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
[] =
1137 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1139 if (is_prefix_of(text_section_sort
[i
], name
))
1145 // Return the output section to use for input section SHNDX, with name
1146 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1147 // index of a relocation section which applies to this section, or 0
1148 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1149 // relocation section if there is one. Set *OFF to the offset of this
1150 // input section without the output section. Return NULL if the
1151 // section should be discarded. Set *OFF to -1 if the section
1152 // contents should not be written directly to the output file, but
1153 // will instead receive special handling.
1155 template<int size
, bool big_endian
>
1157 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1158 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1159 unsigned int sh_type
, unsigned int reloc_shndx
,
1160 unsigned int, off_t
* off
)
1164 if (!this->include_section(object
, name
, shdr
))
1167 // In a relocatable link a grouped section must not be combined with
1168 // any other sections.
1170 if (parameters
->options().relocatable()
1171 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1173 // Some flags in the input section should not be automatically
1174 // copied to the output section.
1175 elfcpp::Elf_Xword flags
= (shdr
.get_sh_flags()
1176 & ~ elfcpp::SHF_COMPRESSED
);
1177 name
= this->namepool_
.add(name
, true, NULL
);
1178 os
= this->make_output_section(name
, sh_type
, flags
,
1179 ORDER_INVALID
, false);
1183 // All ".text.unlikely.*" sections can be moved to a unique
1184 // segment with --text-unlikely-segment option.
1185 bool text_unlikely_segment
1186 = (parameters
->options().text_unlikely_segment()
1187 && is_prefix_of(".text.unlikely",
1188 object
->section_name(shndx
).c_str()));
1189 if (text_unlikely_segment
)
1191 elfcpp::Elf_Xword flags
1192 = this->get_output_section_flags(shdr
.get_sh_flags());
1194 Stringpool::Key name_key
;
1195 const char* os_name
= this->namepool_
.add(".text.unlikely", true,
1197 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1198 ORDER_INVALID
, false);
1199 // Map this output section to a unique segment. This is done to
1200 // separate "text" that is not likely to be executed from "text"
1201 // that is likely executed.
1202 os
->set_is_unique_segment();
1206 // Plugins can choose to place one or more subsets of sections in
1207 // unique segments and this is done by mapping these section subsets
1208 // to unique output sections. Check if this section needs to be
1209 // remapped to a unique output section.
1210 Section_segment_map::iterator it
1211 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1212 if (it
== this->section_segment_map_
.end())
1214 os
= this->choose_output_section(object
, name
, sh_type
,
1215 shdr
.get_sh_flags(), true,
1216 ORDER_INVALID
, false, false,
1221 // We know the name of the output section, directly call
1222 // get_output_section here by-passing choose_output_section.
1223 elfcpp::Elf_Xword flags
1224 = this->get_output_section_flags(shdr
.get_sh_flags());
1226 const char* os_name
= it
->second
->name
;
1227 Stringpool::Key name_key
;
1228 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1229 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1230 ORDER_INVALID
, false);
1231 if (!os
->is_unique_segment())
1233 os
->set_is_unique_segment();
1234 os
->set_extra_segment_flags(it
->second
->flags
);
1235 os
->set_segment_alignment(it
->second
->align
);
1243 // By default the GNU linker sorts input sections whose names match
1244 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1245 // sections are sorted by name. This is used to implement
1246 // constructor priority ordering. We are compatible. When we put
1247 // .ctor sections in .init_array and .dtor sections in .fini_array,
1248 // we must also sort plain .ctor and .dtor sections.
1249 if (!this->script_options_
->saw_sections_clause()
1250 && !parameters
->options().relocatable()
1251 && (is_prefix_of(".ctors.", name
)
1252 || is_prefix_of(".dtors.", name
)
1253 || is_prefix_of(".init_array.", name
)
1254 || is_prefix_of(".fini_array.", name
)
1255 || (parameters
->options().ctors_in_init_array()
1256 && (strcmp(name
, ".ctors") == 0
1257 || strcmp(name
, ".dtors") == 0))))
1258 os
->set_must_sort_attached_input_sections();
1260 // By default the GNU linker sorts some special text sections ahead
1261 // of others. We are compatible.
1262 if (parameters
->options().text_reorder()
1263 && !this->script_options_
->saw_sections_clause()
1264 && !this->is_section_ordering_specified()
1265 && !parameters
->options().relocatable()
1266 && Layout::special_ordering_of_input_section(name
) >= 0)
1267 os
->set_must_sort_attached_input_sections();
1269 // If this is a .ctors or .ctors.* section being mapped to a
1270 // .init_array section, or a .dtors or .dtors.* section being mapped
1271 // to a .fini_array section, we will need to reverse the words if
1272 // there is more than one. Record this section for later. See
1273 // ctors_sections_in_init_array above.
1274 if (!this->script_options_
->saw_sections_clause()
1275 && !parameters
->options().relocatable()
1276 && shdr
.get_sh_size() > size
/ 8
1277 && (((strcmp(name
, ".ctors") == 0
1278 || is_prefix_of(".ctors.", name
))
1279 && strcmp(os
->name(), ".init_array") == 0)
1280 || ((strcmp(name
, ".dtors") == 0
1281 || is_prefix_of(".dtors.", name
))
1282 && strcmp(os
->name(), ".fini_array") == 0)))
1283 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1285 // FIXME: Handle SHF_LINK_ORDER somewhere.
1287 elfcpp::Elf_Xword orig_flags
= os
->flags();
1289 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1290 this->script_options_
->saw_sections_clause());
1292 // If the flags changed, we may have to change the order.
1293 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1295 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1296 elfcpp::Elf_Xword new_flags
=
1297 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1298 if (orig_flags
!= new_flags
)
1299 os
->set_order(this->default_section_order(os
, false));
1302 this->have_added_input_section_
= true;
1307 // Maps section SECN to SEGMENT s.
1309 Layout::insert_section_segment_map(Const_section_id secn
,
1310 Unique_segment_info
*s
)
1312 gold_assert(this->unique_segment_for_sections_specified_
);
1313 this->section_segment_map_
[secn
] = s
;
1316 // Handle a relocation section when doing a relocatable link.
1318 template<int size
, bool big_endian
>
1320 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>*,
1322 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1323 Output_section
* data_section
,
1324 Relocatable_relocs
* rr
)
1326 gold_assert(parameters
->options().relocatable()
1327 || parameters
->options().emit_relocs());
1329 int sh_type
= shdr
.get_sh_type();
1332 if (sh_type
== elfcpp::SHT_REL
)
1334 else if (sh_type
== elfcpp::SHT_RELA
)
1338 name
+= data_section
->name();
1340 // If the output data section already has a reloc section, use that;
1341 // otherwise, make a new one.
1342 Output_section
* os
= data_section
->reloc_section();
1345 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1346 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1347 ORDER_INVALID
, false);
1348 os
->set_should_link_to_symtab();
1349 os
->set_info_section(data_section
);
1350 data_section
->set_reloc_section(os
);
1353 Output_section_data
* posd
;
1354 if (sh_type
== elfcpp::SHT_REL
)
1356 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1357 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1361 else if (sh_type
== elfcpp::SHT_RELA
)
1363 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1364 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1371 os
->add_output_section_data(posd
);
1372 rr
->set_output_data(posd
);
1377 // Handle a group section when doing a relocatable link.
1379 template<int size
, bool big_endian
>
1381 Layout::layout_group(Symbol_table
* symtab
,
1382 Sized_relobj_file
<size
, big_endian
>* object
,
1384 const char* group_section_name
,
1385 const char* signature
,
1386 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1387 elfcpp::Elf_Word flags
,
1388 std::vector
<unsigned int>* shndxes
)
1390 gold_assert(parameters
->options().relocatable());
1391 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1392 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1393 Output_section
* os
= this->make_output_section(group_section_name
,
1395 shdr
.get_sh_flags(),
1396 ORDER_INVALID
, false);
1398 // We need to find a symbol with the signature in the symbol table.
1399 // If we don't find one now, we need to look again later.
1400 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1402 os
->set_info_symndx(sym
);
1405 // Reserve some space to minimize reallocations.
1406 if (this->group_signatures_
.empty())
1407 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1409 // We will wind up using a symbol whose name is the signature.
1410 // So just put the signature in the symbol name pool to save it.
1411 signature
= symtab
->canonicalize_name(signature
);
1412 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1415 os
->set_should_link_to_symtab();
1418 section_size_type entry_count
=
1419 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1420 Output_section_data
* posd
=
1421 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1423 os
->add_output_section_data(posd
);
1426 // Special GNU handling of sections name .eh_frame. They will
1427 // normally hold exception frame data as defined by the C++ ABI
1428 // (http://codesourcery.com/cxx-abi/).
1430 template<int size
, bool big_endian
>
1432 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1433 const unsigned char* symbols
,
1435 const unsigned char* symbol_names
,
1436 off_t symbol_names_size
,
1438 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1439 unsigned int reloc_shndx
, unsigned int reloc_type
,
1442 const unsigned int unwind_section_type
=
1443 parameters
->target().unwind_section_type();
1445 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1446 || shdr
.get_sh_type() == unwind_section_type
);
1447 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1449 Output_section
* os
= this->make_eh_frame_section(object
);
1453 gold_assert(this->eh_frame_section_
== os
);
1455 elfcpp::Elf_Xword orig_flags
= os
->flags();
1457 Eh_frame::Eh_frame_section_disposition disp
=
1458 Eh_frame::EH_UNRECOGNIZED_SECTION
;
1459 if (!parameters
->incremental())
1461 disp
= this->eh_frame_data_
->add_ehframe_input_section(object
,
1471 if (disp
== Eh_frame::EH_OPTIMIZABLE_SECTION
)
1473 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1475 // A writable .eh_frame section is a RELRO section.
1476 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1477 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1480 os
->set_order(ORDER_RELRO
);
1487 if (disp
== Eh_frame::EH_END_MARKER_SECTION
&& !this->added_eh_frame_data_
)
1489 // We found the end marker section, so now we can add the set of
1490 // optimized sections to the output section. We need to postpone
1491 // adding this until we've found a section we can optimize so that
1492 // the .eh_frame section in crtbeginT.o winds up at the start of
1493 // the output section.
1494 os
->add_output_section_data(this->eh_frame_data_
);
1495 this->added_eh_frame_data_
= true;
1498 // We couldn't handle this .eh_frame section for some reason.
1499 // Add it as a normal section.
1500 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1501 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1502 reloc_shndx
, saw_sections_clause
);
1503 this->have_added_input_section_
= true;
1505 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1506 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1507 os
->set_order(this->default_section_order(os
, false));
1513 Layout::finalize_eh_frame_section()
1515 // If we never found an end marker section, we need to add the
1516 // optimized eh sections to the output section now.
1517 if (!parameters
->incremental()
1518 && this->eh_frame_section_
!= NULL
1519 && !this->added_eh_frame_data_
)
1521 this->eh_frame_section_
->add_output_section_data(this->eh_frame_data_
);
1522 this->added_eh_frame_data_
= true;
1526 // Create and return the magic .eh_frame section. Create
1527 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1528 // input .eh_frame section; it may be NULL.
1531 Layout::make_eh_frame_section(const Relobj
* object
)
1533 const unsigned int unwind_section_type
=
1534 parameters
->target().unwind_section_type();
1536 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1537 unwind_section_type
,
1538 elfcpp::SHF_ALLOC
, false,
1539 ORDER_EHFRAME
, false, false,
1544 if (this->eh_frame_section_
== NULL
)
1546 this->eh_frame_section_
= os
;
1547 this->eh_frame_data_
= new Eh_frame();
1549 // For incremental linking, we do not optimize .eh_frame sections
1550 // or create a .eh_frame_hdr section.
1551 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1553 Output_section
* hdr_os
=
1554 this->choose_output_section(NULL
, ".eh_frame_hdr",
1555 unwind_section_type
,
1556 elfcpp::SHF_ALLOC
, false,
1557 ORDER_EHFRAME
, false, false,
1562 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1563 this->eh_frame_data_
);
1564 hdr_os
->add_output_section_data(hdr_posd
);
1566 hdr_os
->set_after_input_sections();
1568 if (!this->script_options_
->saw_phdrs_clause())
1570 Output_segment
* hdr_oseg
;
1571 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1573 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1577 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1585 // Add an exception frame for a PLT. This is called from target code.
1588 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1589 size_t cie_length
, const unsigned char* fde_data
,
1592 if (parameters
->incremental())
1594 // FIXME: Maybe this could work some day....
1597 Output_section
* os
= this->make_eh_frame_section(NULL
);
1600 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1601 fde_data
, fde_length
);
1602 if (!this->added_eh_frame_data_
)
1604 os
->add_output_section_data(this->eh_frame_data_
);
1605 this->added_eh_frame_data_
= true;
1609 // Remove all post-map .eh_frame information for a PLT.
1612 Layout::remove_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1615 if (parameters
->incremental())
1617 // FIXME: Maybe this could work some day....
1620 this->eh_frame_data_
->remove_ehframe_for_plt(plt
, cie_data
, cie_length
);
1623 // Scan a .debug_info or .debug_types section, and add summary
1624 // information to the .gdb_index section.
1626 template<int size
, bool big_endian
>
1628 Layout::add_to_gdb_index(bool is_type_unit
,
1629 Sized_relobj
<size
, big_endian
>* object
,
1630 const unsigned char* symbols
,
1633 unsigned int reloc_shndx
,
1634 unsigned int reloc_type
)
1636 if (this->gdb_index_data_
== NULL
)
1638 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1639 elfcpp::SHT_PROGBITS
, 0,
1640 false, ORDER_INVALID
,
1641 false, false, false);
1645 this->gdb_index_data_
= new Gdb_index(os
);
1646 os
->add_output_section_data(this->gdb_index_data_
);
1647 os
->set_after_input_sections();
1650 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1651 symbols_size
, shndx
, reloc_shndx
,
1655 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1656 // the output section.
1659 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1660 elfcpp::Elf_Xword flags
,
1661 Output_section_data
* posd
,
1662 Output_section_order order
, bool is_relro
)
1664 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1665 false, order
, is_relro
,
1668 os
->add_output_section_data(posd
);
1672 // Map section flags to segment flags.
1675 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1677 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1678 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1679 ret
|= elfcpp::PF_W
;
1680 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1681 ret
|= elfcpp::PF_X
;
1685 // Make a new Output_section, and attach it to segments as
1686 // appropriate. ORDER is the order in which this section should
1687 // appear in the output segment. IS_RELRO is true if this is a relro
1688 // (read-only after relocations) section.
1691 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1692 elfcpp::Elf_Xword flags
,
1693 Output_section_order order
, bool is_relro
)
1696 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1697 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1698 && is_compressible_debug_section(name
))
1699 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1701 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1702 && parameters
->options().strip_debug_non_line()
1703 && strcmp(".debug_abbrev", name
) == 0)
1705 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1707 if (this->debug_info_
)
1708 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1710 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1711 && parameters
->options().strip_debug_non_line()
1712 && strcmp(".debug_info", name
) == 0)
1714 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1716 if (this->debug_abbrev_
)
1717 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1721 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1722 // not have correct section types. Force them here.
1723 if (type
== elfcpp::SHT_PROGBITS
)
1725 if (is_prefix_of(".init_array", name
))
1726 type
= elfcpp::SHT_INIT_ARRAY
;
1727 else if (is_prefix_of(".preinit_array", name
))
1728 type
= elfcpp::SHT_PREINIT_ARRAY
;
1729 else if (is_prefix_of(".fini_array", name
))
1730 type
= elfcpp::SHT_FINI_ARRAY
;
1733 // FIXME: const_cast is ugly.
1734 Target
* target
= const_cast<Target
*>(¶meters
->target());
1735 os
= target
->make_output_section(name
, type
, flags
);
1738 // With -z relro, we have to recognize the special sections by name.
1739 // There is no other way.
1740 bool is_relro_local
= false;
1741 if (!this->script_options_
->saw_sections_clause()
1742 && parameters
->options().relro()
1743 && (flags
& elfcpp::SHF_ALLOC
) != 0
1744 && (flags
& elfcpp::SHF_WRITE
) != 0)
1746 if (type
== elfcpp::SHT_PROGBITS
)
1748 if ((flags
& elfcpp::SHF_TLS
) != 0)
1750 else if (strcmp(name
, ".data.rel.ro") == 0)
1752 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1755 is_relro_local
= true;
1757 else if (strcmp(name
, ".ctors") == 0
1758 || strcmp(name
, ".dtors") == 0
1759 || strcmp(name
, ".jcr") == 0)
1762 else if (type
== elfcpp::SHT_INIT_ARRAY
1763 || type
== elfcpp::SHT_FINI_ARRAY
1764 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1771 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1772 order
= this->default_section_order(os
, is_relro_local
);
1774 os
->set_order(order
);
1776 parameters
->target().new_output_section(os
);
1778 this->section_list_
.push_back(os
);
1780 // The GNU linker by default sorts some sections by priority, so we
1781 // do the same. We need to know that this might happen before we
1782 // attach any input sections.
