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 lto_slim_object_(false),
470 script_output_section_data_list_(),
471 segment_states_(NULL
),
472 relaxation_debug_check_(NULL
),
473 section_order_map_(),
474 section_segment_map_(),
475 input_section_position_(),
476 input_section_glob_(),
477 incremental_base_(NULL
),
481 // Make space for more than enough segments for a typical file.
482 // This is just for efficiency--it's OK if we wind up needing more.
483 this->segment_list_
.reserve(12);
485 // We expect two unattached Output_data objects: the file header and
486 // the segment headers.
487 this->special_output_list_
.reserve(2);
489 // Initialize structure needed for an incremental build.
490 if (parameters
->incremental())
491 this->incremental_inputs_
= new Incremental_inputs
;
493 // The section name pool is worth optimizing in all cases, because
494 // it is small, but there are often overlaps due to .rel sections.
495 this->namepool_
.set_optimize();
498 // For incremental links, record the base file to be modified.
501 Layout::set_incremental_base(Incremental_binary
* base
)
503 this->incremental_base_
= base
;
504 this->free_list_
.init(base
->output_file()->filesize(), true);
507 // Hash a key we use to look up an output section mapping.
510 Layout::Hash_key::operator()(const Layout::Key
& k
) const
512 return k
.first
+ k
.second
.first
+ k
.second
.second
;
515 // These are the debug sections that are actually used by gdb.
516 // Currently, we've checked versions of gdb up to and including 7.4.
517 // We only check the part of the name that follows ".debug_" or
520 static const char* gdb_sections
[] =
523 "addr", // Fission extension
524 // "aranges", // not used by gdb as of 7.4
533 // "pubnames", // not used by gdb as of 7.4
534 // "pubtypes", // not used by gdb as of 7.4
535 // "gnu_pubnames", // Fission extension
536 // "gnu_pubtypes", // Fission extension
542 // This is the minimum set of sections needed for line numbers.
544 static const char* lines_only_debug_sections
[] =
547 // "addr", // Fission extension
548 // "aranges", // not used by gdb as of 7.4
557 // "pubnames", // not used by gdb as of 7.4
558 // "pubtypes", // not used by gdb as of 7.4
559 // "gnu_pubnames", // Fission extension
560 // "gnu_pubtypes", // Fission extension
563 "str_offsets", // Fission extension
566 // These sections are the DWARF fast-lookup tables, and are not needed
567 // when building a .gdb_index section.
569 static const char* gdb_fast_lookup_sections
[] =
578 // Returns whether the given debug section is in the list of
579 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
580 // portion of the name following ".debug_" or ".zdebug_".
583 is_gdb_debug_section(const char* suffix
)
585 // We can do this faster: binary search or a hashtable. But why bother?
586 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
587 if (strcmp(suffix
, gdb_sections
[i
]) == 0)
592 // Returns whether the given section is needed for lines-only debugging.
595 is_lines_only_debug_section(const char* suffix
)
597 // We can do this faster: binary search or a hashtable. But why bother?
599 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
601 if (strcmp(suffix
, lines_only_debug_sections
[i
]) == 0)
606 // Returns whether the given section is a fast-lookup section that
607 // will not be needed when building a .gdb_index section.
610 is_gdb_fast_lookup_section(const char* suffix
)
612 // We can do this faster: binary search or a hashtable. But why bother?
614 i
< sizeof(gdb_fast_lookup_sections
)/sizeof(*gdb_fast_lookup_sections
);
616 if (strcmp(suffix
, gdb_fast_lookup_sections
[i
]) == 0)
621 // Sometimes we compress sections. This is typically done for
622 // sections that are not part of normal program execution (such as
623 // .debug_* sections), and where the readers of these sections know
624 // how to deal with compressed sections. This routine doesn't say for
625 // certain whether we'll compress -- it depends on commandline options
626 // as well -- just whether this section is a candidate for compression.
627 // (The Output_compressed_section class decides whether to compress
628 // a given section, and picks the name of the compressed section.)
631 is_compressible_debug_section(const char* secname
)
633 return (is_prefix_of(".debug", secname
));
636 // We may see compressed debug sections in input files. Return TRUE
637 // if this is the name of a compressed debug section.
640 is_compressed_debug_section(const char* secname
)
642 return (is_prefix_of(".zdebug", secname
));
646 corresponding_uncompressed_section_name(std::string secname
)
648 gold_assert(secname
[0] == '.' && secname
[1] == 'z');
649 std::string
ret(".");
650 ret
.append(secname
, 2, std::string::npos
);
654 // Whether to include this section in the link.
656 template<int size
, bool big_endian
>
658 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
659 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
661 if (!parameters
->options().relocatable()
662 && (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
))
665 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
667 if ((sh_type
>= elfcpp::SHT_LOOS
&& sh_type
<= elfcpp::SHT_HIOS
)
668 || (sh_type
>= elfcpp::SHT_LOPROC
&& sh_type
<= elfcpp::SHT_HIPROC
))
669 return parameters
->target().should_include_section(sh_type
);
673 case elfcpp::SHT_NULL
:
674 case elfcpp::SHT_SYMTAB
:
675 case elfcpp::SHT_DYNSYM
:
676 case elfcpp::SHT_HASH
:
677 case elfcpp::SHT_DYNAMIC
:
678 case elfcpp::SHT_SYMTAB_SHNDX
:
681 case elfcpp::SHT_STRTAB
:
682 // Discard the sections which have special meanings in the ELF
683 // ABI. Keep others (e.g., .stabstr). We could also do this by
684 // checking the sh_link fields of the appropriate sections.
685 return (strcmp(name
, ".dynstr") != 0
686 && strcmp(name
, ".strtab") != 0
687 && strcmp(name
, ".shstrtab") != 0);
689 case elfcpp::SHT_RELA
:
690 case elfcpp::SHT_REL
:
691 case elfcpp::SHT_GROUP
:
692 // If we are emitting relocations these should be handled
694 gold_assert(!parameters
->options().relocatable());
697 case elfcpp::SHT_PROGBITS
:
698 if (parameters
->options().strip_debug()
699 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
701 if (is_debug_info_section(name
))
704 if (parameters
->options().strip_debug_non_line()
705 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
707 // Debugging sections can only be recognized by name.
708 if (is_prefix_of(".debug_", name
)
709 && !is_lines_only_debug_section(name
+ 7))
711 if (is_prefix_of(".zdebug_", name
)
712 && !is_lines_only_debug_section(name
+ 8))
715 if (parameters
->options().strip_debug_gdb()
716 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
718 // Debugging sections can only be recognized by name.
719 if (is_prefix_of(".debug_", name
)
720 && !is_gdb_debug_section(name
+ 7))
722 if (is_prefix_of(".zdebug_", name
)
723 && !is_gdb_debug_section(name
+ 8))
726 if (parameters
->options().gdb_index()
727 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
729 // When building .gdb_index, we can strip .debug_pubnames,
730 // .debug_pubtypes, and .debug_aranges sections.
731 if (is_prefix_of(".debug_", name
)
732 && is_gdb_fast_lookup_section(name
+ 7))
734 if (is_prefix_of(".zdebug_", name
)
735 && is_gdb_fast_lookup_section(name
+ 8))
738 if (parameters
->options().strip_lto_sections()
739 && !parameters
->options().relocatable()
740 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
742 // Ignore LTO sections containing intermediate code.
743 if (is_prefix_of(".gnu.lto_", name
))
746 // The GNU linker strips .gnu_debuglink sections, so we do too.
747 // This is a feature used to keep debugging information in
749 if (strcmp(name
, ".gnu_debuglink") == 0)
758 // Return an output section named NAME, or NULL if there is none.
761 Layout::find_output_section(const char* name
) const
763 for (Section_list::const_iterator p
= this->section_list_
.begin();
764 p
!= this->section_list_
.end();
766 if (strcmp((*p
)->name(), name
) == 0)
771 // Return an output segment of type TYPE, with segment flags SET set
772 // and segment flags CLEAR clear. Return NULL if there is none.
775 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
776 elfcpp::Elf_Word clear
) const
778 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
779 p
!= this->segment_list_
.end();
781 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
782 && ((*p
)->flags() & set
) == set
783 && ((*p
)->flags() & clear
) == 0)
788 // When we put a .ctors or .dtors section with more than one word into
789 // a .init_array or .fini_array section, we need to reverse the words
790 // in the .ctors/.dtors section. This is because .init_array executes
791 // constructors front to back, where .ctors executes them back to
792 // front, and vice-versa for .fini_array/.dtors. Although we do want
793 // to remap .ctors/.dtors into .init_array/.fini_array because it can
794 // be more efficient, we don't want to change the order in which
795 // constructors/destructors are run. This set just keeps track of
796 // these sections which need to be reversed. It is only changed by
797 // Layout::layout. It should be a private member of Layout, but that
798 // would require layout.h to #include object.h to get the definition
800 static Unordered_set
<Section_id
, Section_id_hash
> ctors_sections_in_init_array
;
802 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
803 // .init_array/.fini_array section.
806 Layout::is_ctors_in_init_array(Relobj
* relobj
, unsigned int shndx
) const
808 return (ctors_sections_in_init_array
.find(Section_id(relobj
, shndx
))
809 != ctors_sections_in_init_array
.end());
812 // Return the output section to use for section NAME with type TYPE
813 // and section flags FLAGS. NAME must be canonicalized in the string
814 // pool, and NAME_KEY is the key. ORDER is where this should appear
815 // in the output sections. IS_RELRO is true for a relro section.
818 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
819 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
820 Output_section_order order
, bool is_relro
)
822 elfcpp::Elf_Word lookup_type
= type
;
824 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
825 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
826 // .init_array, .fini_array, and .preinit_array sections by name
827 // whatever their type in the input file. We do this because the
828 // types are not always right in the input files.
829 if (lookup_type
== elfcpp::SHT_INIT_ARRAY
830 || lookup_type
== elfcpp::SHT_FINI_ARRAY
831 || lookup_type
== elfcpp::SHT_PREINIT_ARRAY
)
832 lookup_type
= elfcpp::SHT_PROGBITS
;
834 elfcpp::Elf_Xword lookup_flags
= flags
;
836 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
837 // read-write with read-only sections. Some other ELF linkers do
838 // not do this. FIXME: Perhaps there should be an option
840 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
842 const Key
key(name_key
, std::make_pair(lookup_type
, lookup_flags
));
843 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
844 std::pair
<Section_name_map::iterator
, bool> ins(
845 this->section_name_map_
.insert(v
));
848 return ins
.first
->second
;
851 // This is the first time we've seen this name/type/flags
852 // combination. For compatibility with the GNU linker, we
853 // combine sections with contents and zero flags with sections
854 // with non-zero flags. This is a workaround for cases where
855 // assembler code forgets to set section flags. FIXME: Perhaps
856 // there should be an option to control this.
857 Output_section
* os
= NULL
;
859 if (lookup_type
== elfcpp::SHT_PROGBITS
)
863 Output_section
* same_name
= this->find_output_section(name
);
864 if (same_name
!= NULL
865 && (same_name
->type() == elfcpp::SHT_PROGBITS
866 || same_name
->type() == elfcpp::SHT_INIT_ARRAY
867 || same_name
->type() == elfcpp::SHT_FINI_ARRAY
868 || same_name
->type() == elfcpp::SHT_PREINIT_ARRAY
)
869 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
872 else if ((flags
& elfcpp::SHF_TLS
) == 0)
874 elfcpp::Elf_Xword zero_flags
= 0;
875 const Key
zero_key(name_key
, std::make_pair(lookup_type
,
877 Section_name_map::iterator p
=
878 this->section_name_map_
.find(zero_key
);
879 if (p
!= this->section_name_map_
.end())
885 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
887 ins
.first
->second
= os
;
892 // Returns TRUE iff NAME (an input section from RELOBJ) will
893 // be mapped to an output section that should be KEPT.
896 Layout::keep_input_section(const Relobj
* relobj
, const char* name
)
898 if (! this->script_options_
->saw_sections_clause())
901 Script_sections
* ss
= this->script_options_
->script_sections();
902 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
903 Output_section
** output_section_slot
;
904 Script_sections::Section_type script_section_type
;
907 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
908 &script_section_type
, &keep
, true);
909 return name
!= NULL
&& keep
;
912 // Clear the input section flags that should not be copied to the
916 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags
)
918 // Some flags in the input section should not be automatically
919 // copied to the output section.
920 input_section_flags
&= ~ (elfcpp::SHF_INFO_LINK
922 | elfcpp::SHF_COMPRESSED
924 | elfcpp::SHF_STRINGS
);
926 // We only clear the SHF_LINK_ORDER flag in for
927 // a non-relocatable link.
928 if (!parameters
->options().relocatable())
929 input_section_flags
&= ~elfcpp::SHF_LINK_ORDER
;
931 return input_section_flags
;
934 // Pick the output section to use for section NAME, in input file
935 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
936 // linker created section. IS_INPUT_SECTION is true if we are
937 // choosing an output section for an input section found in a input
938 // file. ORDER is where this section should appear in the output
939 // sections. IS_RELRO is true for a relro section. This will return
940 // NULL if the input section should be discarded. MATCH_INPUT_SPEC
941 // is true if the section name should be matched against input specs
942 // in a linker script.
945 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
946 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
947 bool is_input_section
, Output_section_order order
,
948 bool is_relro
, bool is_reloc
,
949 bool match_input_spec
)
951 // We should not see any input sections after we have attached
952 // sections to segments.
953 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
955 flags
= this->get_output_section_flags(flags
);
957 if (this->script_options_
->saw_sections_clause() && !is_reloc
)
959 // We are using a SECTIONS clause, so the output section is
960 // chosen based only on the name.
962 Script_sections
* ss
= this->script_options_
->script_sections();
963 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
964 Output_section
** output_section_slot
;
965 Script_sections::Section_type script_section_type
;
966 const char* orig_name
= name
;
968 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
969 &script_section_type
, &keep
,
974 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
975 "because it is not allowed by the "
976 "SECTIONS clause of the linker script"),
978 // The SECTIONS clause says to discard this input section.
982 // We can only handle script section types ST_NONE and ST_NOLOAD.
983 switch (script_section_type
)
985 case Script_sections::ST_NONE
:
987 case Script_sections::ST_NOLOAD
:
988 flags
&= elfcpp::SHF_ALLOC
;
994 // If this is an orphan section--one not mentioned in the linker
995 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
996 // default processing below.
998 if (output_section_slot
!= NULL
)
1000 if (*output_section_slot
!= NULL
)
1002 (*output_section_slot
)->update_flags_for_input_section(flags
);
1003 return *output_section_slot
;
1006 // We don't put sections found in the linker script into
1007 // SECTION_NAME_MAP_. That keeps us from getting confused
1008 // if an orphan section is mapped to a section with the same
1009 // name as one in the linker script.
1011 name
= this->namepool_
.add(name
, false, NULL
);
1013 Output_section
* os
= this->make_output_section(name
, type
, flags
,
1016 os
->set_found_in_sections_clause();
1018 // Special handling for NOLOAD sections.
1019 if (script_section_type
== Script_sections::ST_NOLOAD
)
1021 os
->set_is_noload();
1023 // The constructor of Output_section sets addresses of non-ALLOC
1024 // sections to 0 by default. We don't want that for NOLOAD
1025 // sections even if they have no SHF_ALLOC flag.
1026 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
1027 && os
->is_address_valid())
1029 gold_assert(os
->address() == 0
1030 && !os
->is_offset_valid()
1031 && !os
->is_data_size_valid());
1032 os
->reset_address_and_file_offset();
1036 *output_section_slot
= os
;
1041 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1043 size_t len
= strlen(name
);
1044 std::string uncompressed_name
;
1046 // Compressed debug sections should be mapped to the corresponding
1047 // uncompressed section.
1048 if (is_compressed_debug_section(name
))
1051 corresponding_uncompressed_section_name(std::string(name
, len
));
1052 name
= uncompressed_name
.c_str();
1053 len
= uncompressed_name
.length();
1056 // Turn NAME from the name of the input section into the name of the
1058 if (is_input_section
1059 && !this->script_options_
->saw_sections_clause()
1060 && !parameters
->options().relocatable())
1062 const char *orig_name
= name
;
1063 name
= parameters
->target().output_section_name(relobj
, name
, &len
);
1065 name
= Layout::output_section_name(relobj
, orig_name
, &len
);
1068 Stringpool::Key name_key
;
1069 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
1071 // Find or make the output section. The output section is selected
1072 // based on the section name, type, and flags.
1073 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
1076 // For incremental links, record the initial fixed layout of a section
1077 // from the base file, and return a pointer to the Output_section.
1079 template<int size
, bool big_endian
>
1081 Layout::init_fixed_output_section(const char* name
,
1082 elfcpp::Shdr
<size
, big_endian
>& shdr
)
1084 unsigned int sh_type
= shdr
.get_sh_type();
1086 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1087 // PRE_INIT_ARRAY, and NOTE sections.
1088 // All others will be created from scratch and reallocated.
1089 if (!can_incremental_update(sh_type
))
1092 // If we're generating a .gdb_index section, we need to regenerate
1094 if (parameters
->options().gdb_index()
1095 && sh_type
== elfcpp::SHT_PROGBITS
1096 && strcmp(name
, ".gdb_index") == 0)
1099 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
1100 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
1101 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
1102 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
1103 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
1104 shdr
.get_sh_addralign();
1106 // Make the output section.
1107 Stringpool::Key name_key
;
1108 name
= this->namepool_
.add(name
, true, &name_key
);
1109 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
1110 sh_flags
, ORDER_INVALID
, false);
1111 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
1112 if (sh_type
!= elfcpp::SHT_NOBITS
)
1113 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
1117 // Return the index by which an input section should be ordered. This
1118 // is used to sort some .text sections, for compatibility with GNU ld.
1121 Layout::special_ordering_of_input_section(const char* name
)
1123 // The GNU linker has some special handling for some sections that
1124 // wind up in the .text section. Sections that start with these
1125 // prefixes must appear first, and must appear in the order listed
1127 static const char* const text_section_sort
[] =
1136 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1138 if (is_prefix_of(text_section_sort
[i
], name
))
1144 // Return the output section to use for input section SHNDX, with name
1145 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1146 // index of a relocation section which applies to this section, or 0
1147 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1148 // relocation section if there is one. Set *OFF to the offset of this
1149 // input section without the output section. Return NULL if the
1150 // section should be discarded. Set *OFF to -1 if the section
1151 // contents should not be written directly to the output file, but
1152 // will instead receive special handling.
1154 template<int size
, bool big_endian
>
1156 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1157 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1158 unsigned int sh_type
, unsigned int reloc_shndx
,
1159 unsigned int, off_t
* off
)
1163 if (!this->include_section(object
, name
, shdr
))
1166 // In a relocatable link a grouped section must not be combined with
1167 // any other sections.
1169 if (parameters
->options().relocatable()
1170 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1172 // Some flags in the input section should not be automatically
1173 // copied to the output section.
1174 elfcpp::Elf_Xword flags
= (shdr
.get_sh_flags()
1175 & ~ elfcpp::SHF_COMPRESSED
);
1176 name
= this->namepool_
.add(name
, true, NULL
);
1177 os
= this->make_output_section(name
, sh_type
, flags
,
1178 ORDER_INVALID
, false);
1182 // All ".text.unlikely.*" sections can be moved to a unique
1183 // segment with --text-unlikely-segment option.
