1 // layout.cc -- lay out output file sections for gold
3 // Copyright (C) 2006-2014 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
34 #include "libiberty.h"
38 #include "parameters.h"
42 #include "script-sections.h"
47 #include "gdb-index.h"
48 #include "compressed_output.h"
49 #include "reduced_debug_output.h"
52 #include "descriptors.h"
54 #include "incremental.h"
62 // The total number of free lists used.
63 unsigned int Free_list::num_lists
= 0;
64 // The total number of free list nodes used.
65 unsigned int Free_list::num_nodes
= 0;
66 // The total number of calls to Free_list::remove.
67 unsigned int Free_list::num_removes
= 0;
68 // The total number of nodes visited during calls to Free_list::remove.
69 unsigned int Free_list::num_remove_visits
= 0;
70 // The total number of calls to Free_list::allocate.
71 unsigned int Free_list::num_allocates
= 0;
72 // The total number of nodes visited during calls to Free_list::allocate.
73 unsigned int Free_list::num_allocate_visits
= 0;
75 // Initialize the free list. Creates a single free list node that
76 // describes the entire region of length LEN. If EXTEND is true,
77 // allocate() is allowed to extend the region beyond its initial
81 Free_list::init(off_t len
, bool extend
)
83 this->list_
.push_front(Free_list_node(0, len
));
84 this->last_remove_
= this->list_
.begin();
85 this->extend_
= extend
;
87 ++Free_list::num_lists
;
88 ++Free_list::num_nodes
;
91 // Remove a chunk from the free list. Because we start with a single
92 // node that covers the entire section, and remove chunks from it one
93 // at a time, we do not need to coalesce chunks or handle cases that
94 // span more than one free node. We expect to remove chunks from the
95 // free list in order, and we expect to have only a few chunks of free
96 // space left (corresponding to files that have changed since the last
97 // incremental link), so a simple linear list should provide sufficient
101 Free_list::remove(off_t start
, off_t end
)
105 gold_assert(start
< end
);
107 ++Free_list::num_removes
;
109 Iterator p
= this->last_remove_
;
110 if (p
->start_
> start
)
111 p
= this->list_
.begin();
113 for (; p
!= this->list_
.end(); ++p
)
115 ++Free_list::num_remove_visits
;
116 // Find a node that wholly contains the indicated region.
117 if (p
->start_
<= start
&& p
->end_
>= end
)
119 // Case 1: the indicated region spans the whole node.
120 // Add some fuzz to avoid creating tiny free chunks.
121 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
122 p
= this->list_
.erase(p
);
123 // Case 2: remove a chunk from the start of the node.
124 else if (p
->start_
+ 3 >= start
)
126 // Case 3: remove a chunk from the end of the node.
127 else if (p
->end_
<= end
+ 3)
129 // Case 4: remove a chunk from the middle, and split
130 // the node into two.
133 Free_list_node
newnode(p
->start_
, start
);
135 this->list_
.insert(p
, newnode
);
136 ++Free_list::num_nodes
;
138 this->last_remove_
= p
;
143 // Did not find a node containing the given chunk. This could happen
144 // because a small chunk was already removed due to the fuzz.
145 gold_debug(DEBUG_INCREMENTAL
,
146 "Free_list::remove(%d,%d) not found",
147 static_cast<int>(start
), static_cast<int>(end
));
150 // Allocate a chunk of size LEN from the free list. Returns -1ULL
151 // if a sufficiently large chunk of free space is not found.
152 // We use a simple first-fit algorithm.
155 Free_list::allocate(off_t len
, uint64_t align
, off_t minoff
)
157 gold_debug(DEBUG_INCREMENTAL
,
158 "Free_list::allocate(%08lx, %d, %08lx)",
159 static_cast<long>(len
), static_cast<int>(align
),
160 static_cast<long>(minoff
));
162 return align_address(minoff
, align
);
164 ++Free_list::num_allocates
;
166 // We usually want to drop free chunks smaller than 4 bytes.
167 // If we need to guarantee a minimum hole size, though, we need
168 // to keep track of all free chunks.
169 const int fuzz
= this->min_hole_
> 0 ? 0 : 3;
171 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
173 ++Free_list::num_allocate_visits
;
174 off_t start
= p
->start_
> minoff
? p
->start_
: minoff
;
175 start
= align_address(start
, align
);
176 off_t end
= start
+ len
;
177 if (end
> p
->end_
&& p
->end_
== this->length_
&& this->extend_
)
182 if (end
== p
->end_
|| (end
<= p
->end_
- this->min_hole_
))
184 if (p
->start_
+ fuzz
>= start
&& p
->end_
<= end
+ fuzz
)
185 this->list_
.erase(p
);
186 else if (p
->start_
+ fuzz
>= start
)
188 else if (p
->end_
<= end
+ fuzz
)
192 Free_list_node
newnode(p
->start_
, start
);
194 this->list_
.insert(p
, newnode
);
195 ++Free_list::num_nodes
;
202 off_t start
= align_address(this->length_
, align
);
203 this->length_
= start
+ len
;
209 // Dump the free list (for debugging).
213 gold_info("Free list:\n start end length\n");
214 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
215 gold_info(" %08lx %08lx %08lx", static_cast<long>(p
->start_
),
216 static_cast<long>(p
->end_
),
217 static_cast<long>(p
->end_
- p
->start_
));
220 // Print the statistics for the free lists.
222 Free_list::print_stats()
224 fprintf(stderr
, _("%s: total free lists: %u\n"),
225 program_name
, Free_list::num_lists
);
226 fprintf(stderr
, _("%s: total free list nodes: %u\n"),
227 program_name
, Free_list::num_nodes
);
228 fprintf(stderr
, _("%s: calls to Free_list::remove: %u\n"),
229 program_name
, Free_list::num_removes
);
230 fprintf(stderr
, _("%s: nodes visited: %u\n"),
231 program_name
, Free_list::num_remove_visits
);
232 fprintf(stderr
, _("%s: calls to Free_list::allocate: %u\n"),
233 program_name
, Free_list::num_allocates
);
234 fprintf(stderr
, _("%s: nodes visited: %u\n"),
235 program_name
, Free_list::num_allocate_visits
);
238 // A Hash_task computes the MD5 checksum of an array of char.
239 // It has a blocker on either side (i.e., the task cannot run until
240 // the first is unblocked, and it unblocks the second after running).
242 class Hash_task
: public Task
245 Hash_task(const unsigned char* src
,
248 Task_token
* build_id_blocker
,
249 Task_token
* final_blocker
)
250 : src_(src
), size_(size
), dst_(dst
), build_id_blocker_(build_id_blocker
),
251 final_blocker_(final_blocker
)
256 { md5_buffer(reinterpret_cast<const char*>(src_
), size_
, dst_
); }
261 // Unblock FINAL_BLOCKER_ when done.
263 locks(Task_locker
* tl
)
264 { tl
->add(this, this->final_blocker_
); }
268 { return "Hash_task"; }
271 const unsigned char* const src_
;
273 unsigned char* const dst_
;
274 Task_token
* const build_id_blocker_
;
275 Task_token
* const final_blocker_
;
279 Hash_task::is_runnable()
281 if (this->build_id_blocker_
->is_blocked())
282 return this->build_id_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
),
452 array_of_hashes_(NULL
),
453 size_of_array_of_hashes_(0),
458 output_file_size_(-1),
459 have_added_input_section_(false),
460 sections_are_attached_(false),
461 input_requires_executable_stack_(false),
462 input_with_gnu_stack_note_(false),
463 input_without_gnu_stack_note_(false),
464 has_static_tls_(false),
465 any_postprocessing_sections_(false),
466 resized_signatures_(false),
467 have_stabstr_section_(false),
468 section_ordering_specified_(false),
469 unique_segment_for_sections_specified_(false),
470 incremental_inputs_(NULL
),
471 record_output_section_data_from_script_(false),
472 script_output_section_data_list_(),
473 segment_states_(NULL
),
474 relaxation_debug_check_(NULL
),
475 section_order_map_(),
476 section_segment_map_(),
477 input_section_position_(),
478 input_section_glob_(),
479 incremental_base_(NULL
),
482 // Make space for more than enough segments for a typical file.
483 // This is just for efficiency--it's OK if we wind up needing more.
484 this->segment_list_
.reserve(12);
486 // We expect two unattached Output_data objects: the file header and
487 // the segment headers.
488 this->special_output_list_
.reserve(2);
490 // Initialize structure needed for an incremental build.
491 if (parameters
->incremental())
492 this->incremental_inputs_
= new Incremental_inputs
;
494 // The section name pool is worth optimizing in all cases, because
495 // it is small, but there are often overlaps due to .rel sections.
496 this->namepool_
.set_optimize();
499 // For incremental links, record the base file to be modified.
502 Layout::set_incremental_base(Incremental_binary
* base
)
504 this->incremental_base_
= base
;
505 this->free_list_
.init(base
->output_file()->filesize(), true);
508 // Hash a key we use to look up an output section mapping.
511 Layout::Hash_key::operator()(const Layout::Key
& k
) const
513 return k
.first
+ k
.second
.first
+ k
.second
.second
;
516 // These are the debug sections that are actually used by gdb.
517 // Currently, we've checked versions of gdb up to and including 7.4.
518 // We only check the part of the name that follows ".debug_" or
521 static const char* gdb_sections
[] =
524 "addr", // Fission extension
525 // "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
539 // This is the minimum set of sections needed for line numbers.
541 static const char* lines_only_debug_sections
[] =
544 // "addr", // Fission extension
545 // "aranges", // not used by gdb as of 7.4
553 // "pubnames", // not used by gdb as of 7.4
554 // "pubtypes", // not used by gdb as of 7.4
559 // These sections are the DWARF fast-lookup tables, and are not needed
560 // when building a .gdb_index section.
562 static const char* gdb_fast_lookup_sections
[] =
569 // Returns whether the given debug section is in the list of
570 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
571 // portion of the name following ".debug_" or ".zdebug_".
574 is_gdb_debug_section(const char* suffix
)
576 // We can do this faster: binary search or a hashtable. But why bother?
577 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
578 if (strcmp(suffix
, gdb_sections
[i
]) == 0)
583 // Returns whether the given section is needed for lines-only debugging.
586 is_lines_only_debug_section(const char* suffix
)
588 // We can do this faster: binary search or a hashtable. But why bother?
590 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
592 if (strcmp(suffix
, lines_only_debug_sections
[i
]) == 0)
597 // Returns whether the given section is a fast-lookup section that
598 // will not be needed when building a .gdb_index section.
601 is_gdb_fast_lookup_section(const char* suffix
)
603 // We can do this faster: binary search or a hashtable. But why bother?
605 i
< sizeof(gdb_fast_lookup_sections
)/sizeof(*gdb_fast_lookup_sections
);
607 if (strcmp(suffix
, gdb_fast_lookup_sections
[i
]) == 0)
612 // Sometimes we compress sections. This is typically done for
613 // sections that are not part of normal program execution (such as
614 // .debug_* sections), and where the readers of these sections know
615 // how to deal with compressed sections. This routine doesn't say for
616 // certain whether we'll compress -- it depends on commandline options
617 // as well -- just whether this section is a candidate for compression.
618 // (The Output_compressed_section class decides whether to compress
619 // a given section, and picks the name of the compressed section.)
622 is_compressible_debug_section(const char* secname
)
624 return (is_prefix_of(".debug", secname
));
627 // We may see compressed debug sections in input files. Return TRUE
628 // if this is the name of a compressed debug section.
631 is_compressed_debug_section(const char* secname
)
633 return (is_prefix_of(".zdebug", secname
));
636 // Whether to include this section in the link.
638 template<int size
, bool big_endian
>
640 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
641 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
643 if (!parameters
->options().relocatable()
644 && (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
))
647 switch (shdr
.get_sh_type())
649 case elfcpp::SHT_NULL
:
650 case elfcpp::SHT_SYMTAB
:
651 case elfcpp::SHT_DYNSYM
:
652 case elfcpp::SHT_HASH
:
653 case elfcpp::SHT_DYNAMIC
:
654 case elfcpp::SHT_SYMTAB_SHNDX
:
657 case elfcpp::SHT_STRTAB
:
658 // Discard the sections which have special meanings in the ELF
659 // ABI. Keep others (e.g., .stabstr). We could also do this by
660 // checking the sh_link fields of the appropriate sections.
661 return (strcmp(name
, ".dynstr") != 0
662 && strcmp(name
, ".strtab") != 0
663 && strcmp(name
, ".shstrtab") != 0);
665 case elfcpp::SHT_RELA
:
666 case elfcpp::SHT_REL
:
667 case elfcpp::SHT_GROUP
:
668 // If we are emitting relocations these should be handled
670 gold_assert(!parameters
->options().relocatable());
673 case elfcpp::SHT_PROGBITS
:
674 if (parameters
->options().strip_debug()
675 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
677 if (is_debug_info_section(name
))
680 if (parameters
->options().strip_debug_non_line()
681 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
683 // Debugging sections can only be recognized by name.
684 if (is_prefix_of(".debug_", name
)
685 && !is_lines_only_debug_section(name
+ 7))
687 if (is_prefix_of(".zdebug_", name
)
688 && !is_lines_only_debug_section(name
+ 8))
691 if (parameters
->options().strip_debug_gdb()
692 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
694 // Debugging sections can only be recognized by name.
695 if (is_prefix_of(".debug_", name
)
696 && !is_gdb_debug_section(name
+ 7))
698 if (is_prefix_of(".zdebug_", name
)
699 && !is_gdb_debug_section(name
+ 8))
702 if (parameters
->options().gdb_index()
703 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
705 // When building .gdb_index, we can strip .debug_pubnames,
706 // .debug_pubtypes, and .debug_aranges sections.
707 if (is_prefix_of(".debug_", name
)
708 && is_gdb_fast_lookup_section(name
+ 7))
710 if (is_prefix_of(".zdebug_", name
)
711 && is_gdb_fast_lookup_section(name
+ 8))
714 if (parameters
->options().strip_lto_sections()
715 && !parameters
->options().relocatable()
716 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
718 // Ignore LTO sections containing intermediate code.
719 if (is_prefix_of(".gnu.lto_", name
))
722 // The GNU linker strips .gnu_debuglink sections, so we do too.
723 // This is a feature used to keep debugging information in
725 if (strcmp(name
, ".gnu_debuglink") == 0)
734 // Return an output section named NAME, or NULL if there is none.