1783 if (!this->script_options_
->saw_sections_clause()
1784 && !parameters
->options().relocatable()
1785 && (strcmp(name
, ".init_array") == 0
1786 || strcmp(name
, ".fini_array") == 0
1787 || (!parameters
->options().ctors_in_init_array()
1788 && (strcmp(name
, ".ctors") == 0
1789 || strcmp(name
, ".dtors") == 0))))
1790 os
->set_may_sort_attached_input_sections();
1792 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1793 // sections before other .text sections. We are compatible. We
1794 // need to know that this might happen before we attach any input
1796 if (parameters
->options().text_reorder()
1797 && !this->script_options_
->saw_sections_clause()
1798 && !this->is_section_ordering_specified()
1799 && !parameters
->options().relocatable()
1800 && strcmp(name
, ".text") == 0)
1801 os
->set_may_sort_attached_input_sections();
1803 // GNU linker sorts section by name with --sort-section=name.
1804 if (strcmp(parameters
->options().sort_section(), "name") == 0)
1805 os
->set_must_sort_attached_input_sections();
1807 // Check for .stab*str sections, as .stab* sections need to link to
1809 if (type
== elfcpp::SHT_STRTAB
1810 && !this->have_stabstr_section_
1811 && strncmp(name
, ".stab", 5) == 0
1812 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1813 this->have_stabstr_section_
= true;
1815 // During a full incremental link, we add patch space to most
1816 // PROGBITS and NOBITS sections. Flag those that may be
1817 // arbitrarily padded.
1818 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1819 && order
!= ORDER_INTERP
1820 && order
!= ORDER_INIT
1821 && order
!= ORDER_PLT
1822 && order
!= ORDER_FINI
1823 && order
!= ORDER_RELRO_LAST
1824 && order
!= ORDER_NON_RELRO_FIRST
1825 && strcmp(name
, ".eh_frame") != 0
1826 && strcmp(name
, ".ctors") != 0
1827 && strcmp(name
, ".dtors") != 0
1828 && strcmp(name
, ".jcr") != 0)
1830 os
->set_is_patch_space_allowed();
1832 // Certain sections require "holes" to be filled with
1833 // specific fill patterns. These fill patterns may have
1834 // a minimum size, so we must prevent allocations from the
1835 // free list that leave a hole smaller than the minimum.
1836 if (strcmp(name
, ".debug_info") == 0)
1837 os
->set_free_space_fill(new Output_fill_debug_info(false));
1838 else if (strcmp(name
, ".debug_types") == 0)
1839 os
->set_free_space_fill(new Output_fill_debug_info(true));
1840 else if (strcmp(name
, ".debug_line") == 0)
1841 os
->set_free_space_fill(new Output_fill_debug_line());
1844 // If we have already attached the sections to segments, then we
1845 // need to attach this one now. This happens for sections created
1846 // directly by the linker.
1847 if (this->sections_are_attached_
)
1848 this->attach_section_to_segment(¶meters
->target(), os
);
1853 // Return the default order in which a section should be placed in an
1854 // output segment. This function captures a lot of the ideas in
1855 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1856 // linker created section is normally set when the section is created;
1857 // this function is used for input sections.
1859 Output_section_order
1860 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1862 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1863 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1864 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1865 bool is_bss
= false;
1870 case elfcpp::SHT_PROGBITS
:
1872 case elfcpp::SHT_NOBITS
:
1875 case elfcpp::SHT_RELA
:
1876 case elfcpp::SHT_REL
:
1878 return ORDER_DYNAMIC_RELOCS
;
1880 case elfcpp::SHT_HASH
:
1881 case elfcpp::SHT_DYNAMIC
:
1882 case elfcpp::SHT_SHLIB
:
1883 case elfcpp::SHT_DYNSYM
:
1884 case elfcpp::SHT_GNU_HASH
:
1885 case elfcpp::SHT_GNU_verdef
:
1886 case elfcpp::SHT_GNU_verneed
:
1887 case elfcpp::SHT_GNU_versym
:
1889 return ORDER_DYNAMIC_LINKER
;
1891 case elfcpp::SHT_NOTE
:
1892 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1895 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1896 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1898 if (!is_bss
&& !is_write
)
1902 if (strcmp(os
->name(), ".init") == 0)
1904 else if (strcmp(os
->name(), ".fini") == 0)
1906 else if (parameters
->options().keep_text_section_prefix())
1908 // -z,keep-text-section-prefix introduces additional
1910 if (strcmp(os
->name(), ".text.hot") == 0)
1911 return ORDER_TEXT_HOT
;
1912 else if (strcmp(os
->name(), ".text.startup") == 0)
1913 return ORDER_TEXT_STARTUP
;
1914 else if (strcmp(os
->name(), ".text.exit") == 0)
1915 return ORDER_TEXT_EXIT
;
1916 else if (strcmp(os
->name(), ".text.unlikely") == 0)
1917 return ORDER_TEXT_UNLIKELY
;
1920 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1924 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1926 if (os
->is_small_section())
1927 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1928 if (os
->is_large_section())
1929 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1931 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1934 // Attach output sections to segments. This is called after we have
1935 // seen all the input sections.
1938 Layout::attach_sections_to_segments(const Target
* target
)
1940 for (Section_list::iterator p
= this->section_list_
.begin();
1941 p
!= this->section_list_
.end();
1943 this->attach_section_to_segment(target
, *p
);
1945 this->sections_are_attached_
= true;
1948 // Attach an output section to a segment.
1951 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1953 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1954 this->unattached_section_list_
.push_back(os
);
1956 this->attach_allocated_section_to_segment(target
, os
);
1959 // Attach an allocated output section to a segment.
1962 Layout::attach_allocated_section_to_segment(const Target
* target
,
1965 elfcpp::Elf_Xword flags
= os
->flags();
1966 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1968 if (parameters
->options().relocatable())
1971 // If we have a SECTIONS clause, we can't handle the attachment to
1972 // segments until after we've seen all the sections.
1973 if (this->script_options_
->saw_sections_clause())
1976 gold_assert(!this->script_options_
->saw_phdrs_clause());
1978 // This output section goes into a PT_LOAD segment.
1980 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1982 // If this output section's segment has extra flags that need to be set,
1983 // coming from a linker plugin, do that.
1984 seg_flags
|= os
->extra_segment_flags();
1986 // Check for --section-start.
1988 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1990 // In general the only thing we really care about for PT_LOAD
1991 // segments is whether or not they are writable or executable,
1992 // so that is how we search for them.
1993 // Large data sections also go into their own PT_LOAD segment.
1994 // People who need segments sorted on some other basis will
1995 // have to use a linker script.
1997 Segment_list::const_iterator p
;
1998 if (!os
->is_unique_segment())
2000 for (p
= this->segment_list_
.begin();
2001 p
!= this->segment_list_
.end();
2004 if ((*p
)->type() != elfcpp::PT_LOAD
)
2006 if ((*p
)->is_unique_segment())
2008 if (!parameters
->options().omagic()
2009 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
2011 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
2012 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
2014 // If -Tbss was specified, we need to separate the data and BSS
2016 if (parameters
->options().user_set_Tbss())
2018 if ((os
->type() == elfcpp::SHT_NOBITS
)
2019 == (*p
)->has_any_data_sections())
2022 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
2027 if ((*p
)->are_addresses_set())
2030 (*p
)->add_initial_output_data(os
);
2031 (*p
)->update_flags_for_output_section(seg_flags
);
2032 (*p
)->set_addresses(addr
, addr
);
2036 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
2041 if (p
== this->segment_list_
.end()
2042 || os
->is_unique_segment())
2044 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
2046 if (os
->is_large_data_section())
2047 oseg
->set_is_large_data_segment();
2048 oseg
->add_output_section_to_load(this, os
, seg_flags
);
2050 oseg
->set_addresses(addr
, addr
);
2051 // Check if segment should be marked unique. For segments marked
2052 // unique by linker plugins, set the new alignment if specified.
2053 if (os
->is_unique_segment())
2055 oseg
->set_is_unique_segment();
2056 if (os
->segment_alignment() != 0)
2057 oseg
->set_minimum_p_align(os
->segment_alignment());
2061 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
2063 if (os
->type() == elfcpp::SHT_NOTE
)
2065 // See if we already have an equivalent PT_NOTE segment.
2066 for (p
= this->segment_list_
.begin();
2067 p
!= segment_list_
.end();
2070 if ((*p
)->type() == elfcpp::PT_NOTE
2071 && (((*p
)->flags() & elfcpp::PF_W
)
2072 == (seg_flags
& elfcpp::PF_W
)))
2074 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
2079 if (p
== this->segment_list_
.end())
2081 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
2083 oseg
->add_output_section_to_nonload(os
, seg_flags
);
2087 // If we see a loadable SHF_TLS section, we create a PT_TLS
2088 // segment. There can only be one such segment.
2089 if ((flags
& elfcpp::SHF_TLS
) != 0)
2091 if (this->tls_segment_
== NULL
)
2092 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
2093 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2096 // If -z relro is in effect, and we see a relro section, we create a
2097 // PT_GNU_RELRO segment. There can only be one such segment.
2098 if (os
->is_relro() && parameters
->options().relro())
2100 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
2101 if (this->relro_segment_
== NULL
)
2102 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
2103 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2106 // If we see a section named .interp, put it into a PT_INTERP
2107 // segment. This seems broken to me, but this is what GNU ld does,
2108 // and glibc expects it.
2109 if (strcmp(os
->name(), ".interp") == 0
2110 && !this->script_options_
->saw_phdrs_clause())
2112 if (this->interp_segment_
== NULL
)
2113 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
2115 gold_warning(_("multiple '.interp' sections in input files "
2116 "may cause confusing PT_INTERP segment"));
2117 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2121 // Make an output section for a script.
2124 Layout::make_output_section_for_script(
2126 Script_sections::Section_type section_type
)
2128 name
= this->namepool_
.add(name
, false, NULL
);
2129 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
2130 if (section_type
== Script_sections::ST_NOLOAD
)
2132 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
2133 sh_flags
, ORDER_INVALID
,
2135 os
->set_found_in_sections_clause();
2136 if (section_type
== Script_sections::ST_NOLOAD
)
2137 os
->set_is_noload();
2141 // Return the number of segments we expect to see.
2144 Layout::expected_segment_count() const
2146 size_t ret
= this->segment_list_
.size();
2148 // If we didn't see a SECTIONS clause in a linker script, we should
2149 // already have the complete list of segments. Otherwise we ask the
2150 // SECTIONS clause how many segments it expects, and add in the ones
2151 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2153 if (!this->script_options_
->saw_sections_clause())
2157 const Script_sections
* ss
= this->script_options_
->script_sections();
2158 return ret
+ ss
->expected_segment_count(this);
2162 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2163 // is whether we saw a .note.GNU-stack section in the object file.
2164 // GNU_STACK_FLAGS is the section flags. The flags give the
2165 // protection required for stack memory. We record this in an
2166 // executable as a PT_GNU_STACK segment. If an object file does not
2167 // have a .note.GNU-stack segment, we must assume that it is an old
2168 // object. On some targets that will force an executable stack.
2171 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2174 if (!seen_gnu_stack
)
2176 this->input_without_gnu_stack_note_
= true;
2177 if (parameters
->options().warn_execstack()
2178 && parameters
->target().is_default_stack_executable())
2179 gold_warning(_("%s: missing .note.GNU-stack section"
2180 " implies executable stack"),
2181 obj
->name().c_str());
2185 this->input_with_gnu_stack_note_
= true;
2186 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2188 this->input_requires_executable_stack_
= true;
2189 if (parameters
->options().warn_execstack())
2190 gold_warning(_("%s: requires executable stack"),
2191 obj
->name().c_str());
2196 // Read a value with given size and endianness.
2198 static inline uint64_t
2199 read_sized_value(size_t size
, const unsigned char* buf
, bool is_big_endian
,
2200 const Object
* object
)
2206 val
= elfcpp::Swap
<32, true>::readval(buf
);
2208 val
= elfcpp::Swap
<32, false>::readval(buf
);
2213 val
= elfcpp::Swap
<64, true>::readval(buf
);
2215 val
= elfcpp::Swap
<64, false>::readval(buf
);
2219 gold_warning(_("%s: in .note.gnu.property section, "
2220 "pr_datasz must be 4 or 8"),
2221 object
->name().c_str());
2226 // Write a value with given size and endianness.
2229 write_sized_value(uint64_t value
, size_t size
, unsigned char* buf
,
2235 elfcpp::Swap
<32, true>::writeval(buf
, static_cast<uint32_t>(value
));
2237 elfcpp::Swap
<32, false>::writeval(buf
, static_cast<uint32_t>(value
));
2242 elfcpp::Swap
<64, true>::writeval(buf
, value
);
2244 elfcpp::Swap
<64, false>::writeval(buf
, value
);
2248 // We will have already complained about this.
2252 // Handle the .note.gnu.property section at layout time.
2255 Layout::layout_gnu_property(unsigned int note_type
,
2256 unsigned int pr_type
,
2258 const unsigned char* pr_data
,
2259 const Object
* object
)
2261 // We currently support only the one note type.
2262 gold_assert(note_type
== elfcpp::NT_GNU_PROPERTY_TYPE_0
);
2264 if (pr_type
>= elfcpp::GNU_PROPERTY_LOPROC
2265 && pr_type
< elfcpp::GNU_PROPERTY_HIPROC
)
2267 // Target-dependent property value; call the target to record.
2268 const int size
= parameters
->target().get_size();
2269 const bool is_big_endian
= parameters
->target().is_big_endian();
2274 #ifdef HAVE_TARGET_32_BIG
2275 parameters
->sized_target
<32, true>()->
2276 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2284 #ifdef HAVE_TARGET_32_LITTLE
2285 parameters
->sized_target
<32, false>()->
2286 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2293 else if (size
== 64)
2297 #ifdef HAVE_TARGET_64_BIG
2298 parameters
->sized_target
<64, true>()->
2299 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2307 #ifdef HAVE_TARGET_64_LITTLE
2308 parameters
->sized_target
<64, false>()->
2309 record_gnu_property(note_type
, pr_type
, pr_datasz
, pr_data
,
2321 Gnu_properties::iterator pprop
= this->gnu_properties_
.find(pr_type
);
2322 if (pprop
== this->gnu_properties_
.end())
2325 prop
.pr_datasz
= pr_datasz
;
2326 prop
.pr_data
= new unsigned char[pr_datasz
];
2327 memcpy(prop
.pr_data
, pr_data
, pr_datasz
);
2328 this->gnu_properties_
[pr_type
] = prop
;
2332 const bool is_big_endian
= parameters
->target().is_big_endian();
2335 case elfcpp::GNU_PROPERTY_STACK_SIZE
:
2336 // Record the maximum value seen.
2338 uint64_t val1
= read_sized_value(pprop
->second
.pr_datasz
,
2339 pprop
->second
.pr_data
,
2340 is_big_endian
, object
);
2341 uint64_t val2
= read_sized_value(pr_datasz
, pr_data
,
2342 is_big_endian
, object
);
2344 write_sized_value(val2
, pprop
->second
.pr_datasz
,
2345 pprop
->second
.pr_data
, is_big_endian
);
2348 case elfcpp::GNU_PROPERTY_NO_COPY_ON_PROTECTED
:
2349 // No data to merge.
2352 gold_warning(_("%s: unknown program property type %d "
2353 "in .note.gnu.property section"),
2354 object
->name().c_str(), pr_type
);
2359 // Merge per-object properties with program properties.
2360 // This lets the target identify objects that are missing certain
2361 // properties, in cases where properties must be ANDed together.
2364 Layout::merge_gnu_properties(const Object
* object
)
2366 const int size
= parameters
->target().get_size();
2367 const bool is_big_endian
= parameters
->target().is_big_endian();
2372 #ifdef HAVE_TARGET_32_BIG
2373 parameters
->sized_target
<32, true>()->merge_gnu_properties(object
);
2380 #ifdef HAVE_TARGET_32_LITTLE
2381 parameters
->sized_target
<32, false>()->merge_gnu_properties(object
);
2387 else if (size
== 64)
2391 #ifdef HAVE_TARGET_64_BIG
2392 parameters
->sized_target
<64, true>()->merge_gnu_properties(object
);
2399 #ifdef HAVE_TARGET_64_LITTLE
2400 parameters
->sized_target
<64, false>()->merge_gnu_properties(object
);
2410 // Add a target-specific property for the output .note.gnu.property section.
2413 Layout::add_gnu_property(unsigned int note_type
,
2414 unsigned int pr_type
,
2416 const unsigned char* pr_data
)
2418 gold_assert(note_type
== elfcpp::NT_GNU_PROPERTY_TYPE_0
);
2421 prop
.pr_datasz
= pr_datasz
;
2422 prop
.pr_data
= new unsigned char[pr_datasz
];
2423 memcpy(prop
.pr_data
, pr_data
, pr_datasz
);
2424 this->gnu_properties_
[pr_type
] = prop
;
2427 // Create automatic note sections.
2430 Layout::create_notes()
2432 this->create_gnu_properties_note();
2433 this->create_gold_note();
2434 this->create_stack_segment();
2435 this->create_build_id();
2438 // Create the dynamic sections which are needed before we read the
2442 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2444 if (parameters
->doing_static_link())
2447 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2448 elfcpp::SHT_DYNAMIC
,
2450 | elfcpp::SHF_WRITE
),
2452 true, false, false);
2454 // A linker script may discard .dynamic, so check for NULL.