1184 bool text_unlikely_segment
1185 = (parameters
->options().text_unlikely_segment()
1186 && is_prefix_of(".text.unlikely",
1187 object
->section_name(shndx
).c_str()));
1188 if (text_unlikely_segment
)
1190 elfcpp::Elf_Xword flags
1191 = this->get_output_section_flags(shdr
.get_sh_flags());
1193 Stringpool::Key name_key
;
1194 const char* os_name
= this->namepool_
.add(".text.unlikely", true,
1196 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1197 ORDER_INVALID
, false);
1198 // Map this output section to a unique segment. This is done to
1199 // separate "text" that is not likely to be executed from "text"
1200 // that is likely executed.
1201 os
->set_is_unique_segment();
1205 // Plugins can choose to place one or more subsets of sections in
1206 // unique segments and this is done by mapping these section subsets
1207 // to unique output sections. Check if this section needs to be
1208 // remapped to a unique output section.
1209 Section_segment_map::iterator it
1210 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1211 if (it
== this->section_segment_map_
.end())
1213 os
= this->choose_output_section(object
, name
, sh_type
,
1214 shdr
.get_sh_flags(), true,
1215 ORDER_INVALID
, false, false,
1220 // We know the name of the output section, directly call
1221 // get_output_section here by-passing choose_output_section.
1222 elfcpp::Elf_Xword flags
1223 = this->get_output_section_flags(shdr
.get_sh_flags());
1225 const char* os_name
= it
->second
->name
;
1226 Stringpool::Key name_key
;
1227 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1228 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1229 ORDER_INVALID
, false);
1230 if (!os
->is_unique_segment())
1232 os
->set_is_unique_segment();
1233 os
->set_extra_segment_flags(it
->second
->flags
);
1234 os
->set_segment_alignment(it
->second
->align
);
1242 // By default the GNU linker sorts input sections whose names match
1243 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1244 // sections are sorted by name. This is used to implement
1245 // constructor priority ordering. We are compatible. When we put
1246 // .ctor sections in .init_array and .dtor sections in .fini_array,
1247 // we must also sort plain .ctor and .dtor sections.
1248 if (!this->script_options_
->saw_sections_clause()
1249 && !parameters
->options().relocatable()
1250 && (is_prefix_of(".ctors.", name
)
1251 || is_prefix_of(".dtors.", name
)
1252 || is_prefix_of(".init_array.", name
)
1253 || is_prefix_of(".fini_array.", name
)
1254 || (parameters
->options().ctors_in_init_array()
1255 && (strcmp(name
, ".ctors") == 0
1256 || strcmp(name
, ".dtors") == 0))))
1257 os
->set_must_sort_attached_input_sections();
1259 // By default the GNU linker sorts some special text sections ahead
1260 // of others. We are compatible.
1261 if (parameters
->options().text_reorder()
1262 && !this->script_options_
->saw_sections_clause()
1263 && !this->is_section_ordering_specified()
1264 && !parameters
->options().relocatable()
1265 && Layout::special_ordering_of_input_section(name
) >= 0)
1266 os
->set_must_sort_attached_input_sections();
1268 // If this is a .ctors or .ctors.* section being mapped to a
1269 // .init_array section, or a .dtors or .dtors.* section being mapped
1270 // to a .fini_array section, we will need to reverse the words if
1271 // there is more than one. Record this section for later. See
1272 // ctors_sections_in_init_array above.
1273 if (!this->script_options_
->saw_sections_clause()
1274 && !parameters
->options().relocatable()
1275 && shdr
.get_sh_size() > size
/ 8
1276 && (((strcmp(name
, ".ctors") == 0
1277 || is_prefix_of(".ctors.", name
))
1278 && strcmp(os
->name(), ".init_array") == 0)
1279 || ((strcmp(name
, ".dtors") == 0
1280 || is_prefix_of(".dtors.", name
))
1281 && strcmp(os
->name(), ".fini_array") == 0)))
1282 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1284 // FIXME: Handle SHF_LINK_ORDER somewhere.
1286 elfcpp::Elf_Xword orig_flags
= os
->flags();
1288 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1289 this->script_options_
->saw_sections_clause());
1291 // If the flags changed, we may have to change the order.
1292 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1294 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1295 elfcpp::Elf_Xword new_flags
=
1296 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1297 if (orig_flags
!= new_flags
)
1298 os
->set_order(this->default_section_order(os
, false));
1301 this->have_added_input_section_
= true;
1306 // Maps section SECN to SEGMENT s.
1308 Layout::insert_section_segment_map(Const_section_id secn
,
1309 Unique_segment_info
*s
)
1311 gold_assert(this->unique_segment_for_sections_specified_
);
1312 this->section_segment_map_
[secn
] = s
;
1315 // Handle a relocation section when doing a relocatable link.
1317 template<int size
, bool big_endian
>
1319 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>*,
1321 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1322 Output_section
* data_section
,
1323 Relocatable_relocs
* rr
)
1325 gold_assert(parameters
->options().relocatable()
1326 || parameters
->options().emit_relocs());
1328 int sh_type
= shdr
.get_sh_type();
1331 if (sh_type
== elfcpp::SHT_REL
)
1333 else if (sh_type
== elfcpp::SHT_RELA
)
1337 name
+= data_section
->name();
1339 // If the output data section already has a reloc section, use that;
1340 // otherwise, make a new one.
1341 Output_section
* os
= data_section
->reloc_section();
1344 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1345 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1346 ORDER_INVALID
, false);
1347 os
->set_should_link_to_symtab();
1348 os
->set_info_section(data_section
);
1349 data_section
->set_reloc_section(os
);
1352 Output_section_data
* posd
;
1353 if (sh_type
== elfcpp::SHT_REL
)
1355 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1356 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1360 else if (sh_type
== elfcpp::SHT_RELA
)
1362 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1363 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1370 os
->add_output_section_data(posd
);
1371 rr
->set_output_data(posd
);
1376 // Handle a group section when doing a relocatable link.
1378 template<int size
, bool big_endian
>
1380 Layout::layout_group(Symbol_table
* symtab
,
1381 Sized_relobj_file
<size
, big_endian
>* object
,
1383 const char* group_section_name
,
1384 const char* signature
,
1385 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1386 elfcpp::Elf_Word flags
,
1387 std::vector
<unsigned int>* shndxes
)
1389 gold_assert(parameters
->options().relocatable());
1390 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1391 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1392 Output_section
* os
= this->make_output_section(group_section_name
,
1394 shdr
.get_sh_flags(),
1395 ORDER_INVALID
, false);
1397 // We need to find a symbol with the signature in the symbol table.
1398 // If we don't find one now, we need to look again later.
1399 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1401 os
->set_info_symndx(sym
);
1404 // Reserve some space to minimize reallocations.
1405 if (this->group_signatures_
.empty())
1406 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1408 // We will wind up using a symbol whose name is the signature.
1409 // So just put the signature in the symbol name pool to save it.
1410 signature
= symtab
->canonicalize_name(signature
);
1411 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1414 os
->set_should_link_to_symtab();
1417 section_size_type entry_count
=
1418 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1419 Output_section_data
* posd
=
1420 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1422 os
->add_output_section_data(posd
);
1425 // Special GNU handling of sections name .eh_frame. They will
1426 // normally hold exception frame data as defined by the C++ ABI
1427 // (http://codesourcery.com/cxx-abi/).
1429 template<int size
, bool big_endian
>
1431 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1432 const unsigned char* symbols
,
1434 const unsigned char* symbol_names
,
1435 off_t symbol_names_size
,
1437 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1438 unsigned int reloc_shndx
, unsigned int reloc_type
,
1441 const unsigned int unwind_section_type
=
1442 parameters
->target().unwind_section_type();
1444 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1445 || shdr
.get_sh_type() == unwind_section_type
);
1446 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1448 Output_section
* os
= this->make_eh_frame_section(object
);
1452 gold_assert(this->eh_frame_section_
== os
);
1454 elfcpp::Elf_Xword orig_flags
= os
->flags();
1456 Eh_frame::Eh_frame_section_disposition disp
=
1457 Eh_frame::EH_UNRECOGNIZED_SECTION
;
1458 if (!parameters
->incremental())
1460 disp
= this->eh_frame_data_
->add_ehframe_input_section(object
,
1470 if (disp
== Eh_frame::EH_OPTIMIZABLE_SECTION
)
1472 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1474 // A writable .eh_frame section is a RELRO section.
1475 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1476 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1479 os
->set_order(ORDER_RELRO
);
1486 if (disp
== Eh_frame::EH_END_MARKER_SECTION
&& !this->added_eh_frame_data_
)
1488 // We found the end marker section, so now we can add the set of
1489 // optimized sections to the output section. We need to postpone
1490 // adding this until we've found a section we can optimize so that
1491 // the .eh_frame section in crtbeginT.o winds up at the start of
1492 // the output section.
1493 os
->add_output_section_data(this->eh_frame_data_
);
1494 this->added_eh_frame_data_
= true;
1497 // We couldn't handle this .eh_frame section for some reason.
1498 // Add it as a normal section.
1499 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1500 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1501 reloc_shndx
, saw_sections_clause
);
1502 this->have_added_input_section_
= true;
1504 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1505 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1506 os
->set_order(this->default_section_order(os
, false));
1512 Layout::finalize_eh_frame_section()
1514 // If we never found an end marker section, we need to add the
1515 // optimized eh sections to the output section now.
1516 if (!parameters
->incremental()
1517 && this->eh_frame_section_
!= NULL
1518 && !this->added_eh_frame_data_
)
1520 this->eh_frame_section_
->add_output_section_data(this->eh_frame_data_
);
1521 this->added_eh_frame_data_
= true;
1525 // Create and return the magic .eh_frame section. Create
1526 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1527 // input .eh_frame section; it may be NULL.
1530 Layout::make_eh_frame_section(const Relobj
* object
)
1532 const unsigned int unwind_section_type
=
1533 parameters
->target().unwind_section_type();
1535 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1536 unwind_section_type
,
1537 elfcpp::SHF_ALLOC
, false,
1538 ORDER_EHFRAME
, false, false,
1543 if (this->eh_frame_section_
== NULL
)
1545 this->eh_frame_section_
= os
;
1546 this->eh_frame_data_
= new Eh_frame();
1548 // For incremental linking, we do not optimize .eh_frame sections
1549 // or create a .eh_frame_hdr section.
1550 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1552 Output_section
* hdr_os
=
1553 this->choose_output_section(NULL
, ".eh_frame_hdr",
1554 unwind_section_type
,
1555 elfcpp::SHF_ALLOC
, false,
1556 ORDER_EHFRAME
, false, false,
1561 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1562 this->eh_frame_data_
);
1563 hdr_os
->add_output_section_data(hdr_posd
);
1565 hdr_os
->set_after_input_sections();
1567 if (!this->script_options_
->saw_phdrs_clause())
1569 Output_segment
* hdr_oseg
;
1570 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1572 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1576 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1584 // Add an exception frame for a PLT. This is called from target code.
1587 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1588 size_t cie_length
, const unsigned char* fde_data
,
1591 if (parameters
->incremental())
1593 // FIXME: Maybe this could work some day....
1596 Output_section
* os
= this->make_eh_frame_section(NULL
);
1599 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1600 fde_data
, fde_length
);
1601 if (!this->added_eh_frame_data_
)
1603 os
->add_output_section_data(this->eh_frame_data_
);
1604 this->added_eh_frame_data_
= true;
1608 // Remove all post-map .eh_frame information for a PLT.
1611 Layout::remove_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1614 if (parameters
->incremental())
1616 // FIXME: Maybe this could work some day....
1619 this->eh_frame_data_
->remove_ehframe_for_plt(plt
, cie_data
, cie_length
);
1622 // Scan a .debug_info or .debug_types section, and add summary
1623 // information to the .gdb_index section.
1625 template<int size
, bool big_endian
>
1627 Layout::add_to_gdb_index(bool is_type_unit
,
1628 Sized_relobj
<size
, big_endian
>* object
,
1629 const unsigned char* symbols
,
1632 unsigned int reloc_shndx
,
1633 unsigned int reloc_type
)
1635 if (this->gdb_index_data_
== NULL
)
1637 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1638 elfcpp::SHT_PROGBITS
, 0,
1639 false, ORDER_INVALID
,
1640 false, false, false);
1644 this->gdb_index_data_
= new Gdb_index(os
);
1645 os
->add_output_section_data(this->gdb_index_data_
);
1646 os
->set_after_input_sections();
1649 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1650 symbols_size
, shndx
, reloc_shndx
,
1654 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1655 // the output section.
1658 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1659 elfcpp::Elf_Xword flags
,
1660 Output_section_data
* posd
,
1661 Output_section_order order
, bool is_relro
)
1663 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1664 false, order
, is_relro
,
1667 os
->add_output_section_data(posd
);
1671 // Map section flags to segment flags.
1674 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1676 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1677 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1678 ret
|= elfcpp::PF_W
;
1679 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1680 ret
|= elfcpp::PF_X
;
1684 // Make a new Output_section, and attach it to segments as
1685 // appropriate. ORDER is the order in which this section should
1686 // appear in the output segment. IS_RELRO is true if this is a relro
1687 // (read-only after relocations) section.
1690 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1691 elfcpp::Elf_Xword flags
,
1692 Output_section_order order
, bool is_relro
)
1695 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1696 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1697 && is_compressible_debug_section(name
))
1698 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1700 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1701 && parameters
->options().strip_debug_non_line()
1702 && strcmp(".debug_abbrev", name
) == 0)
1704 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1706 if (this->debug_info_
)
1707 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1709 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1710 && parameters
->options().strip_debug_non_line()
1711 && strcmp(".debug_info", name
) == 0)
1713 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1715 if (this->debug_abbrev_
)
1716 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1720 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1721 // not have correct section types. Force them here.
1722 if (type
== elfcpp::SHT_PROGBITS
)
1724 if (is_prefix_of(".init_array", name
))
1725 type
= elfcpp::SHT_INIT_ARRAY
;
1726 else if (is_prefix_of(".preinit_array", name
))
1727 type
= elfcpp::SHT_PREINIT_ARRAY
;
1728 else if (is_prefix_of(".fini_array", name
))
1729 type
= elfcpp::SHT_FINI_ARRAY
;
1732 // FIXME: const_cast is ugly.
1733 Target
* target
= const_cast<Target
*>(¶meters
->target());
1734 os
= target
->make_output_section(name
, type
, flags
);
1737 // With -z relro, we have to recognize the special sections by name.
1738 // There is no other way.
1739 bool is_relro_local
= false;
1740 if (!this->script_options_
->saw_sections_clause()
1741 && parameters
->options().relro()
1742 && (flags
& elfcpp::SHF_ALLOC
) != 0
1743 && (flags
& elfcpp::SHF_WRITE
) != 0)
1745 if (type
== elfcpp::SHT_PROGBITS
)
1747 if ((flags
& elfcpp::SHF_TLS
) != 0)
1749 else if (strcmp(name
, ".data.rel.ro") == 0)
1751 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1754 is_relro_local
= true;
1756 else if (strcmp(name
, ".ctors") == 0
1757 || strcmp(name
, ".dtors") == 0
1758 || strcmp(name
, ".jcr") == 0)
1761 else if (type
== elfcpp::SHT_INIT_ARRAY
1762 || type
== elfcpp::SHT_FINI_ARRAY
1763 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1770 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1771 order
= this->default_section_order(os
, is_relro_local
);
1773 os
->set_order(order
);
1775 parameters
->target().new_output_section(os
);
1777 this->section_list_
.push_back(os
);
1779 // The GNU linker by default sorts some sections by priority, so we
1780 // do the same. We need to know that this might happen before we
1781 // attach any input sections.
1782 if (!this->script_options_
->saw_sections_clause()
1783 && !parameters
->options().relocatable()
1784 && (strcmp(name
, ".init_array") == 0
1785 || strcmp(name
, ".fini_array") == 0
1786 || (!parameters
->options().ctors_in_init_array()
1787 && (strcmp(name
, ".ctors") == 0
1788 || strcmp(name
, ".dtors") == 0))))
1789 os
->set_may_sort_attached_input_sections();
1791 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1792 // sections before other .text sections. We are compatible. We
1793 // need to know that this might happen before we attach any input
1795 if (parameters
->options().text_reorder()
1796 && !this->script_options_
->saw_sections_clause()
1797 && !this->is_section_ordering_specified()
1798 && !parameters
->options().relocatable()
1799 && strcmp(name
, ".text") == 0)
1800 os
->set_may_sort_attached_input_sections();
1802 // GNU linker sorts section by name with --sort-section=name.
1803 if (strcmp(parameters
->options().sort_section(), "name") == 0)
1804 os
->set_must_sort_attached_input_sections();
1806 // Check for .stab*str sections, as .stab* sections need to link to
1808 if (type
== elfcpp::SHT_STRTAB
1809 && !this->have_stabstr_section_
1810 && strncmp(name
, ".stab", 5) == 0
1811 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1812 this->have_stabstr_section_
= true;
1814 // During a full incremental link, we add patch space to most
1815 // PROGBITS and NOBITS sections. Flag those that may be
1816 // arbitrarily padded.
1817 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1818 && order
!= ORDER_INTERP
1819 && order
!= ORDER_INIT
1820 && order
!= ORDER_PLT
1821 && order
!= ORDER_FINI
1822 && order
!= ORDER_RELRO_LAST
1823 && order
!= ORDER_NON_RELRO_FIRST
1824 && strcmp(name
, ".eh_frame") != 0
1825 && strcmp(name
, ".ctors") != 0
1826 && strcmp(name
, ".dtors") != 0
1827 && strcmp(name
, ".jcr") != 0)
1829 os
->set_is_patch_space_allowed();
1831 // Certain sections require "holes" to be filled with
1832 // specific fill patterns. These fill patterns may have
1833 // a minimum size, so we must prevent allocations from the
1834 // free list that leave a hole smaller than the minimum.
1835 if (strcmp(name
, ".debug_info") == 0)
1836 os
->set_free_space_fill(new Output_fill_debug_info(false));
1837 else if (strcmp(name
, ".debug_types") == 0)
1838 os
->set_free_space_fill(new Output_fill_debug_info(true));
1839 else if (strcmp(name
, ".debug_line") == 0)
1840 os
->set_free_space_fill(new Output_fill_debug_line());
1843 // If we have already attached the sections to segments, then we
1844 // need to attach this one now. This happens for sections created
1845 // directly by the linker.
1846 if (this->sections_are_attached_
)
1847 this->attach_section_to_segment(¶meters
->target(), os
);
1852 // Return the default order in which a section should be placed in an
1853 // output segment. This function captures a lot of the ideas in
1854 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1855 // linker created section is normally set when the section is created;
1856 // this function is used for input sections.