737 Layout::find_output_section(const char* name
) const
739 for (Section_list::const_iterator p
= this->section_list_
.begin();
740 p
!= this->section_list_
.end();
742 if (strcmp((*p
)->name(), name
) == 0)
747 // Return an output segment of type TYPE, with segment flags SET set
748 // and segment flags CLEAR clear. Return NULL if there is none.
751 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
752 elfcpp::Elf_Word clear
) const
754 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
755 p
!= this->segment_list_
.end();
757 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
758 && ((*p
)->flags() & set
) == set
759 && ((*p
)->flags() & clear
) == 0)
764 // When we put a .ctors or .dtors section with more than one word into
765 // a .init_array or .fini_array section, we need to reverse the words
766 // in the .ctors/.dtors section. This is because .init_array executes
767 // constructors front to back, where .ctors executes them back to
768 // front, and vice-versa for .fini_array/.dtors. Although we do want
769 // to remap .ctors/.dtors into .init_array/.fini_array because it can
770 // be more efficient, we don't want to change the order in which
771 // constructors/destructors are run. This set just keeps track of
772 // these sections which need to be reversed. It is only changed by
773 // Layout::layout. It should be a private member of Layout, but that
774 // would require layout.h to #include object.h to get the definition
776 static Unordered_set
<Section_id
, Section_id_hash
> ctors_sections_in_init_array
;
778 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
779 // .init_array/.fini_array section.
782 Layout::is_ctors_in_init_array(Relobj
* relobj
, unsigned int shndx
) const
784 return (ctors_sections_in_init_array
.find(Section_id(relobj
, shndx
))
785 != ctors_sections_in_init_array
.end());
788 // Return the output section to use for section NAME with type TYPE
789 // and section flags FLAGS. NAME must be canonicalized in the string
790 // pool, and NAME_KEY is the key. ORDER is where this should appear
791 // in the output sections. IS_RELRO is true for a relro section.
794 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
795 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
796 Output_section_order order
, bool is_relro
)
798 elfcpp::Elf_Word lookup_type
= type
;
800 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
801 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
802 // .init_array, .fini_array, and .preinit_array sections by name
803 // whatever their type in the input file. We do this because the
804 // types are not always right in the input files.
805 if (lookup_type
== elfcpp::SHT_INIT_ARRAY
806 || lookup_type
== elfcpp::SHT_FINI_ARRAY
807 || lookup_type
== elfcpp::SHT_PREINIT_ARRAY
)
808 lookup_type
= elfcpp::SHT_PROGBITS
;
810 elfcpp::Elf_Xword lookup_flags
= flags
;
812 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
813 // read-write with read-only sections. Some other ELF linkers do
814 // not do this. FIXME: Perhaps there should be an option
816 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
818 const Key
key(name_key
, std::make_pair(lookup_type
, lookup_flags
));
819 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
820 std::pair
<Section_name_map::iterator
, bool> ins(
821 this->section_name_map_
.insert(v
));
824 return ins
.first
->second
;
827 // This is the first time we've seen this name/type/flags
828 // combination. For compatibility with the GNU linker, we
829 // combine sections with contents and zero flags with sections
830 // with non-zero flags. This is a workaround for cases where
831 // assembler code forgets to set section flags. FIXME: Perhaps
832 // there should be an option to control this.
833 Output_section
* os
= NULL
;
835 if (lookup_type
== elfcpp::SHT_PROGBITS
)
839 Output_section
* same_name
= this->find_output_section(name
);
840 if (same_name
!= NULL
841 && (same_name
->type() == elfcpp::SHT_PROGBITS
842 || same_name
->type() == elfcpp::SHT_INIT_ARRAY
843 || same_name
->type() == elfcpp::SHT_FINI_ARRAY
844 || same_name
->type() == elfcpp::SHT_PREINIT_ARRAY
)
845 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
848 else if ((flags
& elfcpp::SHF_TLS
) == 0)
850 elfcpp::Elf_Xword zero_flags
= 0;
851 const Key
zero_key(name_key
, std::make_pair(lookup_type
,
853 Section_name_map::iterator p
=
854 this->section_name_map_
.find(zero_key
);
855 if (p
!= this->section_name_map_
.end())
861 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
863 ins
.first
->second
= os
;
868 // Returns TRUE iff NAME (an input section from RELOBJ) will
869 // be mapped to an output section that should be KEPT.
872 Layout::keep_input_section(const Relobj
* relobj
, const char* name
)
874 if (! this->script_options_
->saw_sections_clause())
877 Script_sections
* ss
= this->script_options_
->script_sections();
878 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
879 Output_section
** output_section_slot
;
880 Script_sections::Section_type script_section_type
;
883 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
884 &script_section_type
, &keep
);
885 return name
!= NULL
&& keep
;
888 // Clear the input section flags that should not be copied to the
892 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags
)
894 // Some flags in the input section should not be automatically
895 // copied to the output section.
896 input_section_flags
&= ~ (elfcpp::SHF_INFO_LINK
899 | elfcpp::SHF_STRINGS
);
901 // We only clear the SHF_LINK_ORDER flag in for
902 // a non-relocatable link.
903 if (!parameters
->options().relocatable())
904 input_section_flags
&= ~elfcpp::SHF_LINK_ORDER
;
906 return input_section_flags
;
909 // Pick the output section to use for section NAME, in input file
910 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
911 // linker created section. IS_INPUT_SECTION is true if we are
912 // choosing an output section for an input section found in a input
913 // file. ORDER is where this section should appear in the output
914 // sections. IS_RELRO is true for a relro section. This will return
915 // NULL if the input section should be discarded.
918 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
919 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
920 bool is_input_section
, Output_section_order order
,
923 // We should not see any input sections after we have attached
924 // sections to segments.
925 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
927 flags
= this->get_output_section_flags(flags
);
929 if (this->script_options_
->saw_sections_clause())
931 // We are using a SECTIONS clause, so the output section is
932 // chosen based only on the name.
934 Script_sections
* ss
= this->script_options_
->script_sections();
935 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
936 Output_section
** output_section_slot
;
937 Script_sections::Section_type script_section_type
;
938 const char* orig_name
= name
;
940 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
941 &script_section_type
, &keep
);
945 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
946 "because it is not allowed by the "
947 "SECTIONS clause of the linker script"),
949 // The SECTIONS clause says to discard this input section.
953 // We can only handle script section types ST_NONE and ST_NOLOAD.
954 switch (script_section_type
)
956 case Script_sections::ST_NONE
:
958 case Script_sections::ST_NOLOAD
:
959 flags
&= elfcpp::SHF_ALLOC
;
965 // If this is an orphan section--one not mentioned in the linker
966 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
967 // default processing below.
969 if (output_section_slot
!= NULL
)
971 if (*output_section_slot
!= NULL
)
973 (*output_section_slot
)->update_flags_for_input_section(flags
);
974 return *output_section_slot
;
977 // We don't put sections found in the linker script into
978 // SECTION_NAME_MAP_. That keeps us from getting confused
979 // if an orphan section is mapped to a section with the same
980 // name as one in the linker script.
982 name
= this->namepool_
.add(name
, false, NULL
);
984 Output_section
* os
= this->make_output_section(name
, type
, flags
,
987 os
->set_found_in_sections_clause();
989 // Special handling for NOLOAD sections.
990 if (script_section_type
== Script_sections::ST_NOLOAD
)
994 // The constructor of Output_section sets addresses of non-ALLOC
995 // sections to 0 by default. We don't want that for NOLOAD
996 // sections even if they have no SHF_ALLOC flag.
997 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
998 && os
->is_address_valid())
1000 gold_assert(os
->address() == 0
1001 && !os
->is_offset_valid()
1002 && !os
->is_data_size_valid());
1003 os
->reset_address_and_file_offset();
1007 *output_section_slot
= os
;
1012 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1014 size_t len
= strlen(name
);
1015 char* uncompressed_name
= NULL
;
1017 // Compressed debug sections should be mapped to the corresponding
1018 // uncompressed section.
1019 if (is_compressed_debug_section(name
))
1021 uncompressed_name
= new char[len
];
1022 uncompressed_name
[0] = '.';
1023 gold_assert(name
[0] == '.' && name
[1] == 'z');
1024 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
1025 uncompressed_name
[len
- 1] = '\0';
1027 name
= uncompressed_name
;
1030 // Turn NAME from the name of the input section into the name of the
1032 if (is_input_section
1033 && !this->script_options_
->saw_sections_clause()
1034 && !parameters
->options().relocatable())
1036 const char *orig_name
= name
;
1037 name
= parameters
->target().output_section_name(relobj
, name
, &len
);
1039 name
= Layout::output_section_name(relobj
, orig_name
, &len
);
1042 Stringpool::Key name_key
;
1043 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
1045 if (uncompressed_name
!= NULL
)
1046 delete[] uncompressed_name
;
1048 // Find or make the output section. The output section is selected
1049 // based on the section name, type, and flags.
1050 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
1053 // For incremental links, record the initial fixed layout of a section
1054 // from the base file, and return a pointer to the Output_section.
1056 template<int size
, bool big_endian
>
1058 Layout::init_fixed_output_section(const char* name
,
1059 elfcpp::Shdr
<size
, big_endian
>& shdr
)
1061 unsigned int sh_type
= shdr
.get_sh_type();
1063 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1064 // PRE_INIT_ARRAY, and NOTE sections.
1065 // All others will be created from scratch and reallocated.
1066 if (!can_incremental_update(sh_type
))
1069 // If we're generating a .gdb_index section, we need to regenerate
1071 if (parameters
->options().gdb_index()
1072 && sh_type
== elfcpp::SHT_PROGBITS
1073 && strcmp(name
, ".gdb_index") == 0)
1076 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
1077 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
1078 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
1079 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
1080 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
1081 shdr
.get_sh_addralign();
1083 // Make the output section.
1084 Stringpool::Key name_key
;
1085 name
= this->namepool_
.add(name
, true, &name_key
);
1086 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
1087 sh_flags
, ORDER_INVALID
, false);
1088 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
1089 if (sh_type
!= elfcpp::SHT_NOBITS
)
1090 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
1094 // Return the index by which an input section should be ordered. This
1095 // is used to sort some .text sections, for compatibility with GNU ld.
1098 Layout::special_ordering_of_input_section(const char* name
)
1100 // The GNU linker has some special handling for some sections that
1101 // wind up in the .text section. Sections that start with these
1102 // prefixes must appear first, and must appear in the order listed
1104 static const char* const text_section_sort
[] =
1113 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1115 if (is_prefix_of(text_section_sort
[i
], name
))
1121 // Return the output section to use for input section SHNDX, with name
1122 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1123 // index of a relocation section which applies to this section, or 0
1124 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1125 // relocation section if there is one. Set *OFF to the offset of this
1126 // input section without the output section. Return NULL if the
1127 // section should be discarded. Set *OFF to -1 if the section
1128 // contents should not be written directly to the output file, but
1129 // will instead receive special handling.
1131 template<int size
, bool big_endian
>
1133 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1134 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1135 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
1139 if (!this->include_section(object
, name
, shdr
))
1142 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
1144 // In a relocatable link a grouped section must not be combined with
1145 // any other sections.
1147 if (parameters
->options().relocatable()
1148 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1150 name
= this->namepool_
.add(name
, true, NULL
);
1151 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
1152 ORDER_INVALID
, false);
1156 // Plugins can choose to place one or more subsets of sections in
1157 // unique segments and this is done by mapping these section subsets
1158 // to unique output sections. Check if this section needs to be
1159 // remapped to a unique output section.
1160 Section_segment_map::iterator it
1161 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1162 if (it
== this->section_segment_map_
.end())
1164 os
= this->choose_output_section(object
, name
, sh_type
,
1165 shdr
.get_sh_flags(), true,
1166 ORDER_INVALID
, false);
1170 // We know the name of the output section, directly call
1171 // get_output_section here by-passing choose_output_section.
1172 elfcpp::Elf_Xword flags
1173 = this->get_output_section_flags(shdr
.get_sh_flags());
1175 const char* os_name
= it
->second
->name
;
1176 Stringpool::Key name_key
;
1177 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1178 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1179 ORDER_INVALID
, false);
1180 if (!os
->is_unique_segment())
1182 os
->set_is_unique_segment();
1183 os
->set_extra_segment_flags(it
->second
->flags
);
1184 os
->set_segment_alignment(it
->second
->align
);
1191 // By default the GNU linker sorts input sections whose names match
1192 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1193 // sections are sorted by name. This is used to implement
1194 // constructor priority ordering. We are compatible. When we put
1195 // .ctor sections in .init_array and .dtor sections in .fini_array,
1196 // we must also sort plain .ctor and .dtor sections.
1197 if (!this->script_options_
->saw_sections_clause()
1198 && !parameters
->options().relocatable()
1199 && (is_prefix_of(".ctors.", name
)
1200 || is_prefix_of(".dtors.", name
)
1201 || is_prefix_of(".init_array.", name
)
1202 || is_prefix_of(".fini_array.", name
)
1203 || (parameters
->options().ctors_in_init_array()
1204 && (strcmp(name
, ".ctors") == 0
1205 || strcmp(name
, ".dtors") == 0))))
1206 os
->set_must_sort_attached_input_sections();
1208 // By default the GNU linker sorts some special text sections ahead
1209 // of others. We are compatible.
1210 if (parameters
->options().text_reorder()
1211 && !this->script_options_
->saw_sections_clause()
1212 && !this->is_section_ordering_specified()
1213 && !parameters
->options().relocatable()
1214 && Layout::special_ordering_of_input_section(name
) >= 0)
1215 os
->set_must_sort_attached_input_sections();
1217 // If this is a .ctors or .ctors.* section being mapped to a
1218 // .init_array section, or a .dtors or .dtors.* section being mapped
1219 // to a .fini_array section, we will need to reverse the words if
1220 // there is more than one. Record this section for later. See
1221 // ctors_sections_in_init_array above.
1222 if (!this->script_options_
->saw_sections_clause()
1223 && !parameters
->options().relocatable()
1224 && shdr
.get_sh_size() > size
/ 8
1225 && (((strcmp(name
, ".ctors") == 0
1226 || is_prefix_of(".ctors.", name
))
1227 && strcmp(os
->name(), ".init_array") == 0)
1228 || ((strcmp(name
, ".dtors") == 0
1229 || is_prefix_of(".dtors.", name
))
1230 && strcmp(os
->name(), ".fini_array") == 0)))
1231 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1233 // FIXME: Handle SHF_LINK_ORDER somewhere.