2455 if (this->dynamic_section_
!= NULL
)
2457 this->dynamic_symbol_
=
2458 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2459 Symbol_table::PREDEFINED
,
2460 this->dynamic_section_
, 0, 0,
2461 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2462 elfcpp::STV_HIDDEN
, 0, false, false);
2464 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2466 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2470 // For each output section whose name can be represented as C symbol,
2471 // define __start and __stop symbols for the section. This is a GNU
2475 Layout::define_section_symbols(Symbol_table
* symtab
)
2477 for (Section_list::const_iterator p
= this->section_list_
.begin();
2478 p
!= this->section_list_
.end();
2481 const char* const name
= (*p
)->name();
2482 if (is_cident(name
))
2484 const std::string
name_string(name
);
2485 const std::string
start_name(cident_section_start_prefix
2487 const std::string
stop_name(cident_section_stop_prefix
2490 symtab
->define_in_output_data(start_name
.c_str(),
2492 Symbol_table::PREDEFINED
,
2498 elfcpp::STV_PROTECTED
,
2500 false, // offset_is_from_end
2501 true); // only_if_ref
2503 symtab
->define_in_output_data(stop_name
.c_str(),
2505 Symbol_table::PREDEFINED
,
2511 elfcpp::STV_PROTECTED
,
2513 true, // offset_is_from_end
2514 true); // only_if_ref
2519 // Define symbols for group signatures.
2522 Layout::define_group_signatures(Symbol_table
* symtab
)
2524 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2525 p
!= this->group_signatures_
.end();
2528 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2530 p
->section
->set_info_symndx(sym
);
2533 // Force the name of the group section to the group
2534 // signature, and use the group's section symbol as the
2535 // signature symbol.
2536 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2538 const char* name
= this->namepool_
.add(p
->signature
,
2540 p
->section
->set_name(name
);
2542 p
->section
->set_needs_symtab_index();
2543 p
->section
->set_info_section_symndx(p
->section
);
2547 this->group_signatures_
.clear();
2550 // Find the first read-only PT_LOAD segment, creating one if
2554 Layout::find_first_load_seg(const Target
* target
)
2556 Output_segment
* best
= NULL
;
2557 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2558 p
!= this->segment_list_
.end();
2561 if ((*p
)->type() == elfcpp::PT_LOAD
2562 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2563 && (parameters
->options().omagic()
2564 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2565 && (!target
->isolate_execinstr()
2566 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2568 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2575 gold_assert(!this->script_options_
->saw_phdrs_clause());
2577 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2582 // Save states of all current output segments. Store saved states
2583 // in SEGMENT_STATES.
2586 Layout::save_segments(Segment_states
* segment_states
)
2588 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2589 p
!= this->segment_list_
.end();
2592 Output_segment
* segment
= *p
;
2594 Output_segment
* copy
= new Output_segment(*segment
);
2595 (*segment_states
)[segment
] = copy
;
2599 // Restore states of output segments and delete any segment not found in
2603 Layout::restore_segments(const Segment_states
* segment_states
)
2605 // Go through the segment list and remove any segment added in the
2607 this->tls_segment_
= NULL
;
2608 this->relro_segment_
= NULL
;
2609 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2610 while (list_iter
!= this->segment_list_
.end())
2612 Output_segment
* segment
= *list_iter
;
2613 Segment_states::const_iterator states_iter
=
2614 segment_states
->find(segment
);
2615 if (states_iter
!= segment_states
->end())
2617 const Output_segment
* copy
= states_iter
->second
;
2618 // Shallow copy to restore states.
2621 // Also fix up TLS and RELRO segment pointers as appropriate.
2622 if (segment
->type() == elfcpp::PT_TLS
)
2623 this->tls_segment_
= segment
;
2624 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2625 this->relro_segment_
= segment
;
2631 list_iter
= this->segment_list_
.erase(list_iter
);
2632 // This is a segment created during section layout. It should be
2633 // safe to remove it since we should have removed all pointers to it.
2639 // Clean up after relaxation so that sections can be laid out again.
2642 Layout::clean_up_after_relaxation()
2644 // Restore the segments to point state just prior to the relaxation loop.
2645 Script_sections
* script_section
= this->script_options_
->script_sections();
2646 script_section
->release_segments();
2647 this->restore_segments(this->segment_states_
);
2649 // Reset section addresses and file offsets
2650 for (Section_list::iterator p
= this->section_list_
.begin();
2651 p
!= this->section_list_
.end();
2654 (*p
)->restore_states();
2656 // If an input section changes size because of relaxation,
2657 // we need to adjust the section offsets of all input sections.
2658 // after such a section.
2659 if ((*p
)->section_offsets_need_adjustment())
2660 (*p
)->adjust_section_offsets();
2662 (*p
)->reset_address_and_file_offset();
2665 // Reset special output object address and file offsets.
2666 for (Data_list::iterator p
= this->special_output_list_
.begin();
2667 p
!= this->special_output_list_
.end();
2669 (*p
)->reset_address_and_file_offset();
2671 // A linker script may have created some output section data objects.
2672 // They are useless now.
2673 for (Output_section_data_list::const_iterator p
=
2674 this->script_output_section_data_list_
.begin();
2675 p
!= this->script_output_section_data_list_
.end();
2678 this->script_output_section_data_list_
.clear();
2680 // Special-case fill output objects are recreated each time through
2681 // the relaxation loop.
2682 this->reset_relax_output();
2686 Layout::reset_relax_output()
2688 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
2689 p
!= this->relax_output_list_
.end();
2692 this->relax_output_list_
.clear();
2695 // Prepare for relaxation.
2698 Layout::prepare_for_relaxation()
2700 // Create an relaxation debug check if in debugging mode.
2701 if (is_debugging_enabled(DEBUG_RELAXATION
))
2702 this->relaxation_debug_check_
= new Relaxation_debug_check();
2704 // Save segment states.
2705 this->segment_states_
= new Segment_states();
2706 this->save_segments(this->segment_states_
);
2708 for(Section_list::const_iterator p
= this->section_list_
.begin();
2709 p
!= this->section_list_
.end();
2711 (*p
)->save_states();
2713 if (is_debugging_enabled(DEBUG_RELAXATION
))
2714 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2715 this->section_list_
, this->special_output_list_
,
2716 this->relax_output_list_
);
2718 // Also enable recording of output section data from scripts.
2719 this->record_output_section_data_from_script_
= true;
2722 // If the user set the address of the text segment, that may not be
2723 // compatible with putting the segment headers and file headers into
2724 // that segment. For isolate_execinstr() targets, it's the rodata
2725 // segment rather than text where we might put the headers.
2727 load_seg_unusable_for_headers(const Target
* target
)
2729 const General_options
& options
= parameters
->options();
2730 if (target
->isolate_execinstr())
2731 return (options
.user_set_Trodata_segment()
2732 && options
.Trodata_segment() % target
->abi_pagesize() != 0);
2734 return (options
.user_set_Ttext()
2735 && options
.Ttext() % target
->abi_pagesize() != 0);
2738 // Relaxation loop body: If target has no relaxation, this runs only once
2739 // Otherwise, the target relaxation hook is called at the end of
2740 // each iteration. If the hook returns true, it means re-layout of
2741 // section is required.
2743 // The number of segments created by a linking script without a PHDRS
2744 // clause may be affected by section sizes and alignments. There is
2745 // a remote chance that relaxation causes different number of PT_LOAD
2746 // segments are created and sections are attached to different segments.
2747 // Therefore, we always throw away all segments created during section
2748 // layout. In order to be able to restart the section layout, we keep
2749 // a copy of the segment list right before the relaxation loop and use
2750 // that to restore the segments.
2752 // PASS is the current relaxation pass number.
2753 // SYMTAB is a symbol table.
2754 // PLOAD_SEG is the address of a pointer for the load segment.
2755 // PHDR_SEG is a pointer to the PHDR segment.
2756 // SEGMENT_HEADERS points to the output segment header.
2757 // FILE_HEADER points to the output file header.
2758 // PSHNDX is the address to store the output section index.
2761 Layout::relaxation_loop_body(
2764 Symbol_table
* symtab
,
2765 Output_segment
** pload_seg
,
2766 Output_segment
* phdr_seg
,
2767 Output_segment_headers
* segment_headers
,
2768 Output_file_header
* file_header
,
2769 unsigned int* pshndx
)
2771 // If this is not the first iteration, we need to clean up after
2772 // relaxation so that we can lay out the sections again.
2774 this->clean_up_after_relaxation();
2776 // If there is a SECTIONS clause, put all the input sections into
2777 // the required order.
2778 Output_segment
* load_seg
;
2779 if (this->script_options_
->saw_sections_clause())
2780 load_seg
= this->set_section_addresses_from_script(symtab
);
2781 else if (parameters
->options().relocatable())
2784 load_seg
= this->find_first_load_seg(target
);
2786 if (parameters
->options().oformat_enum()
2787 != General_options::OBJECT_FORMAT_ELF
)
2790 if (load_seg_unusable_for_headers(target
))
2796 gold_assert(phdr_seg
== NULL
2798 || this->script_options_
->saw_sections_clause());
2800 // If the address of the load segment we found has been set by
2801 // --section-start rather than by a script, then adjust the VMA and
2802 // LMA downward if possible to include the file and section headers.
2803 uint64_t header_gap
= 0;
2804 if (load_seg
!= NULL
2805 && load_seg
->are_addresses_set()
2806 && !this->script_options_
->saw_sections_clause()
2807 && !parameters
->options().relocatable())
2809 file_header
->finalize_data_size();
2810 segment_headers
->finalize_data_size();
2811 size_t sizeof_headers
= (file_header
->data_size()
2812 + segment_headers
->data_size());
2813 const uint64_t abi_pagesize
= target
->abi_pagesize();
2814 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2815 hdr_paddr
&= ~(abi_pagesize
- 1);
2816 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2817 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2821 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2822 load_seg
->paddr() - subtract
);
2823 header_gap
= subtract
- sizeof_headers
;
2827 // Lay out the segment headers.
2828 if (!parameters
->options().relocatable())
2830 gold_assert(segment_headers
!= NULL
);
2831 if (header_gap
!= 0 && load_seg
!= NULL
)
2833 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2834 load_seg
->add_initial_output_data(z
);
2836 if (load_seg
!= NULL
)
2837 load_seg
->add_initial_output_data(segment_headers
);
2838 if (phdr_seg
!= NULL
)
2839 phdr_seg
->add_initial_output_data(segment_headers
);
2842 // Lay out the file header.
2843 if (load_seg
!= NULL
)
2844 load_seg
->add_initial_output_data(file_header
);
2846 if (this->script_options_
->saw_phdrs_clause()
2847 && !parameters
->options().relocatable())
2849 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2850 // clause in a linker script.
2851 Script_sections
* ss
= this->script_options_
->script_sections();
2852 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2855 // We set the output section indexes in set_segment_offsets and
2856 // set_section_indexes.
2859 // Set the file offsets of all the segments, and all the sections
2862 if (!parameters
->options().relocatable())
2863 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2865 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2867 // Verify that the dummy relaxation does not change anything.
2868 if (is_debugging_enabled(DEBUG_RELAXATION
))
2871 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2873 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2876 *pload_seg
= load_seg
;
2880 // Search the list of patterns and find the position of the given section
2881 // name in the output section. If the section name matches a glob
2882 // pattern and a non-glob name, then the non-glob position takes
2883 // precedence. Return 0 if no match is found.
2886 Layout::find_section_order_index(const std::string
& section_name
)
2888 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2889 map_it
= this->input_section_position_
.find(section_name
);
2890 if (map_it
!= this->input_section_position_
.end())
2891 return map_it
->second
;
2893 // Absolute match failed. Linear search the glob patterns.
2894 std::vector
<std::string
>::iterator it
;
2895 for (it
= this->input_section_glob_
.begin();
2896 it
!= this->input_section_glob_
.end();
2899 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2901 map_it
= this->input_section_position_
.find(*it
);
2902 gold_assert(map_it
!= this->input_section_position_
.end());
2903 return map_it
->second
;
2909 // Read the sequence of input sections from the file specified with
2910 // option --section-ordering-file.
2913 Layout::read_layout_from_file()
2915 const char* filename
= parameters
->options().section_ordering_file();
2921 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2922 filename
, strerror(errno
));
2924 std::getline(in
, line
); // this chops off the trailing \n, if any
2925 unsigned int position
= 1;
2926 this->set_section_ordering_specified();
2930 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2931 line
.resize(line
.length() - 1);
2932 // Ignore comments, beginning with '#'
2935 std::getline(in
, line
);
2938 this->input_section_position_
[line
] = position
;
2939 // Store all glob patterns in a vector.
2940 if (is_wildcard_string(line
.c_str()))
2941 this->input_section_glob_
.push_back(line
);
2943 std::getline(in
, line
);
2947 // Finalize the layout. When this is called, we have created all the
2948 // output sections and all the output segments which are based on
2949 // input sections. We have several things to do, and we have to do
2950 // them in the right order, so that we get the right results correctly
2953 // 1) Finalize the list of output segments and create the segment
2956 // 2) Finalize the dynamic symbol table and associated sections.
2958 // 3) Determine the final file offset of all the output segments.
2960 // 4) Determine the final file offset of all the SHF_ALLOC output
2963 // 5) Create the symbol table sections and the section name table
2966 // 6) Finalize the symbol table: set symbol values to their final
2967 // value and make a final determination of which symbols are going
2968 // into the output symbol table.
2970 // 7) Create the section table header.
2972 // 8) Determine the final file offset of all the output sections which
2973 // are not SHF_ALLOC, including the section table header.
2975 // 9) Finalize the ELF file header.
2977 // This function returns the size of the output file.
2980 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2981 Target
* target
, const Task
* task
)
2983 unsigned int local_dynamic_count
= 0;
2984 unsigned int forced_local_dynamic_count
= 0;
2986 target
->finalize_sections(this, input_objects
, symtab
);
2988 this->count_local_symbols(task
, input_objects
);
2990 this->link_stabs_sections();
2992 Output_segment
* phdr_seg
= NULL
;
2993 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2995 // There was a dynamic object in the link. We need to create
2996 // some information for the dynamic linker.
2998 // Create the PT_PHDR segment which will hold the program
3000 if (!this->script_options_
->saw_phdrs_clause())
3001 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
3003 // Create the dynamic symbol table, including the hash table.
3004 Output_section
* dynstr
;
3005 std::vector
<Symbol
*> dynamic_symbols
;
3006 Versions
versions(*this->script_options()->version_script_info(),
3008 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
3009 &local_dynamic_count
,
3010 &forced_local_dynamic_count
,
3014 // Create the .interp section to hold the name of the
3015 // interpreter, and put it in a PT_INTERP segment. Don't do it
3016 // if we saw a .interp section in an input file.
3017 if ((!parameters
->options().shared()
3018 || parameters
->options().dynamic_linker() != NULL
)
3019 && this->interp_segment_
== NULL
)
3020 this->create_interp(target
);
3022 // Finish the .dynamic section to hold the dynamic data, and put
3023 // it in a PT_DYNAMIC segment.
3024 this->finish_dynamic_section(input_objects
, symtab
);
3026 // We should have added everything we need to the dynamic string
3028 this->dynpool_
.set_string_offsets();
3030 // Create the version sections. We can't do this until the
3031 // dynamic string table is complete.
3032 this->create_version_sections(&versions
, symtab
,
3033 (local_dynamic_count
3034 + forced_local_dynamic_count
),
3035 dynamic_symbols
, dynstr
);
3037 // Set the size of the _DYNAMIC symbol. We can't do this until
3038 // after we call create_version_sections.
3039 this->set_dynamic_symbol_size(symtab
);
3042 // Create segment headers.
3043 Output_segment_headers
* segment_headers
=
3044 (parameters
->options().relocatable()
3046 : new Output_segment_headers(this->segment_list_
));
3048 // Lay out the file header.
3049 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
3052 this->special_output_list_
.push_back(file_header
);
3053 if (segment_headers
!= NULL
)
3054 this->special_output_list_
.push_back(segment_headers
);
3056 // Find approriate places for orphan output sections if we are using
3058 if (this->script_options_
->saw_sections_clause())
3059 this->place_orphan_sections_in_script();
3061 Output_segment
* load_seg
;
3066 // Take a snapshot of the section layout as needed.
3067 if (target
->may_relax())
3068 this->prepare_for_relaxation();
3070 // Run the relaxation loop to lay out sections.
3073 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
3074 phdr_seg
, segment_headers
, file_header
,
3078 while (target
->may_relax()
3079 && target
->relax(pass
, input_objects
, symtab
, this, task
));
3081 // If there is a load segment that contains the file and program headers,
3082 // provide a symbol __ehdr_start pointing there.
3083 // A program can use this to examine itself robustly.
3084 Symbol
*ehdr_start
= symtab
->lookup("__ehdr_start");
3085 if (ehdr_start
!= NULL
&& ehdr_start
->is_predefined())
3087 if (load_seg
!= NULL
)
3088 ehdr_start
->set_output_segment(load_seg
, Symbol::SEGMENT_START
);
3090 ehdr_start
->set_undefined();
3093 // Set the file offsets of all the non-data sections we've seen so
3094 // far which don't have to wait for the input sections. We need
3095 // this in order to finalize local symbols in non-allocated
3097 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
3099 // Set the section indexes of all unallocated sections seen so far,
3100 // in case any of them are somehow referenced by a symbol.