1858 Output_section_order
1859 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1861 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1862 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1863 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1864 bool is_bss
= false;
1869 case elfcpp::SHT_PROGBITS
:
1871 case elfcpp::SHT_NOBITS
:
1874 case elfcpp::SHT_RELA
:
1875 case elfcpp::SHT_REL
:
1877 return ORDER_DYNAMIC_RELOCS
;
1879 case elfcpp::SHT_HASH
:
1880 case elfcpp::SHT_DYNAMIC
:
1881 case elfcpp::SHT_SHLIB
:
1882 case elfcpp::SHT_DYNSYM
:
1883 case elfcpp::SHT_GNU_HASH
:
1884 case elfcpp::SHT_GNU_verdef
:
1885 case elfcpp::SHT_GNU_verneed
:
1886 case elfcpp::SHT_GNU_versym
:
1888 return ORDER_DYNAMIC_LINKER
;
1890 case elfcpp::SHT_NOTE
:
1891 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1894 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1895 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1897 if (!is_bss
&& !is_write
)
1901 if (strcmp(os
->name(), ".init") == 0)
1903 else if (strcmp(os
->name(), ".fini") == 0)
1905 else if (parameters
->options().keep_text_section_prefix())
1907 // -z,keep-text-section-prefix introduces additional
1909 if (strcmp(os
->name(), ".text.hot") == 0)
1910 return ORDER_TEXT_HOT
;
1911 else if (strcmp(os
->name(), ".text.startup") == 0)
1912 return ORDER_TEXT_STARTUP
;
1913 else if (strcmp(os
->name(), ".text.exit") == 0)
1914 return ORDER_TEXT_EXIT
;
1915 else if (strcmp(os
->name(), ".text.unlikely") == 0)
1916 return ORDER_TEXT_UNLIKELY
;
1919 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1923 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1925 if (os
->is_small_section())
1926 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1927 if (os
->is_large_section())
1928 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1930 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1933 // Attach output sections to segments. This is called after we have
1934 // seen all the input sections.
1937 Layout::attach_sections_to_segments(const Target
* target
)
1939 for (Section_list::iterator p
= this->section_list_
.begin();
1940 p
!= this->section_list_
.end();
1942 this->attach_section_to_segment(target
, *p
);
1944 this->sections_are_attached_
= true;
1947 // Attach an output section to a segment.
1950 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1952 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1953 this->unattached_section_list_
.push_back(os
);
1955 this->attach_allocated_section_to_segment(target
, os
);
1958 // Attach an allocated output section to a segment.
1961 Layout::attach_allocated_section_to_segment(const Target
* target
,
1964 elfcpp::Elf_Xword flags
= os
->flags();
1965 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1967 if (parameters
->options().relocatable())
1970 // If we have a SECTIONS clause, we can't handle the attachment to
1971 // segments until after we've seen all the sections.
1972 if (this->script_options_
->saw_sections_clause())
1975 gold_assert(!this->script_options_
->saw_phdrs_clause());
1977 // This output section goes into a PT_LOAD segment.
1979 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1981 // If this output section's segment has extra flags that need to be set,
1982 // coming from a linker plugin, do that.
1983 seg_flags
|= os
->extra_segment_flags();
1985 // Check for --section-start.
1987 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1989 // In general the only thing we really care about for PT_LOAD
1990 // segments is whether or not they are writable or executable,
1991 // so that is how we search for them.
1992 // Large data sections also go into their own PT_LOAD segment.
1993 // People who need segments sorted on some other basis will
1994 // have to use a linker script.
1996 Segment_list::const_iterator p
;
1997 if (!os
->is_unique_segment())
1999 for (p
= this->segment_list_
.begin();
2000 p
!= this->segment_list_
.end();
2003 if ((*p
)->type() != elfcpp::PT_LOAD
)
2005 if ((*p
)->is_unique_segment())
2007 if (!parameters
->options().omagic()
2008 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
2010 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
2011 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
2013 // If -Tbss was specified, we need to separate the data and BSS
2015 if (parameters
->options().user_set_Tbss())
2017 if ((os
->type() == elfcpp::SHT_NOBITS
)
2018 == (*p
)->has_any_data_sections())
2021 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
2026 if ((*p
)->are_addresses_set())
2029 (*p
)->add_initial_output_data(os
);
2030 (*p
)->update_flags_for_output_section(seg_flags
);
2031 (*p
)->set_addresses(addr
, addr
);
2035 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
2040 if (p
== this->segment_list_
.end()
2041 || os
->is_unique_segment())
2043 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
2045 if (os
->is_large_data_section())
2046 oseg
->set_is_large_data_segment();
2047 oseg
->add_output_section_to_load(this, os
, seg_flags
);
2049 oseg
->set_addresses(addr
, addr
);
2050 // Check if segment should be marked unique. For segments marked
2051 // unique by linker plugins, set the new alignment if specified.
2052 if (os
->is_unique_segment())
2054 oseg
->set_is_unique_segment();
2055 if (os
->segment_alignment() != 0)
2056 oseg
->set_minimum_p_align(os
->segment_alignment());
2060 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
2062 if (os
->type() == elfcpp::SHT_NOTE
)
2064 // See if we already have an equivalent PT_NOTE segment.
2065 for (p
= this->segment_list_
.begin();
2066 p
!= segment_list_
.end();
2069 if ((*p
)->type() == elfcpp::PT_NOTE
2070 && (((*p
)->flags() & elfcpp::PF_W
)
2071 == (seg_flags
& elfcpp::PF_W
)))
2073 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
2078 if (p
== this->segment_list_
.end())
2080 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
2082 oseg
->add_output_section_to_nonload(os
, seg_flags
);
2086 // If we see a loadable SHF_TLS section, we create a PT_TLS
2087 // segment. There can only be one such segment.
2088 if ((flags
& elfcpp::SHF_TLS
) != 0)
2090 if (this->tls_segment_
== NULL
)
2091 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
2092 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2095 // If -z relro is in effect, and we see a relro section, we create a
2096 // PT_GNU_RELRO segment. There can only be one such segment.
2097 if (os
->is_relro() && parameters
->options().relro())
2099 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
2100 if (this->relro_segment_
== NULL
)
2101 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
2102 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2105 // If we see a section named .interp, put it into a PT_INTERP
2106 // segment. This seems broken to me, but this is what GNU ld does,
2107 // and glibc expects it.
2108 if (strcmp(os
->name(), ".interp") == 0
2109 && !this->script_options_
->saw_phdrs_clause())
2111 if (this->interp_segment_
== NULL
)
2112 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
2114 gold_warning(_("multiple '.interp' sections in input files "
2115 "may cause confusing PT_INTERP segment"));
2116 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2120 // Make an output section for a script.
2123 Layout::make_output_section_for_script(
2125 Script_sections::Section_type section_type
)
2127 name
= this->namepool_
.add(name
, false, NULL
);
2128 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
2129 if (section_type
== Script_sections::ST_NOLOAD
)
2131 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
2132 sh_flags
, ORDER_INVALID
,
2134 os
->set_found_in_sections_clause();
2135 if (section_type
== Script_sections::ST_NOLOAD
)
2136 os
->set_is_noload();
2140 // Return the number of segments we expect to see.
2143 Layout::expected_segment_count() const
2145 size_t ret
= this->segment_list_
.size();
2147 // If we didn't see a SECTIONS clause in a linker script, we should
2148 // already have the complete list of segments. Otherwise we ask the
2149 // SECTIONS clause how many segments it expects, and add in the ones
2150 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2152 if (!this->script_options_
->saw_sections_clause())
2156 const Script_sections
* ss
= this->script_options_
->script_sections();
2157 return ret
+ ss
->expected_segment_count(this);
2161 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2162 // is whether we saw a .note.GNU-stack section in the object file.
2163 // GNU_STACK_FLAGS is the section flags. The flags give the
2164 // protection required for stack memory. We record this in an
2165 // executable as a PT_GNU_STACK segment. If an object file does not
2166 // have a .note.GNU-stack segment, we must assume that it is an old
2167 // object. On some targets that will force an executable stack.
2170 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2173 if (!seen_gnu_stack
)
2175 this->input_without_gnu_stack_note_
= true;
2176 if (parameters
->options().warn_execstack()
2177 && parameters
->target().is_default_stack_executable())
2178 gold_warning(_("%s: missing .note.GNU-stack section"
2179 " implies executable stack"),
2180 obj
->name().c_str());
2184 this->input_with_gnu_stack_note_
= true;
2185 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2187 this->input_requires_executable_stack_
= true;
2188 if (parameters
->options().warn_execstack())
2189 gold_warning(_("%s: requires executable stack"),
2190 obj
->name().c_str());
2195 // Read a value with given size and endianness.
2197 static inline uint64_t
2198 read_sized_value(size_t size
, const unsigned char* buf
, bool is_big_endian
,
2199 const Object
* object
)
2205 val
= elfcpp::Swap
<32, true>::readval(buf
);
2207 val
= elfcpp::Swap
<32, false>::readval(buf
);
2212 val
= elfcpp::Swap
<64, true>::readval(buf
);
2214 val
= elfcpp::Swap
<64, false>::readval(buf
);
2218 gold_warning(_("%s: in .note.gnu.property section, "
2219 "pr_datasz must be 4 or 8"),
2220 object
->name().c_str());
2225 // Write a value with given size and endianness.
2228 write_sized_value(uint64_t value
, size_t size
, unsigned char* buf
,
2234 elfcpp::Swap
<32, true>::writeval(buf
, static_cast<uint32_t>(value
));
2236 elfcpp::Swap
<32, false>::writeval(buf
, static_cast<uint32_t>(value
));
2241 elfcpp::Swap
<64, true>::writeval(buf
, value
);
2243 elfcpp::Swap
<64, false>::writeval(buf
, value
);
2247 // We will have already complained about this.
2251 // Handle the .note.gnu.property section at layout time.
2254 Layout::layout_gnu_property(unsigned int note_type
,
2255 unsigned int pr_type
,
2257 const unsigned char* pr_data
,
2258 const Object
* object
)
2260 // We currently support only the one note type.
2261 gold_assert(note_type
== elfcpp::NT_GNU_PROPERTY_TYPE_0
);
2263 if (pr_type
>= elfcpp::GNU_PROPERTY_LOPROC
2264 && pr_type
< elfcpp::GNU_PROPERTY_HIPROC
)
2266 // Target-dependent property value; call the target to record.
2267 const int size
= parameters
->target().get_size();
2268 const bool is_big_endian
= parameters
->target().is_big_endian();
2273 #ifdef HAVE_TARGET_32_BIG
2274 parameters
->sized_target
<32, true>()->
2275 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2283 #ifdef HAVE_TARGET_32_LITTLE
2284 parameters
->sized_target
<32, false>()->
2285 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2292 else if (size
== 64)
2296 #ifdef HAVE_TARGET_64_BIG
2297 parameters
->sized_target
<64, true>()->
2298 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2306 #ifdef HAVE_TARGET_64_LITTLE
2307 parameters
->sized_target
<64, false>()->
2308 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2320 Gnu_properties::iterator pprop
= this->gnu_properties_
.find(pr_type
);
2321 if (pprop
== this->gnu_properties_
.end())
2324 prop
.pr_datasz
= pr_datasz
;
2325 prop
.pr_data
= new unsigned char[pr_datasz
];
2326 memcpy(prop
.pr_data
, pr_data
, pr_datasz
);
2327 this->gnu_properties_
[pr_type
] = prop
;
2331 const bool is_big_endian
= parameters
->target().is_big_endian();
2334 case elfcpp::GNU_PROPERTY_STACK_SIZE
:
2335 // Record the maximum value seen.
2337 uint64_t val1
= read_sized_value(pprop
->second
.pr_datasz
,
2338 pprop
->second
.pr_data
,
2339 is_big_endian
, object
);
2340 uint64_t val2
= read_sized_value(pr_datasz
, pr_data
,
2341 is_big_endian
, object
);
2343 write_sized_value(val2
, pprop
->second
.pr_datasz
,
2344 pprop
->second
.pr_data
, is_big_endian
);
2347 case elfcpp::GNU_PROPERTY_NO_COPY_ON_PROTECTED
:
2348 // No data to merge.
2351 gold_warning(_("%s: unknown program property type %d "
2352 "in .note.gnu.property section"),
2353 object
->name().c_str(), pr_type
);
2358 // Merge per-object properties with program properties.
2359 // This lets the target identify objects that are missing certain
2360 // properties, in cases where properties must be ANDed together.
2363 Layout::merge_gnu_properties(const Object
* object
)
2365 const int size
= parameters
->target().get_size();
2366 const bool is_big_endian
= parameters
->target().is_big_endian();
2371 #ifdef HAVE_TARGET_32_BIG
2372 parameters
->sized_target
<32, true>()->merge_gnu_properties(object
);
2379 #ifdef HAVE_TARGET_32_LITTLE
2380 parameters
->sized_target
<32, false>()->merge_gnu_properties(object
);
2386 else if (size
== 64)
2390 #ifdef HAVE_TARGET_64_BIG
2391 parameters
->sized_target
<64, true>()->merge_gnu_properties(object
);
2398 #ifdef HAVE_TARGET_64_LITTLE
2399 parameters
->sized_target
<64, false>()->merge_gnu_properties(object
);
2409 // Add a target-specific property for the output .note.gnu.property section.
2412 Layout::add_gnu_property(unsigned int note_type
,
2413 unsigned int pr_type
,
2415 const unsigned char* pr_data
)
2417 gold_assert(note_type
== elfcpp::NT_GNU_PROPERTY_TYPE_0
);
2420 prop
.pr_datasz
= pr_datasz
;
2421 prop
.pr_data
= new unsigned char[pr_datasz
];
2422 memcpy(prop
.pr_data
, pr_data
, pr_datasz
);
2423 this->gnu_properties_
[pr_type
] = prop
;
2426 // Create automatic note sections.
2429 Layout::create_notes()
2431 this->create_gnu_properties_note();
2432 this->create_gold_note();
2433 this->create_stack_segment();
2434 this->create_build_id();
2437 // Create the dynamic sections which are needed before we read the
2441 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2443 if (parameters
->doing_static_link())
2446 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2447 elfcpp::SHT_DYNAMIC
,
2449 | elfcpp::SHF_WRITE
),
2451 true, false, false);
2453 // A linker script may discard .dynamic, so check for NULL.
2454 if (this->dynamic_section_
!= NULL
)
2456 this->dynamic_symbol_
=
2457 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2458 Symbol_table::PREDEFINED
,
2459 this->dynamic_section_
, 0, 0,
2460 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2461 elfcpp::STV_HIDDEN
, 0, false, false);
2463 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2465 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2469 // For each output section whose name can be represented as C symbol,
2470 // define __start and __stop symbols for the section. This is a GNU
2474 Layout::define_section_symbols(Symbol_table
* symtab
)
2476 for (Section_list::const_iterator p
= this->section_list_
.begin();
2477 p
!= this->section_list_
.end();
2480 const char* const name
= (*p
)->name();
2481 if (is_cident(name
))
2483 const std::string
name_string(name
);
2484 const std::string
start_name(cident_section_start_prefix
2486 const std::string
stop_name(cident_section_stop_prefix
2489 symtab
->define_in_output_data(start_name
.c_str(),
2491 Symbol_table::PREDEFINED
,
2497 elfcpp::STV_PROTECTED
,
2499 false, // offset_is_from_end
2500 true); // only_if_ref
2502 symtab
->define_in_output_data(stop_name
.c_str(),
2504 Symbol_table::PREDEFINED
,
2510 elfcpp::STV_PROTECTED
,
2512 true, // offset_is_from_end
2513 true); // only_if_ref
2518 // Define symbols for group signatures.
2521 Layout::define_group_signatures(Symbol_table
* symtab
)
2523 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2524 p
!= this->group_signatures_
.end();
2527 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2529 p
->section
->set_info_symndx(sym
);
2532 // Force the name of the group section to the group
2533 // signature, and use the group's section symbol as the
2534 // signature symbol.
2535 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2537 const char* name
= this->namepool_
.add(p
->signature
,
2539 p
->section
->set_name(name
);
2541 p
->section
->set_needs_symtab_index();
2542 p
->section
->set_info_section_symndx(p
->section
);
2546 this->group_signatures_
.clear();
2549 // Find the first read-only PT_LOAD segment, creating one if
2553 Layout::find_first_load_seg(const Target
* target
)
2555 Output_segment
* best
= NULL
;
2556 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2557 p
!= this->segment_list_
.end();
2560 if ((*p
)->type() == elfcpp::PT_LOAD
2561 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2562 && (parameters
->options().omagic()
2563 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2564 && (!target
->isolate_execinstr()
2565 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2567 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2574 gold_assert(!this->script_options_
->saw_phdrs_clause());
2576 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2581 // Save states of all current output segments. Store saved states
2582 // in SEGMENT_STATES.
2585 Layout::save_segments(Segment_states
* segment_states
)
2587 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2588 p
!= this->segment_list_
.end();
2591 Output_segment
* segment
= *p
;
2593 Output_segment
* copy
= new Output_segment(*segment
);
2594 (*segment_states
)[segment
] = copy
;
2598 // Restore states of output segments and delete any segment not found in
2602 Layout::restore_segments(const Segment_states
* segment_states
)
2604 // Go through the segment list and remove any segment added in the
2606 this->tls_segment_
= NULL
;
2607 this->relro_segment_
= NULL
;
2608 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2609 while (list_iter
!= this->segment_list_
.end())
2611 Output_segment
* segment
= *list_iter
;
2612 Segment_states::const_iterator states_iter
=
2613 segment_states
->find(segment
);
2614 if (states_iter
!= segment_states
->end())
2616 const Output_segment
* copy
= states_iter
->second
;
2617 // Shallow copy to restore states.
2620 // Also fix up TLS and RELRO segment pointers as appropriate.
2621 if (segment
->type() == elfcpp::PT_TLS
)
2622 this->tls_segment_
= segment
;
2623 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2624 this->relro_segment_
= segment
;
2630 list_iter
= this->segment_list_
.erase(list_iter
);
2631 // This is a segment created during section layout. It should be
2632 // safe to remove it since we should have removed all pointers to it.
2638 // Clean up after relaxation so that sections can be laid out again.
2641 Layout::clean_up_after_relaxation()
2643 // Restore the segments to point state just prior to the relaxation loop.
2644 Script_sections
* script_section
= this->script_options_
->script_sections();
2645 script_section
->release_segments();
2646 this->restore_segments(this->segment_states_
);
2648 // Reset section addresses and file offsets
2649 for (Section_list::iterator p
= this->section_list_
.begin();
2650 p
!= this->section_list_
.end();
2653 (*p
)->restore_states();
2655 // If an input section changes size because of relaxation,
2656 // we need to adjust the section offsets of all input sections.
2657 // after such a section.
2658 if ((*p
)->section_offsets_need_adjustment())
2659 (*p
)->adjust_section_offsets();
2661 (*p
)->reset_address_and_file_offset();
2664 // Reset special output object address and file offsets.
2665 for (Data_list::iterator p
= this->special_output_list_
.begin();
2666 p
!= this->special_output_list_
.end();
2668 (*p
)->reset_address_and_file_offset();
2670 // A linker script may have created some output section data objects.
2671 // They are useless now.
2672 for (Output_section_data_list::const_iterator p
=
2673 this->script_output_section_data_list_
.begin();
2674 p
!= this->script_output_section_data_list_
.end();
2677 this->script_output_section_data_list_
.clear();
2679 // Special-case fill output objects are recreated each time through
2680 // the relaxation loop.
2681 this->reset_relax_output();
2685 Layout::reset_relax_output()
2687 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
2688 p
!= this->relax_output_list_
.end();
2691 this->relax_output_list_
.clear();
2694 // Prepare for relaxation.
2697 Layout::prepare_for_relaxation()
2699 // Create an relaxation debug check if in debugging mode.
2700 if (is_debugging_enabled(DEBUG_RELAXATION
))
2701 this->relaxation_debug_check_
= new Relaxation_debug_check();
2703 // Save segment states.