1235 elfcpp::Elf_Xword orig_flags
= os
->flags();
1237 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1238 this->script_options_
->saw_sections_clause());
1240 // If the flags changed, we may have to change the order.
1241 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1243 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1244 elfcpp::Elf_Xword new_flags
=
1245 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1246 if (orig_flags
!= new_flags
)
1247 os
->set_order(this->default_section_order(os
, false));
1250 this->have_added_input_section_
= true;
1255 // Maps section SECN to SEGMENT s.
1257 Layout::insert_section_segment_map(Const_section_id secn
,
1258 Unique_segment_info
*s
)
1260 gold_assert(this->unique_segment_for_sections_specified_
);
1261 this->section_segment_map_
[secn
] = s
;
1264 // Handle a relocation section when doing a relocatable link.
1266 template<int size
, bool big_endian
>
1268 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
1270 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1271 Output_section
* data_section
,
1272 Relocatable_relocs
* rr
)
1274 gold_assert(parameters
->options().relocatable()
1275 || parameters
->options().emit_relocs());
1277 int sh_type
= shdr
.get_sh_type();
1280 if (sh_type
== elfcpp::SHT_REL
)
1282 else if (sh_type
== elfcpp::SHT_RELA
)
1286 name
+= data_section
->name();
1288 // In a relocatable link relocs for a grouped section must not be
1289 // combined with other reloc sections.
1291 if (!parameters
->options().relocatable()
1292 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
1293 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
1294 shdr
.get_sh_flags(), false,
1295 ORDER_INVALID
, false);
1298 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1299 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1300 ORDER_INVALID
, false);
1303 os
->set_should_link_to_symtab();
1304 os
->set_info_section(data_section
);
1306 Output_section_data
* posd
;
1307 if (sh_type
== elfcpp::SHT_REL
)
1309 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1310 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1314 else if (sh_type
== elfcpp::SHT_RELA
)
1316 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1317 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1324 os
->add_output_section_data(posd
);
1325 rr
->set_output_data(posd
);
1330 // Handle a group section when doing a relocatable link.
1332 template<int size
, bool big_endian
>
1334 Layout::layout_group(Symbol_table
* symtab
,
1335 Sized_relobj_file
<size
, big_endian
>* object
,
1337 const char* group_section_name
,
1338 const char* signature
,
1339 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1340 elfcpp::Elf_Word flags
,
1341 std::vector
<unsigned int>* shndxes
)
1343 gold_assert(parameters
->options().relocatable());
1344 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1345 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1346 Output_section
* os
= this->make_output_section(group_section_name
,
1348 shdr
.get_sh_flags(),
1349 ORDER_INVALID
, false);
1351 // We need to find a symbol with the signature in the symbol table.
1352 // If we don't find one now, we need to look again later.
1353 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1355 os
->set_info_symndx(sym
);
1358 // Reserve some space to minimize reallocations.
1359 if (this->group_signatures_
.empty())
1360 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1362 // We will wind up using a symbol whose name is the signature.
1363 // So just put the signature in the symbol name pool to save it.
1364 signature
= symtab
->canonicalize_name(signature
);
1365 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1368 os
->set_should_link_to_symtab();
1371 section_size_type entry_count
=
1372 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1373 Output_section_data
* posd
=
1374 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1376 os
->add_output_section_data(posd
);
1379 // Special GNU handling of sections name .eh_frame. They will
1380 // normally hold exception frame data as defined by the C++ ABI
1381 // (http://codesourcery.com/cxx-abi/).
1383 template<int size
, bool big_endian
>
1385 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1386 const unsigned char* symbols
,
1388 const unsigned char* symbol_names
,
1389 off_t symbol_names_size
,
1391 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1392 unsigned int reloc_shndx
, unsigned int reloc_type
,
1395 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1396 || shdr
.get_sh_type() == elfcpp::SHT_X86_64_UNWIND
);
1397 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1399 Output_section
* os
= this->make_eh_frame_section(object
);
1403 gold_assert(this->eh_frame_section_
== os
);
1405 elfcpp::Elf_Xword orig_flags
= os
->flags();
1407 if (!parameters
->incremental()
1408 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1417 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1419 // A writable .eh_frame section is a RELRO section.
1420 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1421 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1424 os
->set_order(ORDER_RELRO
);
1427 // We found a .eh_frame section we are going to optimize, so now
1428 // we can add the set of optimized sections to the output
1429 // section. We need to postpone adding this until we've found a
1430 // section we can optimize so that the .eh_frame section in
1431 // crtbegin.o winds up at the start of the output section.
1432 if (!this->added_eh_frame_data_
)
1434 os
->add_output_section_data(this->eh_frame_data_
);
1435 this->added_eh_frame_data_
= true;
1441 // We couldn't handle this .eh_frame section for some reason.
1442 // Add it as a normal section.
1443 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1444 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1445 reloc_shndx
, saw_sections_clause
);
1446 this->have_added_input_section_
= true;
1448 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1449 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1450 os
->set_order(this->default_section_order(os
, false));
1456 // Create and return the magic .eh_frame section. Create
1457 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1458 // input .eh_frame section; it may be NULL.
1461 Layout::make_eh_frame_section(const Relobj
* object
)
1463 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1465 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1466 elfcpp::SHT_PROGBITS
,
1467 elfcpp::SHF_ALLOC
, false,
1468 ORDER_EHFRAME
, false);
1472 if (this->eh_frame_section_
== NULL
)
1474 this->eh_frame_section_
= os
;
1475 this->eh_frame_data_
= new Eh_frame();
1477 // For incremental linking, we do not optimize .eh_frame sections
1478 // or create a .eh_frame_hdr section.
1479 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1481 Output_section
* hdr_os
=
1482 this->choose_output_section(NULL
, ".eh_frame_hdr",
1483 elfcpp::SHT_PROGBITS
,
1484 elfcpp::SHF_ALLOC
, false,
1485 ORDER_EHFRAME
, false);
1489 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1490 this->eh_frame_data_
);
1491 hdr_os
->add_output_section_data(hdr_posd
);
1493 hdr_os
->set_after_input_sections();
1495 if (!this->script_options_
->saw_phdrs_clause())
1497 Output_segment
* hdr_oseg
;
1498 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1500 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1504 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1512 // Add an exception frame for a PLT. This is called from target code.
1515 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1516 size_t cie_length
, const unsigned char* fde_data
,
1519 if (parameters
->incremental())
1521 // FIXME: Maybe this could work some day....
1524 Output_section
* os
= this->make_eh_frame_section(NULL
);
1527 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1528 fde_data
, fde_length
);
1529 if (!this->added_eh_frame_data_
)
1531 os
->add_output_section_data(this->eh_frame_data_
);
1532 this->added_eh_frame_data_
= true;
1536 // Scan a .debug_info or .debug_types section, and add summary
1537 // information to the .gdb_index section.
1539 template<int size
, bool big_endian
>
1541 Layout::add_to_gdb_index(bool is_type_unit
,
1542 Sized_relobj
<size
, big_endian
>* object
,
1543 const unsigned char* symbols
,
1546 unsigned int reloc_shndx
,
1547 unsigned int reloc_type
)
1549 if (this->gdb_index_data_
== NULL
)
1551 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1552 elfcpp::SHT_PROGBITS
, 0,
1553 false, ORDER_INVALID
,
1558 this->gdb_index_data_
= new Gdb_index(os
);
1559 os
->add_output_section_data(this->gdb_index_data_
);
1560 os
->set_after_input_sections();
1563 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1564 symbols_size
, shndx
, reloc_shndx
,
1568 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1569 // the output section.
1572 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1573 elfcpp::Elf_Xword flags
,
1574 Output_section_data
* posd
,
1575 Output_section_order order
, bool is_relro
)
1577 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1578 false, order
, is_relro
);
1580 os
->add_output_section_data(posd
);
1584 // Map section flags to segment flags.
1587 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1589 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1590 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1591 ret
|= elfcpp::PF_W
;
1592 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1593 ret
|= elfcpp::PF_X
;
1597 // Make a new Output_section, and attach it to segments as
1598 // appropriate. ORDER is the order in which this section should
1599 // appear in the output segment. IS_RELRO is true if this is a relro
1600 // (read-only after relocations) section.
1603 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1604 elfcpp::Elf_Xword flags
,
1605 Output_section_order order
, bool is_relro
)
1608 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1609 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1610 && is_compressible_debug_section(name
))
1611 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1613 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1614 && parameters
->options().strip_debug_non_line()
1615 && strcmp(".debug_abbrev", name
) == 0)
1617 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1619 if (this->debug_info_
)
1620 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1622 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1623 && parameters
->options().strip_debug_non_line()
1624 && strcmp(".debug_info", name
) == 0)
1626 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1628 if (this->debug_abbrev_
)
1629 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1633 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1634 // not have correct section types. Force them here.
1635 if (type
== elfcpp::SHT_PROGBITS
)
1637 if (is_prefix_of(".init_array", name
))
1638 type
= elfcpp::SHT_INIT_ARRAY
;
1639 else if (is_prefix_of(".preinit_array", name
))
1640 type
= elfcpp::SHT_PREINIT_ARRAY
;
1641 else if (is_prefix_of(".fini_array", name
))
1642 type
= elfcpp::SHT_FINI_ARRAY
;
1645 // FIXME: const_cast is ugly.
1646 Target
* target
= const_cast<Target
*>(¶meters
->target());
1647 os
= target
->make_output_section(name
, type
, flags
);
1650 // With -z relro, we have to recognize the special sections by name.
1651 // There is no other way.
1652 bool is_relro_local
= false;
1653 if (!this->script_options_
->saw_sections_clause()
1654 && parameters
->options().relro()
1655 && (flags
& elfcpp::SHF_ALLOC
) != 0
1656 && (flags
& elfcpp::SHF_WRITE
) != 0)
1658 if (type
== elfcpp::SHT_PROGBITS
)
1660 if ((flags
& elfcpp::SHF_TLS
) != 0)
1662 else if (strcmp(name
, ".data.rel.ro") == 0)
1664 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1667 is_relro_local
= true;
1669 else if (strcmp(name
, ".ctors") == 0
1670 || strcmp(name
, ".dtors") == 0
1671 || strcmp(name
, ".jcr") == 0)
1674 else if (type
== elfcpp::SHT_INIT_ARRAY
1675 || type
== elfcpp::SHT_FINI_ARRAY
1676 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1683 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1684 order
= this->default_section_order(os
, is_relro_local
);
1686 os
->set_order(order
);
1688 parameters
->target().new_output_section(os
);
1690 this->section_list_
.push_back(os
);
1692 // The GNU linker by default sorts some sections by priority, so we
1693 // do the same. We need to know that this might happen before we
1694 // attach any input sections.
1695 if (!this->script_options_
->saw_sections_clause()
1696 && !parameters
->options().relocatable()
1697 && (strcmp(name
, ".init_array") == 0
1698 || strcmp(name
, ".fini_array") == 0
1699 || (!parameters
->options().ctors_in_init_array()
1700 && (strcmp(name
, ".ctors") == 0
1701 || strcmp(name
, ".dtors") == 0))))
1702 os
->set_may_sort_attached_input_sections();
1704 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1705 // sections before other .text sections. We are compatible. We
1706 // need to know that this might happen before we attach any input
1708 if (parameters
->options().text_reorder()
1709 && !this->script_options_
->saw_sections_clause()
1710 && !this->is_section_ordering_specified()
1711 && !parameters
->options().relocatable()
1712 && strcmp(name
, ".text") == 0)
1713 os
->set_may_sort_attached_input_sections();
1715 // GNU linker sorts section by name with --sort-section=name.
1716 if (strcmp(parameters
->options().sort_section(), "name") == 0)
1717 os
->set_must_sort_attached_input_sections();
1719 // Check for .stab*str sections, as .stab* sections need to link to
1721 if (type
== elfcpp::SHT_STRTAB
1722 && !this->have_stabstr_section_
1723 && strncmp(name
, ".stab", 5) == 0
1724 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1725 this->have_stabstr_section_
= true;
1727 // During a full incremental link, we add patch space to most
1728 // PROGBITS and NOBITS sections. Flag those that may be
1729 // arbitrarily padded.
1730 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1731 && order
!= ORDER_INTERP
1732 && order
!= ORDER_INIT
1733 && order
!= ORDER_PLT
1734 && order
!= ORDER_FINI
1735 && order
!= ORDER_RELRO_LAST
1736 && order
!= ORDER_NON_RELRO_FIRST
1737 && strcmp(name
, ".eh_frame") != 0
1738 && strcmp(name
, ".ctors") != 0
1739 && strcmp(name
, ".dtors") != 0
1740 && strcmp(name
, ".jcr") != 0)
1742 os
->set_is_patch_space_allowed();
1744 // Certain sections require "holes" to be filled with
1745 // specific fill patterns. These fill patterns may have
1746 // a minimum size, so we must prevent allocations from the
1747 // free list that leave a hole smaller than the minimum.
1748 if (strcmp(name
, ".debug_info") == 0)
1749 os
->set_free_space_fill(new Output_fill_debug_info(false));
1750 else if (strcmp(name
, ".debug_types") == 0)
1751 os
->set_free_space_fill(new Output_fill_debug_info(true));
1752 else if (strcmp(name
, ".debug_line") == 0)
1753 os
->set_free_space_fill(new Output_fill_debug_line());
1756 // If we have already attached the sections to segments, then we
1757 // need to attach this one now. This happens for sections created
1758 // directly by the linker.
1759 if (this->sections_are_attached_
)
1760 this->attach_section_to_segment(¶meters
->target(), os
);
1765 // Return the default order in which a section should be placed in an
1766 // output segment. This function captures a lot of the ideas in
1767 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1768 // linker created section is normally set when the section is created;
1769 // this function is used for input sections.