3101 shndx
= this->set_section_indexes(shndx
);
3103 // Create the symbol table sections.
3104 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
,
3105 local_dynamic_count
);
3106 if (!parameters
->doing_static_link())
3107 this->assign_local_dynsym_offsets(input_objects
);
3109 // Process any symbol assignments from a linker script. This must
3110 // be called after the symbol table has been finalized.
3111 this->script_options_
->finalize_symbols(symtab
, this);
3113 // Create the incremental inputs sections.
3114 if (this->incremental_inputs_
)
3116 this->incremental_inputs_
->finalize();
3117 this->create_incremental_info_sections(symtab
);
3120 // Create the .shstrtab section.
3121 Output_section
* shstrtab_section
= this->create_shstrtab();
3123 // Set the file offsets of the rest of the non-data sections which
3124 // don't have to wait for the input sections.
3125 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
3127 // Now that all sections have been created, set the section indexes
3128 // for any sections which haven't been done yet.
3129 shndx
= this->set_section_indexes(shndx
);
3131 // Create the section table header.
3132 this->create_shdrs(shstrtab_section
, &off
);
3134 // If there are no sections which require postprocessing, we can
3135 // handle the section names now, and avoid a resize later.
3136 if (!this->any_postprocessing_sections_
)
3138 off
= this->set_section_offsets(off
,
3139 POSTPROCESSING_SECTIONS_PASS
);
3141 this->set_section_offsets(off
,
3142 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
3145 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
3147 // Now we know exactly where everything goes in the output file
3148 // (except for non-allocated sections which require postprocessing).
3149 Output_data::layout_complete();
3151 this->output_file_size_
= off
;
3156 // Create a note header following the format defined in the ELF ABI.
3157 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
3158 // of the section to create, DESCSZ is the size of the descriptor.
3159 // ALLOCATE is true if the section should be allocated in memory.
3160 // This returns the new note section. It sets *TRAILING_PADDING to
3161 // the number of trailing zero bytes required.
3164 Layout::create_note(const char* name
, int note_type
,
3165 const char* section_name
, size_t descsz
,
3166 bool allocate
, size_t* trailing_padding
)
3168 // Authorities all agree that the values in a .note field should
3169 // be aligned on 4-byte boundaries for 32-bit binaries. However,
3170 // they differ on what the alignment is for 64-bit binaries.
3171 // The GABI says unambiguously they take 8-byte alignment:
3172 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
3173 // Other documentation says alignment should always be 4 bytes:
3174 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
3175 // GNU ld and GNU readelf both support the latter (at least as of
3176 // version 2.16.91), and glibc always generates the latter for
3177 // .note.ABI-tag (as of version 1.6), so that's the one we go with
3179 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
3180 const int size
= parameters
->target().get_size();
3182 const int size
= 32;
3185 // The contents of the .note section.
3186 size_t namesz
= strlen(name
) + 1;
3187 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
3188 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
3190 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
3192 unsigned char* buffer
= new unsigned char[notehdrsz
];
3193 memset(buffer
, 0, notehdrsz
);
3195 bool is_big_endian
= parameters
->target().is_big_endian();
3201 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
3202 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
3203 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
3207 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
3208 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
3209 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
3212 else if (size
== 64)
3216 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
3217 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
3218 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
3222 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
3223 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
3224 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
3230 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
3232 elfcpp::Elf_Xword flags
= 0;
3233 Output_section_order order
= ORDER_INVALID
;
3236 flags
= elfcpp::SHF_ALLOC
;
3237 order
= ORDER_RO_NOTE
;
3239 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
3241 flags
, false, order
, false,
3246 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
3249 os
->add_output_section_data(posd
);
3251 *trailing_padding
= aligned_descsz
- descsz
;
3256 // Create a .note.gnu.property section to record program properties
3257 // accumulated from the input files.
3260 Layout::create_gnu_properties_note()
3262 parameters
->target().finalize_gnu_properties(this);
3264 if (this->gnu_properties_
.empty())
3267 const unsigned int size
= parameters
->target().get_size();
3268 const bool is_big_endian
= parameters
->target().is_big_endian();
3270 // Compute the total size of the properties array.
3272 for (Gnu_properties::const_iterator prop
= this->gnu_properties_
.begin();
3273 prop
!= this->gnu_properties_
.end();
3276 descsz
= align_address(descsz
+ 8 + prop
->second
.pr_datasz
, size
/ 8);
3279 // Create the note section.
3280 size_t trailing_padding
;
3281 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_PROPERTY_TYPE_0
,
3282 ".note.gnu.property", descsz
,
3283 true, &trailing_padding
);
3286 gold_assert(trailing_padding
== 0);
3288 // Allocate and fill the properties array.
3289 unsigned char* desc
= new unsigned char[descsz
];
3290 unsigned char* p
= desc
;
3291 for (Gnu_properties::const_iterator prop
= this->gnu_properties_
.begin();
3292 prop
!= this->gnu_properties_
.end();
3295 size_t datasz
= prop
->second
.pr_datasz
;
3296 size_t aligned_datasz
= align_address(prop
->second
.pr_datasz
, size
/ 8);
3297 write_sized_value(prop
->first
, 4, p
, is_big_endian
);
3298 write_sized_value(datasz
, 4, p
+ 4, is_big_endian
);
3299 memcpy(p
+ 8, prop
->second
.pr_data
, datasz
);
3300 if (aligned_datasz
> datasz
)
3301 memset(p
+ 8 + datasz
, 0, aligned_datasz
- datasz
);
3302 p
+= 8 + aligned_datasz
;
3304 Output_section_data
* posd
= new Output_data_const(desc
, descsz
, 4);
3305 os
->add_output_section_data(posd
);
3308 // For an executable or shared library, create a note to record the
3309 // version of gold used to create the binary.
3312 Layout::create_gold_note()
3314 if (parameters
->options().relocatable()
3315 || parameters
->incremental_update())
3318 std::string desc
= std::string("gold ") + gold::get_version_string();
3320 size_t trailing_padding
;
3321 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
3322 ".note.gnu.gold-version", desc
.size(),
3323 false, &trailing_padding
);
3327 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3328 os
->add_output_section_data(posd
);
3330 if (trailing_padding
> 0)
3332 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3333 os
->add_output_section_data(posd
);
3337 // Record whether the stack should be executable. This can be set
3338 // from the command line using the -z execstack or -z noexecstack
3339 // options. Otherwise, if any input file has a .note.GNU-stack
3340 // section with the SHF_EXECINSTR flag set, the stack should be
3341 // executable. Otherwise, if at least one input file a
3342 // .note.GNU-stack section, and some input file has no .note.GNU-stack
3343 // section, we use the target default for whether the stack should be
3344 // executable. If -z stack-size was used to set a p_memsz value for
3345 // PT_GNU_STACK, we generate the segment regardless. Otherwise, we
3346 // don't generate a stack note. When generating a object file, we
3347 // create a .note.GNU-stack section with the appropriate marking.
3348 // When generating an executable or shared library, we create a
3349 // PT_GNU_STACK segment.
3352 Layout::create_stack_segment()
3354 bool is_stack_executable
;
3355 if (parameters
->options().is_execstack_set())
3357 is_stack_executable
= parameters
->options().is_stack_executable();
3358 if (!is_stack_executable
3359 && this->input_requires_executable_stack_
3360 && parameters
->options().warn_execstack())
3361 gold_warning(_("one or more inputs require executable stack, "
3362 "but -z noexecstack was given"));
3364 else if (!this->input_with_gnu_stack_note_
3365 && (!parameters
->options().user_set_stack_size()
3366 || parameters
->options().relocatable()))
3370 if (this->input_requires_executable_stack_
)
3371 is_stack_executable
= true;
3372 else if (this->input_without_gnu_stack_note_
)
3373 is_stack_executable
=
3374 parameters
->target().is_default_stack_executable();
3376 is_stack_executable
= false;
3379 if (parameters
->options().relocatable())
3381 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
3382 elfcpp::Elf_Xword flags
= 0;
3383 if (is_stack_executable
)
3384 flags
|= elfcpp::SHF_EXECINSTR
;
3385 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
3386 ORDER_INVALID
, false);
3390 if (this->script_options_
->saw_phdrs_clause())
3392 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
3393 if (is_stack_executable
)
3394 flags
|= elfcpp::PF_X
;
3395 Output_segment
* seg
=
3396 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
3397 seg
->set_size(parameters
->options().stack_size());
3398 // BFD lets targets override this default alignment, but the only
3399 // targets that do so are ones that Gold does not support so far.
3400 seg
->set_minimum_p_align(16);
3404 // If --build-id was used, set up the build ID note.
3407 Layout::create_build_id()
3409 if (!parameters
->options().user_set_build_id())
3412 const char* style
= parameters
->options().build_id();
3413 if (strcmp(style
, "none") == 0)
3416 // Set DESCSZ to the size of the note descriptor. When possible,
3417 // set DESC to the note descriptor contents.
3420 if (strcmp(style
, "md5") == 0)
3422 else if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
3424 else if (strcmp(style
, "uuid") == 0)
3427 const size_t uuidsz
= 128 / 8;
3429 char buffer
[uuidsz
];
3430 memset(buffer
, 0, uuidsz
);
3432 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
3434 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3438 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
3439 release_descriptor(descriptor
, true);
3441 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
3442 else if (static_cast<size_t>(got
) != uuidsz
)
3443 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3447 desc
.assign(buffer
, uuidsz
);
3449 #else // __MINGW32__
3451 typedef RPC_STATUS (RPC_ENTRY
*UuidCreateFn
)(UUID
*Uuid
);
3453 HMODULE rpc_library
= LoadLibrary("rpcrt4.dll");
3455 gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll"));
3458 UuidCreateFn uuid_create
= reinterpret_cast<UuidCreateFn
>(
3459 GetProcAddress(rpc_library
, "UuidCreate"));
3461 gold_error(_("--build-id=uuid failed: could not find UuidCreate"));
3462 else if (uuid_create(&uuid
) != RPC_S_OK
)
3463 gold_error(_("__build_id=uuid failed: call UuidCreate() failed"));
3464 FreeLibrary(rpc_library
);
3466 desc
.assign(reinterpret_cast<const char *>(&uuid
), sizeof(UUID
));
3467 descsz
= sizeof(UUID
);
3468 #endif // __MINGW32__
3470 else if (strncmp(style
, "0x", 2) == 0)
3473 const char* p
= style
+ 2;
3476 if (hex_p(p
[0]) && hex_p(p
[1]))
3478 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
3482 else if (*p
== '-' || *p
== ':')
3485 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3488 descsz
= desc
.size();
3491 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
3494 size_t trailing_padding
;
3495 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
3496 ".note.gnu.build-id", descsz
, true,
3503 // We know the value already, so we fill it in now.
3504 gold_assert(desc
.size() == descsz
);
3506 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3507 os
->add_output_section_data(posd
);
3509 if (trailing_padding
!= 0)
3511 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3512 os
->add_output_section_data(posd
);
3517 // We need to compute a checksum after we have completed the
3519 gold_assert(trailing_padding
== 0);
3520 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3521 os
->add_output_section_data(this->build_id_note_
);
3525 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3526 // field of the former should point to the latter. I'm not sure who
3527 // started this, but the GNU linker does it, and some tools depend
3531 Layout::link_stabs_sections()
3533 if (!this->have_stabstr_section_
)
3536 for (Section_list::iterator p
= this->section_list_
.begin();
3537 p
!= this->section_list_
.end();
3540 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3543 const char* name
= (*p
)->name();
3544 if (strncmp(name
, ".stab", 5) != 0)
3547 size_t len
= strlen(name
);
3548 if (strcmp(name
+ len
- 3, "str") != 0)
3551 std::string
stab_name(name
, len
- 3);
3552 Output_section
* stab_sec
;
3553 stab_sec
= this->find_output_section(stab_name
.c_str());
3554 if (stab_sec
!= NULL
)
3555 stab_sec
->set_link_section(*p
);
3559 // Create .gnu_incremental_inputs and related sections needed
3560 // for the next run of incremental linking to check what has changed.
3563 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3565 Incremental_inputs
* incr
= this->incremental_inputs_
;
3567 gold_assert(incr
!= NULL
);
3569 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3570 incr
->create_data_sections(symtab
);
3572 // Add the .gnu_incremental_inputs section.
3573 const char* incremental_inputs_name
=
3574 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3575 Output_section
* incremental_inputs_os
=
3576 this->make_output_section(incremental_inputs_name
,
3577 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3578 ORDER_INVALID
, false);
3579 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3581 // Add the .gnu_incremental_symtab section.
3582 const char* incremental_symtab_name
=
3583 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3584 Output_section
* incremental_symtab_os
=
3585 this->make_output_section(incremental_symtab_name
,
3586 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3587 ORDER_INVALID
, false);
3588 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3589 incremental_symtab_os
->set_entsize(4);
3591 // Add the .gnu_incremental_relocs section.
3592 const char* incremental_relocs_name
=
3593 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3594 Output_section
* incremental_relocs_os
=
3595 this->make_output_section(incremental_relocs_name
,
3596 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3597 ORDER_INVALID
, false);
3598 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3599 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3601 // Add the .gnu_incremental_got_plt section.
3602 const char* incremental_got_plt_name
=
3603 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3604 Output_section
* incremental_got_plt_os
=
3605 this->make_output_section(incremental_got_plt_name
,
3606 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3607 ORDER_INVALID
, false);
3608 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3610 // Add the .gnu_incremental_strtab section.
3611 const char* incremental_strtab_name
=
3612 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3613 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3614 elfcpp::SHT_STRTAB
, 0,
3615 ORDER_INVALID
, false);
3616 Output_data_strtab
* strtab_data
=
3617 new Output_data_strtab(incr
->get_stringpool());
3618 incremental_strtab_os
->add_output_section_data(strtab_data
);
3620 incremental_inputs_os
->set_after_input_sections();
3621 incremental_symtab_os
->set_after_input_sections();
3622 incremental_relocs_os
->set_after_input_sections();
3623 incremental_got_plt_os
->set_after_input_sections();
3625 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3626 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3627 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3628 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3631 // Return whether SEG1 should be before SEG2 in the output file. This
3632 // is based entirely on the segment type and flags. When this is
3633 // called the segment addresses have normally not yet been set.
3636 Layout::segment_precedes(const Output_segment
* seg1
,
3637 const Output_segment
* seg2
)
3639 // In order to produce a stable ordering if we're called with the same pointer
3644 elfcpp::Elf_Word type1
= seg1
->type();
3645 elfcpp::Elf_Word type2
= seg2
->type();
3647 // The single PT_PHDR segment is required to precede any loadable
3648 // segment. We simply make it always first.
3649 if (type1
== elfcpp::PT_PHDR
)
3651 gold_assert(type2
!= elfcpp::PT_PHDR
);
3654 if (type2
== elfcpp::PT_PHDR
)
3657 // The single PT_INTERP segment is required to precede any loadable
3658 // segment. We simply make it always second.
3659 if (type1
== elfcpp::PT_INTERP
)
3661 gold_assert(type2
!= elfcpp::PT_INTERP
);
3664 if (type2
== elfcpp::PT_INTERP
)
3667 // We then put PT_LOAD segments before any other segments.
3668 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3670 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3673 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3674 // segment, because that is where the dynamic linker expects to find
3675 // it (this is just for efficiency; other positions would also work
3677 if (type1
== elfcpp::PT_TLS
3678 && type2
!= elfcpp::PT_TLS
3679 && type2
!= elfcpp::PT_GNU_RELRO
)
3681 if (type2
== elfcpp::PT_TLS
3682 && type1
!= elfcpp::PT_TLS
3683 && type1
!= elfcpp::PT_GNU_RELRO
)
3686 // We put the PT_GNU_RELRO segment last, because that is where the
3687 // dynamic linker expects to find it (as with PT_TLS, this is just
3689 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3691 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3694 const elfcpp::Elf_Word flags1
= seg1
->flags();
3695 const elfcpp::Elf_Word flags2
= seg2
->flags();
3697 // The order of non-PT_LOAD segments is unimportant. We simply sort
3698 // by the numeric segment type and flags values. There should not
3699 // be more than one segment with the same type and flags, except
3700 // when a linker script specifies such.
3701 if (type1
!= elfcpp::PT_LOAD
)
3704 return type1
< type2
;
3705 gold_assert(flags1
!= flags2
3706 || this->script_options_
->saw_phdrs_clause());
3707 return flags1
< flags2
;
3710 // If the addresses are set already, sort by load address.
3711 if (seg1
->are_addresses_set())
3713 if (!seg2
->are_addresses_set())
3716 unsigned int section_count1
= seg1
->output_section_count();
3717 unsigned int section_count2
= seg2
->output_section_count();
3718 if (section_count1
== 0 && section_count2
> 0)
3720 if (section_count1
> 0 && section_count2
== 0)
3723 uint64_t paddr1
= (seg1
->are_addresses_set()
3725 : seg1
->first_section_load_address());
3726 uint64_t paddr2
= (seg2
->are_addresses_set()
3728 : seg2
->first_section_load_address());
3730 if (paddr1
!= paddr2
)
3731 return paddr1
< paddr2
;
3733 else if (seg2
->are_addresses_set())
3736 // A segment which holds large data comes after a segment which does
3737 // not hold large data.