2704 this->segment_states_
= new Segment_states();
2705 this->save_segments(this->segment_states_
);
2707 for(Section_list::const_iterator p
= this->section_list_
.begin();
2708 p
!= this->section_list_
.end();
2710 (*p
)->save_states();
2712 if (is_debugging_enabled(DEBUG_RELAXATION
))
2713 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2714 this->section_list_
, this->special_output_list_
,
2715 this->relax_output_list_
);
2717 // Also enable recording of output section data from scripts.
2718 this->record_output_section_data_from_script_
= true;
2721 // If the user set the address of the text segment, that may not be
2722 // compatible with putting the segment headers and file headers into
2723 // that segment. For isolate_execinstr() targets, it's the rodata
2724 // segment rather than text where we might put the headers.
2726 load_seg_unusable_for_headers(const Target
* target
)
2728 const General_options
& options
= parameters
->options();
2729 if (target
->isolate_execinstr())
2730 return (options
.user_set_Trodata_segment()
2731 && options
.Trodata_segment() % target
->abi_pagesize() != 0);
2733 return (options
.user_set_Ttext()
2734 && options
.Ttext() % target
->abi_pagesize() != 0);
2737 // Relaxation loop body: If target has no relaxation, this runs only once
2738 // Otherwise, the target relaxation hook is called at the end of
2739 // each iteration. If the hook returns true, it means re-layout of
2740 // section is required.
2742 // The number of segments created by a linking script without a PHDRS
2743 // clause may be affected by section sizes and alignments. There is
2744 // a remote chance that relaxation causes different number of PT_LOAD
2745 // segments are created and sections are attached to different segments.
2746 // Therefore, we always throw away all segments created during section
2747 // layout. In order to be able to restart the section layout, we keep
2748 // a copy of the segment list right before the relaxation loop and use
2749 // that to restore the segments.
2751 // PASS is the current relaxation pass number.
2752 // SYMTAB is a symbol table.
2753 // PLOAD_SEG is the address of a pointer for the load segment.
2754 // PHDR_SEG is a pointer to the PHDR segment.
2755 // SEGMENT_HEADERS points to the output segment header.
2756 // FILE_HEADER points to the output file header.
2757 // PSHNDX is the address to store the output section index.
2760 Layout::relaxation_loop_body(
2763 Symbol_table
* symtab
,
2764 Output_segment
** pload_seg
,
2765 Output_segment
* phdr_seg
,
2766 Output_segment_headers
* segment_headers
,
2767 Output_file_header
* file_header
,
2768 unsigned int* pshndx
)
2770 // If this is not the first iteration, we need to clean up after
2771 // relaxation so that we can lay out the sections again.
2773 this->clean_up_after_relaxation();
2775 // If there is a SECTIONS clause, put all the input sections into
2776 // the required order.
2777 Output_segment
* load_seg
;
2778 if (this->script_options_
->saw_sections_clause())
2779 load_seg
= this->set_section_addresses_from_script(symtab
);
2780 else if (parameters
->options().relocatable())
2783 load_seg
= this->find_first_load_seg(target
);
2785 if (parameters
->options().oformat_enum()
2786 != General_options::OBJECT_FORMAT_ELF
)
2789 if (load_seg_unusable_for_headers(target
))
2795 gold_assert(phdr_seg
== NULL
2797 || this->script_options_
->saw_sections_clause());
2799 // If the address of the load segment we found has been set by
2800 // --section-start rather than by a script, then adjust the VMA and
2801 // LMA downward if possible to include the file and section headers.
2802 uint64_t header_gap
= 0;
2803 if (load_seg
!= NULL
2804 && load_seg
->are_addresses_set()
2805 && !this->script_options_
->saw_sections_clause()
2806 && !parameters
->options().relocatable())
2808 file_header
->finalize_data_size();
2809 segment_headers
->finalize_data_size();
2810 size_t sizeof_headers
= (file_header
->data_size()
2811 + segment_headers
->data_size());
2812 const uint64_t abi_pagesize
= target
->abi_pagesize();
2813 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2814 hdr_paddr
&= ~(abi_pagesize
- 1);
2815 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2816 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2820 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2821 load_seg
->paddr() - subtract
);
2822 header_gap
= subtract
- sizeof_headers
;
2826 // Lay out the segment headers.
2827 if (!parameters
->options().relocatable())
2829 gold_assert(segment_headers
!= NULL
);
2830 if (header_gap
!= 0 && load_seg
!= NULL
)
2832 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2833 load_seg
->add_initial_output_data(z
);
2835 if (load_seg
!= NULL
)
2836 load_seg
->add_initial_output_data(segment_headers
);
2837 if (phdr_seg
!= NULL
)
2838 phdr_seg
->add_initial_output_data(segment_headers
);
2841 // Lay out the file header.
2842 if (load_seg
!= NULL
)
2843 load_seg
->add_initial_output_data(file_header
);
2845 if (this->script_options_
->saw_phdrs_clause()
2846 && !parameters
->options().relocatable())
2848 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2849 // clause in a linker script.
2850 Script_sections
* ss
= this->script_options_
->script_sections();
2851 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2854 // We set the output section indexes in set_segment_offsets and
2855 // set_section_indexes.
2858 // Set the file offsets of all the segments, and all the sections
2861 if (!parameters
->options().relocatable())
2862 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2864 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2866 // Verify that the dummy relaxation does not change anything.
2867 if (is_debugging_enabled(DEBUG_RELAXATION
))
2870 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2872 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2875 *pload_seg
= load_seg
;
2879 // Search the list of patterns and find the position of the given section
2880 // name in the output section. If the section name matches a glob
2881 // pattern and a non-glob name, then the non-glob position takes
2882 // precedence. Return 0 if no match is found.
2885 Layout::find_section_order_index(const std::string
& section_name
)
2887 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2888 map_it
= this->input_section_position_
.find(section_name
);
2889 if (map_it
!= this->input_section_position_
.end())
2890 return map_it
->second
;
2892 // Absolute match failed. Linear search the glob patterns.
2893 std::vector
<std::string
>::iterator it
;
2894 for (it
= this->input_section_glob_
.begin();
2895 it
!= this->input_section_glob_
.end();
2898 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2900 map_it
= this->input_section_position_
.find(*it
);
2901 gold_assert(map_it
!= this->input_section_position_
.end());
2902 return map_it
->second
;
2908 // Read the sequence of input sections from the file specified with
2909 // option --section-ordering-file.
2912 Layout::read_layout_from_file()
2914 const char* filename
= parameters
->options().section_ordering_file();
2920 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2921 filename
, strerror(errno
));
2923 std::getline(in
, line
); // this chops off the trailing \n, if any
2924 unsigned int position
= 1;
2925 this->set_section_ordering_specified();
2929 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2930 line
.resize(line
.length() - 1);
2931 // Ignore comments, beginning with '#'
2934 std::getline(in
, line
);
2937 this->input_section_position_
[line
] = position
;
2938 // Store all glob patterns in a vector.
2939 if (is_wildcard_string(line
.c_str()))
2940 this->input_section_glob_
.push_back(line
);
2942 std::getline(in
, line
);
2946 // Finalize the layout. When this is called, we have created all the
2947 // output sections and all the output segments which are based on
2948 // input sections. We have several things to do, and we have to do
2949 // them in the right order, so that we get the right results correctly
2952 // 1) Finalize the list of output segments and create the segment
2955 // 2) Finalize the dynamic symbol table and associated sections.
2957 // 3) Determine the final file offset of all the output segments.
2959 // 4) Determine the final file offset of all the SHF_ALLOC output
2962 // 5) Create the symbol table sections and the section name table
2965 // 6) Finalize the symbol table: set symbol values to their final
2966 // value and make a final determination of which symbols are going
2967 // into the output symbol table.
2969 // 7) Create the section table header.
2971 // 8) Determine the final file offset of all the output sections which
2972 // are not SHF_ALLOC, including the section table header.
2974 // 9) Finalize the ELF file header.
2976 // This function returns the size of the output file.
2979 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2980 Target
* target
, const Task
* task
)
2982 unsigned int local_dynamic_count
= 0;
2983 unsigned int forced_local_dynamic_count
= 0;
2985 target
->finalize_sections(this, input_objects
, symtab
);
2987 this->count_local_symbols(task
, input_objects
);
2989 this->link_stabs_sections();
2991 Output_segment
* phdr_seg
= NULL
;
2992 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2994 // There was a dynamic object in the link. We need to create
2995 // some information for the dynamic linker.
2997 // Create the PT_PHDR segment which will hold the program
2999 if (!this->script_options_
->saw_phdrs_clause())
3000 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
3002 // Create the dynamic symbol table, including the hash table.
3003 Output_section
* dynstr
;
3004 std::vector
<Symbol
*> dynamic_symbols
;
3005 Versions
versions(*this->script_options()->version_script_info(),
3007 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
3008 &local_dynamic_count
,
3009 &forced_local_dynamic_count
,
3013 // Create the .interp section to hold the name of the
3014 // interpreter, and put it in a PT_INTERP segment. Don't do it
3015 // if we saw a .interp section in an input file.
3016 if ((!parameters
->options().shared()
3017 || parameters
->options().dynamic_linker() != NULL
)
3018 && this->interp_segment_
== NULL
)
3019 this->create_interp(target
);
3021 // Finish the .dynamic section to hold the dynamic data, and put
3022 // it in a PT_DYNAMIC segment.
3023 this->finish_dynamic_section(input_objects
, symtab
);
3025 // We should have added everything we need to the dynamic string
3027 this->dynpool_
.set_string_offsets();
3029 // Create the version sections. We can't do this until the
3030 // dynamic string table is complete.
3031 this->create_version_sections(&versions
, symtab
,
3032 (local_dynamic_count
3033 + forced_local_dynamic_count
),
3034 dynamic_symbols
, dynstr
);
3036 // Set the size of the _DYNAMIC symbol. We can't do this until
3037 // after we call create_version_sections.
3038 this->set_dynamic_symbol_size(symtab
);
3041 // Create segment headers.
3042 Output_segment_headers
* segment_headers
=
3043 (parameters
->options().relocatable()
3045 : new Output_segment_headers(this->segment_list_
));
3047 // Lay out the file header.
3048 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
3051 this->special_output_list_
.push_back(file_header
);
3052 if (segment_headers
!= NULL
)
3053 this->special_output_list_
.push_back(segment_headers
);
3055 // Find approriate places for orphan output sections if we are using
3057 if (this->script_options_
->saw_sections_clause())
3058 this->place_orphan_sections_in_script();
3060 Output_segment
* load_seg
;
3065 // Take a snapshot of the section layout as needed.
3066 if (target
->may_relax())
3067 this->prepare_for_relaxation();
3069 // Run the relaxation loop to lay out sections.
3072 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
3073 phdr_seg
, segment_headers
, file_header
,
3077 while (target
->may_relax()
3078 && target
->relax(pass
, input_objects
, symtab
, this, task
));
3080 // If there is a load segment that contains the file and program headers,
3081 // provide a symbol __ehdr_start pointing there.
3082 // A program can use this to examine itself robustly.
3083 Symbol
*ehdr_start
= symtab
->lookup("__ehdr_start");
3084 if (ehdr_start
!= NULL
&& ehdr_start
->is_predefined())
3086 if (load_seg
!= NULL
)
3087 ehdr_start
->set_output_segment(load_seg
, Symbol::SEGMENT_START
);
3089 ehdr_start
->set_undefined();
3092 // Set the file offsets of all the non-data sections we've seen so
3093 // far which don't have to wait for the input sections. We need
3094 // this in order to finalize local symbols in non-allocated
3096 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
3098 // Set the section indexes of all unallocated sections seen so far,
3099 // in case any of them are somehow referenced by a symbol.
3100 shndx
= this->set_section_indexes(shndx
);
3102 // Create the symbol table sections.
3103 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
,
3104 local_dynamic_count
);
3105 if (!parameters
->doing_static_link())
3106 this->assign_local_dynsym_offsets(input_objects
);
3108 // Process any symbol assignments from a linker script. This must
3109 // be called after the symbol table has been finalized.
3110 this->script_options_
->finalize_symbols(symtab
, this);
3112 // Create the incremental inputs sections.
3113 if (this->incremental_inputs_
)
3115 this->incremental_inputs_
->finalize();
3116 this->create_incremental_info_sections(symtab
);
3119 // Create the .shstrtab section.
3120 Output_section
* shstrtab_section
= this->create_shstrtab();
3122 // Set the file offsets of the rest of the non-data sections which
3123 // don't have to wait for the input sections.
3124 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
3126 // Now that all sections have been created, set the section indexes
3127 // for any sections which haven't been done yet.
3128 shndx
= this->set_section_indexes(shndx
);
3130 // Create the section table header.
3131 this->create_shdrs(shstrtab_section
, &off
);
3133 // If there are no sections which require postprocessing, we can
3134 // handle the section names now, and avoid a resize later.
3135 if (!this->any_postprocessing_sections_
)
3137 off
= this->set_section_offsets(off
,
3138 POSTPROCESSING_SECTIONS_PASS
);
3140 this->set_section_offsets(off
,
3141 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
3144 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
3146 // Now we know exactly where everything goes in the output file
3147 // (except for non-allocated sections which require postprocessing).
3148 Output_data::layout_complete();
3150 this->output_file_size_
= off
;
3155 // Create a note header following the format defined in the ELF ABI.
3156 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
3157 // of the section to create, DESCSZ is the size of the descriptor.
3158 // ALLOCATE is true if the section should be allocated in memory.
3159 // This returns the new note section. It sets *TRAILING_PADDING to
3160 // the number of trailing zero bytes required.
3163 Layout::create_note(const char* name
, int note_type
,
3164 const char* section_name
, size_t descsz
,
3165 bool allocate
, size_t* trailing_padding
)
3167 // Authorities all agree that the values in a .note field should
3168 // be aligned on 4-byte boundaries for 32-bit binaries. However,
3169 // they differ on what the alignment is for 64-bit binaries.
3170 // The GABI says unambiguously they take 8-byte alignment:
3171 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
3172 // Other documentation says alignment should always be 4 bytes:
3173 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
3174 // GNU ld and GNU readelf both support the latter (at least as of
3175 // version 2.16.91), and glibc always generates the latter for
3176 // .note.ABI-tag (as of version 1.6), so that's the one we go with
3178 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
3179 const int size
= parameters
->target().get_size();
3181 const int size
= 32;
3184 // The contents of the .note section.
3185 size_t namesz
= strlen(name
) + 1;
3186 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
3187 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
3189 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
3191 unsigned char* buffer
= new unsigned char[notehdrsz
];
3192 memset(buffer
, 0, notehdrsz
);
3194 bool is_big_endian
= parameters
->target().is_big_endian();
3200 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
3201 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
3202 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
3206 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
3207 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
3208 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
3211 else if (size
== 64)
3215 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
3216 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
3217 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
3221 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
3222 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
3223 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
3229 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
3231 elfcpp::Elf_Xword flags
= 0;
3232 Output_section_order order
= ORDER_INVALID
;
3235 flags
= elfcpp::SHF_ALLOC
;
3236 order
= ORDER_RO_NOTE
;
3238 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
3240 flags
, false, order
, false,
3245 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
3248 os
->add_output_section_data(posd
);
3250 *trailing_padding
= aligned_descsz
- descsz
;
3255 // Create a .note.gnu.property section to record program properties
3256 // accumulated from the input files.
3259 Layout::create_gnu_properties_note()
3261 parameters
->target().finalize_gnu_properties(this);
3263 if (this->gnu_properties_
.empty())
3266 const unsigned int size
= parameters
->target().get_size();
3267 const bool is_big_endian
= parameters
->target().is_big_endian();
3269 // Compute the total size of the properties array.
3271 for (Gnu_properties::const_iterator prop
= this->gnu_properties_
.begin();
3272 prop
!= this->gnu_properties_
.end();
3275 descsz
= align_address(descsz
+ 8 + prop
->second
.pr_datasz
, size
/ 8);
3278 // Create the note section.
3279 size_t trailing_padding
;
3280 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_PROPERTY_TYPE_0
,
3281 ".note.gnu.property", descsz
,
3282 true, &trailing_padding
);
3285 gold_assert(trailing_padding
== 0);
3287 // Allocate and fill the properties array.
3288 unsigned char* desc
= new unsigned char[descsz
];
3289 unsigned char* p
= desc
;
3290 for (Gnu_properties::const_iterator prop
= this->gnu_properties_
.begin();
3291 prop
!= this->gnu_properties_
.end();
3294 size_t datasz
= prop
->second
.pr_datasz
;
3295 size_t aligned_datasz
= align_address(prop
->second
.pr_datasz
, size
/ 8);
3296 write_sized_value(prop
->first
, 4, p
, is_big_endian
);
3297 write_sized_value(datasz
, 4, p
+ 4, is_big_endian
);
3298 memcpy(p
+ 8, prop
->second
.pr_data
, datasz
);
3299 if (aligned_datasz
> datasz
)
3300 memset(p
+ 8 + datasz
, 0, aligned_datasz
- datasz
);
3301 p
+= 8 + aligned_datasz
;
3303 Output_section_data
* posd
= new Output_data_const(desc
, descsz
, 4);
3304 os
->add_output_section_data(posd
);
3307 // For an executable or shared library, create a note to record the
3308 // version of gold used to create the binary.
3311 Layout::create_gold_note()
3313 if (parameters
->options().relocatable()
3314 || parameters
->incremental_update())
3317 std::string desc
= std::string("gold ") + gold::get_version_string();
3319 size_t trailing_padding
;
3320 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
3321 ".note.gnu.gold-version", desc
.size(),
3322 false, &trailing_padding
);
3326 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3327 os
->add_output_section_data(posd
);
3329 if (trailing_padding
> 0)
3331 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3332 os
->add_output_section_data(posd
);
3336 // Record whether the stack should be executable. This can be set
3337 // from the command line using the -z execstack or -z noexecstack
3338 // options. Otherwise, if any input file has a .note.GNU-stack
3339 // section with the SHF_EXECINSTR flag set, the stack should be
3340 // executable. Otherwise, if at least one input file a
3341 // .note.GNU-stack section, and some input file has no .note.GNU-stack
3342 // section, we use the target default for whether the stack should be
3343 // executable. If -z stack-size was used to set a p_memsz value for
3344 // PT_GNU_STACK, we generate the segment regardless. Otherwise, we
3345 // don't generate a stack note. When generating a object file, we
3346 // create a .note.GNU-stack section with the appropriate marking.
3347 // When generating an executable or shared library, we create a
3348 // PT_GNU_STACK segment.
3351 Layout::create_stack_segment()
3353 bool is_stack_executable
;
3354 if (parameters
->options().is_execstack_set())
3356 is_stack_executable
= parameters
->options().is_stack_executable();
3357 if (!is_stack_executable
3358 && this->input_requires_executable_stack_
3359 && parameters
->options().warn_execstack())
3360 gold_warning(_("one or more inputs require executable stack, "
3361 "but -z noexecstack was given"));
3363 else if (!this->input_with_gnu_stack_note_
3364 && (!parameters
->options().user_set_stack_size()
3365 || parameters
->options().relocatable()))
3369 if (this->input_requires_executable_stack_
)
3370 is_stack_executable
= true;
3371 else if (this->input_without_gnu_stack_note_
)
3372 is_stack_executable
=
3373 parameters
->target().is_default_stack_executable();
3375 is_stack_executable
= false;
3378 if (parameters
->options().relocatable())
3380 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
3381 elfcpp::Elf_Xword flags
= 0;
3382 if (is_stack_executable
)
3383 flags
|= elfcpp::SHF_EXECINSTR
;
3384 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
3385 ORDER_INVALID
, false);
3389 if (this->script_options_
->saw_phdrs_clause())
3391 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
3392 if (is_stack_executable
)
3393 flags
|= elfcpp::PF_X
;
3394 Output_segment
* seg
=
3395 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
3396 seg
->set_size(parameters
->options().stack_size());
3397 // BFD lets targets override this default alignment, but the only
3398 // targets that do so are ones that Gold does not support so far.