1771 Output_section_order
1772 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1774 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1775 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1776 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1777 bool is_bss
= false;
1782 case elfcpp::SHT_PROGBITS
:
1784 case elfcpp::SHT_NOBITS
:
1787 case elfcpp::SHT_RELA
:
1788 case elfcpp::SHT_REL
:
1790 return ORDER_DYNAMIC_RELOCS
;
1792 case elfcpp::SHT_HASH
:
1793 case elfcpp::SHT_DYNAMIC
:
1794 case elfcpp::SHT_SHLIB
:
1795 case elfcpp::SHT_DYNSYM
:
1796 case elfcpp::SHT_GNU_HASH
:
1797 case elfcpp::SHT_GNU_verdef
:
1798 case elfcpp::SHT_GNU_verneed
:
1799 case elfcpp::SHT_GNU_versym
:
1801 return ORDER_DYNAMIC_LINKER
;
1803 case elfcpp::SHT_NOTE
:
1804 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1807 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1808 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1810 if (!is_bss
&& !is_write
)
1814 if (strcmp(os
->name(), ".init") == 0)
1816 else if (strcmp(os
->name(), ".fini") == 0)
1819 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1823 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1825 if (os
->is_small_section())
1826 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1827 if (os
->is_large_section())
1828 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1830 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1833 // Attach output sections to segments. This is called after we have
1834 // seen all the input sections.
1837 Layout::attach_sections_to_segments(const Target
* target
)
1839 for (Section_list::iterator p
= this->section_list_
.begin();
1840 p
!= this->section_list_
.end();
1842 this->attach_section_to_segment(target
, *p
);
1844 this->sections_are_attached_
= true;
1847 // Attach an output section to a segment.
1850 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1852 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1853 this->unattached_section_list_
.push_back(os
);
1855 this->attach_allocated_section_to_segment(target
, os
);
1858 // Attach an allocated output section to a segment.
1861 Layout::attach_allocated_section_to_segment(const Target
* target
,
1864 elfcpp::Elf_Xword flags
= os
->flags();
1865 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1867 if (parameters
->options().relocatable())
1870 // If we have a SECTIONS clause, we can't handle the attachment to
1871 // segments until after we've seen all the sections.
1872 if (this->script_options_
->saw_sections_clause())
1875 gold_assert(!this->script_options_
->saw_phdrs_clause());
1877 // This output section goes into a PT_LOAD segment.
1879 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1881 // If this output section's segment has extra flags that need to be set,
1882 // coming from a linker plugin, do that.
1883 seg_flags
|= os
->extra_segment_flags();
1885 // Check for --section-start.
1887 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1889 // In general the only thing we really care about for PT_LOAD
1890 // segments is whether or not they are writable or executable,
1891 // so that is how we search for them.
1892 // Large data sections also go into their own PT_LOAD segment.
1893 // People who need segments sorted on some other basis will
1894 // have to use a linker script.
1896 Segment_list::const_iterator p
;
1897 if (!os
->is_unique_segment())
1899 for (p
= this->segment_list_
.begin();
1900 p
!= this->segment_list_
.end();
1903 if ((*p
)->type() != elfcpp::PT_LOAD
)
1905 if ((*p
)->is_unique_segment())
1907 if (!parameters
->options().omagic()
1908 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1910 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
1911 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1913 // If -Tbss was specified, we need to separate the data and BSS
1915 if (parameters
->options().user_set_Tbss())
1917 if ((os
->type() == elfcpp::SHT_NOBITS
)
1918 == (*p
)->has_any_data_sections())
1921 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1926 if ((*p
)->are_addresses_set())
1929 (*p
)->add_initial_output_data(os
);
1930 (*p
)->update_flags_for_output_section(seg_flags
);
1931 (*p
)->set_addresses(addr
, addr
);
1935 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1940 if (p
== this->segment_list_
.end()
1941 || os
->is_unique_segment())
1943 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1945 if (os
->is_large_data_section())
1946 oseg
->set_is_large_data_segment();
1947 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1949 oseg
->set_addresses(addr
, addr
);
1950 // Check if segment should be marked unique. For segments marked
1951 // unique by linker plugins, set the new alignment if specified.
1952 if (os
->is_unique_segment())
1954 oseg
->set_is_unique_segment();
1955 if (os
->segment_alignment() != 0)
1956 oseg
->set_minimum_p_align(os
->segment_alignment());
1960 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1962 if (os
->type() == elfcpp::SHT_NOTE
)
1964 // See if we already have an equivalent PT_NOTE segment.
1965 for (p
= this->segment_list_
.begin();
1966 p
!= segment_list_
.end();
1969 if ((*p
)->type() == elfcpp::PT_NOTE
1970 && (((*p
)->flags() & elfcpp::PF_W
)
1971 == (seg_flags
& elfcpp::PF_W
)))
1973 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1978 if (p
== this->segment_list_
.end())
1980 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1982 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1986 // If we see a loadable SHF_TLS section, we create a PT_TLS
1987 // segment. There can only be one such segment.
1988 if ((flags
& elfcpp::SHF_TLS
) != 0)
1990 if (this->tls_segment_
== NULL
)
1991 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1992 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1995 // If -z relro is in effect, and we see a relro section, we create a
1996 // PT_GNU_RELRO segment. There can only be one such segment.
1997 if (os
->is_relro() && parameters
->options().relro())
1999 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
2000 if (this->relro_segment_
== NULL
)
2001 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
2002 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2005 // If we see a section named .interp, put it into a PT_INTERP
2006 // segment. This seems broken to me, but this is what GNU ld does,
2007 // and glibc expects it.
2008 if (strcmp(os
->name(), ".interp") == 0
2009 && !this->script_options_
->saw_phdrs_clause())
2011 if (this->interp_segment_
== NULL
)
2012 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
2014 gold_warning(_("multiple '.interp' sections in input files "
2015 "may cause confusing PT_INTERP segment"));
2016 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2020 // Make an output section for a script.
2023 Layout::make_output_section_for_script(
2025 Script_sections::Section_type section_type
)
2027 name
= this->namepool_
.add(name
, false, NULL
);
2028 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
2029 if (section_type
== Script_sections::ST_NOLOAD
)
2031 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
2032 sh_flags
, ORDER_INVALID
,
2034 os
->set_found_in_sections_clause();
2035 if (section_type
== Script_sections::ST_NOLOAD
)
2036 os
->set_is_noload();
2040 // Return the number of segments we expect to see.
2043 Layout::expected_segment_count() const
2045 size_t ret
= this->segment_list_
.size();
2047 // If we didn't see a SECTIONS clause in a linker script, we should
2048 // already have the complete list of segments. Otherwise we ask the
2049 // SECTIONS clause how many segments it expects, and add in the ones
2050 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2052 if (!this->script_options_
->saw_sections_clause())
2056 const Script_sections
* ss
= this->script_options_
->script_sections();
2057 return ret
+ ss
->expected_segment_count(this);
2061 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2062 // is whether we saw a .note.GNU-stack section in the object file.
2063 // GNU_STACK_FLAGS is the section flags. The flags give the
2064 // protection required for stack memory. We record this in an
2065 // executable as a PT_GNU_STACK segment. If an object file does not
2066 // have a .note.GNU-stack segment, we must assume that it is an old
2067 // object. On some targets that will force an executable stack.
2070 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2073 if (!seen_gnu_stack
)
2075 this->input_without_gnu_stack_note_
= true;
2076 if (parameters
->options().warn_execstack()
2077 && parameters
->target().is_default_stack_executable())
2078 gold_warning(_("%s: missing .note.GNU-stack section"
2079 " implies executable stack"),
2080 obj
->name().c_str());
2084 this->input_with_gnu_stack_note_
= true;
2085 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2087 this->input_requires_executable_stack_
= true;
2088 if (parameters
->options().warn_execstack()
2089 || parameters
->options().is_stack_executable())
2090 gold_warning(_("%s: requires executable stack"),
2091 obj
->name().c_str());
2096 // Create automatic note sections.
2099 Layout::create_notes()
2101 this->create_gold_note();
2102 this->create_executable_stack_info();
2103 this->create_build_id();
2106 // Create the dynamic sections which are needed before we read the
2110 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2112 if (parameters
->doing_static_link())
2115 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2116 elfcpp::SHT_DYNAMIC
,
2118 | elfcpp::SHF_WRITE
),
2122 // A linker script may discard .dynamic, so check for NULL.
2123 if (this->dynamic_section_
!= NULL
)
2125 this->dynamic_symbol_
=
2126 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2127 Symbol_table::PREDEFINED
,
2128 this->dynamic_section_
, 0, 0,
2129 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2130 elfcpp::STV_HIDDEN
, 0, false, false);
2132 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2134 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2138 // For each output section whose name can be represented as C symbol,
2139 // define __start and __stop symbols for the section. This is a GNU
2143 Layout::define_section_symbols(Symbol_table
* symtab
)
2145 for (Section_list::const_iterator p
= this->section_list_
.begin();
2146 p
!= this->section_list_
.end();
2149 const char* const name
= (*p
)->name();
2150 if (is_cident(name
))
2152 const std::string
name_string(name
);
2153 const std::string
start_name(cident_section_start_prefix
2155 const std::string
stop_name(cident_section_stop_prefix
2158 symtab
->define_in_output_data(start_name
.c_str(),
2160 Symbol_table::PREDEFINED
,
2166 elfcpp::STV_DEFAULT
,
2168 false, // offset_is_from_end
2169 true); // only_if_ref
2171 symtab
->define_in_output_data(stop_name
.c_str(),
2173 Symbol_table::PREDEFINED
,
2179 elfcpp::STV_DEFAULT
,
2181 true, // offset_is_from_end
2182 true); // only_if_ref
2187 // Define symbols for group signatures.
2190 Layout::define_group_signatures(Symbol_table
* symtab
)
2192 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2193 p
!= this->group_signatures_
.end();
2196 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2198 p
->section
->set_info_symndx(sym
);
2201 // Force the name of the group section to the group
2202 // signature, and use the group's section symbol as the
2203 // signature symbol.
2204 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2206 const char* name
= this->namepool_
.add(p
->signature
,
2208 p
->section
->set_name(name
);
2210 p
->section
->set_needs_symtab_index();
2211 p
->section
->set_info_section_symndx(p
->section
);
2215 this->group_signatures_
.clear();
2218 // Find the first read-only PT_LOAD segment, creating one if
2222 Layout::find_first_load_seg(const Target
* target
)
2224 Output_segment
* best
= NULL
;
2225 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2226 p
!= this->segment_list_
.end();
2229 if ((*p
)->type() == elfcpp::PT_LOAD
2230 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2231 && (parameters
->options().omagic()
2232 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2233 && (!target
->isolate_execinstr()
2234 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2236 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2243 gold_assert(!this->script_options_
->saw_phdrs_clause());
2245 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2250 // Save states of all current output segments. Store saved states
2251 // in SEGMENT_STATES.
2254 Layout::save_segments(Segment_states
* segment_states
)
2256 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2257 p
!= this->segment_list_
.end();
2260 Output_segment
* segment
= *p
;
2262 Output_segment
* copy
= new Output_segment(*segment
);
2263 (*segment_states
)[segment
] = copy
;
2267 // Restore states of output segments and delete any segment not found in
2271 Layout::restore_segments(const Segment_states
* segment_states
)
2273 // Go through the segment list and remove any segment added in the
2275 this->tls_segment_
= NULL
;
2276 this->relro_segment_
= NULL
;
2277 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2278 while (list_iter
!= this->segment_list_
.end())
2280 Output_segment
* segment
= *list_iter
;
2281 Segment_states::const_iterator states_iter
=
2282 segment_states
->find(segment
);
2283 if (states_iter
!= segment_states
->end())
2285 const Output_segment
* copy
= states_iter
->second
;
2286 // Shallow copy to restore states.
2289 // Also fix up TLS and RELRO segment pointers as appropriate.
2290 if (segment
->type() == elfcpp::PT_TLS
)
2291 this->tls_segment_
= segment
;
2292 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2293 this->relro_segment_
= segment
;
2299 list_iter
= this->segment_list_
.erase(list_iter
);
2300 // This is a segment created during section layout. It should be
2301 // safe to remove it since we should have removed all pointers to it.
2307 // Clean up after relaxation so that sections can be laid out again.
2310 Layout::clean_up_after_relaxation()
2312 // Restore the segments to point state just prior to the relaxation loop.
2313 Script_sections
* script_section
= this->script_options_
->script_sections();
2314 script_section
->release_segments();
2315 this->restore_segments(this->segment_states_
);
2317 // Reset section addresses and file offsets
2318 for (Section_list::iterator p
= this->section_list_
.begin();
2319 p
!= this->section_list_
.end();
2322 (*p
)->restore_states();
2324 // If an input section changes size because of relaxation,
2325 // we need to adjust the section offsets of all input sections.
2326 // after such a section.
2327 if ((*p
)->section_offsets_need_adjustment())
2328 (*p
)->adjust_section_offsets();
2330 (*p
)->reset_address_and_file_offset();
2333 // Reset special output object address and file offsets.
2334 for (Data_list::iterator p
= this->special_output_list_
.begin();
2335 p
!= this->special_output_list_
.end();
2337 (*p
)->reset_address_and_file_offset();
2339 // A linker script may have created some output section data objects.
2340 // They are useless now.
2341 for (Output_section_data_list::const_iterator p
=
2342 this->script_output_section_data_list_
.begin();
2343 p
!= this->script_output_section_data_list_
.end();
2346 this->script_output_section_data_list_
.clear();
2348 // Special-case fill output objects are recreated each time through
2349 // the relaxation loop.
2350 this->reset_relax_output();
2354 Layout::reset_relax_output()
2356 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
2357 p
!= this->relax_output_list_
.end();
2360 this->relax_output_list_
.clear();
2363 // Prepare for relaxation.
2366 Layout::prepare_for_relaxation()
2368 // Create an relaxation debug check if in debugging mode.
2369 if (is_debugging_enabled(DEBUG_RELAXATION
))
2370 this->relaxation_debug_check_
= new Relaxation_debug_check();
2372 // Save segment states.
2373 this->segment_states_
= new Segment_states();
2374 this->save_segments(this->segment_states_
);
2376 for(Section_list::const_iterator p
= this->section_list_
.begin();
2377 p
!= this->section_list_
.end();
2379 (*p
)->save_states();
2381 if (is_debugging_enabled(DEBUG_RELAXATION
))
2382 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2383 this->section_list_
, this->special_output_list_
,
2384 this->relax_output_list_
);
2386 // Also enable recording of output section data from scripts.
2387 this->record_output_section_data_from_script_
= true;
2390 // If the user set the address of the text segment, that may not be
2391 // compatible with putting the segment headers and file headers into
2392 // that segment. For isolate_execinstr() targets, it's the rodata
2393 // segment rather than text where we might put the headers.