3738 if (seg1
->is_large_data_segment())
3740 if (!seg2
->is_large_data_segment())
3743 else if (seg2
->is_large_data_segment())
3746 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3747 // segments come before writable segments. Then writable segments
3748 // with data come before writable segments without data. Then
3749 // executable segments come before non-executable segments. Then
3750 // the unlikely case of a non-readable segment comes before the
3751 // normal case of a readable segment. If there are multiple
3752 // segments with the same type and flags, we require that the
3753 // address be set, and we sort by virtual address and then physical
3755 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3756 return (flags1
& elfcpp::PF_W
) == 0;
3757 if ((flags1
& elfcpp::PF_W
) != 0
3758 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3759 return seg1
->has_any_data_sections();
3760 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3761 return (flags1
& elfcpp::PF_X
) != 0;
3762 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3763 return (flags1
& elfcpp::PF_R
) == 0;
3765 // We shouldn't get here--we shouldn't create segments which we
3766 // can't distinguish. Unless of course we are using a weird linker
3767 // script or overlapping --section-start options. We could also get
3768 // here if plugins want unique segments for subsets of sections.
3769 gold_assert(this->script_options_
->saw_phdrs_clause()
3770 || parameters
->options().any_section_start()
3771 || this->is_unique_segment_for_sections_specified()
3772 || parameters
->options().text_unlikely_segment());
3776 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3779 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3781 uint64_t unsigned_off
= off
;
3782 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3783 | (addr
& (abi_pagesize
- 1)));
3784 if (aligned_off
< unsigned_off
)
3785 aligned_off
+= abi_pagesize
;
3789 // On targets where the text segment contains only executable code,
3790 // a non-executable segment is never the text segment.
3793 is_text_segment(const Target
* target
, const Output_segment
* seg
)
3795 elfcpp::Elf_Xword flags
= seg
->flags();
3796 if ((flags
& elfcpp::PF_W
) != 0)
3798 if ((flags
& elfcpp::PF_X
) == 0)
3799 return !target
->isolate_execinstr();
3803 // Set the file offsets of all the segments, and all the sections they
3804 // contain. They have all been created. LOAD_SEG must be laid out
3805 // first. Return the offset of the data to follow.
3808 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3809 unsigned int* pshndx
)
3811 // Sort them into the final order. We use a stable sort so that we
3812 // don't randomize the order of indistinguishable segments created
3813 // by linker scripts.
3814 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3815 Layout::Compare_segments(this));
3817 // Find the PT_LOAD segments, and set their addresses and offsets
3818 // and their section's addresses and offsets.
3819 uint64_t start_addr
;
3820 if (parameters
->options().user_set_Ttext())
3821 start_addr
= parameters
->options().Ttext();
3822 else if (parameters
->options().output_is_position_independent())
3825 start_addr
= target
->default_text_segment_address();
3827 uint64_t addr
= start_addr
;
3830 // If LOAD_SEG is NULL, then the file header and segment headers
3831 // will not be loadable. But they still need to be at offset 0 in
3832 // the file. Set their offsets now.
3833 if (load_seg
== NULL
)
3835 for (Data_list::iterator p
= this->special_output_list_
.begin();
3836 p
!= this->special_output_list_
.end();
3839 off
= align_address(off
, (*p
)->addralign());
3840 (*p
)->set_address_and_file_offset(0, off
);
3841 off
+= (*p
)->data_size();
3845 unsigned int increase_relro
= this->increase_relro_
;
3846 if (this->script_options_
->saw_sections_clause())
3849 const bool check_sections
= parameters
->options().check_sections();
3850 Output_segment
* last_load_segment
= NULL
;
3852 unsigned int shndx_begin
= *pshndx
;
3853 unsigned int shndx_load_seg
= *pshndx
;
3855 for (Segment_list::iterator p
= this->segment_list_
.begin();
3856 p
!= this->segment_list_
.end();
3859 if ((*p
)->type() == elfcpp::PT_LOAD
)
3861 if (target
->isolate_execinstr())
3863 // When we hit the segment that should contain the
3864 // file headers, reset the file offset so we place
3865 // it and subsequent segments appropriately.
3866 // We'll fix up the preceding segments below.
3874 shndx_load_seg
= *pshndx
;
3880 // Verify that the file headers fall into the first segment.
3881 if (load_seg
!= NULL
&& load_seg
!= *p
)
3886 bool are_addresses_set
= (*p
)->are_addresses_set();
3887 if (are_addresses_set
)
3889 // When it comes to setting file offsets, we care about
3890 // the physical address.
3891 addr
= (*p
)->paddr();
3893 else if (parameters
->options().user_set_Ttext()
3894 && (parameters
->options().omagic()
3895 || is_text_segment(target
, *p
)))
3897 are_addresses_set
= true;
3899 else if (parameters
->options().user_set_Trodata_segment()
3900 && ((*p
)->flags() & (elfcpp::PF_W
| elfcpp::PF_X
)) == 0)
3902 addr
= parameters
->options().Trodata_segment();
3903 are_addresses_set
= true;
3905 else if (parameters
->options().user_set_Tdata()
3906 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3907 && (!parameters
->options().user_set_Tbss()
3908 || (*p
)->has_any_data_sections()))
3910 addr
= parameters
->options().Tdata();
3911 are_addresses_set
= true;
3913 else if (parameters
->options().user_set_Tbss()
3914 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3915 && !(*p
)->has_any_data_sections())
3917 addr
= parameters
->options().Tbss();
3918 are_addresses_set
= true;
3921 uint64_t orig_addr
= addr
;
3922 uint64_t orig_off
= off
;
3924 uint64_t aligned_addr
= 0;
3925 uint64_t abi_pagesize
= target
->abi_pagesize();
3926 uint64_t common_pagesize
= target
->common_pagesize();
3928 if (!parameters
->options().nmagic()
3929 && !parameters
->options().omagic())
3930 (*p
)->set_minimum_p_align(abi_pagesize
);
3932 if (!are_addresses_set
)
3934 // Skip the address forward one page, maintaining the same
3935 // position within the page. This lets us store both segments
3936 // overlapping on a single page in the file, but the loader will
3937 // put them on different pages in memory. We will revisit this
3938 // decision once we know the size of the segment.
3940 uint64_t max_align
= (*p
)->maximum_alignment();
3941 if (max_align
> abi_pagesize
)
3942 addr
= align_address(addr
, max_align
);
3943 aligned_addr
= addr
;
3947 // This is the segment that will contain the file
3948 // headers, so its offset will have to be exactly zero.
3949 gold_assert(orig_off
== 0);
3951 // If the target wants a fixed minimum distance from the
3952 // text segment to the read-only segment, move up now.
3954 start_addr
+ (parameters
->options().user_set_rosegment_gap()
3955 ? parameters
->options().rosegment_gap()
3956 : target
->rosegment_gap());
3957 if (addr
< min_addr
)
3960 // But this is not the first segment! To make its
3961 // address congruent with its offset, that address better
3962 // be aligned to the ABI-mandated page size.
3963 addr
= align_address(addr
, abi_pagesize
);
3964 aligned_addr
= addr
;
3968 if ((addr
& (abi_pagesize
- 1)) != 0)
3969 addr
= addr
+ abi_pagesize
;
3971 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3975 if (!parameters
->options().nmagic()
3976 && !parameters
->options().omagic())
3978 // Here we are also taking care of the case when
3979 // the maximum segment alignment is larger than the page size.
3980 off
= align_file_offset(off
, addr
,
3981 std::max(abi_pagesize
,
3982 (*p
)->maximum_alignment()));
3986 // This is -N or -n with a section script which prevents
3987 // us from using a load segment. We need to ensure that
3988 // the file offset is aligned to the alignment of the
3989 // segment. This is because the linker script
3990 // implicitly assumed a zero offset. If we don't align
3991 // here, then the alignment of the sections in the
3992 // linker script may not match the alignment of the
3993 // sections in the set_section_addresses call below,
3994 // causing an error about dot moving backward.
3995 off
= align_address(off
, (*p
)->maximum_alignment());
3998 unsigned int shndx_hold
= *pshndx
;
3999 bool has_relro
= false;
4000 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
4006 // Now that we know the size of this segment, we may be able
4007 // to save a page in memory, at the cost of wasting some
4008 // file space, by instead aligning to the start of a new
4009 // page. Here we use the real machine page size rather than
4010 // the ABI mandated page size. If the segment has been
4011 // aligned so that the relro data ends at a page boundary,
4012 // we do not try to realign it.
4014 if (!are_addresses_set
4016 && aligned_addr
!= addr
4017 && !parameters
->incremental())
4019 uint64_t first_off
= (common_pagesize
4021 & (common_pagesize
- 1)));
4022 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
4025 && ((aligned_addr
& ~ (common_pagesize
- 1))
4026 != (new_addr
& ~ (common_pagesize
- 1)))
4027 && first_off
+ last_off
<= common_pagesize
)
4029 *pshndx
= shndx_hold
;
4030 addr
= align_address(aligned_addr
, common_pagesize
);
4031 addr
= align_address(addr
, (*p
)->maximum_alignment());
4032 if ((addr
& (abi_pagesize
- 1)) != 0)
4033 addr
= addr
+ abi_pagesize
;
4034 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
4035 off
= align_file_offset(off
, addr
, abi_pagesize
);
4037 increase_relro
= this->increase_relro_
;
4038 if (this->script_options_
->saw_sections_clause())
4042 new_addr
= (*p
)->set_section_addresses(target
, this,
4052 // Implement --check-sections. We know that the segments
4053 // are sorted by LMA.
4054 if (check_sections
&& last_load_segment
!= NULL
)
4056 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
4057 if (last_load_segment
->paddr() + last_load_segment
->memsz()
4060 unsigned long long lb1
= last_load_segment
->paddr();
4061 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
4062 unsigned long long lb2
= (*p
)->paddr();
4063 unsigned long long le2
= lb2
+ (*p
)->memsz();
4064 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
4065 "[0x%llx -> 0x%llx]"),
4066 lb1
, le1
, lb2
, le2
);
4069 last_load_segment
= *p
;
4073 if (load_seg
!= NULL
&& target
->isolate_execinstr())
4075 // Process the early segments again, setting their file offsets
4076 // so they land after the segments starting at LOAD_SEG.
4077 off
= align_file_offset(off
, 0, target
->abi_pagesize());
4079 this->reset_relax_output();
4081 for (Segment_list::iterator p
= this->segment_list_
.begin();
4085 if ((*p
)->type() == elfcpp::PT_LOAD
)
4087 // We repeat the whole job of assigning addresses and
4088 // offsets, but we really only want to change the offsets and
4089 // must ensure that the addresses all come out the same as
4090 // they did the first time through.
4091 bool has_relro
= false;
4092 const uint64_t old_addr
= (*p
)->vaddr();
4093 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
4094 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
4100 gold_assert(new_addr
== old_end
);
4104 gold_assert(shndx_begin
== shndx_load_seg
);
4107 // Handle the non-PT_LOAD segments, setting their offsets from their
4108 // section's offsets.
4109 for (Segment_list::iterator p
= this->segment_list_
.begin();
4110 p
!= this->segment_list_
.end();
4113 // PT_GNU_STACK was set up correctly when it was created.
4114 if ((*p
)->type() != elfcpp::PT_LOAD
4115 && (*p
)->type() != elfcpp::PT_GNU_STACK
)
4116 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
4121 // Set the TLS offsets for each section in the PT_TLS segment.
4122 if (this->tls_segment_
!= NULL
)
4123 this->tls_segment_
->set_tls_offsets();
4128 // Set the offsets of all the allocated sections when doing a
4129 // relocatable link. This does the same jobs as set_segment_offsets,
4130 // only for a relocatable link.
4133 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
4134 unsigned int* pshndx
)
4138 file_header
->set_address_and_file_offset(0, 0);
4139 off
+= file_header
->data_size();
4141 for (Section_list::iterator p
= this->section_list_
.begin();
4142 p
!= this->section_list_
.end();
4145 // We skip unallocated sections here, except that group sections
4146 // have to come first.
4147 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
4148 && (*p
)->type() != elfcpp::SHT_GROUP
)
4151 off
= align_address(off
, (*p
)->addralign());
4153 // The linker script might have set the address.
4154 if (!(*p
)->is_address_valid())
4155 (*p
)->set_address(0);
4156 (*p
)->set_file_offset(off
);
4157 (*p
)->finalize_data_size();
4158 if ((*p
)->type() != elfcpp::SHT_NOBITS
)
4159 off
+= (*p
)->data_size();
4161 (*p
)->set_out_shndx(*pshndx
);
4168 // Set the file offset of all the sections not associated with a
4172 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
4174 off_t startoff
= off
;
4177 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
4178 p
!= this->unattached_section_list_
.end();
4181 // The symtab section is handled in create_symtab_sections.
4182 if (*p
== this->symtab_section_
)
4185 // If we've already set the data size, don't set it again.
4186 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
4189 if (pass
== BEFORE_INPUT_SECTIONS_PASS
4190 && (*p
)->requires_postprocessing())
4192 (*p
)->create_postprocessing_buffer();
4193 this->any_postprocessing_sections_
= true;
4196 if (pass
== BEFORE_INPUT_SECTIONS_PASS
4197 && (*p
)->after_input_sections())
4199 else if (pass
== POSTPROCESSING_SECTIONS_PASS
4200 && (!(*p
)->after_input_sections()
4201 || (*p
)->type() == elfcpp::SHT_STRTAB
))
4203 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
4204 && (!(*p
)->after_input_sections()
4205 || (*p
)->type() != elfcpp::SHT_STRTAB
))
4208 if (!parameters
->incremental_update())
4210 off
= align_address(off
, (*p
)->addralign());
4211 (*p
)->set_file_offset(off
);
4212 (*p
)->finalize_data_size();
4216 // Incremental update: allocate file space from free list.
4217 (*p
)->pre_finalize_data_size();
4218 off_t current_size
= (*p
)->current_data_size();
4219 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
4222 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
4223 this->free_list_
.dump();
4224 gold_assert((*p
)->output_section() != NULL
);
4225 gold_fallback(_("out of patch space for section %s; "
4226 "relink with --incremental-full"),
4227 (*p
)->output_section()->name());
4229 (*p
)->set_file_offset(off
);
4230 (*p
)->finalize_data_size();
4231 if ((*p
)->data_size() > current_size
)
4233 gold_assert((*p
)->output_section() != NULL
);
4234 gold_fallback(_("%s: section changed size; "
4235 "relink with --incremental-full"),
4236 (*p
)->output_section()->name());
4238 gold_debug(DEBUG_INCREMENTAL
,
4239 "set_section_offsets: %08lx %08lx %s",
4240 static_cast<long>(off
),
4241 static_cast<long>((*p
)->data_size()),
4242 ((*p
)->output_section() != NULL
4243 ? (*p
)->output_section()->name() : "(special)"));
4246 off
+= (*p
)->data_size();
4250 // At this point the name must be set.
4251 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
4252 this->namepool_
.add((*p
)->name(), false, NULL
);
4257 // Set the section indexes of all the sections not associated with a
4261 Layout::set_section_indexes(unsigned int shndx
)
4263 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
4264 p
!= this->unattached_section_list_
.end();
4267 if (!(*p
)->has_out_shndx())
4269 (*p
)->set_out_shndx(shndx
);
4276 // Set the section addresses according to the linker script. This is
4277 // only called when we see a SECTIONS clause. This returns the
4278 // program segment which should hold the file header and segment
4279 // headers, if any. It will return NULL if they should not be in a
4283 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
4285 Script_sections
* ss
= this->script_options_
->script_sections();
4286 gold_assert(ss
->saw_sections_clause());
4287 return this->script_options_
->set_section_addresses(symtab
, this);
4290 // Place the orphan sections in the linker script.
4293 Layout::place_orphan_sections_in_script()
4295 Script_sections
* ss
= this->script_options_
->script_sections();
4296 gold_assert(ss
->saw_sections_clause());
4298 // Place each orphaned output section in the script.
4299 for (Section_list::iterator p
= this->section_list_
.begin();
4300 p
!= this->section_list_
.end();
4303 if (!(*p
)->found_in_sections_clause())
4304 ss
->place_orphan(*p
);
4308 // Count the local symbols in the regular symbol table and the dynamic
4309 // symbol table, and build the respective string pools.
4312 Layout::count_local_symbols(const Task
* task
,
4313 const Input_objects
* input_objects
)
4315 // First, figure out an upper bound on the number of symbols we'll
4316 // be inserting into each pool. This helps us create the pools with
4317 // the right size, to avoid unnecessary hashtable resizing.
4318 unsigned int symbol_count
= 0;
4319 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4320 p
!= input_objects
->relobj_end();
4322 symbol_count
+= (*p
)->local_symbol_count();
4324 // Go from "upper bound" to "estimate." We overcount for two
4325 // reasons: we double-count symbols that occur in more than one
4326 // object file, and we count symbols that are dropped from the
4327 // output. Add it all together and assume we overcount by 100%.