3399 seg
->set_minimum_p_align(16);
3403 // If --build-id was used, set up the build ID note.
3406 Layout::create_build_id()
3408 if (!parameters
->options().user_set_build_id())
3411 const char* style
= parameters
->options().build_id();
3412 if (strcmp(style
, "none") == 0)
3415 // Set DESCSZ to the size of the note descriptor. When possible,
3416 // set DESC to the note descriptor contents.
3419 if (strcmp(style
, "md5") == 0)
3421 else if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
3423 else if (strcmp(style
, "uuid") == 0)
3426 const size_t uuidsz
= 128 / 8;
3428 char buffer
[uuidsz
];
3429 memset(buffer
, 0, uuidsz
);
3431 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
3433 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3437 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
3438 release_descriptor(descriptor
, true);
3440 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
3441 else if (static_cast<size_t>(got
) != uuidsz
)
3442 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3446 desc
.assign(buffer
, uuidsz
);
3448 #else // __MINGW32__
3450 typedef RPC_STATUS (RPC_ENTRY
*UuidCreateFn
)(UUID
*Uuid
);
3452 HMODULE rpc_library
= LoadLibrary("rpcrt4.dll");
3454 gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll"));
3457 UuidCreateFn uuid_create
= reinterpret_cast<UuidCreateFn
>(
3458 GetProcAddress(rpc_library
, "UuidCreate"));
3460 gold_error(_("--build-id=uuid failed: could not find UuidCreate"));
3461 else if (uuid_create(&uuid
) != RPC_S_OK
)
3462 gold_error(_("__build_id=uuid failed: call UuidCreate() failed"));
3463 FreeLibrary(rpc_library
);
3465 desc
.assign(reinterpret_cast<const char *>(&uuid
), sizeof(UUID
));
3466 descsz
= sizeof(UUID
);
3467 #endif // __MINGW32__
3469 else if (strncmp(style
, "0x", 2) == 0)
3472 const char* p
= style
+ 2;
3475 if (hex_p(p
[0]) && hex_p(p
[1]))
3477 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
3481 else if (*p
== '-' || *p
== ':')
3484 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3487 descsz
= desc
.size();
3490 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
3493 size_t trailing_padding
;
3494 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
3495 ".note.gnu.build-id", descsz
, true,
3502 // We know the value already, so we fill it in now.
3503 gold_assert(desc
.size() == descsz
);
3505 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3506 os
->add_output_section_data(posd
);
3508 if (trailing_padding
!= 0)
3510 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3511 os
->add_output_section_data(posd
);
3516 // We need to compute a checksum after we have completed the
3518 gold_assert(trailing_padding
== 0);
3519 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3520 os
->add_output_section_data(this->build_id_note_
);
3524 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3525 // field of the former should point to the latter. I'm not sure who
3526 // started this, but the GNU linker does it, and some tools depend
3530 Layout::link_stabs_sections()
3532 if (!this->have_stabstr_section_
)
3535 for (Section_list::iterator p
= this->section_list_
.begin();
3536 p
!= this->section_list_
.end();
3539 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3542 const char* name
= (*p
)->name();
3543 if (strncmp(name
, ".stab", 5) != 0)
3546 size_t len
= strlen(name
);
3547 if (strcmp(name
+ len
- 3, "str") != 0)
3550 std::string
stab_name(name
, len
- 3);
3551 Output_section
* stab_sec
;
3552 stab_sec
= this->find_output_section(stab_name
.c_str());
3553 if (stab_sec
!= NULL
)
3554 stab_sec
->set_link_section(*p
);
3558 // Create .gnu_incremental_inputs and related sections needed
3559 // for the next run of incremental linking to check what has changed.
3562 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3564 Incremental_inputs
* incr
= this->incremental_inputs_
;
3566 gold_assert(incr
!= NULL
);
3568 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3569 incr
->create_data_sections(symtab
);
3571 // Add the .gnu_incremental_inputs section.
3572 const char* incremental_inputs_name
=
3573 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3574 Output_section
* incremental_inputs_os
=
3575 this->make_output_section(incremental_inputs_name
,
3576 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3577 ORDER_INVALID
, false);
3578 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3580 // Add the .gnu_incremental_symtab section.
3581 const char* incremental_symtab_name
=
3582 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3583 Output_section
* incremental_symtab_os
=
3584 this->make_output_section(incremental_symtab_name
,
3585 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3586 ORDER_INVALID
, false);
3587 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3588 incremental_symtab_os
->set_entsize(4);
3590 // Add the .gnu_incremental_relocs section.
3591 const char* incremental_relocs_name
=
3592 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3593 Output_section
* incremental_relocs_os
=
3594 this->make_output_section(incremental_relocs_name
,
3595 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3596 ORDER_INVALID
, false);
3597 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3598 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3600 // Add the .gnu_incremental_got_plt section.
3601 const char* incremental_got_plt_name
=
3602 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3603 Output_section
* incremental_got_plt_os
=
3604 this->make_output_section(incremental_got_plt_name
,
3605 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3606 ORDER_INVALID
, false);
3607 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3609 // Add the .gnu_incremental_strtab section.
3610 const char* incremental_strtab_name
=
3611 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3612 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3613 elfcpp::SHT_STRTAB
, 0,
3614 ORDER_INVALID
, false);
3615 Output_data_strtab
* strtab_data
=
3616 new Output_data_strtab(incr
->get_stringpool());
3617 incremental_strtab_os
->add_output_section_data(strtab_data
);
3619 incremental_inputs_os
->set_after_input_sections();
3620 incremental_symtab_os
->set_after_input_sections();
3621 incremental_relocs_os
->set_after_input_sections();
3622 incremental_got_plt_os
->set_after_input_sections();
3624 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3625 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3626 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3627 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3630 // Return whether SEG1 should be before SEG2 in the output file. This
3631 // is based entirely on the segment type and flags. When this is
3632 // called the segment addresses have normally not yet been set.
3635 Layout::segment_precedes(const Output_segment
* seg1
,
3636 const Output_segment
* seg2
)
3638 // In order to produce a stable ordering if we're called with the same pointer
3643 elfcpp::Elf_Word type1
= seg1
->type();
3644 elfcpp::Elf_Word type2
= seg2
->type();
3646 // The single PT_PHDR segment is required to precede any loadable
3647 // segment. We simply make it always first.
3648 if (type1
== elfcpp::PT_PHDR
)
3650 gold_assert(type2
!= elfcpp::PT_PHDR
);
3653 if (type2
== elfcpp::PT_PHDR
)
3656 // The single PT_INTERP segment is required to precede any loadable
3657 // segment. We simply make it always second.
3658 if (type1
== elfcpp::PT_INTERP
)
3660 gold_assert(type2
!= elfcpp::PT_INTERP
);
3663 if (type2
== elfcpp::PT_INTERP
)
3666 // We then put PT_LOAD segments before any other segments.
3667 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3669 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3672 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3673 // segment, because that is where the dynamic linker expects to find
3674 // it (this is just for efficiency; other positions would also work
3676 if (type1
== elfcpp::PT_TLS
3677 && type2
!= elfcpp::PT_TLS
3678 && type2
!= elfcpp::PT_GNU_RELRO
)
3680 if (type2
== elfcpp::PT_TLS
3681 && type1
!= elfcpp::PT_TLS
3682 && type1
!= elfcpp::PT_GNU_RELRO
)
3685 // We put the PT_GNU_RELRO segment last, because that is where the
3686 // dynamic linker expects to find it (as with PT_TLS, this is just
3688 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3690 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3693 const elfcpp::Elf_Word flags1
= seg1
->flags();
3694 const elfcpp::Elf_Word flags2
= seg2
->flags();
3696 // The order of non-PT_LOAD segments is unimportant. We simply sort
3697 // by the numeric segment type and flags values. There should not
3698 // be more than one segment with the same type and flags, except
3699 // when a linker script specifies such.
3700 if (type1
!= elfcpp::PT_LOAD
)
3703 return type1
< type2
;
3704 gold_assert(flags1
!= flags2
3705 || this->script_options_
->saw_phdrs_clause());
3706 return flags1
< flags2
;
3709 // If the addresses are set already, sort by load address.
3710 if (seg1
->are_addresses_set())
3712 if (!seg2
->are_addresses_set())
3715 unsigned int section_count1
= seg1
->output_section_count();
3716 unsigned int section_count2
= seg2
->output_section_count();
3717 if (section_count1
== 0 && section_count2
> 0)
3719 if (section_count1
> 0 && section_count2
== 0)
3722 uint64_t paddr1
= (seg1
->are_addresses_set()
3724 : seg1
->first_section_load_address());
3725 uint64_t paddr2
= (seg2
->are_addresses_set()
3727 : seg2
->first_section_load_address());
3729 if (paddr1
!= paddr2
)
3730 return paddr1
< paddr2
;
3732 else if (seg2
->are_addresses_set())
3735 // A segment which holds large data comes after a segment which does
3736 // not hold large data.
3737 if (seg1
->is_large_data_segment())
3739 if (!seg2
->is_large_data_segment())
3742 else if (seg2
->is_large_data_segment())
3745 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3746 // segments come before writable segments. Then writable segments
3747 // with data come before writable segments without data. Then
3748 // executable segments come before non-executable segments. Then
3749 // the unlikely case of a non-readable segment comes before the
3750 // normal case of a readable segment. If there are multiple
3751 // segments with the same type and flags, we require that the
3752 // address be set, and we sort by virtual address and then physical
3754 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3755 return (flags1
& elfcpp::PF_W
) == 0;
3756 if ((flags1
& elfcpp::PF_W
) != 0
3757 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3758 return seg1
->has_any_data_sections();
3759 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3760 return (flags1
& elfcpp::PF_X
) != 0;
3761 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3762 return (flags1
& elfcpp::PF_R
) == 0;
3764 // We shouldn't get here--we shouldn't create segments which we
3765 // can't distinguish. Unless of course we are using a weird linker
3766 // script or overlapping --section-start options. We could also get
3767 // here if plugins want unique segments for subsets of sections.
3768 gold_assert(this->script_options_
->saw_phdrs_clause()
3769 || parameters
->options().any_section_start()
3770 || this->is_unique_segment_for_sections_specified()
3771 || parameters
->options().text_unlikely_segment());
3775 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3778 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3780 uint64_t unsigned_off
= off
;
3781 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3782 | (addr
& (abi_pagesize
- 1)));
3783 if (aligned_off
< unsigned_off
)
3784 aligned_off
+= abi_pagesize
;
3788 // On targets where the text segment contains only executable code,
3789 // a non-executable segment is never the text segment.
3792 is_text_segment(const Target
* target
, const Output_segment
* seg
)
3794 elfcpp::Elf_Xword flags
= seg
->flags();
3795 if ((flags
& elfcpp::PF_W
) != 0)
3797 if ((flags
& elfcpp::PF_X
) == 0)
3798 return !target
->isolate_execinstr();
3802 // Set the file offsets of all the segments, and all the sections they
3803 // contain. They have all been created. LOAD_SEG must be laid out
3804 // first. Return the offset of the data to follow.
3807 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3808 unsigned int* pshndx
)
3810 // Sort them into the final order. We use a stable sort so that we
3811 // don't randomize the order of indistinguishable segments created
3812 // by linker scripts.
3813 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3814 Layout::Compare_segments(this));
3816 // Find the PT_LOAD segments, and set their addresses and offsets
3817 // and their section's addresses and offsets.
3818 uint64_t start_addr
;
3819 if (parameters
->options().user_set_Ttext())
3820 start_addr
= parameters
->options().Ttext();
3821 else if (parameters
->options().output_is_position_independent())
3824 start_addr
= target
->default_text_segment_address();
3826 uint64_t addr
= start_addr
;
3829 // If LOAD_SEG is NULL, then the file header and segment headers
3830 // will not be loadable. But they still need to be at offset 0 in
3831 // the file. Set their offsets now.
3832 if (load_seg
== NULL
)
3834 for (Data_list::iterator p
= this->special_output_list_
.begin();
3835 p
!= this->special_output_list_
.end();
3838 off
= align_address(off
, (*p
)->addralign());
3839 (*p
)->set_address_and_file_offset(0, off
);
3840 off
+= (*p
)->data_size();
3844 unsigned int increase_relro
= this->increase_relro_
;
3845 if (this->script_options_
->saw_sections_clause())
3848 const bool check_sections
= parameters
->options().check_sections();
3849 Output_segment
* last_load_segment
= NULL
;
3851 unsigned int shndx_begin
= *pshndx
;
3852 unsigned int shndx_load_seg
= *pshndx
;
3854 for (Segment_list::iterator p
= this->segment_list_
.begin();
3855 p
!= this->segment_list_
.end();
3858 if ((*p
)->type() == elfcpp::PT_LOAD
)
3860 if (target
->isolate_execinstr())
3862 // When we hit the segment that should contain the
3863 // file headers, reset the file offset so we place
3864 // it and subsequent segments appropriately.
3865 // We'll fix up the preceding segments below.
3873 shndx_load_seg
= *pshndx
;
3879 // Verify that the file headers fall into the first segment.
3880 if (load_seg
!= NULL
&& load_seg
!= *p
)
3885 bool are_addresses_set
= (*p
)->are_addresses_set();
3886 if (are_addresses_set
)
3888 // When it comes to setting file offsets, we care about
3889 // the physical address.
3890 addr
= (*p
)->paddr();
3892 else if (parameters
->options().user_set_Ttext()
3893 && (parameters
->options().omagic()
3894 || is_text_segment(target
, *p
)))
3896 are_addresses_set
= true;
3898 else if (parameters
->options().user_set_Trodata_segment()
3899 && ((*p
)->flags() & (elfcpp::PF_W
| elfcpp::PF_X
)) == 0)
3901 addr
= parameters
->options().Trodata_segment();
3902 are_addresses_set
= true;
3904 else if (parameters
->options().user_set_Tdata()
3905 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3906 && (!parameters
->options().user_set_Tbss()
3907 || (*p
)->has_any_data_sections()))
3909 addr
= parameters
->options().Tdata();
3910 are_addresses_set
= true;
3912 else if (parameters
->options().user_set_Tbss()
3913 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3914 && !(*p
)->has_any_data_sections())
3916 addr
= parameters
->options().Tbss();
3917 are_addresses_set
= true;
3920 uint64_t orig_addr
= addr
;
3921 uint64_t orig_off
= off
;
3923 uint64_t aligned_addr
= 0;
3924 uint64_t abi_pagesize
= target
->abi_pagesize();
3925 uint64_t common_pagesize
= target
->common_pagesize();
3927 if (!parameters
->options().nmagic()
3928 && !parameters
->options().omagic())
3929 (*p
)->set_minimum_p_align(abi_pagesize
);
3931 if (!are_addresses_set
)
3933 // Skip the address forward one page, maintaining the same
3934 // position within the page. This lets us store both segments
3935 // overlapping on a single page in the file, but the loader will
3936 // put them on different pages in memory. We will revisit this
3937 // decision once we know the size of the segment.
3939 uint64_t max_align
= (*p
)->maximum_alignment();
3940 if (max_align
> abi_pagesize
)
3941 addr
= align_address(addr
, max_align
);
3942 aligned_addr
= addr
;
3946 // This is the segment that will contain the file
3947 // headers, so its offset will have to be exactly zero.
3948 gold_assert(orig_off
== 0);
3950 // If the target wants a fixed minimum distance from the
3951 // text segment to the read-only segment, move up now.
3953 start_addr
+ (parameters
->options().user_set_rosegment_gap()
3954 ? parameters
->options().rosegment_gap()
3955 : target
->rosegment_gap());
3956 if (addr
< min_addr
)
3959 // But this is not the first segment! To make its
3960 // address congruent with its offset, that address better
3961 // be aligned to the ABI-mandated page size.
3962 addr
= align_address(addr
, abi_pagesize
);
3963 aligned_addr
= addr
;
3967 if ((addr
& (abi_pagesize
- 1)) != 0)
3968 addr
= addr
+ abi_pagesize
;
3970 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3974 if (!parameters
->options().nmagic()
3975 && !parameters
->options().omagic())
3977 // Here we are also taking care of the case when
3978 // the maximum segment alignment is larger than the page size.
3979 off
= align_file_offset(off
, addr
,
3980 std::max(abi_pagesize
,
3981 (*p
)->maximum_alignment()));
3985 // This is -N or -n with a section script which prevents
3986 // us from using a load segment. We need to ensure that
3987 // the file offset is aligned to the alignment of the
3988 // segment. This is because the linker script
3989 // implicitly assumed a zero offset. If we don't align
3990 // here, then the alignment of the sections in the
3991 // linker script may not match the alignment of the
3992 // sections in the set_section_addresses call below,
3993 // causing an error about dot moving backward.
3994 off
= align_address(off
, (*p
)->maximum_alignment());
3997 unsigned int shndx_hold
= *pshndx
;
3998 bool has_relro
= false;
3999 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
4005 // Now that we know the size of this segment, we may be able
4006 // to save a page in memory, at the cost of wasting some
4007 // file space, by instead aligning to the start of a new
4008 // page. Here we use the real machine page size rather than
4009 // the ABI mandated page size. If the segment has been
4010 // aligned so that the relro data ends at a page boundary,
4011 // we do not try to realign it.
4013 if (!are_addresses_set
4015 && aligned_addr
!= addr
4016 && !parameters
->incremental())
4018 uint64_t first_off
= (common_pagesize
4020 & (common_pagesize
- 1)));
4021 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
4024 && ((aligned_addr
& ~ (common_pagesize
- 1))
4025 != (new_addr
& ~ (common_pagesize
- 1)))
4026 && first_off
+ last_off
<= common_pagesize
)
4028 *pshndx
= shndx_hold
;
4029 addr
= align_address(aligned_addr
, common_pagesize
);
4030 addr
= align_address(addr
, (*p
)->maximum_alignment());
4031 if ((addr
& (abi_pagesize
- 1)) != 0)
4032 addr
= addr
+ abi_pagesize
;
4033 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
4034 off
= align_file_offset(off
, addr
, abi_pagesize
);
4036 increase_relro
= this->increase_relro_
;
4037 if (this->script_options_
->saw_sections_clause())
4041 new_addr
= (*p
)->set_section_addresses(target
, this,
4051 // Implement --check-sections. We know that the segments
4052 // are sorted by LMA.
4053 if (check_sections
&& last_load_segment
!= NULL
)
4055 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
4056 if (last_load_segment
->paddr() + last_load_segment
->memsz()
4059 unsigned long long lb1
= last_load_segment
->paddr();
4060 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
4061 unsigned long long lb2
= (*p
)->paddr();
4062 unsigned long long le2
= lb2
+ (*p
)->memsz();
4063 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
4064 "[0x%llx -> 0x%llx]"),
4065 lb1
, le1
, lb2
, le2
);
4068 last_load_segment
= *p
;
4072 if (load_seg
!= NULL
&& target
->isolate_execinstr())
4074 // Process the early segments again, setting their file offsets
4075 // so they land after the segments starting at LOAD_SEG.