2395 load_seg_unusable_for_headers(const Target
* target
)
2397 const General_options
& options
= parameters
->options();
2398 if (target
->isolate_execinstr())
2399 return (options
.user_set_Trodata_segment()
2400 && options
.Trodata_segment() % target
->abi_pagesize() != 0);
2402 return (options
.user_set_Ttext()
2403 && options
.Ttext() % target
->abi_pagesize() != 0);
2406 // Relaxation loop body: If target has no relaxation, this runs only once
2407 // Otherwise, the target relaxation hook is called at the end of
2408 // each iteration. If the hook returns true, it means re-layout of
2409 // section is required.
2411 // The number of segments created by a linking script without a PHDRS
2412 // clause may be affected by section sizes and alignments. There is
2413 // a remote chance that relaxation causes different number of PT_LOAD
2414 // segments are created and sections are attached to different segments.
2415 // Therefore, we always throw away all segments created during section
2416 // layout. In order to be able to restart the section layout, we keep
2417 // a copy of the segment list right before the relaxation loop and use
2418 // that to restore the segments.
2420 // PASS is the current relaxation pass number.
2421 // SYMTAB is a symbol table.
2422 // PLOAD_SEG is the address of a pointer for the load segment.
2423 // PHDR_SEG is a pointer to the PHDR segment.
2424 // SEGMENT_HEADERS points to the output segment header.
2425 // FILE_HEADER points to the output file header.
2426 // PSHNDX is the address to store the output section index.
2429 Layout::relaxation_loop_body(
2432 Symbol_table
* symtab
,
2433 Output_segment
** pload_seg
,
2434 Output_segment
* phdr_seg
,
2435 Output_segment_headers
* segment_headers
,
2436 Output_file_header
* file_header
,
2437 unsigned int* pshndx
)
2439 // If this is not the first iteration, we need to clean up after
2440 // relaxation so that we can lay out the sections again.
2442 this->clean_up_after_relaxation();
2444 // If there is a SECTIONS clause, put all the input sections into
2445 // the required order.
2446 Output_segment
* load_seg
;
2447 if (this->script_options_
->saw_sections_clause())
2448 load_seg
= this->set_section_addresses_from_script(symtab
);
2449 else if (parameters
->options().relocatable())
2452 load_seg
= this->find_first_load_seg(target
);
2454 if (parameters
->options().oformat_enum()
2455 != General_options::OBJECT_FORMAT_ELF
)
2458 if (load_seg_unusable_for_headers(target
))
2464 gold_assert(phdr_seg
== NULL
2466 || this->script_options_
->saw_sections_clause());
2468 // If the address of the load segment we found has been set by
2469 // --section-start rather than by a script, then adjust the VMA and
2470 // LMA downward if possible to include the file and section headers.
2471 uint64_t header_gap
= 0;
2472 if (load_seg
!= NULL
2473 && load_seg
->are_addresses_set()
2474 && !this->script_options_
->saw_sections_clause()
2475 && !parameters
->options().relocatable())
2477 file_header
->finalize_data_size();
2478 segment_headers
->finalize_data_size();
2479 size_t sizeof_headers
= (file_header
->data_size()
2480 + segment_headers
->data_size());
2481 const uint64_t abi_pagesize
= target
->abi_pagesize();
2482 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2483 hdr_paddr
&= ~(abi_pagesize
- 1);
2484 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2485 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2489 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2490 load_seg
->paddr() - subtract
);
2491 header_gap
= subtract
- sizeof_headers
;
2495 // Lay out the segment headers.
2496 if (!parameters
->options().relocatable())
2498 gold_assert(segment_headers
!= NULL
);
2499 if (header_gap
!= 0 && load_seg
!= NULL
)
2501 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2502 load_seg
->add_initial_output_data(z
);
2504 if (load_seg
!= NULL
)
2505 load_seg
->add_initial_output_data(segment_headers
);
2506 if (phdr_seg
!= NULL
)
2507 phdr_seg
->add_initial_output_data(segment_headers
);
2510 // Lay out the file header.
2511 if (load_seg
!= NULL
)
2512 load_seg
->add_initial_output_data(file_header
);
2514 if (this->script_options_
->saw_phdrs_clause()
2515 && !parameters
->options().relocatable())
2517 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2518 // clause in a linker script.
2519 Script_sections
* ss
= this->script_options_
->script_sections();
2520 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2523 // We set the output section indexes in set_segment_offsets and
2524 // set_section_indexes.
2527 // Set the file offsets of all the segments, and all the sections
2530 if (!parameters
->options().relocatable())
2531 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2533 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2535 // Verify that the dummy relaxation does not change anything.
2536 if (is_debugging_enabled(DEBUG_RELAXATION
))
2539 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2541 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2544 *pload_seg
= load_seg
;
2548 // Search the list of patterns and find the postion of the given section
2549 // name in the output section. If the section name matches a glob
2550 // pattern and a non-glob name, then the non-glob position takes
2551 // precedence. Return 0 if no match is found.
2554 Layout::find_section_order_index(const std::string
& section_name
)
2556 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2557 map_it
= this->input_section_position_
.find(section_name
);
2558 if (map_it
!= this->input_section_position_
.end())
2559 return map_it
->second
;
2561 // Absolute match failed. Linear search the glob patterns.
2562 std::vector
<std::string
>::iterator it
;
2563 for (it
= this->input_section_glob_
.begin();
2564 it
!= this->input_section_glob_
.end();
2567 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2569 map_it
= this->input_section_position_
.find(*it
);
2570 gold_assert(map_it
!= this->input_section_position_
.end());
2571 return map_it
->second
;
2577 // Read the sequence of input sections from the file specified with
2578 // option --section-ordering-file.
2581 Layout::read_layout_from_file()
2583 const char* filename
= parameters
->options().section_ordering_file();
2589 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2590 filename
, strerror(errno
));
2592 std::getline(in
, line
); // this chops off the trailing \n, if any
2593 unsigned int position
= 1;
2594 this->set_section_ordering_specified();
2598 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2599 line
.resize(line
.length() - 1);
2600 // Ignore comments, beginning with '#'
2603 std::getline(in
, line
);
2606 this->input_section_position_
[line
] = position
;
2607 // Store all glob patterns in a vector.
2608 if (is_wildcard_string(line
.c_str()))
2609 this->input_section_glob_
.push_back(line
);
2611 std::getline(in
, line
);
2615 // Finalize the layout. When this is called, we have created all the
2616 // output sections and all the output segments which are based on
2617 // input sections. We have several things to do, and we have to do
2618 // them in the right order, so that we get the right results correctly
2621 // 1) Finalize the list of output segments and create the segment
2624 // 2) Finalize the dynamic symbol table and associated sections.
2626 // 3) Determine the final file offset of all the output segments.
2628 // 4) Determine the final file offset of all the SHF_ALLOC output
2631 // 5) Create the symbol table sections and the section name table
2634 // 6) Finalize the symbol table: set symbol values to their final
2635 // value and make a final determination of which symbols are going
2636 // into the output symbol table.
2638 // 7) Create the section table header.
2640 // 8) Determine the final file offset of all the output sections which
2641 // are not SHF_ALLOC, including the section table header.
2643 // 9) Finalize the ELF file header.
2645 // This function returns the size of the output file.
2648 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2649 Target
* target
, const Task
* task
)
2651 target
->finalize_sections(this, input_objects
, symtab
);
2653 this->count_local_symbols(task
, input_objects
);
2655 this->link_stabs_sections();
2657 Output_segment
* phdr_seg
= NULL
;
2658 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2660 // There was a dynamic object in the link. We need to create
2661 // some information for the dynamic linker.
2663 // Create the PT_PHDR segment which will hold the program
2665 if (!this->script_options_
->saw_phdrs_clause())
2666 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2668 // Create the dynamic symbol table, including the hash table.
2669 Output_section
* dynstr
;
2670 std::vector
<Symbol
*> dynamic_symbols
;
2671 unsigned int local_dynamic_count
;
2672 Versions
versions(*this->script_options()->version_script_info(),
2674 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2675 &local_dynamic_count
, &dynamic_symbols
,
2678 // Create the .interp section to hold the name of the
2679 // interpreter, and put it in a PT_INTERP segment. Don't do it
2680 // if we saw a .interp section in an input file.
2681 if ((!parameters
->options().shared()
2682 || parameters
->options().dynamic_linker() != NULL
)
2683 && this->interp_segment_
== NULL
)
2684 this->create_interp(target
);
2686 // Finish the .dynamic section to hold the dynamic data, and put
2687 // it in a PT_DYNAMIC segment.
2688 this->finish_dynamic_section(input_objects
, symtab
);
2690 // We should have added everything we need to the dynamic string
2692 this->dynpool_
.set_string_offsets();
2694 // Create the version sections. We can't do this until the
2695 // dynamic string table is complete.
2696 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2697 dynamic_symbols
, dynstr
);
2699 // Set the size of the _DYNAMIC symbol. We can't do this until
2700 // after we call create_version_sections.
2701 this->set_dynamic_symbol_size(symtab
);
2704 // Create segment headers.
2705 Output_segment_headers
* segment_headers
=
2706 (parameters
->options().relocatable()
2708 : new Output_segment_headers(this->segment_list_
));
2710 // Lay out the file header.
2711 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
2714 this->special_output_list_
.push_back(file_header
);
2715 if (segment_headers
!= NULL
)
2716 this->special_output_list_
.push_back(segment_headers
);
2718 // Find approriate places for orphan output sections if we are using
2720 if (this->script_options_
->saw_sections_clause())
2721 this->place_orphan_sections_in_script();
2723 Output_segment
* load_seg
;
2728 // Take a snapshot of the section layout as needed.
2729 if (target
->may_relax())
2730 this->prepare_for_relaxation();
2732 // Run the relaxation loop to lay out sections.
2735 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2736 phdr_seg
, segment_headers
, file_header
,
2740 while (target
->may_relax()
2741 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2743 // If there is a load segment that contains the file and program headers,
2744 // provide a symbol __ehdr_start pointing there.
2745 // A program can use this to examine itself robustly.
2746 if (load_seg
!= NULL
)
2747 symtab
->define_in_output_segment("__ehdr_start", NULL
,
2748 Symbol_table::PREDEFINED
, load_seg
, 0, 0,
2749 elfcpp::STT_NOTYPE
, elfcpp::STB_GLOBAL
,
2750 elfcpp::STV_HIDDEN
, 0,
2751 Symbol::SEGMENT_START
, true);
2753 // Set the file offsets of all the non-data sections we've seen so
2754 // far which don't have to wait for the input sections. We need
2755 // this in order to finalize local symbols in non-allocated
2757 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2759 // Set the section indexes of all unallocated sections seen so far,
2760 // in case any of them are somehow referenced by a symbol.
2761 shndx
= this->set_section_indexes(shndx
);
2763 // Create the symbol table sections.
2764 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2765 if (!parameters
->doing_static_link())
2766 this->assign_local_dynsym_offsets(input_objects
);
2768 // Process any symbol assignments from a linker script. This must
2769 // be called after the symbol table has been finalized.
2770 this->script_options_
->finalize_symbols(symtab
, this);
2772 // Create the incremental inputs sections.
2773 if (this->incremental_inputs_
)
2775 this->incremental_inputs_
->finalize();
2776 this->create_incremental_info_sections(symtab
);
2779 // Create the .shstrtab section.
2780 Output_section
* shstrtab_section
= this->create_shstrtab();
2782 // Set the file offsets of the rest of the non-data sections which
2783 // don't have to wait for the input sections.
2784 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2786 // Now that all sections have been created, set the section indexes
2787 // for any sections which haven't been done yet.
2788 shndx
= this->set_section_indexes(shndx
);
2790 // Create the section table header.
2791 this->create_shdrs(shstrtab_section
, &off
);
2793 // If there are no sections which require postprocessing, we can
2794 // handle the section names now, and avoid a resize later.
2795 if (!this->any_postprocessing_sections_
)
2797 off
= this->set_section_offsets(off
,
2798 POSTPROCESSING_SECTIONS_PASS
);
2800 this->set_section_offsets(off
,
2801 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2804 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2806 // Now we know exactly where everything goes in the output file
2807 // (except for non-allocated sections which require postprocessing).
2808 Output_data::layout_complete();
2810 this->output_file_size_
= off
;
2815 // Create a note header following the format defined in the ELF ABI.
2816 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2817 // of the section to create, DESCSZ is the size of the descriptor.
2818 // ALLOCATE is true if the section should be allocated in memory.
2819 // This returns the new note section. It sets *TRAILING_PADDING to
2820 // the number of trailing zero bytes required.
2823 Layout::create_note(const char* name
, int note_type
,
2824 const char* section_name
, size_t descsz
,
2825 bool allocate
, size_t* trailing_padding
)
2827 // Authorities all agree that the values in a .note field should
2828 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2829 // they differ on what the alignment is for 64-bit binaries.
2830 // The GABI says unambiguously they take 8-byte alignment:
2831 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2832 // Other documentation says alignment should always be 4 bytes:
2833 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2834 // GNU ld and GNU readelf both support the latter (at least as of
2835 // version 2.16.91), and glibc always generates the latter for
2836 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2838 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2839 const int size
= parameters
->target().get_size();
2841 const int size
= 32;
2844 // The contents of the .note section.
2845 size_t namesz
= strlen(name
) + 1;
2846 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2847 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2849 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2851 unsigned char* buffer
= new unsigned char[notehdrsz
];
2852 memset(buffer
, 0, notehdrsz
);
2854 bool is_big_endian
= parameters
->target().is_big_endian();
2860 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2861 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2862 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2866 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2867 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2868 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2871 else if (size
== 64)
2875 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2876 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2877 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2881 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2882 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2883 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2889 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2891 elfcpp::Elf_Xword flags
= 0;
2892 Output_section_order order
= ORDER_INVALID
;
2895 flags
= elfcpp::SHF_ALLOC
;
2896 order
= ORDER_RO_NOTE
;
2898 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2900 flags
, false, order
, false);
2904 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2907 os
->add_output_section_data(posd
);
2909 *trailing_padding
= aligned_descsz
- descsz
;
2914 // For an executable or shared library, create a note to record the
2915 // version of gold used to create the binary.
