* object
,
6401 const unsigned char* symbols
,
6404 unsigned int reloc_shndx
,
6405 unsigned int reloc_type
);
6408 #ifdef HAVE_TARGET_64_LITTLE
6411 Layout::add_to_gdb_index(bool is_type_unit
,
6412 Sized_relobj
<64, false>* object
,
6413 const unsigned char* symbols
,
6416 unsigned int reloc_shndx
,
6417 unsigned int reloc_type
);
6420 #ifdef HAVE_TARGET_64_BIG
6423 Layout::add_to_gdb_index(bool is_type_unit
,
6424 Sized_relobj
<64, true>* object
,
6425 const unsigned char* symbols
,
6428 unsigned int reloc_shndx
,
6429 unsigned int reloc_type
);
6432 } // End namespace gold.