4076 off
= align_file_offset(off
, 0, target
->abi_pagesize());
4078 this->reset_relax_output();
4080 for (Segment_list::iterator p
= this->segment_list_
.begin();
4084 if ((*p
)->type() == elfcpp::PT_LOAD
)
4086 // We repeat the whole job of assigning addresses and
4087 // offsets, but we really only want to change the offsets and
4088 // must ensure that the addresses all come out the same as
4089 // they did the first time through.
4090 bool has_relro
= false;
4091 const uint64_t old_addr
= (*p
)->vaddr();
4092 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
4093 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
4099 gold_assert(new_addr
== old_end
);
4103 gold_assert(shndx_begin
== shndx_load_seg
);
4106 // Handle the non-PT_LOAD segments, setting their offsets from their
4107 // section's offsets.
4108 for (Segment_list::iterator p
= this->segment_list_
.begin();
4109 p
!= this->segment_list_
.end();
4112 // PT_GNU_STACK was set up correctly when it was created.
4113 if ((*p
)->type() != elfcpp::PT_LOAD
4114 && (*p
)->type() != elfcpp::PT_GNU_STACK
)
4115 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
4120 // Set the TLS offsets for each section in the PT_TLS segment.
4121 if (this->tls_segment_
!= NULL
)
4122 this->tls_segment_
->set_tls_offsets();
4127 // Set the offsets of all the allocated sections when doing a
4128 // relocatable link. This does the same jobs as set_segment_offsets,
4129 // only for a relocatable link.
4132 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
4133 unsigned int* pshndx
)
4137 file_header
->set_address_and_file_offset(0, 0);
4138 off
+= file_header
->data_size();
4140 for (Section_list::iterator p
= this->section_list_
.begin();
4141 p
!= this->section_list_
.end();
4144 // We skip unallocated sections here, except that group sections
4145 // have to come first.
4146 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
4147 && (*p
)->type() != elfcpp::SHT_GROUP
)
4150 off
= align_address(off
, (*p
)->addralign());
4152 // The linker script might have set the address.
4153 if (!(*p
)->is_address_valid())
4154 (*p
)->set_address(0);
4155 (*p
)->set_file_offset(off
);
4156 (*p
)->finalize_data_size();
4157 if ((*p
)->type() != elfcpp::SHT_NOBITS
)
4158 off
+= (*p
)->data_size();
4160 (*p
)->set_out_shndx(*pshndx
);
4167 // Set the file offset of all the sections not associated with a
4171 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
4173 off_t startoff
= off
;
4176 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
4177 p
!= this->unattached_section_list_
.end();
4180 // The symtab section is handled in create_symtab_sections.
4181 if (*p
== this->symtab_section_
)
4184 // If we've already set the data size, don't set it again.
4185 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
4188 if (pass
== BEFORE_INPUT_SECTIONS_PASS
4189 && (*p
)->requires_postprocessing())
4191 (*p
)->create_postprocessing_buffer();
4192 this->any_postprocessing_sections_
= true;
4195 if (pass
== BEFORE_INPUT_SECTIONS_PASS
4196 && (*p
)->after_input_sections())
4198 else if (pass
== POSTPROCESSING_SECTIONS_PASS
4199 && (!(*p
)->after_input_sections()
4200 || (*p
)->type() == elfcpp::SHT_STRTAB
))
4202 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
4203 && (!(*p
)->after_input_sections()
4204 || (*p
)->type() != elfcpp::SHT_STRTAB
))
4207 if (!parameters
->incremental_update())
4209 off
= align_address(off
, (*p
)->addralign());
4210 (*p
)->set_file_offset(off
);
4211 (*p
)->finalize_data_size();
4215 // Incremental update: allocate file space from free list.
4216 (*p
)->pre_finalize_data_size();
4217 off_t current_size
= (*p
)->current_data_size();
4218 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
4221 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
4222 this->free_list_
.dump();
4223 gold_assert((*p
)->output_section() != NULL
);
4224 gold_fallback(_("out of patch space for section %s; "
4225 "relink with --incremental-full"),
4226 (*p
)->output_section()->name());
4228 (*p
)->set_file_offset(off
);
4229 (*p
)->finalize_data_size();
4230 if ((*p
)->data_size() > current_size
)
4232 gold_assert((*p
)->output_section() != NULL
);
4233 gold_fallback(_("%s: section changed size; "
4234 "relink with --incremental-full"),
4235 (*p
)->output_section()->name());
4237 gold_debug(DEBUG_INCREMENTAL
,
4238 "set_section_offsets: %08lx %08lx %s",
4239 static_cast<long>(off
),
4240 static_cast<long>((*p
)->data_size()),
4241 ((*p
)->output_section() != NULL
4242 ? (*p
)->output_section()->name() : "(special)"));
4245 off
+= (*p
)->data_size();
4249 // At this point the name must be set.
4250 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
4251 this->namepool_
.add((*p
)->name(), false, NULL
);
4256 // Set the section indexes of all the sections not associated with a
4260 Layout::set_section_indexes(unsigned int shndx
)
4262 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
4263 p
!= this->unattached_section_list_
.end();
4266 if (!(*p
)->has_out_shndx())
4268 (*p
)->set_out_shndx(shndx
);
4275 // Set the section addresses according to the linker script. This is
4276 // only called when we see a SECTIONS clause. This returns the
4277 // program segment which should hold the file header and segment
4278 // headers, if any. It will return NULL if they should not be in a
4282 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
4284 Script_sections
* ss
= this->script_options_
->script_sections();
4285 gold_assert(ss
->saw_sections_clause());
4286 return this->script_options_
->set_section_addresses(symtab
, this);
4289 // Place the orphan sections in the linker script.
4292 Layout::place_orphan_sections_in_script()
4294 Script_sections
* ss
= this->script_options_
->script_sections();
4295 gold_assert(ss
->saw_sections_clause());
4297 // Place each orphaned output section in the script.
4298 for (Section_list::iterator p
= this->section_list_
.begin();
4299 p
!= this->section_list_
.end();
4302 if (!(*p
)->found_in_sections_clause())
4303 ss
->place_orphan(*p
);
4307 // Count the local symbols in the regular symbol table and the dynamic
4308 // symbol table, and build the respective string pools.
4311 Layout::count_local_symbols(const Task
* task
,
4312 const Input_objects
* input_objects
)
4314 // First, figure out an upper bound on the number of symbols we'll
4315 // be inserting into each pool. This helps us create the pools with
4316 // the right size, to avoid unnecessary hashtable resizing.
4317 unsigned int symbol_count
= 0;
4318 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4319 p
!= input_objects
->relobj_end();
4321 symbol_count
+= (*p
)->local_symbol_count();
4323 // Go from "upper bound" to "estimate." We overcount for two
4324 // reasons: we double-count symbols that occur in more than one
4325 // object file, and we count symbols that are dropped from the
4326 // output. Add it all together and assume we overcount by 100%.
4329 // We assume all symbols will go into both the sympool and dynpool.
4330 this->sympool_
.reserve(symbol_count
);
4331 this->dynpool_
.reserve(symbol_count
);
4333 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4334 p
!= input_objects
->relobj_end();
4337 Task_lock_obj
<Object
> tlo(task
, *p
);
4338 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
4342 // Create the symbol table sections. Here we also set the final
4343 // values of the symbols. At this point all the loadable sections are
4344 // fully laid out. SHNUM is the number of sections so far.
4347 Layout::create_symtab_sections(const Input_objects
* input_objects
,
4348 Symbol_table
* symtab
,
4351 unsigned int local_dynamic_count
)
4355 if (parameters
->target().get_size() == 32)
4357 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4360 else if (parameters
->target().get_size() == 64)
4362 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4368 // Compute file offsets relative to the start of the symtab section.
4371 // Save space for the dummy symbol at the start of the section. We
4372 // never bother to write this out--it will just be left as zero.
4374 unsigned int local_symbol_index
= 1;
4376 // Add STT_SECTION symbols for each Output section which needs one.
4377 for (Section_list::iterator p
= this->section_list_
.begin();
4378 p
!= this->section_list_
.end();
4381 if (!(*p
)->needs_symtab_index())
4382 (*p
)->set_symtab_index(-1U);
4385 (*p
)->set_symtab_index(local_symbol_index
);
4386 ++local_symbol_index
;
4391 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4392 p
!= input_objects
->relobj_end();
4395 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
4397 off
+= (index
- local_symbol_index
) * symsize
;
4398 local_symbol_index
= index
;
4401 unsigned int local_symcount
= local_symbol_index
;
4402 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
4406 if (this->dynsym_section_
== NULL
)
4413 off_t locsize
= local_dynamic_count
* this->dynsym_section_
->entsize();
4414 dynoff
= this->dynsym_section_
->offset() + locsize
;
4415 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
4416 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
4417 == this->dynsym_section_
->data_size() - locsize
);
4420 off_t global_off
= off
;
4421 off
= symtab
->finalize(off
, dynoff
, local_dynamic_count
, dyncount
,
4422 &this->sympool_
, &local_symcount
);
4424 if (!parameters
->options().strip_all())
4426 this->sympool_
.set_string_offsets();
4428 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
4429 Output_section
* osymtab
= this->make_output_section(symtab_name
,
4433 this->symtab_section_
= osymtab
;
4435 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
4437 osymtab
->add_output_section_data(pos
);
4439 // We generate a .symtab_shndx section if we have more than
4440 // SHN_LORESERVE sections. Technically it is possible that we
4441 // don't need one, because it is possible that there are no
4442 // symbols in any of sections with indexes larger than
4443 // SHN_LORESERVE. That is probably unusual, though, and it is
4444 // easier to always create one than to compute section indexes
4445 // twice (once here, once when writing out the symbols).
4446 if (shnum
>= elfcpp::SHN_LORESERVE
)
4448 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
4450 Output_section
* osymtab_xindex
=
4451 this->make_output_section(symtab_xindex_name
,
4452 elfcpp::SHT_SYMTAB_SHNDX
, 0,
4453 ORDER_INVALID
, false);
4455 size_t symcount
= off
/ symsize
;
4456 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
4458 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
4460 osymtab_xindex
->set_link_section(osymtab
);
4461 osymtab_xindex
->set_addralign(4);
4462 osymtab_xindex
->set_entsize(4);
4464 osymtab_xindex
->set_after_input_sections();
4466 // This tells the driver code to wait until the symbol table
4467 // has written out before writing out the postprocessing
4468 // sections, including the .symtab_shndx section.
4469 this->any_postprocessing_sections_
= true;
4472 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
4473 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
4478 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
4479 ostrtab
->add_output_section_data(pstr
);
4482 if (!parameters
->incremental_update())
4483 symtab_off
= align_address(*poff
, align
);
4486 symtab_off
= this->allocate(off
, align
, *poff
);
4488 gold_fallback(_("out of patch space for symbol table; "
4489 "relink with --incremental-full"));
4490 gold_debug(DEBUG_INCREMENTAL
,
4491 "create_symtab_sections: %08lx %08lx .symtab",
4492 static_cast<long>(symtab_off
),
4493 static_cast<long>(off
));
4496 symtab
->set_file_offset(symtab_off
+ global_off
);
4497 osymtab
->set_file_offset(symtab_off
);
4498 osymtab
->finalize_data_size();
4499 osymtab
->set_link_section(ostrtab
);
4500 osymtab
->set_info(local_symcount
);
4501 osymtab
->set_entsize(symsize
);
4503 if (symtab_off
+ off
> *poff
)
4504 *poff
= symtab_off
+ off
;
4508 // Create the .shstrtab section, which holds the names of the
4509 // sections. At the time this is called, we have created all the
4510 // output sections except .shstrtab itself.
4513 Layout::create_shstrtab()
4515 // FIXME: We don't need to create a .shstrtab section if we are
4516 // stripping everything.
4518 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
4520 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
4521 ORDER_INVALID
, false);
4523 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
4525 // We can't write out this section until we've set all the
4526 // section names, and we don't set the names of compressed
4527 // output sections until relocations are complete. FIXME: With
4528 // the current names we use, this is unnecessary.
4529 os
->set_after_input_sections();
4532 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
4533 os
->add_output_section_data(posd
);
4538 // Create the section headers. SIZE is 32 or 64. OFF is the file
4542 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
4544 Output_section_headers
* oshdrs
;
4545 oshdrs
= new Output_section_headers(this,
4546 &this->segment_list_
,
4547 &this->section_list_
,
4548 &this->unattached_section_list_
,
4552 if (!parameters
->incremental_update())
4553 off
= align_address(*poff
, oshdrs
->addralign());
4556 oshdrs
->pre_finalize_data_size();
4557 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
4559 gold_fallback(_("out of patch space for section header table; "
4560 "relink with --incremental-full"));
4561 gold_debug(DEBUG_INCREMENTAL
,
4562 "create_shdrs: %08lx %08lx (section header table)",
4563 static_cast<long>(off
),
4564 static_cast<long>(off
+ oshdrs
->data_size()));
4566 oshdrs
->set_address_and_file_offset(0, off
);
4567 off
+= oshdrs
->data_size();
4570 this->section_headers_
= oshdrs
;
4573 // Count the allocated sections.
4576 Layout::allocated_output_section_count() const
4578 size_t section_count
= 0;
4579 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4580 p
!= this->segment_list_
.end();
4582 section_count
+= (*p
)->output_section_count();
4583 return section_count
;
4586 // Create the dynamic symbol table.
4587 // *PLOCAL_DYNAMIC_COUNT will be set to the number of local symbols
4588 // from input objects, and *PFORCED_LOCAL_DYNAMIC_COUNT will be set
4589 // to the number of global symbols that have been forced local.
4590 // We need to remember the former because the forced-local symbols are
4591 // written along with the global symbols in Symtab::write_globals().
4594 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4595 Symbol_table
* symtab
,
4596 Output_section
** pdynstr
,
4597 unsigned int* plocal_dynamic_count
,
4598 unsigned int* pforced_local_dynamic_count
,
4599 std::vector
<Symbol
*>* pdynamic_symbols
,
4600 Versions
* pversions
)
4602 // Count all the symbols in the dynamic symbol table, and set the
4603 // dynamic symbol indexes.
4605 // Skip symbol 0, which is always all zeroes.
4606 unsigned int index
= 1;
4608 // Add STT_SECTION symbols for each Output section which needs one.
4609 for (Section_list::iterator p
= this->section_list_
.begin();
4610 p
!= this->section_list_
.end();
4613 if (!(*p
)->needs_dynsym_index())
4614 (*p
)->set_dynsym_index(-1U);
4617 (*p
)->set_dynsym_index(index
);
4622 // Count the local symbols that need to go in the dynamic symbol table,
4623 // and set the dynamic symbol indexes.
4624 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4625 p
!= input_objects
->relobj_end();
4628 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4632 unsigned int local_symcount
= index
;
4633 unsigned int forced_local_count
= 0;
4635 index
= symtab
->set_dynsym_indexes(index
, &forced_local_count
,
4636 pdynamic_symbols
, &this->dynpool_
,
4639 *plocal_dynamic_count
= local_symcount
;
4640 *pforced_local_dynamic_count
= forced_local_count
;
4644 const int size
= parameters
->target().get_size();
4647 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4650 else if (size
== 64)
4652 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4658 // Create the dynamic symbol table section.
4660 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4664 ORDER_DYNAMIC_LINKER
,
4665 false, false, false);
4667 // Check for NULL as a linker script may discard .dynsym.
4670 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4673 dynsym
->add_output_section_data(odata
);
4675 dynsym
->set_info(local_symcount
+ forced_local_count
);
4676 dynsym
->set_entsize(symsize
);
4677 dynsym
->set_addralign(align
);
4679 this->dynsym_section_
= dynsym
;
4682 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4685 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4686 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4689 // If there are more than SHN_LORESERVE allocated sections, we
4690 // create a .dynsym_shndx section. It is possible that we don't
4691 // need one, because it is possible that there are no dynamic
4692 // symbols in any of the sections with indexes larger than
4693 // SHN_LORESERVE. This is probably unusual, though, and at this
4694 // time we don't know the actual section indexes so it is
4695 // inconvenient to check.
4696 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4698 Output_section
* dynsym_xindex
=
4699 this->choose_output_section(NULL
, ".dynsym_shndx",
4700 elfcpp::SHT_SYMTAB_SHNDX
,
4702 false, ORDER_DYNAMIC_LINKER
, false, false,
4705 if (dynsym_xindex
!= NULL
)
4707 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4709 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4711 dynsym_xindex
->set_link_section(dynsym
);
4712 dynsym_xindex
->set_addralign(4);
4713 dynsym_xindex
->set_entsize(4);
4715 dynsym_xindex
->set_after_input_sections();
4717 // This tells the driver code to wait until the symbol table
4718 // has written out before writing out the postprocessing
4719 // sections, including the .dynsym_shndx section.
4720 this->any_postprocessing_sections_
= true;
4724 // Create the dynamic string table section.
4726 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4730 ORDER_DYNAMIC_LINKER
,
4731 false, false, false);
4735 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4736 dynstr
->add_output_section_data(strdata
);
4739 dynsym
->set_link_section(dynstr
);
4740 if (this->dynamic_section_
!= NULL
)
4741 this->dynamic_section_
->set_link_section(dynstr
);
4745 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4746 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4750 // Create the hash tables. The Gnu-style hash table must be
4751 // built first, because it changes the order of the symbols
4752 // in the dynamic symbol table.
4754 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4755 || strcmp(parameters
->options().hash_style(), "both") == 0)
4757 unsigned char* phash
;
4758 unsigned int hashlen
;
4759 Dynobj::create_gnu_hash_table(*pdynamic_symbols
,
4760 local_symcount
+ forced_local_count
,
4763 Output_section
* hashsec
=
4764 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4765 elfcpp::SHF_ALLOC
, false,
4766 ORDER_DYNAMIC_LINKER
, false, false,
4769 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4773 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4774 hashsec
->add_output_section_data(hashdata
);
4776 if (hashsec
!= NULL
)
4779 hashsec
->set_link_section(dynsym
);
4781 // For a 64-bit target, the entries in .gnu.hash do not have
4782 // a uniform size, so we only set the entry size for a
4784 if (parameters
->target().get_size() == 32)
4785 hashsec
->set_entsize(4);
4788 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4792 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4793 || strcmp(parameters
->options().hash_style(), "both") == 0)
4795 unsigned char* phash
;
4796 unsigned int hashlen
;
4797 Dynobj::create_elf_hash_table(*pdynamic_symbols
,
4798 local_symcount
+ forced_local_count
,
4801 Output_section
* hashsec
=
4802 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4803 elfcpp::SHF_ALLOC
, false,
4804 ORDER_DYNAMIC_LINKER
, false, false,
4807 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4811 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4812 hashsec
->add_output_section_data(hashdata
);
4814 if (hashsec
!= NULL
)
4817 hashsec
->set_link_section(dynsym
);
4818 hashsec
->set_entsize(parameters
->target().hash_entry_size() / 8);
4822 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4826 // Assign offsets to each local portion of the dynamic symbol table.
4829 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4831 Output_section
* dynsym
= this->dynsym_section_
;
4835 off_t off
= dynsym
->offset();
4837 // Skip the dummy symbol at the start of the section.
4838 off
+= dynsym
->entsize();
4840 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4841 p
!= input_objects
->relobj_end();
4844 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4845 off
+= count
* dynsym
->entsize();
4849 // Create the version sections.