2918 Layout::create_gold_note()
2920 if (parameters
->options().relocatable()
2921 || parameters
->incremental_update())
2924 std::string desc
= std::string("gold ") + gold::get_version_string();
2926 size_t trailing_padding
;
2927 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2928 ".note.gnu.gold-version", desc
.size(),
2929 false, &trailing_padding
);
2933 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2934 os
->add_output_section_data(posd
);
2936 if (trailing_padding
> 0)
2938 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2939 os
->add_output_section_data(posd
);
2943 // Record whether the stack should be executable. This can be set
2944 // from the command line using the -z execstack or -z noexecstack
2945 // options. Otherwise, if any input file has a .note.GNU-stack
2946 // section with the SHF_EXECINSTR flag set, the stack should be
2947 // executable. Otherwise, if at least one input file a
2948 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2949 // section, we use the target default for whether the stack should be
2950 // executable. Otherwise, we don't generate a stack note. When
2951 // generating a object file, we create a .note.GNU-stack section with
2952 // the appropriate marking. When generating an executable or shared
2953 // library, we create a PT_GNU_STACK segment.
2956 Layout::create_executable_stack_info()
2958 bool is_stack_executable
;
2959 if (parameters
->options().is_execstack_set())
2960 is_stack_executable
= parameters
->options().is_stack_executable();
2961 else if (!this->input_with_gnu_stack_note_
)
2965 if (this->input_requires_executable_stack_
)
2966 is_stack_executable
= true;
2967 else if (this->input_without_gnu_stack_note_
)
2968 is_stack_executable
=
2969 parameters
->target().is_default_stack_executable();
2971 is_stack_executable
= false;
2974 if (parameters
->options().relocatable())
2976 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2977 elfcpp::Elf_Xword flags
= 0;
2978 if (is_stack_executable
)
2979 flags
|= elfcpp::SHF_EXECINSTR
;
2980 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2981 ORDER_INVALID
, false);
2985 if (this->script_options_
->saw_phdrs_clause())
2987 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2988 if (is_stack_executable
)
2989 flags
|= elfcpp::PF_X
;
2990 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2994 // If --build-id was used, set up the build ID note.
2997 Layout::create_build_id()
2999 if (!parameters
->options().user_set_build_id())
3002 const char* style
= parameters
->options().build_id();
3003 if (strcmp(style
, "none") == 0)
3006 // Set DESCSZ to the size of the note descriptor. When possible,
3007 // set DESC to the note descriptor contents.
3010 if (strcmp(style
, "md5") == 0)
3012 else if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
3014 else if (strcmp(style
, "uuid") == 0)
3016 const size_t uuidsz
= 128 / 8;
3018 char buffer
[uuidsz
];
3019 memset(buffer
, 0, uuidsz
);
3021 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
3023 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3027 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
3028 release_descriptor(descriptor
, true);
3030 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
3031 else if (static_cast<size_t>(got
) != uuidsz
)
3032 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3036 desc
.assign(buffer
, uuidsz
);
3039 else if (strncmp(style
, "0x", 2) == 0)
3042 const char* p
= style
+ 2;
3045 if (hex_p(p
[0]) && hex_p(p
[1]))
3047 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
3051 else if (*p
== '-' || *p
== ':')
3054 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3057 descsz
= desc
.size();
3060 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
3063 size_t trailing_padding
;
3064 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
3065 ".note.gnu.build-id", descsz
, true,
3072 // We know the value already, so we fill it in now.
3073 gold_assert(desc
.size() == descsz
);
3075 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3076 os
->add_output_section_data(posd
);
3078 if (trailing_padding
!= 0)
3080 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3081 os
->add_output_section_data(posd
);
3086 // We need to compute a checksum after we have completed the
3088 gold_assert(trailing_padding
== 0);
3089 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3090 os
->add_output_section_data(this->build_id_note_
);
3094 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3095 // field of the former should point to the latter. I'm not sure who
3096 // started this, but the GNU linker does it, and some tools depend
3100 Layout::link_stabs_sections()
3102 if (!this->have_stabstr_section_
)
3105 for (Section_list::iterator p
= this->section_list_
.begin();
3106 p
!= this->section_list_
.end();
3109 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3112 const char* name
= (*p
)->name();
3113 if (strncmp(name
, ".stab", 5) != 0)
3116 size_t len
= strlen(name
);
3117 if (strcmp(name
+ len
- 3, "str") != 0)
3120 std::string
stab_name(name
, len
- 3);
3121 Output_section
* stab_sec
;
3122 stab_sec
= this->find_output_section(stab_name
.c_str());
3123 if (stab_sec
!= NULL
)
3124 stab_sec
->set_link_section(*p
);
3128 // Create .gnu_incremental_inputs and related sections needed
3129 // for the next run of incremental linking to check what has changed.
3132 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3134 Incremental_inputs
* incr
= this->incremental_inputs_
;
3136 gold_assert(incr
!= NULL
);
3138 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3139 incr
->create_data_sections(symtab
);
3141 // Add the .gnu_incremental_inputs section.
3142 const char* incremental_inputs_name
=
3143 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3144 Output_section
* incremental_inputs_os
=
3145 this->make_output_section(incremental_inputs_name
,
3146 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3147 ORDER_INVALID
, false);
3148 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3150 // Add the .gnu_incremental_symtab section.
3151 const char* incremental_symtab_name
=
3152 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3153 Output_section
* incremental_symtab_os
=
3154 this->make_output_section(incremental_symtab_name
,
3155 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3156 ORDER_INVALID
, false);
3157 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3158 incremental_symtab_os
->set_entsize(4);
3160 // Add the .gnu_incremental_relocs section.
3161 const char* incremental_relocs_name
=
3162 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3163 Output_section
* incremental_relocs_os
=
3164 this->make_output_section(incremental_relocs_name
,
3165 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3166 ORDER_INVALID
, false);
3167 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3168 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3170 // Add the .gnu_incremental_got_plt section.
3171 const char* incremental_got_plt_name
=
3172 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3173 Output_section
* incremental_got_plt_os
=
3174 this->make_output_section(incremental_got_plt_name
,
3175 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3176 ORDER_INVALID
, false);
3177 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3179 // Add the .gnu_incremental_strtab section.
3180 const char* incremental_strtab_name
=
3181 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3182 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3183 elfcpp::SHT_STRTAB
, 0,
3184 ORDER_INVALID
, false);
3185 Output_data_strtab
* strtab_data
=
3186 new Output_data_strtab(incr
->get_stringpool());
3187 incremental_strtab_os
->add_output_section_data(strtab_data
);
3189 incremental_inputs_os
->set_after_input_sections();
3190 incremental_symtab_os
->set_after_input_sections();
3191 incremental_relocs_os
->set_after_input_sections();
3192 incremental_got_plt_os
->set_after_input_sections();
3194 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3195 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3196 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3197 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3200 // Return whether SEG1 should be before SEG2 in the output file. This
3201 // is based entirely on the segment type and flags. When this is
3202 // called the segment addresses have normally not yet been set.
3205 Layout::segment_precedes(const Output_segment
* seg1
,
3206 const Output_segment
* seg2
)
3208 elfcpp::Elf_Word type1
= seg1
->type();
3209 elfcpp::Elf_Word type2
= seg2
->type();
3211 // The single PT_PHDR segment is required to precede any loadable
3212 // segment. We simply make it always first.
3213 if (type1
== elfcpp::PT_PHDR
)
3215 gold_assert(type2
!= elfcpp::PT_PHDR
);
3218 if (type2
== elfcpp::PT_PHDR
)
3221 // The single PT_INTERP segment is required to precede any loadable
3222 // segment. We simply make it always second.
3223 if (type1
== elfcpp::PT_INTERP
)
3225 gold_assert(type2
!= elfcpp::PT_INTERP
);
3228 if (type2
== elfcpp::PT_INTERP
)
3231 // We then put PT_LOAD segments before any other segments.
3232 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3234 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3237 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3238 // segment, because that is where the dynamic linker expects to find
3239 // it (this is just for efficiency; other positions would also work
3241 if (type1
== elfcpp::PT_TLS
3242 && type2
!= elfcpp::PT_TLS
3243 && type2
!= elfcpp::PT_GNU_RELRO
)
3245 if (type2
== elfcpp::PT_TLS
3246 && type1
!= elfcpp::PT_TLS
3247 && type1
!= elfcpp::PT_GNU_RELRO
)
3250 // We put the PT_GNU_RELRO segment last, because that is where the
3251 // dynamic linker expects to find it (as with PT_TLS, this is just
3253 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3255 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3258 const elfcpp::Elf_Word flags1
= seg1
->flags();
3259 const elfcpp::Elf_Word flags2
= seg2
->flags();
3261 // The order of non-PT_LOAD segments is unimportant. We simply sort
3262 // by the numeric segment type and flags values. There should not
3263 // be more than one segment with the same type and flags, except
3264 // when a linker script specifies such.
3265 if (type1
!= elfcpp::PT_LOAD
)
3268 return type1
< type2
;
3269 gold_assert(flags1
!= flags2
3270 || this->script_options_
->saw_phdrs_clause());
3271 return flags1
< flags2
;
3274 // If the addresses are set already, sort by load address.
3275 if (seg1
->are_addresses_set())
3277 if (!seg2
->are_addresses_set())
3280 unsigned int section_count1
= seg1
->output_section_count();
3281 unsigned int section_count2
= seg2
->output_section_count();
3282 if (section_count1
== 0 && section_count2
> 0)
3284 if (section_count1
> 0 && section_count2
== 0)
3287 uint64_t paddr1
= (seg1
->are_addresses_set()
3289 : seg1
->first_section_load_address());
3290 uint64_t paddr2
= (seg2
->are_addresses_set()
3292 : seg2
->first_section_load_address());
3294 if (paddr1
!= paddr2
)
3295 return paddr1
< paddr2
;
3297 else if (seg2
->are_addresses_set())
3300 // A segment which holds large data comes after a segment which does
3301 // not hold large data.
3302 if (seg1
->is_large_data_segment())
3304 if (!seg2
->is_large_data_segment())
3307 else if (seg2
->is_large_data_segment())
3310 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3311 // segments come before writable segments. Then writable segments
3312 // with data come before writable segments without data. Then
3313 // executable segments come before non-executable segments. Then
3314 // the unlikely case of a non-readable segment comes before the
3315 // normal case of a readable segment. If there are multiple
3316 // segments with the same type and flags, we require that the
3317 // address be set, and we sort by virtual address and then physical
3319 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3320 return (flags1
& elfcpp::PF_W
) == 0;
3321 if ((flags1
& elfcpp::PF_W
) != 0
3322 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3323 return seg1
->has_any_data_sections();
3324 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3325 return (flags1
& elfcpp::PF_X
) != 0;
3326 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3327 return (flags1
& elfcpp::PF_R
) == 0;
3329 // We shouldn't get here--we shouldn't create segments which we
3330 // can't distinguish. Unless of course we are using a weird linker
3331 // script or overlapping --section-start options. We could also get
3332 // here if plugins want unique segments for subsets of sections.
3333 gold_assert(this->script_options_
->saw_phdrs_clause()
3334 || parameters
->options().any_section_start()
3335 || this->is_unique_segment_for_sections_specified());
3339 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3342 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3344 uint64_t unsigned_off
= off
;
3345 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3346 | (addr
& (abi_pagesize
- 1)));
3347 if (aligned_off
< unsigned_off
)
3348 aligned_off
+= abi_pagesize
;
3352 // On targets where the text segment contains only executable code,
3353 // a non-executable segment is never the text segment.
3356 is_text_segment(const Target
* target
, const Output_segment
* seg
)
3358 elfcpp::Elf_Xword flags
= seg
->flags();
3359 if ((flags
& elfcpp::PF_W
) != 0)
3361 if ((flags
& elfcpp::PF_X
) == 0)
3362 return !target
->isolate_execinstr();
3366 // Set the file offsets of all the segments, and all the sections they
3367 // contain. They have all been created. LOAD_SEG must be be laid out
3368 // first. Return the offset of the data to follow.
3371 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3372 unsigned int* pshndx
)
3374 // Sort them into the final order. We use a stable sort so that we
3375 // don't randomize the order of indistinguishable segments created
3376 // by linker scripts.
3377 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3378 Layout::Compare_segments(this));
3380 // Find the PT_LOAD segments, and set their addresses and offsets
3381 // and their section's addresses and offsets.
3382 uint64_t start_addr
;
3383 if (parameters
->options().user_set_Ttext())
3384 start_addr
= parameters
->options().Ttext();
3385 else if (parameters
->options().output_is_position_independent())
3388 start_addr
= target
->default_text_segment_address();
3390 uint64_t addr
= start_addr
;
3393 // If LOAD_SEG is NULL, then the file header and segment headers
3394 // will not be loadable. But they still need to be at offset 0 in
3395 // the file. Set their offsets now.
3396 if (load_seg
== NULL
)
3398 for (Data_list::iterator p
= this->special_output_list_
.begin();
3399 p
!= this->special_output_list_
.end();
3402 off
= align_address(off
, (*p
)->addralign());
3403 (*p
)->set_address_and_file_offset(0, off
);
3404 off
+= (*p
)->data_size();
3408 unsigned int increase_relro
= this->increase_relro_
;
3409 if (this->script_options_
->saw_sections_clause())
3412 const bool check_sections
= parameters
->options().check_sections();
3413 Output_segment
* last_load_segment
= NULL
;
3415 unsigned int shndx_begin
= *pshndx
;
3416 unsigned int shndx_load_seg
= *pshndx
;
3418 for (Segment_list::iterator p
= this->segment_list_
.begin();
3419 p
!= this->segment_list_
.end();
3422 if ((*p
)->type() == elfcpp::PT_LOAD
)
3424 if (target
->isolate_execinstr())
3426 // When we hit the segment that should contain the
3427 // file headers, reset the file offset so we place
3428 // it and subsequent segments appropriately.
3429 // We'll fix up the preceding segments below.
3437 shndx_load_seg
= *pshndx
;
3443 // Verify that the file headers fall into the first segment.
3444 if (load_seg
!= NULL
&& load_seg
!= *p
)
3449 bool are_addresses_set
= (*p
)->are_addresses_set();
3450 if (are_addresses_set
)
3452 // When it comes to setting file offsets, we care about
3453 // the physical address.