4330 // We assume all symbols will go into both the sympool and dynpool.
4331 this->sympool_
.reserve(symbol_count
);
4332 this->dynpool_
.reserve(symbol_count
);
4334 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4335 p
!= input_objects
->relobj_end();
4338 Task_lock_obj
<Object
> tlo(task
, *p
);
4339 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
4343 // Create the symbol table sections. Here we also set the final
4344 // values of the symbols. At this point all the loadable sections are
4345 // fully laid out. SHNUM is the number of sections so far.
4348 Layout::create_symtab_sections(const Input_objects
* input_objects
,
4349 Symbol_table
* symtab
,
4352 unsigned int local_dynamic_count
)
4356 if (parameters
->target().get_size() == 32)
4358 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4361 else if (parameters
->target().get_size() == 64)
4363 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4369 // Compute file offsets relative to the start of the symtab section.
4372 // Save space for the dummy symbol at the start of the section. We
4373 // never bother to write this out--it will just be left as zero.
4375 unsigned int local_symbol_index
= 1;
4377 // Add STT_SECTION symbols for each Output section which needs one.
4378 for (Section_list::iterator p
= this->section_list_
.begin();
4379 p
!= this->section_list_
.end();
4382 if (!(*p
)->needs_symtab_index())
4383 (*p
)->set_symtab_index(-1U);
4386 (*p
)->set_symtab_index(local_symbol_index
);
4387 ++local_symbol_index
;
4392 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4393 p
!= input_objects
->relobj_end();
4396 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
4398 off
+= (index
- local_symbol_index
) * symsize
;
4399 local_symbol_index
= index
;
4402 unsigned int local_symcount
= local_symbol_index
;
4403 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
4407 if (this->dynsym_section_
== NULL
)
4414 off_t locsize
= local_dynamic_count
* this->dynsym_section_
->entsize();
4415 dynoff
= this->dynsym_section_
->offset() + locsize
;
4416 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
4417 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
4418 == this->dynsym_section_
->data_size() - locsize
);
4421 off_t global_off
= off
;
4422 off
= symtab
->finalize(off
, dynoff
, local_dynamic_count
, dyncount
,
4423 &this->sympool_
, &local_symcount
);
4425 if (!parameters
->options().strip_all())
4427 this->sympool_
.set_string_offsets();
4429 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
4430 Output_section
* osymtab
= this->make_output_section(symtab_name
,
4434 this->symtab_section_
= osymtab
;
4436 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
4438 osymtab
->add_output_section_data(pos
);
4440 // We generate a .symtab_shndx section if we have more than
4441 // SHN_LORESERVE sections. Technically it is possible that we
4442 // don't need one, because it is possible that there are no
4443 // symbols in any of sections with indexes larger than
4444 // SHN_LORESERVE. That is probably unusual, though, and it is
4445 // easier to always create one than to compute section indexes
4446 // twice (once here, once when writing out the symbols).
4447 if (shnum
>= elfcpp::SHN_LORESERVE
)
4449 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
4451 Output_section
* osymtab_xindex
=
4452 this->make_output_section(symtab_xindex_name
,
4453 elfcpp::SHT_SYMTAB_SHNDX
, 0,
4454 ORDER_INVALID
, false);
4456 size_t symcount
= off
/ symsize
;
4457 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
4459 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
4461 osymtab_xindex
->set_link_section(osymtab
);
4462 osymtab_xindex
->set_addralign(4);
4463 osymtab_xindex
->set_entsize(4);
4465 osymtab_xindex
->set_after_input_sections();
4467 // This tells the driver code to wait until the symbol table
4468 // has written out before writing out the postprocessing
4469 // sections, including the .symtab_shndx section.
4470 this->any_postprocessing_sections_
= true;
4473 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
4474 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
4479 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
4480 ostrtab
->add_output_section_data(pstr
);
4483 if (!parameters
->incremental_update())
4484 symtab_off
= align_address(*poff
, align
);
4487 symtab_off
= this->allocate(off
, align
, *poff
);
4489 gold_fallback(_("out of patch space for symbol table; "
4490 "relink with --incremental-full"));
4491 gold_debug(DEBUG_INCREMENTAL
,
4492 "create_symtab_sections: %08lx %08lx .symtab",
4493 static_cast<long>(symtab_off
),
4494 static_cast<long>(off
));
4497 symtab
->set_file_offset(symtab_off
+ global_off
);
4498 osymtab
->set_file_offset(symtab_off
);
4499 osymtab
->finalize_data_size();
4500 osymtab
->set_link_section(ostrtab
);
4501 osymtab
->set_info(local_symcount
);
4502 osymtab
->set_entsize(symsize
);
4504 if (symtab_off
+ off
> *poff
)
4505 *poff
= symtab_off
+ off
;
4509 // Create the .shstrtab section, which holds the names of the
4510 // sections. At the time this is called, we have created all the
4511 // output sections except .shstrtab itself.
4514 Layout::create_shstrtab()
4516 // FIXME: We don't need to create a .shstrtab section if we are
4517 // stripping everything.
4519 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
4521 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
4522 ORDER_INVALID
, false);
4524 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
4526 // We can't write out this section until we've set all the
4527 // section names, and we don't set the names of compressed
4528 // output sections until relocations are complete. FIXME: With
4529 // the current names we use, this is unnecessary.
4530 os
->set_after_input_sections();
4533 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
4534 os
->add_output_section_data(posd
);
4539 // Create the section headers. SIZE is 32 or 64. OFF is the file
4543 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
4545 Output_section_headers
* oshdrs
;
4546 oshdrs
= new Output_section_headers(this,
4547 &this->segment_list_
,
4548 &this->section_list_
,
4549 &this->unattached_section_list_
,
4553 if (!parameters
->incremental_update())
4554 off
= align_address(*poff
, oshdrs
->addralign());
4557 oshdrs
->pre_finalize_data_size();
4558 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
4560 gold_fallback(_("out of patch space for section header table; "
4561 "relink with --incremental-full"));
4562 gold_debug(DEBUG_INCREMENTAL
,
4563 "create_shdrs: %08lx %08lx (section header table)",
4564 static_cast<long>(off
),
4565 static_cast<long>(off
+ oshdrs
->data_size()));
4567 oshdrs
->set_address_and_file_offset(0, off
);
4568 off
+= oshdrs
->data_size();
4571 this->section_headers_
= oshdrs
;
4574 // Count the allocated sections.
4577 Layout::allocated_output_section_count() const
4579 size_t section_count
= 0;
4580 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4581 p
!= this->segment_list_
.end();
4583 section_count
+= (*p
)->output_section_count();
4584 return section_count
;
4587 // Create the dynamic symbol table.
4588 // *PLOCAL_DYNAMIC_COUNT will be set to the number of local symbols
4589 // from input objects, and *PFORCED_LOCAL_DYNAMIC_COUNT will be set
4590 // to the number of global symbols that have been forced local.
4591 // We need to remember the former because the forced-local symbols are
4592 // written along with the global symbols in Symtab::write_globals().
4595 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4596 Symbol_table
* symtab
,
4597 Output_section
** pdynstr
,
4598 unsigned int* plocal_dynamic_count
,
4599 unsigned int* pforced_local_dynamic_count
,
4600 std::vector
<Symbol
*>* pdynamic_symbols
,
4601 Versions
* pversions
)
4603 // Count all the symbols in the dynamic symbol table, and set the
4604 // dynamic symbol indexes.
4606 // Skip symbol 0, which is always all zeroes.
4607 unsigned int index
= 1;
4609 // Add STT_SECTION symbols for each Output section which needs one.
4610 for (Section_list::iterator p
= this->section_list_
.begin();
4611 p
!= this->section_list_
.end();
4614 if (!(*p
)->needs_dynsym_index())
4615 (*p
)->set_dynsym_index(-1U);
4618 (*p
)->set_dynsym_index(index
);
4623 // Count the local symbols that need to go in the dynamic symbol table,
4624 // and set the dynamic symbol indexes.
4625 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4626 p
!= input_objects
->relobj_end();
4629 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4633 unsigned int local_symcount
= index
;
4634 unsigned int forced_local_count
= 0;
4636 index
= symtab
->set_dynsym_indexes(index
, &forced_local_count
,
4637 pdynamic_symbols
, &this->dynpool_
,
4640 *plocal_dynamic_count
= local_symcount
;
4641 *pforced_local_dynamic_count
= forced_local_count
;
4645 const int size
= parameters
->target().get_size();
4648 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4651 else if (size
== 64)
4653 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4659 // Create the dynamic symbol table section.
4661 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4665 ORDER_DYNAMIC_LINKER
,
4666 false, false, false);
4668 // Check for NULL as a linker script may discard .dynsym.
4671 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4674 dynsym
->add_output_section_data(odata
);
4676 dynsym
->set_info(local_symcount
+ forced_local_count
);
4677 dynsym
->set_entsize(symsize
);
4678 dynsym
->set_addralign(align
);
4680 this->dynsym_section_
= dynsym
;
4683 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4686 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4687 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4690 // If there are more than SHN_LORESERVE allocated sections, we
4691 // create a .dynsym_shndx section. It is possible that we don't
4692 // need one, because it is possible that there are no dynamic
4693 // symbols in any of the sections with indexes larger than
4694 // SHN_LORESERVE. This is probably unusual, though, and at this
4695 // time we don't know the actual section indexes so it is
4696 // inconvenient to check.
4697 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4699 Output_section
* dynsym_xindex
=
4700 this->choose_output_section(NULL
, ".dynsym_shndx",
4701 elfcpp::SHT_SYMTAB_SHNDX
,
4703 false, ORDER_DYNAMIC_LINKER
, false, false,
4706 if (dynsym_xindex
!= NULL
)
4708 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4710 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4712 dynsym_xindex
->set_link_section(dynsym
);
4713 dynsym_xindex
->set_addralign(4);
4714 dynsym_xindex
->set_entsize(4);
4716 dynsym_xindex
->set_after_input_sections();
4718 // This tells the driver code to wait until the symbol table
4719 // has written out before writing out the postprocessing
4720 // sections, including the .dynsym_shndx section.
4721 this->any_postprocessing_sections_
= true;
4725 // Create the dynamic string table section.
4727 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4731 ORDER_DYNAMIC_LINKER
,
4732 false, false, false);
4736 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4737 dynstr
->add_output_section_data(strdata
);
4740 dynsym
->set_link_section(dynstr
);
4741 if (this->dynamic_section_
!= NULL
)
4742 this->dynamic_section_
->set_link_section(dynstr
);
4746 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4747 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4751 // Create the hash tables. The Gnu-style hash table must be
4752 // built first, because it changes the order of the symbols
4753 // in the dynamic symbol table.
4755 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4756 || strcmp(parameters
->options().hash_style(), "both") == 0)
4758 unsigned char* phash
;
4759 unsigned int hashlen
;
4760 Dynobj::create_gnu_hash_table(*pdynamic_symbols
,
4761 local_symcount
+ forced_local_count
,
4764 Output_section
* hashsec
=
4765 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4766 elfcpp::SHF_ALLOC
, false,
4767 ORDER_DYNAMIC_LINKER
, false, false,
4770 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4774 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4775 hashsec
->add_output_section_data(hashdata
);
4777 if (hashsec
!= NULL
)
4780 hashsec
->set_link_section(dynsym
);
4782 // For a 64-bit target, the entries in .gnu.hash do not have
4783 // a uniform size, so we only set the entry size for a
4785 if (parameters
->target().get_size() == 32)
4786 hashsec
->set_entsize(4);
4789 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4793 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4794 || strcmp(parameters
->options().hash_style(), "both") == 0)
4796 unsigned char* phash
;
4797 unsigned int hashlen
;
4798 Dynobj::create_elf_hash_table(*pdynamic_symbols
,
4799 local_symcount
+ forced_local_count
,
4802 Output_section
* hashsec
=
4803 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4804 elfcpp::SHF_ALLOC
, false,
4805 ORDER_DYNAMIC_LINKER
, false, false,
4808 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4812 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4813 hashsec
->add_output_section_data(hashdata
);
4815 if (hashsec
!= NULL
)
4818 hashsec
->set_link_section(dynsym
);
4819 hashsec
->set_entsize(parameters
->target().hash_entry_size() / 8);
4823 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4827 // Assign offsets to each local portion of the dynamic symbol table.
4830 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4832 Output_section
* dynsym
= this->dynsym_section_
;
4836 off_t off
= dynsym
->offset();
4838 // Skip the dummy symbol at the start of the section.
4839 off
+= dynsym
->entsize();
4841 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4842 p
!= input_objects
->relobj_end();
4845 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4846 off
+= count
* dynsym
->entsize();
4850 // Create the version sections.
4853 Layout::create_version_sections(const Versions
* versions
,
4854 const Symbol_table
* symtab
,
4855 unsigned int local_symcount
,
4856 const std::vector
<Symbol
*>& dynamic_symbols
,
4857 const Output_section
* dynstr
)
4859 if (!versions
->any_defs() && !versions
->any_needs())
4862 switch (parameters
->size_and_endianness())
4864 #ifdef HAVE_TARGET_32_LITTLE
4865 case Parameters::TARGET_32_LITTLE
:
4866 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4868 dynamic_symbols
, dynstr
);
4871 #ifdef HAVE_TARGET_32_BIG
4872 case Parameters::TARGET_32_BIG
:
4873 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4875 dynamic_symbols
, dynstr
);
4878 #ifdef HAVE_TARGET_64_LITTLE
4879 case Parameters::TARGET_64_LITTLE
:
4880 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4882 dynamic_symbols
, dynstr
);
4885 #ifdef HAVE_TARGET_64_BIG
4886 case Parameters::TARGET_64_BIG
:
4887 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4889 dynamic_symbols
, dynstr
);
4897 // Create the version sections, sized version.
4899 template<int size
, bool big_endian
>
4901 Layout::sized_create_version_sections(
4902 const Versions
* versions
,
4903 const Symbol_table
* symtab
,
4904 unsigned int local_symcount
,
4905 const std::vector
<Symbol
*>& dynamic_symbols
,
4906 const Output_section
* dynstr
)
4908 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4909 elfcpp::SHT_GNU_versym
,
4912 ORDER_DYNAMIC_LINKER
,
4913 false, false, false);
4915 // Check for NULL since a linker script may discard this section.
4918 unsigned char* vbuf
;
4920 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4926 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4929 vsec
->add_output_section_data(vdata
);
4930 vsec
->set_entsize(2);
4931 vsec
->set_link_section(this->dynsym_section_
);
4934 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4935 if (odyn
!= NULL
&& vsec
!= NULL
)
4936 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4938 if (versions
->any_defs())
4940 Output_section
* vdsec
;
4941 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4942 elfcpp::SHT_GNU_verdef
,
4944 false, ORDER_DYNAMIC_LINKER
, false,
4949 unsigned char* vdbuf
;
4950 unsigned int vdsize
;
4951 unsigned int vdentries
;
4952 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4956 Output_section_data
* vddata
=
4957 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4959 vdsec
->add_output_section_data(vddata
);
4960 vdsec
->set_link_section(dynstr
);
4961 vdsec
->set_info(vdentries
);
4965 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4966 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4971 if (versions
->any_needs())
4973 Output_section
* vnsec
;
4974 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4975 elfcpp::SHT_GNU_verneed
,
4977 false, ORDER_DYNAMIC_LINKER
, false,
4982 unsigned char* vnbuf
;
4983 unsigned int vnsize
;
4984 unsigned int vnentries
;
4985 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4989 Output_section_data
* vndata
=
4990 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4992 vnsec
->add_output_section_data(vndata
);
4993 vnsec
->set_link_section(dynstr
);
4994 vnsec
->set_info(vnentries
);
4998 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4999 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
5005 // Create the .interp section and PT_INTERP segment.
5008 Layout::create_interp(const Target
* target
)
5010 gold_assert(this->interp_segment_
== NULL
);
5012 const char* interp
= parameters
->options().dynamic_linker();
5015 interp
= target
->dynamic_linker();
5016 gold_assert(interp
!= NULL
);
5019 size_t len
= strlen(interp
) + 1;
5021 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
5023 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
5024 elfcpp::SHT_PROGBITS
,
5026 false, ORDER_INTERP
,
5027 false, false, false);
5029 osec
->add_output_section_data(odata
);
5032 // Add dynamic tags for the PLT and the dynamic relocs. This is
5033 // called by the target-specific code. This does nothing if not doing
5036 // USE_REL is true for REL relocs rather than RELA relocs.
5038 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
5040 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
5041 // and we also set DT_PLTREL. We use PLT_REL's output section, since
5042 // some targets have multiple reloc sections in PLT_REL.