4852 Layout::create_version_sections(const Versions
* versions
,
4853 const Symbol_table
* symtab
,
4854 unsigned int local_symcount
,
4855 const std::vector
<Symbol
*>& dynamic_symbols
,
4856 const Output_section
* dynstr
)
4858 if (!versions
->any_defs() && !versions
->any_needs())
4861 switch (parameters
->size_and_endianness())
4863 #ifdef HAVE_TARGET_32_LITTLE
4864 case Parameters::TARGET_32_LITTLE
:
4865 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4867 dynamic_symbols
, dynstr
);
4870 #ifdef HAVE_TARGET_32_BIG
4871 case Parameters::TARGET_32_BIG
:
4872 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4874 dynamic_symbols
, dynstr
);
4877 #ifdef HAVE_TARGET_64_LITTLE
4878 case Parameters::TARGET_64_LITTLE
:
4879 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4881 dynamic_symbols
, dynstr
);
4884 #ifdef HAVE_TARGET_64_BIG
4885 case Parameters::TARGET_64_BIG
:
4886 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4888 dynamic_symbols
, dynstr
);
4896 // Create the version sections, sized version.
4898 template<int size
, bool big_endian
>
4900 Layout::sized_create_version_sections(
4901 const Versions
* versions
,
4902 const Symbol_table
* symtab
,
4903 unsigned int local_symcount
,
4904 const std::vector
<Symbol
*>& dynamic_symbols
,
4905 const Output_section
* dynstr
)
4907 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4908 elfcpp::SHT_GNU_versym
,
4911 ORDER_DYNAMIC_LINKER
,
4912 false, false, false);
4914 // Check for NULL since a linker script may discard this section.
4917 unsigned char* vbuf
;
4919 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4925 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4928 vsec
->add_output_section_data(vdata
);
4929 vsec
->set_entsize(2);
4930 vsec
->set_link_section(this->dynsym_section_
);
4933 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4934 if (odyn
!= NULL
&& vsec
!= NULL
)
4935 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4937 if (versions
->any_defs())
4939 Output_section
* vdsec
;
4940 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4941 elfcpp::SHT_GNU_verdef
,
4943 false, ORDER_DYNAMIC_LINKER
, false,
4948 unsigned char* vdbuf
;
4949 unsigned int vdsize
;
4950 unsigned int vdentries
;
4951 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4955 Output_section_data
* vddata
=
4956 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4958 vdsec
->add_output_section_data(vddata
);
4959 vdsec
->set_link_section(dynstr
);
4960 vdsec
->set_info(vdentries
);
4964 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4965 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4970 if (versions
->any_needs())
4972 Output_section
* vnsec
;
4973 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4974 elfcpp::SHT_GNU_verneed
,
4976 false, ORDER_DYNAMIC_LINKER
, false,
4981 unsigned char* vnbuf
;
4982 unsigned int vnsize
;
4983 unsigned int vnentries
;
4984 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4988 Output_section_data
* vndata
=
4989 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4991 vnsec
->add_output_section_data(vndata
);
4992 vnsec
->set_link_section(dynstr
);
4993 vnsec
->set_info(vnentries
);
4997 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4998 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
5004 // Create the .interp section and PT_INTERP segment.
5007 Layout::create_interp(const Target
* target
)
5009 gold_assert(this->interp_segment_
== NULL
);
5011 const char* interp
= parameters
->options().dynamic_linker();
5014 interp
= target
->dynamic_linker();
5015 gold_assert(interp
!= NULL
);
5018 size_t len
= strlen(interp
) + 1;
5020 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
5022 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
5023 elfcpp::SHT_PROGBITS
,
5025 false, ORDER_INTERP
,
5026 false, false, false);
5028 osec
->add_output_section_data(odata
);
5031 // Add dynamic tags for the PLT and the dynamic relocs. This is
5032 // called by the target-specific code. This does nothing if not doing
5035 // USE_REL is true for REL relocs rather than RELA relocs.
5037 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
5039 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
5040 // and we also set DT_PLTREL. We use PLT_REL's output section, since
5041 // some targets have multiple reloc sections in PLT_REL.
5043 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
5044 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
5047 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
5051 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
5052 const Output_data
* plt_rel
,
5053 const Output_data_reloc_generic
* dyn_rel
,
5054 bool add_debug
, bool dynrel_includes_plt
)
5056 Output_data_dynamic
* odyn
= this->dynamic_data_
;
5060 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
5061 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
5063 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
5065 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
5066 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
5067 odyn
->add_constant(elfcpp::DT_PLTREL
,
5068 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
5071 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
5072 || (dynrel_includes_plt
5074 && plt_rel
->output_section() != NULL
))
5076 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
5077 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
5078 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
5080 ? dyn_rel
->output_section()
5081 : plt_rel
->output_section()));
5082 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
5083 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
5084 odyn
->add_section_size(size_tag
,
5085 dyn_rel
->output_section(),
5086 plt_rel
->output_section());
5087 else if (have_dyn_rel
)
5088 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
5090 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
5091 const int size
= parameters
->target().get_size();
5096 rel_tag
= elfcpp::DT_RELENT
;
5098 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
5099 else if (size
== 64)
5100 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
5106 rel_tag
= elfcpp::DT_RELAENT
;
5108 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
5109 else if (size
== 64)
5110 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
5114 odyn
->add_constant(rel_tag
, rel_size
);
5116 if (parameters
->options().combreloc() && have_dyn_rel
)
5118 size_t c
= dyn_rel
->relative_reloc_count();
5120 odyn
->add_constant((use_rel
5121 ? elfcpp::DT_RELCOUNT
5122 : elfcpp::DT_RELACOUNT
),
5127 if (add_debug
&& !parameters
->options().shared())
5129 // The value of the DT_DEBUG tag is filled in by the dynamic
5130 // linker at run time, and used by the debugger.
5131 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
5136 Layout::add_target_specific_dynamic_tag(elfcpp::DT tag
, unsigned int val
)
5138 Output_data_dynamic
* odyn
= this->dynamic_data_
;
5141 odyn
->add_constant(tag
, val
);
5144 // Finish the .dynamic section and PT_DYNAMIC segment.
5147 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
5148 const Symbol_table
* symtab
)
5150 if (!this->script_options_
->saw_phdrs_clause()
5151 && this->dynamic_section_
!= NULL
)
5153 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
5156 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
5157 elfcpp::PF_R
| elfcpp::PF_W
);
5160 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
5164 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
5165 p
!= input_objects
->dynobj_end();
5168 if (!(*p
)->is_needed() && (*p
)->as_needed())
5170 // This dynamic object was linked with --as-needed, but it
5175 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
5178 if (parameters
->options().shared())
5180 const char* soname
= parameters
->options().soname();
5182 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
5185 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
5186 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
5187 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
5189 sym
= symtab
->lookup(parameters
->options().fini());
5190 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
5191 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
5193 // Look for .init_array, .preinit_array and .fini_array by checking
5195 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
5196 p
!= this->section_list_
.end();
5198 switch((*p
)->type())
5200 case elfcpp::SHT_FINI_ARRAY
:
5201 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
5202 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
5204 case elfcpp::SHT_INIT_ARRAY
:
5205 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
5206 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
5208 case elfcpp::SHT_PREINIT_ARRAY
:
5209 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
5210 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
5216 // Add a DT_RPATH entry if needed.
5217 const General_options::Dir_list
& rpath(parameters
->options().rpath());
5220 std::string rpath_val
;
5221 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
5225 if (rpath_val
.empty())
5226 rpath_val
= p
->name();
5229 // Eliminate duplicates.
5230 General_options::Dir_list::const_iterator q
;
5231 for (q
= rpath
.begin(); q
!= p
; ++q
)
5232 if (q
->name() == p
->name())
5237 rpath_val
+= p
->name();
5242 if (!parameters
->options().enable_new_dtags())
5243 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
5245 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
5248 // Look for text segments that have dynamic relocations.
5249 bool have_textrel
= false;
5250 if (!this->script_options_
->saw_sections_clause())
5252 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5253 p
!= this->segment_list_
.end();
5256 if ((*p
)->type() == elfcpp::PT_LOAD
5257 && ((*p
)->flags() & elfcpp::PF_W
) == 0
5258 && (*p
)->has_dynamic_reloc())
5260 have_textrel
= true;
5267 // We don't know the section -> segment mapping, so we are
5268 // conservative and just look for readonly sections with
5269 // relocations. If those sections wind up in writable segments,
5270 // then we have created an unnecessary DT_TEXTREL entry.
5271 for (Section_list::const_iterator p
= this->section_list_
.begin();
5272 p
!= this->section_list_
.end();
5275 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
5276 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
5277 && (*p
)->has_dynamic_reloc())
5279 have_textrel
= true;
5285 if (parameters
->options().filter() != NULL
)
5286 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
5287 if (parameters
->options().any_auxiliary())
5289 for (options::String_set::const_iterator p
=
5290 parameters
->options().auxiliary_begin();
5291 p
!= parameters
->options().auxiliary_end();
5293 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
5296 // Add a DT_FLAGS entry if necessary.
5297 unsigned int flags
= 0;
5300 // Add a DT_TEXTREL for compatibility with older loaders.
5301 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
5302 flags
|= elfcpp::DF_TEXTREL
;
5304 if (parameters
->options().text())
5305 gold_error(_("read-only segment has dynamic relocations"));
5306 else if (parameters
->options().warn_shared_textrel()
5307 && parameters
->options().shared())
5308 gold_warning(_("shared library text segment is not shareable"));
5310 if (parameters
->options().shared() && this->has_static_tls())
5311 flags
|= elfcpp::DF_STATIC_TLS
;
5312 if (parameters
->options().origin())
5313 flags
|= elfcpp::DF_ORIGIN
;
5314 if (parameters
->options().Bsymbolic()
5315 && !parameters
->options().have_dynamic_list())
5317 flags
|= elfcpp::DF_SYMBOLIC
;
5318 // Add DT_SYMBOLIC for compatibility with older loaders.
5319 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
5321 if (parameters
->options().now())
5322 flags
|= elfcpp::DF_BIND_NOW
;
5324 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
5327 if (parameters
->options().global())
5328 flags
|= elfcpp::DF_1_GLOBAL
;
5329 if (parameters
->options().initfirst())
5330 flags
|= elfcpp::DF_1_INITFIRST
;
5331 if (parameters
->options().interpose())
5332 flags
|= elfcpp::DF_1_INTERPOSE
;
5333 if (parameters
->options().loadfltr())
5334 flags
|= elfcpp::DF_1_LOADFLTR
;
5335 if (parameters
->options().nodefaultlib())
5336 flags
|= elfcpp::DF_1_NODEFLIB
;
5337 if (parameters
->options().nodelete())
5338 flags
|= elfcpp::DF_1_NODELETE
;
5339 if (parameters
->options().nodlopen())
5340 flags
|= elfcpp::DF_1_NOOPEN
;
5341 if (parameters
->options().nodump())
5342 flags
|= elfcpp::DF_1_NODUMP
;
5343 if (!parameters
->options().shared())
5344 flags
&= ~(elfcpp::DF_1_INITFIRST
5345 | elfcpp::DF_1_NODELETE
5346 | elfcpp::DF_1_NOOPEN
);
5347 if (parameters
->options().origin())
5348 flags
|= elfcpp::DF_1_ORIGIN
;
5349 if (parameters
->options().now())
5350 flags
|= elfcpp::DF_1_NOW
;
5351 if (parameters
->options().Bgroup())
5352 flags
|= elfcpp::DF_1_GROUP
;
5354 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
5357 // Set the size of the _DYNAMIC symbol table to be the size of the
5361 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
5363 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
5366 odyn
->finalize_data_size();
5367 if (this->dynamic_symbol_
== NULL
)
5369 off_t data_size
= odyn
->data_size();
5370 const int size
= parameters
->target().get_size();
5372 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
5373 else if (size
== 64)
5374 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
5379 // The mapping of input section name prefixes to output section names.
5380 // In some cases one prefix is itself a prefix of another prefix; in
5381 // such a case the longer prefix must come first. These prefixes are
5382 // based on the GNU linker default ELF linker script.
5384 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
5385 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
5386 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
5388 MAPPING_INIT(".text.", ".text"),
5389 MAPPING_INIT(".rodata.", ".rodata"),
5390 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
5391 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
5392 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
5393 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
5394 MAPPING_INIT(".data.", ".data"),
5395 MAPPING_INIT(".bss.", ".bss"),
5396 MAPPING_INIT(".tdata.", ".tdata"),
5397 MAPPING_INIT(".tbss.", ".tbss"),
5398 MAPPING_INIT(".init_array.", ".init_array"),
5399 MAPPING_INIT(".fini_array.", ".fini_array"),
5400 MAPPING_INIT(".sdata.", ".sdata"),
5401 MAPPING_INIT(".sbss.", ".sbss"),
5402 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
5403 // differently depending on whether it is creating a shared library.
5404 MAPPING_INIT(".sdata2.", ".sdata"),
5405 MAPPING_INIT(".sbss2.", ".sbss"),
5406 MAPPING_INIT(".lrodata.", ".lrodata"),
5407 MAPPING_INIT(".ldata.", ".ldata"),
5408 MAPPING_INIT(".lbss.", ".lbss"),
5409 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
5410 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
5411 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
5412 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
5413 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
5414 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
5415 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
5416 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
5417 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
5418 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
5419 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
5420 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
5421 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
5422 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
5423 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
5424 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5425 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5426 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5427 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5428 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5429 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5430 MAPPING_INIT(".gnu.build.attributes.", ".gnu.build.attributes"),
5433 // Mapping for ".text" section prefixes with -z,keep-text-section-prefix.
5434 const Layout::Section_name_mapping
Layout::text_section_name_mapping
[] =
5436 MAPPING_INIT(".text.hot.", ".text.hot"),
5437 MAPPING_INIT_EXACT(".text.hot", ".text.hot"),
5438 MAPPING_INIT(".text.unlikely.", ".text.unlikely"),
5439 MAPPING_INIT_EXACT(".text.unlikely", ".text.unlikely"),
5440 MAPPING_INIT(".text.startup.", ".text.startup"),
5441 MAPPING_INIT_EXACT(".text.startup", ".text.startup"),
5442 MAPPING_INIT(".text.exit.", ".text.exit"),
5443 MAPPING_INIT_EXACT(".text.exit", ".text.exit"),
5444 MAPPING_INIT(".text.", ".text"),
5447 #undef MAPPING_INIT_EXACT
5449 const int Layout::section_name_mapping_count
=
5450 (sizeof(Layout::section_name_mapping
)
5451 / sizeof(Layout::section_name_mapping
[0]));
5453 const int Layout::text_section_name_mapping_count
=
5454 (sizeof(Layout::text_section_name_mapping
)
5455 / sizeof(Layout::text_section_name_mapping
[0]));
5457 // Find section name NAME in PSNM and return the mapped name if found
5458 // with the length set in PLEN.
5460 Layout::match_section_name(const Layout::Section_name_mapping
* psnm
,
5462 const char* name
, size_t* plen
)
5464 for (int i
= 0; i
< count
; ++i
, ++psnm
)
5466 if (psnm
->fromlen
> 0)
5468 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
5470 *plen
= psnm
->tolen
;
5476 if (strcmp(name
, psnm
->from
) == 0)
5478 *plen
= psnm
->tolen
;
5486 // Choose the output section name to use given an input section name.
5487 // Set *PLEN to the length of the name. *PLEN is initialized to the
5491 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
5494 // gcc 4.3 generates the following sorts of section names when it
5495 // needs a section name specific to a function:
5501 // .data.rel.local.FN
5503 // .data.rel.ro.local.FN
5510 // The GNU linker maps all of those to the part before the .FN,
5511 // except that .data.rel.local.FN is mapped to .data, and
5512 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5513 // beginning with .data.rel.ro.local are grouped together.
5515 // For an anonymous namespace, the string FN can contain a '.'.
5517 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5518 // GNU linker maps to .rodata.
5520 // The .data.rel.ro sections are used with -z relro. The sections
5521 // are recognized by name. We use the same names that the GNU
5522 // linker does for these sections.
5524 // It is hard to handle this in a principled way, so we don't even
5525 // try. We use a table of mappings. If the input section name is
5526 // not found in the table, we simply use it as the output section
5529 if (parameters
->options().keep_text_section_prefix()
5530 && is_prefix_of(".text", name
))
5532 const char* match
= match_section_name(text_section_name_mapping
,
5533 text_section_name_mapping_count
,
5539 const char* match
= match_section_name(section_name_mapping
,
5540 section_name_mapping_count
, name
, plen
);
5544 // As an additional complication, .ctors sections are output in
5545 // either .ctors or .init_array sections, and .dtors sections are
5546 // output in either .dtors or .fini_array sections.
5547 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
5549 if (parameters
->options().ctors_in_init_array())
5552 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5557 return name
[1] == 'c' ? ".ctors" : ".dtors";
5560 if (parameters
->options().ctors_in_init_array()
5561 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
5563 // To make .init_array/.fini_array work with gcc we must exclude
5564 // .ctors and .dtors sections from the crtbegin and crtend
5567 || (!Layout::match_file_name(relobj
, "crtbegin")
5568 && !Layout::match_file_name(relobj
, "crtend")))
5571 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5578 // Return true if RELOBJ is an input file whose base name matches
5579 // FILE_NAME. The base name must have an extension of ".o", and must
5580 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5581 // to match crtbegin.o as well as crtbeginS.o without getting confused
5582 // by other possibilities. Overall matching the file name this way is
5583 // a dreadful hack, but the GNU linker does it in order to better
5584 // support gcc, and we need to be compatible.
5587 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
5589 const std::string
& file_name(relobj
->name());
5590 const char* base_name
= lbasename(file_name
.c_str());
5591 size_t match_len
= strlen(match
);
5592 if (strncmp(base_name
, match
, match_len
) != 0)
5594 size_t base_len
= strlen(base_name
);
5595 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
5597 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
5600 // Check if a comdat group or .gnu.linkonce section with the given
5601 // NAME is selected for the link. If there is already a section,
5602 // *KEPT_SECTION is set to point to the existing section and the
5603 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5604 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5605 // *KEPT_SECTION is set to the internal copy and the function returns
5609 Layout::find_or_add_kept_section(const std::string
& name
,
5614 Kept_section
** kept_section
)
5616 // It's normal to see a couple of entries here, for the x86 thunk
5617 // sections. If we see more than a few, we're linking a C++
5618 // program, and we resize to get more space to minimize rehashing.
5619 if (this->signatures_
.size() > 4
5620 && !this->resized_signatures_
)
5622 reserve_unordered_map(&this->signatures_
,
5623 this->number_of_input_files_
* 64);
5624 this->resized_signatures_
= true;
5627 Kept_section candidate
;
5628 std::pair
<Signatures::iterator
, bool> ins
=
5629 this->signatures_
.insert(std::make_pair(name
, candidate
));
5631 if (kept_section
!= NULL
)
5632 *kept_section
= &ins
.first
->second
;
5635 // This is the first time we've seen this signature.
5636 ins
.first
->second
.set_object(object
);
5637 ins
.first
->second
.set_shndx(shndx
);
5639 ins
.first
->second
.set_is_comdat();
5641 ins
.first
->second
.set_is_group_name();
5645 // We have already seen this signature.
5647 if (ins
.first
->second
.is_group_name())
5649 // We've already seen a real section group with this signature.
5650 // If the kept group is from a plugin object, and we're in the
5651 // replacement phase, accept the new one as a replacement.