3454 addr
= (*p
)->paddr();
3456 else if (parameters
->options().user_set_Ttext()
3457 && (parameters
->options().omagic()
3458 || is_text_segment(target
, *p
)))
3460 are_addresses_set
= true;
3462 else if (parameters
->options().user_set_Trodata_segment()
3463 && ((*p
)->flags() & (elfcpp::PF_W
| elfcpp::PF_X
)) == 0)
3465 addr
= parameters
->options().Trodata_segment();
3466 are_addresses_set
= true;
3468 else if (parameters
->options().user_set_Tdata()
3469 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3470 && (!parameters
->options().user_set_Tbss()
3471 || (*p
)->has_any_data_sections()))
3473 addr
= parameters
->options().Tdata();
3474 are_addresses_set
= true;
3476 else if (parameters
->options().user_set_Tbss()
3477 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3478 && !(*p
)->has_any_data_sections())
3480 addr
= parameters
->options().Tbss();
3481 are_addresses_set
= true;
3484 uint64_t orig_addr
= addr
;
3485 uint64_t orig_off
= off
;
3487 uint64_t aligned_addr
= 0;
3488 uint64_t abi_pagesize
= target
->abi_pagesize();
3489 uint64_t common_pagesize
= target
->common_pagesize();
3491 if (!parameters
->options().nmagic()
3492 && !parameters
->options().omagic())
3493 (*p
)->set_minimum_p_align(abi_pagesize
);
3495 if (!are_addresses_set
)
3497 // Skip the address forward one page, maintaining the same
3498 // position within the page. This lets us store both segments
3499 // overlapping on a single page in the file, but the loader will
3500 // put them on different pages in memory. We will revisit this
3501 // decision once we know the size of the segment.
3503 addr
= align_address(addr
, (*p
)->maximum_alignment());
3504 aligned_addr
= addr
;
3508 // This is the segment that will contain the file
3509 // headers, so its offset will have to be exactly zero.
3510 gold_assert(orig_off
== 0);
3512 // If the target wants a fixed minimum distance from the
3513 // text segment to the read-only segment, move up now.
3515 start_addr
+ (parameters
->options().user_set_rosegment_gap()
3516 ? parameters
->options().rosegment_gap()
3517 : target
->rosegment_gap());
3518 if (addr
< min_addr
)
3521 // But this is not the first segment! To make its
3522 // address congruent with its offset, that address better
3523 // be aligned to the ABI-mandated page size.
3524 addr
= align_address(addr
, abi_pagesize
);
3525 aligned_addr
= addr
;
3529 if ((addr
& (abi_pagesize
- 1)) != 0)
3530 addr
= addr
+ abi_pagesize
;
3532 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3536 if (!parameters
->options().nmagic()
3537 && !parameters
->options().omagic())
3539 // Here we are also taking care of the case when
3540 // the maximum segment alignment is larger than the page size.
3541 off
= align_file_offset(off
, addr
,
3542 std::max(abi_pagesize
,
3543 (*p
)->maximum_alignment()));
3547 // This is -N or -n with a section script which prevents
3548 // us from using a load segment. We need to ensure that
3549 // the file offset is aligned to the alignment of the
3550 // segment. This is because the linker script
3551 // implicitly assumed a zero offset. If we don't align
3552 // here, then the alignment of the sections in the
3553 // linker script may not match the alignment of the
3554 // sections in the set_section_addresses call below,
3555 // causing an error about dot moving backward.
3556 off
= align_address(off
, (*p
)->maximum_alignment());
3559 unsigned int shndx_hold
= *pshndx
;
3560 bool has_relro
= false;
3561 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
3567 // Now that we know the size of this segment, we may be able
3568 // to save a page in memory, at the cost of wasting some
3569 // file space, by instead aligning to the start of a new
3570 // page. Here we use the real machine page size rather than
3571 // the ABI mandated page size. If the segment has been
3572 // aligned so that the relro data ends at a page boundary,
3573 // we do not try to realign it.
3575 if (!are_addresses_set
3577 && aligned_addr
!= addr
3578 && !parameters
->incremental())
3580 uint64_t first_off
= (common_pagesize
3582 & (common_pagesize
- 1)));
3583 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
3586 && ((aligned_addr
& ~ (common_pagesize
- 1))
3587 != (new_addr
& ~ (common_pagesize
- 1)))
3588 && first_off
+ last_off
<= common_pagesize
)
3590 *pshndx
= shndx_hold
;
3591 addr
= align_address(aligned_addr
, common_pagesize
);
3592 addr
= align_address(addr
, (*p
)->maximum_alignment());
3593 if ((addr
& (abi_pagesize
- 1)) != 0)
3594 addr
= addr
+ abi_pagesize
;
3595 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3596 off
= align_file_offset(off
, addr
, abi_pagesize
);
3598 increase_relro
= this->increase_relro_
;
3599 if (this->script_options_
->saw_sections_clause())
3603 new_addr
= (*p
)->set_section_addresses(target
, this,
3613 // Implement --check-sections. We know that the segments
3614 // are sorted by LMA.
3615 if (check_sections
&& last_load_segment
!= NULL
)
3617 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
3618 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3621 unsigned long long lb1
= last_load_segment
->paddr();
3622 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3623 unsigned long long lb2
= (*p
)->paddr();
3624 unsigned long long le2
= lb2
+ (*p
)->memsz();
3625 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3626 "[0x%llx -> 0x%llx]"),
3627 lb1
, le1
, lb2
, le2
);
3630 last_load_segment
= *p
;
3634 if (load_seg
!= NULL
&& target
->isolate_execinstr())
3636 // Process the early segments again, setting their file offsets
3637 // so they land after the segments starting at LOAD_SEG.
3638 off
= align_file_offset(off
, 0, target
->abi_pagesize());
3640 this->reset_relax_output();
3642 for (Segment_list::iterator p
= this->segment_list_
.begin();
3646 if ((*p
)->type() == elfcpp::PT_LOAD
)
3648 // We repeat the whole job of assigning addresses and
3649 // offsets, but we really only want to change the offsets and
3650 // must ensure that the addresses all come out the same as
3651 // they did the first time through.
3652 bool has_relro
= false;
3653 const uint64_t old_addr
= (*p
)->vaddr();
3654 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
3655 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
3661 gold_assert(new_addr
== old_end
);
3665 gold_assert(shndx_begin
== shndx_load_seg
);
3668 // Handle the non-PT_LOAD segments, setting their offsets from their
3669 // section's offsets.
3670 for (Segment_list::iterator p
= this->segment_list_
.begin();
3671 p
!= this->segment_list_
.end();
3674 if ((*p
)->type() != elfcpp::PT_LOAD
)
3675 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3680 // Set the TLS offsets for each section in the PT_TLS segment.
3681 if (this->tls_segment_
!= NULL
)
3682 this->tls_segment_
->set_tls_offsets();
3687 // Set the offsets of all the allocated sections when doing a
3688 // relocatable link. This does the same jobs as set_segment_offsets,
3689 // only for a relocatable link.
3692 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3693 unsigned int* pshndx
)
3697 file_header
->set_address_and_file_offset(0, 0);
3698 off
+= file_header
->data_size();
3700 for (Section_list::iterator p
= this->section_list_
.begin();
3701 p
!= this->section_list_
.end();
3704 // We skip unallocated sections here, except that group sections
3705 // have to come first.
3706 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3707 && (*p
)->type() != elfcpp::SHT_GROUP
)
3710 off
= align_address(off
, (*p
)->addralign());
3712 // The linker script might have set the address.
3713 if (!(*p
)->is_address_valid())
3714 (*p
)->set_address(0);
3715 (*p
)->set_file_offset(off
);
3716 (*p
)->finalize_data_size();
3717 if ((*p
)->type() != elfcpp::SHT_NOBITS
)
3718 off
+= (*p
)->data_size();
3720 (*p
)->set_out_shndx(*pshndx
);
3727 // Set the file offset of all the sections not associated with a
3731 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3733 off_t startoff
= off
;
3736 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3737 p
!= this->unattached_section_list_
.end();
3740 // The symtab section is handled in create_symtab_sections.
3741 if (*p
== this->symtab_section_
)
3744 // If we've already set the data size, don't set it again.
3745 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3748 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3749 && (*p
)->requires_postprocessing())
3751 (*p
)->create_postprocessing_buffer();
3752 this->any_postprocessing_sections_
= true;
3755 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3756 && (*p
)->after_input_sections())
3758 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3759 && (!(*p
)->after_input_sections()
3760 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3762 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3763 && (!(*p
)->after_input_sections()
3764 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3767 if (!parameters
->incremental_update())
3769 off
= align_address(off
, (*p
)->addralign());
3770 (*p
)->set_file_offset(off
);
3771 (*p
)->finalize_data_size();
3775 // Incremental update: allocate file space from free list.
3776 (*p
)->pre_finalize_data_size();
3777 off_t current_size
= (*p
)->current_data_size();
3778 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3781 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3782 this->free_list_
.dump();
3783 gold_assert((*p
)->output_section() != NULL
);
3784 gold_fallback(_("out of patch space for section %s; "
3785 "relink with --incremental-full"),
3786 (*p
)->output_section()->name());
3788 (*p
)->set_file_offset(off
);
3789 (*p
)->finalize_data_size();
3790 if ((*p
)->data_size() > current_size
)
3792 gold_assert((*p
)->output_section() != NULL
);
3793 gold_fallback(_("%s: section changed size; "
3794 "relink with --incremental-full"),
3795 (*p
)->output_section()->name());
3797 gold_debug(DEBUG_INCREMENTAL
,
3798 "set_section_offsets: %08lx %08lx %s",
3799 static_cast<long>(off
),
3800 static_cast<long>((*p
)->data_size()),
3801 ((*p
)->output_section() != NULL
3802 ? (*p
)->output_section()->name() : "(special)"));
3805 off
+= (*p
)->data_size();
3809 // At this point the name must be set.
3810 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3811 this->namepool_
.add((*p
)->name(), false, NULL
);
3816 // Set the section indexes of all the sections not associated with a
3820 Layout::set_section_indexes(unsigned int shndx
)
3822 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3823 p
!= this->unattached_section_list_
.end();
3826 if (!(*p
)->has_out_shndx())
3828 (*p
)->set_out_shndx(shndx
);
3835 // Set the section addresses according to the linker script. This is
3836 // only called when we see a SECTIONS clause. This returns the
3837 // program segment which should hold the file header and segment
3838 // headers, if any. It will return NULL if they should not be in a
3842 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3844 Script_sections
* ss
= this->script_options_
->script_sections();
3845 gold_assert(ss
->saw_sections_clause());
3846 return this->script_options_
->set_section_addresses(symtab
, this);
3849 // Place the orphan sections in the linker script.
3852 Layout::place_orphan_sections_in_script()
3854 Script_sections
* ss
= this->script_options_
->script_sections();
3855 gold_assert(ss
->saw_sections_clause());
3857 // Place each orphaned output section in the script.
3858 for (Section_list::iterator p
= this->section_list_
.begin();
3859 p
!= this->section_list_
.end();
3862 if (!(*p
)->found_in_sections_clause())
3863 ss
->place_orphan(*p
);
3867 // Count the local symbols in the regular symbol table and the dynamic
3868 // symbol table, and build the respective string pools.
3871 Layout::count_local_symbols(const Task
* task
,
3872 const Input_objects
* input_objects
)
3874 // First, figure out an upper bound on the number of symbols we'll
3875 // be inserting into each pool. This helps us create the pools with
3876 // the right size, to avoid unnecessary hashtable resizing.
3877 unsigned int symbol_count
= 0;
3878 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3879 p
!= input_objects
->relobj_end();
3881 symbol_count
+= (*p
)->local_symbol_count();
3883 // Go from "upper bound" to "estimate." We overcount for two
3884 // reasons: we double-count symbols that occur in more than one
3885 // object file, and we count symbols that are dropped from the
3886 // output. Add it all together and assume we overcount by 100%.
3889 // We assume all symbols will go into both the sympool and dynpool.
3890 this->sympool_
.reserve(symbol_count
);
3891 this->dynpool_
.reserve(symbol_count
);
3893 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3894 p
!= input_objects
->relobj_end();
3897 Task_lock_obj
<Object
> tlo(task
, *p
);
3898 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3902 // Create the symbol table sections. Here we also set the final
3903 // values of the symbols. At this point all the loadable sections are
3904 // fully laid out. SHNUM is the number of sections so far.
3907 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3908 Symbol_table
* symtab
,
3914 if (parameters
->target().get_size() == 32)
3916 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3919 else if (parameters
->target().get_size() == 64)
3921 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3927 // Compute file offsets relative to the start of the symtab section.
3930 // Save space for the dummy symbol at the start of the section. We
3931 // never bother to write this out--it will just be left as zero.
3933 unsigned int local_symbol_index
= 1;
3935 // Add STT_SECTION symbols for each Output section which needs one.
3936 for (Section_list::iterator p
= this->section_list_
.begin();
3937 p
!= this->section_list_
.end();
3940 if (!(*p
)->needs_symtab_index())
3941 (*p
)->set_symtab_index(-1U);
3944 (*p
)->set_symtab_index(local_symbol_index
);
3945 ++local_symbol_index
;
3950 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3951 p
!= input_objects
->relobj_end();
3954 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3956 off
+= (index
- local_symbol_index
) * symsize
;
3957 local_symbol_index
= index
;
3960 unsigned int local_symcount
= local_symbol_index
;
3961 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3964 size_t dyn_global_index
;
3966 if (this->dynsym_section_
== NULL
)
3969 dyn_global_index
= 0;
3974 dyn_global_index
= this->dynsym_section_
->info();
3975 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3976 dynoff
= this->dynsym_section_
->offset() + locsize
;
3977 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3978 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3979 == this->dynsym_section_
->data_size() - locsize
);
3982 off_t global_off
= off
;
3983 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3984 &this->sympool_
, &local_symcount
);
3986 if (!parameters
->options().strip_all())
3988 this->sympool_
.set_string_offsets();
3990 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3991 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3995 this->symtab_section_
= osymtab
;
3997 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3999 osymtab
->add_output_section_data(pos
);
4001 // We generate a .symtab_shndx section if we have more than
4002 // SHN_LORESERVE sections. Technically it is possible that we
4003 // don't need one, because it is possible that there are no
4004 // symbols in any of sections with indexes larger than
4005 // SHN_LORESERVE. That is probably unusual, though, and it is
4006 // easier to always create one than to compute section indexes
4007 // twice (once here, once when writing out the symbols).