5044 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
5045 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
5048 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
5052 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
5053 const Output_data
* plt_rel
,
5054 const Output_data_reloc_generic
* dyn_rel
,
5055 bool add_debug
, bool dynrel_includes_plt
)
5057 Output_data_dynamic
* odyn
= this->dynamic_data_
;
5061 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
5062 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
5064 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
5066 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
5067 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
5068 odyn
->add_constant(elfcpp::DT_PLTREL
,
5069 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
5072 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
5073 || (dynrel_includes_plt
5075 && plt_rel
->output_section() != NULL
))
5077 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
5078 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
5079 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
5081 ? dyn_rel
->output_section()
5082 : plt_rel
->output_section()));
5083 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
5084 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
5085 odyn
->add_section_size(size_tag
,
5086 dyn_rel
->output_section(),
5087 plt_rel
->output_section());
5088 else if (have_dyn_rel
)
5089 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
5091 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
5092 const int size
= parameters
->target().get_size();
5097 rel_tag
= elfcpp::DT_RELENT
;
5099 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
5100 else if (size
== 64)
5101 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
5107 rel_tag
= elfcpp::DT_RELAENT
;
5109 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
5110 else if (size
== 64)
5111 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
5115 odyn
->add_constant(rel_tag
, rel_size
);
5117 if (parameters
->options().combreloc() && have_dyn_rel
)
5119 size_t c
= dyn_rel
->relative_reloc_count();
5121 odyn
->add_constant((use_rel
5122 ? elfcpp::DT_RELCOUNT
5123 : elfcpp::DT_RELACOUNT
),
5128 if (add_debug
&& !parameters
->options().shared())
5130 // The value of the DT_DEBUG tag is filled in by the dynamic
5131 // linker at run time, and used by the debugger.
5132 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
5137 Layout::add_target_specific_dynamic_tag(elfcpp::DT tag
, unsigned int val
)
5139 Output_data_dynamic
* odyn
= this->dynamic_data_
;
5142 odyn
->add_constant(tag
, val
);
5145 // Finish the .dynamic section and PT_DYNAMIC segment.
5148 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
5149 const Symbol_table
* symtab
)
5151 if (!this->script_options_
->saw_phdrs_clause()
5152 && this->dynamic_section_
!= NULL
)
5154 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
5157 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
5158 elfcpp::PF_R
| elfcpp::PF_W
);
5161 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
5165 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
5166 p
!= input_objects
->dynobj_end();
5169 if (!(*p
)->is_needed() && (*p
)->as_needed())
5171 // This dynamic object was linked with --as-needed, but it
5176 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
5179 if (parameters
->options().shared())
5181 const char* soname
= parameters
->options().soname();
5183 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
5186 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
5187 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
5188 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
5190 sym
= symtab
->lookup(parameters
->options().fini());
5191 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
5192 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
5194 // Look for .init_array, .preinit_array and .fini_array by checking
5196 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
5197 p
!= this->section_list_
.end();
5199 switch((*p
)->type())
5201 case elfcpp::SHT_FINI_ARRAY
:
5202 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
5203 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
5205 case elfcpp::SHT_INIT_ARRAY
:
5206 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
5207 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
5209 case elfcpp::SHT_PREINIT_ARRAY
:
5210 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
5211 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
5217 // Add a DT_RPATH entry if needed.
5218 const General_options::Dir_list
& rpath(parameters
->options().rpath());
5221 std::string rpath_val
;
5222 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
5226 if (rpath_val
.empty())
5227 rpath_val
= p
->name();
5230 // Eliminate duplicates.
5231 General_options::Dir_list::const_iterator q
;
5232 for (q
= rpath
.begin(); q
!= p
; ++q
)
5233 if (q
->name() == p
->name())
5238 rpath_val
+= p
->name();
5243 if (!parameters
->options().enable_new_dtags())
5244 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
5246 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
5249 // Look for text segments that have dynamic relocations.
5250 bool have_textrel
= false;
5251 if (!this->script_options_
->saw_sections_clause())
5253 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5254 p
!= this->segment_list_
.end();
5257 if ((*p
)->type() == elfcpp::PT_LOAD
5258 && ((*p
)->flags() & elfcpp::PF_W
) == 0
5259 && (*p
)->has_dynamic_reloc())
5261 have_textrel
= true;
5268 // We don't know the section -> segment mapping, so we are
5269 // conservative and just look for readonly sections with
5270 // relocations. If those sections wind up in writable segments,
5271 // then we have created an unnecessary DT_TEXTREL entry.
5272 for (Section_list::const_iterator p
= this->section_list_
.begin();
5273 p
!= this->section_list_
.end();
5276 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
5277 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
5278 && (*p
)->has_dynamic_reloc())
5280 have_textrel
= true;
5286 if (parameters
->options().filter() != NULL
)
5287 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
5288 if (parameters
->options().any_auxiliary())
5290 for (options::String_set::const_iterator p
=
5291 parameters
->options().auxiliary_begin();
5292 p
!= parameters
->options().auxiliary_end();
5294 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
5297 // Add a DT_FLAGS entry if necessary.
5298 unsigned int flags
= 0;
5301 // Add a DT_TEXTREL for compatibility with older loaders.
5302 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
5303 flags
|= elfcpp::DF_TEXTREL
;
5305 if (parameters
->options().text())
5306 gold_error(_("read-only segment has dynamic relocations"));
5307 else if (parameters
->options().warn_shared_textrel()
5308 && parameters
->options().shared())
5309 gold_warning(_("shared library text segment is not shareable"));
5311 if (parameters
->options().shared() && this->has_static_tls())
5312 flags
|= elfcpp::DF_STATIC_TLS
;
5313 if (parameters
->options().origin())
5314 flags
|= elfcpp::DF_ORIGIN
;
5315 if (parameters
->options().Bsymbolic()
5316 && !parameters
->options().have_dynamic_list())
5318 flags
|= elfcpp::DF_SYMBOLIC
;
5319 // Add DT_SYMBOLIC for compatibility with older loaders.
5320 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
5322 if (parameters
->options().now())
5323 flags
|= elfcpp::DF_BIND_NOW
;
5325 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
5328 if (parameters
->options().global())
5329 flags
|= elfcpp::DF_1_GLOBAL
;
5330 if (parameters
->options().initfirst())
5331 flags
|= elfcpp::DF_1_INITFIRST
;
5332 if (parameters
->options().interpose())
5333 flags
|= elfcpp::DF_1_INTERPOSE
;
5334 if (parameters
->options().loadfltr())
5335 flags
|= elfcpp::DF_1_LOADFLTR
;
5336 if (parameters
->options().nodefaultlib())
5337 flags
|= elfcpp::DF_1_NODEFLIB
;
5338 if (parameters
->options().nodelete())
5339 flags
|= elfcpp::DF_1_NODELETE
;
5340 if (parameters
->options().nodlopen())
5341 flags
|= elfcpp::DF_1_NOOPEN
;
5342 if (parameters
->options().nodump())
5343 flags
|= elfcpp::DF_1_NODUMP
;
5344 if (!parameters
->options().shared())
5345 flags
&= ~(elfcpp::DF_1_INITFIRST
5346 | elfcpp::DF_1_NODELETE
5347 | elfcpp::DF_1_NOOPEN
);
5348 if (parameters
->options().origin())
5349 flags
|= elfcpp::DF_1_ORIGIN
;
5350 if (parameters
->options().now())
5351 flags
|= elfcpp::DF_1_NOW
;
5352 if (parameters
->options().Bgroup())
5353 flags
|= elfcpp::DF_1_GROUP
;
5355 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
5358 // Set the size of the _DYNAMIC symbol table to be the size of the
5362 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
5364 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
5367 odyn
->finalize_data_size();
5368 if (this->dynamic_symbol_
== NULL
)
5370 off_t data_size
= odyn
->data_size();
5371 const int size
= parameters
->target().get_size();
5373 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
5374 else if (size
== 64)
5375 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
5380 // The mapping of input section name prefixes to output section names.
5381 // In some cases one prefix is itself a prefix of another prefix; in
5382 // such a case the longer prefix must come first. These prefixes are
5383 // based on the GNU linker default ELF linker script.
5385 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
5386 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
5387 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
5389 MAPPING_INIT(".text.", ".text"),
5390 MAPPING_INIT(".rodata.", ".rodata"),
5391 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
5392 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
5393 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
5394 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
5395 MAPPING_INIT(".data.", ".data"),
5396 MAPPING_INIT(".bss.", ".bss"),
5397 MAPPING_INIT(".tdata.", ".tdata"),
5398 MAPPING_INIT(".tbss.", ".tbss"),
5399 MAPPING_INIT(".init_array.", ".init_array"),
5400 MAPPING_INIT(".fini_array.", ".fini_array"),
5401 MAPPING_INIT(".sdata.", ".sdata"),
5402 MAPPING_INIT(".sbss.", ".sbss"),
5403 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
5404 // differently depending on whether it is creating a shared library.
5405 MAPPING_INIT(".sdata2.", ".sdata"),
5406 MAPPING_INIT(".sbss2.", ".sbss"),
5407 MAPPING_INIT(".lrodata.", ".lrodata"),
5408 MAPPING_INIT(".ldata.", ".ldata"),
5409 MAPPING_INIT(".lbss.", ".lbss"),
5410 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
5411 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
5412 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
5413 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
5414 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
5415 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
5416 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
5417 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
5418 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
5419 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
5420 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
5421 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
5422 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
5423 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
5424 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
5425 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5426 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5427 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5428 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5429 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5430 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5431 MAPPING_INIT(".gnu.build.attributes.", ".gnu.build.attributes"),
5434 // Mapping for ".text" section prefixes with -z,keep-text-section-prefix.
5435 const Layout::Section_name_mapping
Layout::text_section_name_mapping
[] =
5437 MAPPING_INIT(".text.hot.", ".text.hot"),
5438 MAPPING_INIT_EXACT(".text.hot", ".text.hot"),
5439 MAPPING_INIT(".text.unlikely.", ".text.unlikely"),
5440 MAPPING_INIT_EXACT(".text.unlikely", ".text.unlikely"),
5441 MAPPING_INIT(".text.startup.", ".text.startup"),
5442 MAPPING_INIT_EXACT(".text.startup", ".text.startup"),
5443 MAPPING_INIT(".text.exit.", ".text.exit"),
5444 MAPPING_INIT_EXACT(".text.exit", ".text.exit"),
5445 MAPPING_INIT(".text.", ".text"),
5448 #undef MAPPING_INIT_EXACT
5450 const int Layout::section_name_mapping_count
=
5451 (sizeof(Layout::section_name_mapping
)
5452 / sizeof(Layout::section_name_mapping
[0]));
5454 const int Layout::text_section_name_mapping_count
=
5455 (sizeof(Layout::text_section_name_mapping
)
5456 / sizeof(Layout::text_section_name_mapping
[0]));
5458 // Find section name NAME in PSNM and return the mapped name if found
5459 // with the length set in PLEN.
5461 Layout::match_section_name(const Layout::Section_name_mapping
* psnm
,
5463 const char* name
, size_t* plen
)
5465 for (int i
= 0; i
< count
; ++i
, ++psnm
)
5467 if (psnm
->fromlen
> 0)
5469 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
5471 *plen
= psnm
->tolen
;
5477 if (strcmp(name
, psnm
->from
) == 0)
5479 *plen
= psnm
->tolen
;
5487 // Choose the output section name to use given an input section name.
5488 // Set *PLEN to the length of the name. *PLEN is initialized to the
5492 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
5495 // gcc 4.3 generates the following sorts of section names when it
5496 // needs a section name specific to a function:
5502 // .data.rel.local.FN
5504 // .data.rel.ro.local.FN
5511 // The GNU linker maps all of those to the part before the .FN,
5512 // except that .data.rel.local.FN is mapped to .data, and
5513 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5514 // beginning with .data.rel.ro.local are grouped together.
5516 // For an anonymous namespace, the string FN can contain a '.'.
5518 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5519 // GNU linker maps to .rodata.
5521 // The .data.rel.ro sections are used with -z relro. The sections
5522 // are recognized by name. We use the same names that the GNU
5523 // linker does for these sections.
5525 // It is hard to handle this in a principled way, so we don't even
5526 // try. We use a table of mappings. If the input section name is
5527 // not found in the table, we simply use it as the output section
5530 if (parameters
->options().keep_text_section_prefix()
5531 && is_prefix_of(".text", name
))
5533 const char* match
= match_section_name(text_section_name_mapping
,
5534 text_section_name_mapping_count
,
5540 const char* match
= match_section_name(section_name_mapping
,
5541 section_name_mapping_count
, name
, plen
);
5545 // As an additional complication, .ctors sections are output in
5546 // either .ctors or .init_array sections, and .dtors sections are
5547 // output in either .dtors or .fini_array sections.
5548 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
5550 if (parameters
->options().ctors_in_init_array())
5553 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5558 return name
[1] == 'c' ? ".ctors" : ".dtors";
5561 if (parameters
->options().ctors_in_init_array()
5562 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
5564 // To make .init_array/.fini_array work with gcc we must exclude
5565 // .ctors and .dtors sections from the crtbegin and crtend
5568 || (!Layout::match_file_name(relobj
, "crtbegin")
5569 && !Layout::match_file_name(relobj
, "crtend")))
5572 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5579 // Return true if RELOBJ is an input file whose base name matches
5580 // FILE_NAME. The base name must have an extension of ".o", and must
5581 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5582 // to match crtbegin.o as well as crtbeginS.o without getting confused
5583 // by other possibilities. Overall matching the file name this way is
5584 // a dreadful hack, but the GNU linker does it in order to better
5585 // support gcc, and we need to be compatible.
5588 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
5590 const std::string
& file_name(relobj
->name());
5591 const char* base_name
= lbasename(file_name
.c_str());
5592 size_t match_len
= strlen(match
);
5593 if (strncmp(base_name
, match
, match_len
) != 0)
5595 size_t base_len
= strlen(base_name
);
5596 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
5598 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
5601 // Check if a comdat group or .gnu.linkonce section with the given
5602 // NAME is selected for the link. If there is already a section,
5603 // *KEPT_SECTION is set to point to the existing section and the
5604 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5605 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5606 // *KEPT_SECTION is set to the internal copy and the function returns
5610 Layout::find_or_add_kept_section(const std::string
& name
,
5615 Kept_section
** kept_section
)
5617 // It's normal to see a couple of entries here, for the x86 thunk
5618 // sections. If we see more than a few, we're linking a C++
5619 // program, and we resize to get more space to minimize rehashing.
5620 if (this->signatures_
.size() > 4
5621 && !this->resized_signatures_
)
5623 reserve_unordered_map(&this->signatures_
,
5624 this->number_of_input_files_
* 64);
5625 this->resized_signatures_
= true;
5628 Kept_section candidate
;
5629 std::pair
<Signatures::iterator
, bool> ins
=
5630 this->signatures_
.insert(std::make_pair(name
, candidate
));
5632 if (kept_section
!= NULL
)
5633 *kept_section
= &ins
.first
->second
;
5636 // This is the first time we've seen this signature.
5637 ins
.first
->second
.set_object(object
);
5638 ins
.first
->second
.set_shndx(shndx
);
5640 ins
.first
->second
.set_is_comdat();
5642 ins
.first
->second
.set_is_group_name();
5646 // We have already seen this signature.
5648 if (ins
.first
->second
.is_group_name())
5650 // We've already seen a real section group with this signature.
5651 // If the kept group is from a plugin object, and we're in the
5652 // replacement phase, accept the new one as a replacement.
5653 if (ins
.first
->second
.object() == NULL
5654 && parameters
->options().plugins()->in_replacement_phase())
5656 ins
.first
->second
.set_object(object
);
5657 ins
.first
->second
.set_shndx(shndx
);
5662 else if (is_group_name
)
5664 // This is a real section group, and we've already seen a
5665 // linkonce section with this signature. Record that we've seen
5666 // a section group, and don't include this section group.
5667 ins
.first
->second
.set_is_group_name();
5672 // We've already seen a linkonce section and this is a linkonce
5673 // section. These don't block each other--this may be the same
5674 // symbol name with different section types.
5679 // Store the allocated sections into the section list.
5682 Layout::get_allocated_sections(Section_list
* section_list
) const
5684 for (Section_list::const_iterator p
= this->section_list_
.begin();
5685 p
!= this->section_list_
.end();
5687 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5688 section_list
->push_back(*p
);
5691 // Store the executable sections into the section list.
5694 Layout::get_executable_sections(Section_list
* section_list
) const
5696 for (Section_list::const_iterator p
= this->section_list_
.begin();
5697 p
!= this->section_list_
.end();
5699 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5700 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5701 section_list
->push_back(*p
);
5704 // Create an output segment.
5707 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5709 gold_assert(!parameters
->options().relocatable());
5710 Output_segment
* oseg
= new Output_segment(type
, flags
);
5711 this->segment_list_
.push_back(oseg
);
5713 if (type
== elfcpp::PT_TLS
)
5714 this->tls_segment_
= oseg
;
5715 else if (type
== elfcpp::PT_GNU_RELRO
)
5716 this->relro_segment_
= oseg
;
5717 else if (type
== elfcpp::PT_INTERP
)
5718 this->interp_segment_
= oseg
;
5723 // Return the file offset of the normal symbol table.
5726 Layout::symtab_section_offset() const
5728 if (this->symtab_section_
!= NULL
)
5729 return this->symtab_section_
->offset();
5733 // Return the section index of the normal symbol table. It may have
5734 // been stripped by the -s/--strip-all option.
5737 Layout::symtab_section_shndx() const
5739 if (this->symtab_section_
!= NULL
)
5740 return this->symtab_section_
->out_shndx();
5744 // Write out the Output_sections. Most won't have anything to write,
5745 // since most of the data will come from input sections which are
5746 // handled elsewhere. But some Output_sections do have Output_data.