5652 if (ins
.first
->second
.object() == NULL
5653 && parameters
->options().plugins()->in_replacement_phase())
5655 ins
.first
->second
.set_object(object
);
5656 ins
.first
->second
.set_shndx(shndx
);
5661 else if (is_group_name
)
5663 // This is a real section group, and we've already seen a
5664 // linkonce section with this signature. Record that we've seen
5665 // a section group, and don't include this section group.
5666 ins
.first
->second
.set_is_group_name();
5671 // We've already seen a linkonce section and this is a linkonce
5672 // section. These don't block each other--this may be the same
5673 // symbol name with different section types.
5678 // Store the allocated sections into the section list.
5681 Layout::get_allocated_sections(Section_list
* section_list
) const
5683 for (Section_list::const_iterator p
= this->section_list_
.begin();
5684 p
!= this->section_list_
.end();
5686 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5687 section_list
->push_back(*p
);
5690 // Store the executable sections into the section list.
5693 Layout::get_executable_sections(Section_list
* section_list
) const
5695 for (Section_list::const_iterator p
= this->section_list_
.begin();
5696 p
!= this->section_list_
.end();
5698 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5699 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5700 section_list
->push_back(*p
);
5703 // Create an output segment.
5706 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5708 gold_assert(!parameters
->options().relocatable());
5709 Output_segment
* oseg
= new Output_segment(type
, flags
);
5710 this->segment_list_
.push_back(oseg
);
5712 if (type
== elfcpp::PT_TLS
)
5713 this->tls_segment_
= oseg
;
5714 else if (type
== elfcpp::PT_GNU_RELRO
)
5715 this->relro_segment_
= oseg
;
5716 else if (type
== elfcpp::PT_INTERP
)
5717 this->interp_segment_
= oseg
;
5722 // Return the file offset of the normal symbol table.
5725 Layout::symtab_section_offset() const
5727 if (this->symtab_section_
!= NULL
)
5728 return this->symtab_section_
->offset();
5732 // Return the section index of the normal symbol table. It may have
5733 // been stripped by the -s/--strip-all option.
5736 Layout::symtab_section_shndx() const
5738 if (this->symtab_section_
!= NULL
)
5739 return this->symtab_section_
->out_shndx();
5743 // Write out the Output_sections. Most won't have anything to write,
5744 // since most of the data will come from input sections which are
5745 // handled elsewhere. But some Output_sections do have Output_data.
5748 Layout::write_output_sections(Output_file
* of
) const
5750 for (Section_list::const_iterator p
= this->section_list_
.begin();
5751 p
!= this->section_list_
.end();
5754 if (!(*p
)->after_input_sections())
5759 // Write out data not associated with a section or the symbol table.
5762 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5764 if (!parameters
->options().strip_all())
5766 const Output_section
* symtab_section
= this->symtab_section_
;
5767 for (Section_list::const_iterator p
= this->section_list_
.begin();
5768 p
!= this->section_list_
.end();
5771 if ((*p
)->needs_symtab_index())
5773 gold_assert(symtab_section
!= NULL
);
5774 unsigned int index
= (*p
)->symtab_index();
5775 gold_assert(index
> 0 && index
!= -1U);
5776 off_t off
= (symtab_section
->offset()
5777 + index
* symtab_section
->entsize());
5778 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5783 const Output_section
* dynsym_section
= this->dynsym_section_
;
5784 for (Section_list::const_iterator p
= this->section_list_
.begin();
5785 p
!= this->section_list_
.end();
5788 if ((*p
)->needs_dynsym_index())
5790 gold_assert(dynsym_section
!= NULL
);
5791 unsigned int index
= (*p
)->dynsym_index();
5792 gold_assert(index
> 0 && index
!= -1U);
5793 off_t off
= (dynsym_section
->offset()
5794 + index
* dynsym_section
->entsize());
5795 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5799 // Write out the Output_data which are not in an Output_section.
5800 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5801 p
!= this->special_output_list_
.end();
5805 // Write out the Output_data which are not in an Output_section
5806 // and are regenerated in each iteration of relaxation.
5807 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
5808 p
!= this->relax_output_list_
.end();
5813 // Write out the Output_sections which can only be written after the
5814 // input sections are complete.
5817 Layout::write_sections_after_input_sections(Output_file
* of
)
5819 // Determine the final section offsets, and thus the final output
5820 // file size. Note we finalize the .shstrab last, to allow the
5821 // after_input_section sections to modify their section-names before
5823 if (this->any_postprocessing_sections_
)
5825 off_t off
= this->output_file_size_
;
5826 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5828 // Now that we've finalized the names, we can finalize the shstrab.
5830 this->set_section_offsets(off
,
5831 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5833 if (off
> this->output_file_size_
)
5836 this->output_file_size_
= off
;
5840 for (Section_list::const_iterator p
= this->section_list_
.begin();
5841 p
!= this->section_list_
.end();
5844 if ((*p
)->after_input_sections())
5848 this->section_headers_
->write(of
);
5851 // If a tree-style build ID was requested, the parallel part of that computation
5852 // is already done, and the final hash-of-hashes is computed here. For other
5853 // types of build IDs, all the work is done here.
5856 Layout::write_build_id(Output_file
* of
, unsigned char* array_of_hashes
,
5857 size_t size_of_hashes
) const
5859 if (this->build_id_note_
== NULL
)
5862 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5863 this->build_id_note_
->data_size());
5865 if (array_of_hashes
== NULL
)
5867 const size_t output_file_size
= this->output_file_size();
5868 const unsigned char* iv
= of
->get_input_view(0, output_file_size
);
5869 const char* style
= parameters
->options().build_id();
5871 // If we get here with style == "tree" then the output must be
5872 // too small for chunking, and we use SHA-1 in that case.
5873 if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
5874 sha1_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5875 else if (strcmp(style
, "md5") == 0)
5876 md5_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5880 of
->free_input_view(0, output_file_size
, iv
);
5884 // Non-overlapping substrings of the output file have been hashed.
5885 // Compute SHA-1 hash of the hashes.
5886 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes
),
5887 size_of_hashes
, ov
);
5888 delete[] array_of_hashes
;
5891 of
->write_output_view(this->build_id_note_
->offset(),
5892 this->build_id_note_
->data_size(),
5896 // Write out a binary file. This is called after the link is
5897 // complete. IN is the temporary output file we used to generate the
5898 // ELF code. We simply walk through the segments, read them from
5899 // their file offset in IN, and write them to their load address in
5900 // the output file. FIXME: with a bit more work, we could support
5901 // S-records and/or Intel hex format here.
5904 Layout::write_binary(Output_file
* in
) const
5906 gold_assert(parameters
->options().oformat_enum()
5907 == General_options::OBJECT_FORMAT_BINARY
);
5909 // Get the size of the binary file.
5910 uint64_t max_load_address
= 0;
5911 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5912 p
!= this->segment_list_
.end();
5915 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5917 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5918 if (max_paddr
> max_load_address
)
5919 max_load_address
= max_paddr
;
5923 Output_file
out(parameters
->options().output_file_name());
5924 out
.open(max_load_address
);
5926 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5927 p
!= this->segment_list_
.end();
5930 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5932 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5934 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5936 memcpy(vout
, vin
, (*p
)->filesz());
5937 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5938 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5945 // Print the output sections to the map file.
5948 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5950 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5951 p
!= this->segment_list_
.end();
5953 (*p
)->print_sections_to_mapfile(mapfile
);
5954 for (Section_list::const_iterator p
= this->unattached_section_list_
.begin();
5955 p
!= this->unattached_section_list_
.end();
5957 (*p
)->print_to_mapfile(mapfile
);
5960 // Print statistical information to stderr. This is used for --stats.
5963 Layout::print_stats() const
5965 this->namepool_
.print_stats("section name pool");
5966 this->sympool_
.print_stats("output symbol name pool");
5967 this->dynpool_
.print_stats("dynamic name pool");
5969 for (Section_list::const_iterator p
= this->section_list_
.begin();
5970 p
!= this->section_list_
.end();
5972 (*p
)->print_merge_stats();
5975 // Write_sections_task methods.
5977 // We can always run this task.
5980 Write_sections_task::is_runnable()
5985 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5989 Write_sections_task::locks(Task_locker
* tl
)
5991 tl
->add(this, this->output_sections_blocker_
);
5992 if (this->input_sections_blocker_
!= NULL
)
5993 tl
->add(this, this->input_sections_blocker_
);
5994 tl
->add(this, this->final_blocker_
);
5997 // Run the task--write out the data.
6000 Write_sections_task::run(Workqueue
*)
6002 this->layout_
->write_output_sections(this->of_
);
6005 // Write_data_task methods.
6007 // We can always run this task.
6010 Write_data_task::is_runnable()
6015 // We need to unlock FINAL_BLOCKER when finished.
6018 Write_data_task::locks(Task_locker
* tl
)
6020 tl
->add(this, this->final_blocker_
);
6023 // Run the task--write out the data.
6026 Write_data_task::run(Workqueue
*)
6028 this->layout_
->write_data(this->symtab_
, this->of_
);
6031 // Write_symbols_task methods.
6033 // We can always run this task.
6036 Write_symbols_task::is_runnable()
6041 // We need to unlock FINAL_BLOCKER when finished.
6044 Write_symbols_task::locks(Task_locker
* tl
)
6046 tl
->add(this, this->final_blocker_
);
6049 // Run the task--write out the symbols.
6052 Write_symbols_task::run(Workqueue
*)
6054 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
6055 this->layout_
->symtab_xindex(),
6056 this->layout_
->dynsym_xindex(), this->of_
);
6059 // Write_after_input_sections_task methods.
6061 // We can only run this task after the input sections have completed.
6064 Write_after_input_sections_task::is_runnable()
6066 if (this->input_sections_blocker_
->is_blocked())
6067 return this->input_sections_blocker_
;
6071 // We need to unlock FINAL_BLOCKER when finished.
6074 Write_after_input_sections_task::locks(Task_locker
* tl
)
6076 tl
->add(this, this->final_blocker_
);
6082 Write_after_input_sections_task::run(Workqueue
*)
6084 this->layout_
->write_sections_after_input_sections(this->of_
);
6087 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
6088 // or as a "tree" where each chunk of the string is hashed and then those
6089 // hashes are put into a (much smaller) string which is hashed with sha1.
6090 // We compute a checksum over the entire file because that is simplest.
6093 Build_id_task_runner::run(Workqueue
* workqueue
, const Task
*)
6095 Task_token
* post_hash_tasks_blocker
= new Task_token(true);
6096 const Layout
* layout
= this->layout_
;
6097 Output_file
* of
= this->of_
;
6098 const size_t filesize
= (layout
->output_file_size() <= 0 ? 0
6099 : static_cast<size_t>(layout
->output_file_size()));
6100 unsigned char* array_of_hashes
= NULL
;
6101 size_t size_of_hashes
= 0;
6103 if (strcmp(this->options_
->build_id(), "tree") == 0
6104 && this->options_
->build_id_chunk_size_for_treehash() > 0
6106 && (filesize
>= this->options_
->build_id_min_file_size_for_treehash()))
6108 static const size_t MD5_OUTPUT_SIZE_IN_BYTES
= 16;
6109 const size_t chunk_size
=
6110 this->options_
->build_id_chunk_size_for_treehash();
6111 const size_t num_hashes
= ((filesize
- 1) / chunk_size
) + 1;
6112 post_hash_tasks_blocker
->add_blockers(num_hashes
);
6113 size_of_hashes
= num_hashes
* MD5_OUTPUT_SIZE_IN_BYTES
;
6114 array_of_hashes
= new unsigned char[size_of_hashes
];
6115 unsigned char *dst
= array_of_hashes
;
6116 for (size_t i
= 0, src_offset
= 0; i
< num_hashes
;
6117 i
++, dst
+= MD5_OUTPUT_SIZE_IN_BYTES
, src_offset
+= chunk_size
)
6119 size_t size
= std::min(chunk_size
, filesize
- src_offset
);
6120 workqueue
->queue(new Hash_task(of
,
6124 post_hash_tasks_blocker
));
6128 // Queue the final task to write the build id and close the output file.
6129 workqueue
->queue(new Task_function(new Close_task_runner(this->options_
,
6134 post_hash_tasks_blocker
,
6135 "Task_function Close_task_runner"));
6138 // Close_task_runner methods.
6140 // Finish up the build ID computation, if necessary, and write a binary file,
6141 // if necessary. Then close the output file.
6144 Close_task_runner::run(Workqueue
*, const Task
*)
6146 // At this point the multi-threaded part of the build ID computation,
6147 // if any, is done. See Build_id_task_runner.
6148 this->layout_
->write_build_id(this->of_
, this->array_of_hashes_
,
6149 this->size_of_hashes_
);
6151 // If we've been asked to create a binary file, we do so here.
6152 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
6153 this->layout_
->write_binary(this->of_
);
6158 // Instantiate the templates we need. We could use the configure
6159 // script to restrict this to only the ones for implemented targets.
6161 #ifdef HAVE_TARGET_32_LITTLE
6164 Layout::init_fixed_output_section
<32, false>(
6166 elfcpp::Shdr
<32, false>& shdr
);
6169 #ifdef HAVE_TARGET_32_BIG
6172 Layout::init_fixed_output_section
<32, true>(
6174 elfcpp::Shdr
<32, true>& shdr
);
6177 #ifdef HAVE_TARGET_64_LITTLE
6180 Layout::init_fixed_output_section
<64, false>(
6182 elfcpp::Shdr
<64, false>& shdr
);
6185 #ifdef HAVE_TARGET_64_BIG
6188 Layout::init_fixed_output_section
<64, true>(
6190 elfcpp::Shdr
<64, true>& shdr
);
6193 #ifdef HAVE_TARGET_32_LITTLE
6196 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
6199 const elfcpp::Shdr
<32, false>& shdr
,
6200 unsigned int, unsigned int, unsigned int, off_t
*);
6203 #ifdef HAVE_TARGET_32_BIG
6206 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
6209 const elfcpp::Shdr
<32, true>& shdr
,
6210 unsigned int, unsigned int, unsigned int, off_t
*);
6213 #ifdef HAVE_TARGET_64_LITTLE
6216 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
6219 const elfcpp::Shdr
<64, false>& shdr
,
6220 unsigned int, unsigned int, unsigned int, off_t
*);
6223 #ifdef HAVE_TARGET_64_BIG
6226 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
6229 const elfcpp::Shdr
<64, true>& shdr
,
6230 unsigned int, unsigned int, unsigned int, off_t
*);
6233 #ifdef HAVE_TARGET_32_LITTLE
6236 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
6237 unsigned int reloc_shndx
,
6238 const elfcpp::Shdr
<32, false>& shdr
,
6239 Output_section
* data_section
,
6240 Relocatable_relocs
* rr
);
6243 #ifdef HAVE_TARGET_32_BIG
6246 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
6247 unsigned int reloc_shndx
,
6248 const elfcpp::Shdr
<32, true>& shdr
,
6249 Output_section
* data_section
,
6250 Relocatable_relocs
* rr
);
6253 #ifdef HAVE_TARGET_64_LITTLE
6256 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
6257 unsigned int reloc_shndx
,
6258 const elfcpp::Shdr
<64, false>& shdr
,
6259 Output_section
* data_section
,
6260 Relocatable_relocs
* rr
);
6263 #ifdef HAVE_TARGET_64_BIG
6266 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
6267 unsigned int reloc_shndx
,
6268 const elfcpp::Shdr
<64, true>& shdr
,
6269 Output_section
* data_section
,
6270 Relocatable_relocs
* rr
);
6273 #ifdef HAVE_TARGET_32_LITTLE
6276 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
6277 Sized_relobj_file
<32, false>* object
,
6279 const char* group_section_name
,
6280 const char* signature
,
6281 const elfcpp::Shdr
<32, false>& shdr
,
6282 elfcpp::Elf_Word flags
,
6283 std::vector
<unsigned int>* shndxes
);
6286 #ifdef HAVE_TARGET_32_BIG
6289 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
6290 Sized_relobj_file
<32, true>* object
,
6292 const char* group_section_name
,
6293 const char* signature
,
6294 const elfcpp::Shdr
<32, true>& shdr
,
6295 elfcpp::Elf_Word flags
,
6296 std::vector
<unsigned int>* shndxes
);
6299 #ifdef HAVE_TARGET_64_LITTLE
6302 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
6303 Sized_relobj_file
<64, false>* object
,
6305 const char* group_section_name
,
6306 const char* signature
,
6307 const elfcpp::Shdr
<64, false>& shdr
,
6308 elfcpp::Elf_Word flags
,
6309 std::vector
<unsigned int>* shndxes
);
6312 #ifdef HAVE_TARGET_64_BIG
6315 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
6316 Sized_relobj_file
<64, true>* object
,
6318 const char* group_section_name
,
6319 const char* signature
,
6320 const elfcpp::Shdr
<64, true>& shdr
,
6321 elfcpp::Elf_Word flags
,
6322 std::vector
<unsigned int>* shndxes
);
6325 #ifdef HAVE_TARGET_32_LITTLE
6328 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
6329 const unsigned char* symbols
,
6331 const unsigned char* symbol_names
,
6332 off_t symbol_names_size
,
6334 const elfcpp::Shdr
<32, false>& shdr
,
6335 unsigned int reloc_shndx
,
6336 unsigned int reloc_type
,
6340 #ifdef HAVE_TARGET_32_BIG
6343 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
6344 const unsigned char* symbols
,
6346 const unsigned char* symbol_names
,
6347 off_t symbol_names_size
,
6349 const elfcpp::Shdr
<32, true>& shdr
,
6350 unsigned int reloc_shndx
,
6351 unsigned int reloc_type
,
6355 #ifdef HAVE_TARGET_64_LITTLE
6358 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
6359 const unsigned char* symbols
,
6361 const unsigned char* symbol_names
,
6362 off_t symbol_names_size
,
6364 const elfcpp::Shdr
<64, false>& shdr
,
6365 unsigned int reloc_shndx
,
6366 unsigned int reloc_type
,
6370 #ifdef HAVE_TARGET_64_BIG
6373 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
6374 const unsigned char* symbols
,
6376 const unsigned char* symbol_names
,
6377 off_t symbol_names_size
,
6379 const elfcpp::Shdr
<64, true>& shdr
,
6380 unsigned int reloc_shndx
,
6381 unsigned int reloc_type
,
6385 #ifdef HAVE_TARGET_32_LITTLE
6388 Layout::add_to_gdb_index(bool is_type_unit
,
6389 Sized_relobj
<32, false>* object
,
6390 const unsigned char* symbols
,
6393 unsigned int reloc_shndx
,
6394 unsigned int reloc_type
);
6397 #ifdef HAVE_TARGET_32_BIG
6400 Layout::add_to_gdb_index(bool is_type_unit
,
6401 Sized_relobj
<32, true>* object
,
6402 const unsigned char* symbols
,
6405 unsigned int reloc_shndx
,
6406 unsigned int reloc_type
);
6409 #ifdef HAVE_TARGET_64_LITTLE
6412 Layout::add_to_gdb_index(bool is_type_unit
,
6413 Sized_relobj
<64, false>* object
,
6414 const unsigned char* symbols
,
6417 unsigned int reloc_shndx
,
6418 unsigned int reloc_type
);
6421 #ifdef HAVE_TARGET_64_BIG
6424 Layout::add_to_gdb_index(bool is_type_unit
,
6425 Sized_relobj
<64, true>* object
,
6426 const unsigned char* symbols
,
6429 unsigned int reloc_shndx
,
6430 unsigned int reloc_type
);
6433 } // End namespace gold.