5749 Layout::write_output_sections(Output_file
* of
) const
5751 for (Section_list::const_iterator p
= this->section_list_
.begin();
5752 p
!= this->section_list_
.end();
5755 if (!(*p
)->after_input_sections())
5760 // Write out data not associated with a section or the symbol table.
5763 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5765 if (!parameters
->options().strip_all())
5767 const Output_section
* symtab_section
= this->symtab_section_
;
5768 for (Section_list::const_iterator p
= this->section_list_
.begin();
5769 p
!= this->section_list_
.end();
5772 if ((*p
)->needs_symtab_index())
5774 gold_assert(symtab_section
!= NULL
);
5775 unsigned int index
= (*p
)->symtab_index();
5776 gold_assert(index
> 0 && index
!= -1U);
5777 off_t off
= (symtab_section
->offset()
5778 + index
* symtab_section
->entsize());
5779 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5784 const Output_section
* dynsym_section
= this->dynsym_section_
;
5785 for (Section_list::const_iterator p
= this->section_list_
.begin();
5786 p
!= this->section_list_
.end();
5789 if ((*p
)->needs_dynsym_index())
5791 gold_assert(dynsym_section
!= NULL
);
5792 unsigned int index
= (*p
)->dynsym_index();
5793 gold_assert(index
> 0 && index
!= -1U);
5794 off_t off
= (dynsym_section
->offset()
5795 + index
* dynsym_section
->entsize());
5796 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5800 // Write out the Output_data which are not in an Output_section.
5801 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5802 p
!= this->special_output_list_
.end();
5806 // Write out the Output_data which are not in an Output_section
5807 // and are regenerated in each iteration of relaxation.
5808 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
5809 p
!= this->relax_output_list_
.end();
5814 // Write out the Output_sections which can only be written after the
5815 // input sections are complete.
5818 Layout::write_sections_after_input_sections(Output_file
* of
)
5820 // Determine the final section offsets, and thus the final output
5821 // file size. Note we finalize the .shstrab last, to allow the
5822 // after_input_section sections to modify their section-names before
5824 if (this->any_postprocessing_sections_
)
5826 off_t off
= this->output_file_size_
;
5827 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5829 // Now that we've finalized the names, we can finalize the shstrab.
5831 this->set_section_offsets(off
,
5832 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5834 if (off
> this->output_file_size_
)
5837 this->output_file_size_
= off
;
5841 for (Section_list::const_iterator p
= this->section_list_
.begin();
5842 p
!= this->section_list_
.end();
5845 if ((*p
)->after_input_sections())
5849 this->section_headers_
->write(of
);
5852 // If a tree-style build ID was requested, the parallel part of that computation
5853 // is already done, and the final hash-of-hashes is computed here. For other
5854 // types of build IDs, all the work is done here.
5857 Layout::write_build_id(Output_file
* of
, unsigned char* array_of_hashes
,
5858 size_t size_of_hashes
) const
5860 if (this->build_id_note_
== NULL
)
5863 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5864 this->build_id_note_
->data_size());
5866 if (array_of_hashes
== NULL
)
5868 const size_t output_file_size
= this->output_file_size();
5869 const unsigned char* iv
= of
->get_input_view(0, output_file_size
);
5870 const char* style
= parameters
->options().build_id();
5872 // If we get here with style == "tree" then the output must be
5873 // too small for chunking, and we use SHA-1 in that case.
5874 if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
5875 sha1_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5876 else if (strcmp(style
, "md5") == 0)
5877 md5_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5881 of
->free_input_view(0, output_file_size
, iv
);
5885 // Non-overlapping substrings of the output file have been hashed.
5886 // Compute SHA-1 hash of the hashes.
5887 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes
),
5888 size_of_hashes
, ov
);
5889 delete[] array_of_hashes
;
5892 of
->write_output_view(this->build_id_note_
->offset(),
5893 this->build_id_note_
->data_size(),
5897 // Write out a binary file. This is called after the link is
5898 // complete. IN is the temporary output file we used to generate the
5899 // ELF code. We simply walk through the segments, read them from
5900 // their file offset in IN, and write them to their load address in
5901 // the output file. FIXME: with a bit more work, we could support
5902 // S-records and/or Intel hex format here.
5905 Layout::write_binary(Output_file
* in
) const
5907 gold_assert(parameters
->options().oformat_enum()
5908 == General_options::OBJECT_FORMAT_BINARY
);
5910 // Get the size of the binary file.
5911 uint64_t max_load_address
= 0;
5912 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5913 p
!= this->segment_list_
.end();
5916 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5918 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5919 if (max_paddr
> max_load_address
)
5920 max_load_address
= max_paddr
;
5924 Output_file
out(parameters
->options().output_file_name());
5925 out
.open(max_load_address
);
5927 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5928 p
!= this->segment_list_
.end();
5931 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5933 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5935 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5937 memcpy(vout
, vin
, (*p
)->filesz());
5938 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5939 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5946 // Print the output sections to the map file.
5949 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5951 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5952 p
!= this->segment_list_
.end();
5954 (*p
)->print_sections_to_mapfile(mapfile
);
5955 for (Section_list::const_iterator p
= this->unattached_section_list_
.begin();
5956 p
!= this->unattached_section_list_
.end();
5958 (*p
)->print_to_mapfile(mapfile
);
5961 // Print statistical information to stderr. This is used for --stats.
5964 Layout::print_stats() const
5966 this->namepool_
.print_stats("section name pool");
5967 this->sympool_
.print_stats("output symbol name pool");
5968 this->dynpool_
.print_stats("dynamic name pool");
5970 for (Section_list::const_iterator p
= this->section_list_
.begin();
5971 p
!= this->section_list_
.end();
5973 (*p
)->print_merge_stats();
5976 // Write_sections_task methods.
5978 // We can always run this task.
5981 Write_sections_task::is_runnable()
5986 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5990 Write_sections_task::locks(Task_locker
* tl
)
5992 tl
->add(this, this->output_sections_blocker_
);
5993 if (this->input_sections_blocker_
!= NULL
)
5994 tl
->add(this, this->input_sections_blocker_
);
5995 tl
->add(this, this->final_blocker_
);
5998 // Run the task--write out the data.
6001 Write_sections_task::run(Workqueue
*)
6003 this->layout_
->write_output_sections(this->of_
);
6006 // Write_data_task methods.
6008 // We can always run this task.
6011 Write_data_task::is_runnable()
6016 // We need to unlock FINAL_BLOCKER when finished.
6019 Write_data_task::locks(Task_locker
* tl
)
6021 tl
->add(this, this->final_blocker_
);
6024 // Run the task--write out the data.
6027 Write_data_task::run(Workqueue
*)
6029 this->layout_
->write_data(this->symtab_
, this->of_
);
6032 // Write_symbols_task methods.
6034 // We can always run this task.
6037 Write_symbols_task::is_runnable()
6042 // We need to unlock FINAL_BLOCKER when finished.
6045 Write_symbols_task::locks(Task_locker
* tl
)
6047 tl
->add(this, this->final_blocker_
);
6050 // Run the task--write out the symbols.
6053 Write_symbols_task::run(Workqueue
*)
6055 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
6056 this->layout_
->symtab_xindex(),
6057 this->layout_
->dynsym_xindex(), this->of_
);
6060 // Write_after_input_sections_task methods.
6062 // We can only run this task after the input sections have completed.
6065 Write_after_input_sections_task::is_runnable()
6067 if (this->input_sections_blocker_
->is_blocked())
6068 return this->input_sections_blocker_
;
6072 // We need to unlock FINAL_BLOCKER when finished.
6075 Write_after_input_sections_task::locks(Task_locker
* tl
)
6077 tl
->add(this, this->final_blocker_
);
6083 Write_after_input_sections_task::run(Workqueue
*)
6085 this->layout_
->write_sections_after_input_sections(this->of_
);
6088 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
6089 // or as a "tree" where each chunk of the string is hashed and then those
6090 // hashes are put into a (much smaller) string which is hashed with sha1.
6091 // We compute a checksum over the entire file because that is simplest.
6094 Build_id_task_runner::run(Workqueue
* workqueue
, const Task
*)
6096 Task_token
* post_hash_tasks_blocker
= new Task_token(true);
6097 const Layout
* layout
= this->layout_
;
6098 Output_file
* of
= this->of_
;
6099 const size_t filesize
= (layout
->output_file_size() <= 0 ? 0
6100 : static_cast<size_t>(layout
->output_file_size()));
6101 unsigned char* array_of_hashes
= NULL
;
6102 size_t size_of_hashes
= 0;
6104 if (strcmp(this->options_
->build_id(), "tree") == 0
6105 && this->options_
->build_id_chunk_size_for_treehash() > 0
6107 && (filesize
>= this->options_
->build_id_min_file_size_for_treehash()))
6109 static const size_t MD5_OUTPUT_SIZE_IN_BYTES
= 16;
6110 const size_t chunk_size
=
6111 this->options_
->build_id_chunk_size_for_treehash();
6112 const size_t num_hashes
= ((filesize
- 1) / chunk_size
) + 1;
6113 post_hash_tasks_blocker
->add_blockers(num_hashes
);
6114 size_of_hashes
= num_hashes
* MD5_OUTPUT_SIZE_IN_BYTES
;
6115 array_of_hashes
= new unsigned char[size_of_hashes
];
6116 unsigned char *dst
= array_of_hashes
;
6117 for (size_t i
= 0, src_offset
= 0; i
< num_hashes
;
6118 i
++, dst
+= MD5_OUTPUT_SIZE_IN_BYTES
, src_offset
+= chunk_size
)
6120 size_t size
= std::min(chunk_size
, filesize
- src_offset
);
6121 workqueue
->queue(new Hash_task(of
,
6125 post_hash_tasks_blocker
));
6129 // Queue the final task to write the build id and close the output file.
6130 workqueue
->queue(new Task_function(new Close_task_runner(this->options_
,
6135 post_hash_tasks_blocker
,
6136 "Task_function Close_task_runner"));
6139 // Close_task_runner methods.
6141 // Finish up the build ID computation, if necessary, and write a binary file,
6142 // if necessary. Then close the output file.
6145 Close_task_runner::run(Workqueue
*, const Task
*)
6147 // At this point the multi-threaded part of the build ID computation,
6148 // if any, is done. See Build_id_task_runner.
6149 this->layout_
->write_build_id(this->of_
, this->array_of_hashes_
,
6150 this->size_of_hashes_
);
6152 // If we've been asked to create a binary file, we do so here.
6153 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
6154 this->layout_
->write_binary(this->of_
);
6159 // Instantiate the templates we need. We could use the configure
6160 // script to restrict this to only the ones for implemented targets.
6162 #ifdef HAVE_TARGET_32_LITTLE
6165 Layout::init_fixed_output_section
<32, false>(
6167 elfcpp::Shdr
<32, false>& shdr
);
6170 #ifdef HAVE_TARGET_32_BIG
6173 Layout::init_fixed_output_section
<32, true>(
6175 elfcpp::Shdr
<32, true>& shdr
);
6178 #ifdef HAVE_TARGET_64_LITTLE
6181 Layout::init_fixed_output_section
<64, false>(
6183 elfcpp::Shdr
<64, false>& shdr
);
6186 #ifdef HAVE_TARGET_64_BIG
6189 Layout::init_fixed_output_section
<64, true>(
6191 elfcpp::Shdr
<64, true>& shdr
);
6194 #ifdef HAVE_TARGET_32_LITTLE
6197 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
6200 const elfcpp::Shdr
<32, false>& shdr
,
6201 unsigned int, unsigned int, unsigned int, off_t
*);
6204 #ifdef HAVE_TARGET_32_BIG
6207 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
6210 const elfcpp::Shdr
<32, true>& shdr
,
6211 unsigned int, unsigned int, unsigned int, off_t
*);
6214 #ifdef HAVE_TARGET_64_LITTLE
6217 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
6220 const elfcpp::Shdr
<64, false>& shdr
,
6221 unsigned int, unsigned int, unsigned int, off_t
*);
6224 #ifdef HAVE_TARGET_64_BIG
6227 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
6230 const elfcpp::Shdr
<64, true>& shdr
,
6231 unsigned int, unsigned int, unsigned int, off_t
*);
6234 #ifdef HAVE_TARGET_32_LITTLE
6237 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
6238 unsigned int reloc_shndx
,
6239 const elfcpp::Shdr
<32, false>& shdr
,
6240 Output_section
* data_section
,
6241 Relocatable_relocs
* rr
);
6244 #ifdef HAVE_TARGET_32_BIG
6247 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
6248 unsigned int reloc_shndx
,
6249 const elfcpp::Shdr
<32, true>& shdr
,
6250 Output_section
* data_section
,
6251 Relocatable_relocs
* rr
);
6254 #ifdef HAVE_TARGET_64_LITTLE
6257 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
6258 unsigned int reloc_shndx
,
6259 const elfcpp::Shdr
<64, false>& shdr
,
6260 Output_section
* data_section
,
6261 Relocatable_relocs
* rr
);
6264 #ifdef HAVE_TARGET_64_BIG
6267 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
6268 unsigned int reloc_shndx
,
6269 const elfcpp::Shdr
<64, true>& shdr
,
6270 Output_section
* data_section
,
6271 Relocatable_relocs
* rr
);
6274 #ifdef HAVE_TARGET_32_LITTLE
6277 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
6278 Sized_relobj_file
<32, false>* object
,
6280 const char* group_section_name
,
6281 const char* signature
,
6282 const elfcpp::Shdr
<32, false>& shdr
,
6283 elfcpp::Elf_Word flags
,
6284 std::vector
<unsigned int>* shndxes
);
6287 #ifdef HAVE_TARGET_32_BIG
6290 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
6291 Sized_relobj_file
<32, true>* object
,
6293 const char* group_section_name
,
6294 const char* signature
,
6295 const elfcpp::Shdr
<32, true>& shdr
,
6296 elfcpp::Elf_Word flags
,
6297 std::vector
<unsigned int>* shndxes
);
6300 #ifdef HAVE_TARGET_64_LITTLE
6303 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
6304 Sized_relobj_file
<64, false>* object
,
6306 const char* group_section_name
,
6307 const char* signature
,
6308 const elfcpp::Shdr
<64, false>& shdr
,
6309 elfcpp::Elf_Word flags
,
6310 std::vector
<unsigned int>* shndxes
);
6313 #ifdef HAVE_TARGET_64_BIG
6316 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
6317 Sized_relobj_file
<64, true>* object
,
6319 const char* group_section_name
,
6320 const char* signature
,
6321 const elfcpp::Shdr
<64, true>& shdr
,
6322 elfcpp::Elf_Word flags
,
6323 std::vector
<unsigned int>* shndxes
);
6326 #ifdef HAVE_TARGET_32_LITTLE
6329 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
6330 const unsigned char* symbols
,
6332 const unsigned char* symbol_names
,
6333 off_t symbol_names_size
,
6335 const elfcpp::Shdr
<32, false>& shdr
,
6336 unsigned int reloc_shndx
,
6337 unsigned int reloc_type
,
6341 #ifdef HAVE_TARGET_32_BIG
6344 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
6345 const unsigned char* symbols
,
6347 const unsigned char* symbol_names
,
6348 off_t symbol_names_size
,
6350 const elfcpp::Shdr
<32, true>& shdr
,
6351 unsigned int reloc_shndx
,
6352 unsigned int reloc_type
,
6356 #ifdef HAVE_TARGET_64_LITTLE
6359 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
6360 const unsigned char* symbols
,
6362 const unsigned char* symbol_names
,
6363 off_t symbol_names_size
,
6365 const elfcpp::Shdr
<64, false>& shdr
,
6366 unsigned int reloc_shndx
,
6367 unsigned int reloc_type
,
6371 #ifdef HAVE_TARGET_64_BIG
6374 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
6375 const unsigned char* symbols
,
6377 const unsigned char* symbol_names
,
6378 off_t symbol_names_size
,
6380 const elfcpp::Shdr
<64, true>& shdr
,
6381 unsigned int reloc_shndx
,
6382 unsigned int reloc_type
,
6386 #ifdef HAVE_TARGET_32_LITTLE
6389 Layout::add_to_gdb_index(bool is_type_unit
,
6390 Sized_relobj
<32, false>* object
,
6391 const unsigned char* symbols
,
6394 unsigned int reloc_shndx
,
6395 unsigned int reloc_type
);
6398 #ifdef HAVE_TARGET_32_BIG
6401 Layout::add_to_gdb_index(bool is_type_unit
,
6402 Sized_relobj
<32, true>* object
,
6403 const unsigned char* symbols
,
6406 unsigned int reloc_shndx
,
6407 unsigned int reloc_type
);
6410 #ifdef HAVE_TARGET_64_LITTLE
6413 Layout::add_to_gdb_index(bool is_type_unit
,
6414 Sized_relobj
<64, false>* object
,
6415 const unsigned char* symbols
,
6418 unsigned int reloc_shndx
,
6419 unsigned int reloc_type
);
6422 #ifdef HAVE_TARGET_64_BIG
6425 Layout::add_to_gdb_index(bool is_type_unit
,
6426 Sized_relobj
<64, true>* object
,
6427 const unsigned char* symbols
,
6430 unsigned int reloc_shndx
,
6431 unsigned int reloc_type
);
6434 } // End namespace gold.