4008 if (shnum
>= elfcpp::SHN_LORESERVE
)
4010 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
4012 Output_section
* osymtab_xindex
=
4013 this->make_output_section(symtab_xindex_name
,
4014 elfcpp::SHT_SYMTAB_SHNDX
, 0,
4015 ORDER_INVALID
, false);
4017 size_t symcount
= off
/ symsize
;
4018 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
4020 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
4022 osymtab_xindex
->set_link_section(osymtab
);
4023 osymtab_xindex
->set_addralign(4);
4024 osymtab_xindex
->set_entsize(4);
4026 osymtab_xindex
->set_after_input_sections();
4028 // This tells the driver code to wait until the symbol table
4029 // has written out before writing out the postprocessing
4030 // sections, including the .symtab_shndx section.
4031 this->any_postprocessing_sections_
= true;
4034 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
4035 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
4040 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
4041 ostrtab
->add_output_section_data(pstr
);
4044 if (!parameters
->incremental_update())
4045 symtab_off
= align_address(*poff
, align
);
4048 symtab_off
= this->allocate(off
, align
, *poff
);
4050 gold_fallback(_("out of patch space for symbol table; "
4051 "relink with --incremental-full"));
4052 gold_debug(DEBUG_INCREMENTAL
,
4053 "create_symtab_sections: %08lx %08lx .symtab",
4054 static_cast<long>(symtab_off
),
4055 static_cast<long>(off
));
4058 symtab
->set_file_offset(symtab_off
+ global_off
);
4059 osymtab
->set_file_offset(symtab_off
);
4060 osymtab
->finalize_data_size();
4061 osymtab
->set_link_section(ostrtab
);
4062 osymtab
->set_info(local_symcount
);
4063 osymtab
->set_entsize(symsize
);
4065 if (symtab_off
+ off
> *poff
)
4066 *poff
= symtab_off
+ off
;
4070 // Create the .shstrtab section, which holds the names of the
4071 // sections. At the time this is called, we have created all the
4072 // output sections except .shstrtab itself.
4075 Layout::create_shstrtab()
4077 // FIXME: We don't need to create a .shstrtab section if we are
4078 // stripping everything.
4080 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
4082 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
4083 ORDER_INVALID
, false);
4085 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
4087 // We can't write out this section until we've set all the
4088 // section names, and we don't set the names of compressed
4089 // output sections until relocations are complete. FIXME: With
4090 // the current names we use, this is unnecessary.
4091 os
->set_after_input_sections();
4094 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
4095 os
->add_output_section_data(posd
);
4100 // Create the section headers. SIZE is 32 or 64. OFF is the file
4104 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
4106 Output_section_headers
* oshdrs
;
4107 oshdrs
= new Output_section_headers(this,
4108 &this->segment_list_
,
4109 &this->section_list_
,
4110 &this->unattached_section_list_
,
4114 if (!parameters
->incremental_update())
4115 off
= align_address(*poff
, oshdrs
->addralign());
4118 oshdrs
->pre_finalize_data_size();
4119 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
4121 gold_fallback(_("out of patch space for section header table; "
4122 "relink with --incremental-full"));
4123 gold_debug(DEBUG_INCREMENTAL
,
4124 "create_shdrs: %08lx %08lx (section header table)",
4125 static_cast<long>(off
),
4126 static_cast<long>(off
+ oshdrs
->data_size()));
4128 oshdrs
->set_address_and_file_offset(0, off
);
4129 off
+= oshdrs
->data_size();
4132 this->section_headers_
= oshdrs
;
4135 // Count the allocated sections.
4138 Layout::allocated_output_section_count() const
4140 size_t section_count
= 0;
4141 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4142 p
!= this->segment_list_
.end();
4144 section_count
+= (*p
)->output_section_count();
4145 return section_count
;
4148 // Create the dynamic symbol table.
4151 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4152 Symbol_table
* symtab
,
4153 Output_section
** pdynstr
,
4154 unsigned int* plocal_dynamic_count
,
4155 std::vector
<Symbol
*>* pdynamic_symbols
,
4156 Versions
* pversions
)
4158 // Count all the symbols in the dynamic symbol table, and set the
4159 // dynamic symbol indexes.
4161 // Skip symbol 0, which is always all zeroes.
4162 unsigned int index
= 1;
4164 // Add STT_SECTION symbols for each Output section which needs one.
4165 for (Section_list::iterator p
= this->section_list_
.begin();
4166 p
!= this->section_list_
.end();
4169 if (!(*p
)->needs_dynsym_index())
4170 (*p
)->set_dynsym_index(-1U);
4173 (*p
)->set_dynsym_index(index
);
4178 // Count the local symbols that need to go in the dynamic symbol table,
4179 // and set the dynamic symbol indexes.
4180 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4181 p
!= input_objects
->relobj_end();
4184 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4188 unsigned int local_symcount
= index
;
4189 *plocal_dynamic_count
= local_symcount
;
4191 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
4192 &this->dynpool_
, pversions
);
4196 const int size
= parameters
->target().get_size();
4199 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4202 else if (size
== 64)
4204 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4210 // Create the dynamic symbol table section.
4212 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4216 ORDER_DYNAMIC_LINKER
,
4219 // Check for NULL as a linker script may discard .dynsym.
4222 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4225 dynsym
->add_output_section_data(odata
);
4227 dynsym
->set_info(local_symcount
);
4228 dynsym
->set_entsize(symsize
);
4229 dynsym
->set_addralign(align
);
4231 this->dynsym_section_
= dynsym
;
4234 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4237 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4238 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4241 // If there are more than SHN_LORESERVE allocated sections, we
4242 // create a .dynsym_shndx section. It is possible that we don't
4243 // need one, because it is possible that there are no dynamic
4244 // symbols in any of the sections with indexes larger than
4245 // SHN_LORESERVE. This is probably unusual, though, and at this
4246 // time we don't know the actual section indexes so it is
4247 // inconvenient to check.
4248 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4250 Output_section
* dynsym_xindex
=
4251 this->choose_output_section(NULL
, ".dynsym_shndx",
4252 elfcpp::SHT_SYMTAB_SHNDX
,
4254 false, ORDER_DYNAMIC_LINKER
, false);
4256 if (dynsym_xindex
!= NULL
)
4258 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4260 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4262 dynsym_xindex
->set_link_section(dynsym
);
4263 dynsym_xindex
->set_addralign(4);
4264 dynsym_xindex
->set_entsize(4);
4266 dynsym_xindex
->set_after_input_sections();
4268 // This tells the driver code to wait until the symbol table
4269 // has written out before writing out the postprocessing
4270 // sections, including the .dynsym_shndx section.
4271 this->any_postprocessing_sections_
= true;
4275 // Create the dynamic string table section.
4277 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4281 ORDER_DYNAMIC_LINKER
,
4286 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4287 dynstr
->add_output_section_data(strdata
);
4290 dynsym
->set_link_section(dynstr
);
4291 if (this->dynamic_section_
!= NULL
)
4292 this->dynamic_section_
->set_link_section(dynstr
);
4296 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4297 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4301 // Create the hash tables.
4303 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4304 || strcmp(parameters
->options().hash_style(), "both") == 0)
4306 unsigned char* phash
;
4307 unsigned int hashlen
;
4308 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
4311 Output_section
* hashsec
=
4312 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4313 elfcpp::SHF_ALLOC
, false,
4314 ORDER_DYNAMIC_LINKER
, false);
4316 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4320 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4321 hashsec
->add_output_section_data(hashdata
);
4323 if (hashsec
!= NULL
)
4326 hashsec
->set_link_section(dynsym
);
4327 hashsec
->set_entsize(4);
4331 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4334 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4335 || strcmp(parameters
->options().hash_style(), "both") == 0)
4337 unsigned char* phash
;
4338 unsigned int hashlen
;
4339 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
4342 Output_section
* hashsec
=
4343 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4344 elfcpp::SHF_ALLOC
, false,
4345 ORDER_DYNAMIC_LINKER
, false);
4347 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4351 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4352 hashsec
->add_output_section_data(hashdata
);
4354 if (hashsec
!= NULL
)
4357 hashsec
->set_link_section(dynsym
);
4359 // For a 64-bit target, the entries in .gnu.hash do not have
4360 // a uniform size, so we only set the entry size for a
4362 if (parameters
->target().get_size() == 32)
4363 hashsec
->set_entsize(4);
4366 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4371 // Assign offsets to each local portion of the dynamic symbol table.
4374 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4376 Output_section
* dynsym
= this->dynsym_section_
;
4380 off_t off
= dynsym
->offset();
4382 // Skip the dummy symbol at the start of the section.
4383 off
+= dynsym
->entsize();
4385 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4386 p
!= input_objects
->relobj_end();
4389 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4390 off
+= count
* dynsym
->entsize();
4394 // Create the version sections.
4397 Layout::create_version_sections(const Versions
* versions
,
4398 const Symbol_table
* symtab
,
4399 unsigned int local_symcount
,
4400 const std::vector
<Symbol
*>& dynamic_symbols
,
4401 const Output_section
* dynstr
)
4403 if (!versions
->any_defs() && !versions
->any_needs())
4406 switch (parameters
->size_and_endianness())
4408 #ifdef HAVE_TARGET_32_LITTLE
4409 case Parameters::TARGET_32_LITTLE
:
4410 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4412 dynamic_symbols
, dynstr
);
4415 #ifdef HAVE_TARGET_32_BIG
4416 case Parameters::TARGET_32_BIG
:
4417 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4419 dynamic_symbols
, dynstr
);
4422 #ifdef HAVE_TARGET_64_LITTLE
4423 case Parameters::TARGET_64_LITTLE
:
4424 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4426 dynamic_symbols
, dynstr
);
4429 #ifdef HAVE_TARGET_64_BIG
4430 case Parameters::TARGET_64_BIG
:
4431 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4433 dynamic_symbols
, dynstr
);
4441 // Create the version sections, sized version.
4443 template<int size
, bool big_endian
>
4445 Layout::sized_create_version_sections(
4446 const Versions
* versions
,
4447 const Symbol_table
* symtab
,
4448 unsigned int local_symcount
,
4449 const std::vector
<Symbol
*>& dynamic_symbols
,
4450 const Output_section
* dynstr
)
4452 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4453 elfcpp::SHT_GNU_versym
,
4456 ORDER_DYNAMIC_LINKER
,
4459 // Check for NULL since a linker script may discard this section.
4462 unsigned char* vbuf
;
4464 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4470 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4473 vsec
->add_output_section_data(vdata
);
4474 vsec
->set_entsize(2);
4475 vsec
->set_link_section(this->dynsym_section_
);
4478 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4479 if (odyn
!= NULL
&& vsec
!= NULL
)
4480 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4482 if (versions
->any_defs())
4484 Output_section
* vdsec
;
4485 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4486 elfcpp::SHT_GNU_verdef
,
4488 false, ORDER_DYNAMIC_LINKER
, false);
4492 unsigned char* vdbuf
;
4493 unsigned int vdsize
;
4494 unsigned int vdentries
;
4495 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4499 Output_section_data
* vddata
=
4500 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4502 vdsec
->add_output_section_data(vddata
);
4503 vdsec
->set_link_section(dynstr
);
4504 vdsec
->set_info(vdentries
);
4508 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4509 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4514 if (versions
->any_needs())
4516 Output_section
* vnsec
;
4517 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4518 elfcpp::SHT_GNU_verneed
,
4520 false, ORDER_DYNAMIC_LINKER
, false);
4524 unsigned char* vnbuf
;
4525 unsigned int vnsize
;
4526 unsigned int vnentries
;
4527 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4531 Output_section_data
* vndata
=
4532 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4534 vnsec
->add_output_section_data(vndata
);
4535 vnsec
->set_link_section(dynstr
);
4536 vnsec
->set_info(vnentries
);
4540 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4541 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
4547 // Create the .interp section and PT_INTERP segment.
4550 Layout::create_interp(const Target
* target
)
4552 gold_assert(this->interp_segment_
== NULL
);
4554 const char* interp
= parameters
->options().dynamic_linker();
4557 interp
= target
->dynamic_linker();
4558 gold_assert(interp
!= NULL
);
4561 size_t len
= strlen(interp
) + 1;
4563 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
4565 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
4566 elfcpp::SHT_PROGBITS
,
4568 false, ORDER_INTERP
,
4571 osec
->add_output_section_data(odata
);
4574 // Add dynamic tags for the PLT and the dynamic relocs. This is
4575 // called by the target-specific code. This does nothing if not doing
4578 // USE_REL is true for REL relocs rather than RELA relocs.
4580 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4582 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4583 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4584 // some targets have multiple reloc sections in PLT_REL.
4586 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4587 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4590 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4594 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
4595 const Output_data
* plt_rel
,
4596 const Output_data_reloc_generic
* dyn_rel
,
4597 bool add_debug
, bool dynrel_includes_plt
)
4599 Output_data_dynamic
* odyn
= this->dynamic_data_
;
4603 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
4604 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
4606 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
4608 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
4609 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
4610 odyn
->add_constant(elfcpp::DT_PLTREL
,
4611 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
4614 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
4615 || (dynrel_includes_plt
4617 && plt_rel
->output_section() != NULL
))
4619 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
4620 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
4621 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
4623 ? dyn_rel
->output_section()
4624 : plt_rel
->output_section()));
4625 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
4626 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
4627 odyn
->add_section_size(size_tag
,
4628 dyn_rel
->output_section(),
4629 plt_rel
->output_section());
4630 else if (have_dyn_rel
)
4631 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
4633 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
4634 const int size
= parameters
->target().get_size();
4639 rel_tag
= elfcpp::DT_RELENT
;
4641 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
4642 else if (size
== 64)
4643 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
4649 rel_tag
= elfcpp::DT_RELAENT
;
4651 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
4652 else if (size
== 64)
4653 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
4657 odyn
->add_constant(rel_tag
, rel_size
);
4659 if (parameters
->options().combreloc() && have_dyn_rel
)
4661 size_t c
= dyn_rel
->relative_reloc_count();
4663 odyn
->add_constant((use_rel
4664 ? elfcpp::DT_RELCOUNT
4665 : elfcpp::DT_RELACOUNT
),
4670 if (add_debug
&& !parameters
->options().shared())
4672 // The value of the DT_DEBUG tag is filled in by the dynamic
4673 // linker at run time, and used by the debugger.
4674 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
4678 // Finish the .dynamic section and PT_DYNAMIC segment.
4681 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
4682 const Symbol_table
* symtab
)
4684 if (!this->script_options_
->saw_phdrs_clause()
4685 && this->dynamic_section_
!= NULL
)
4687 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
4690 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
4691 elfcpp::PF_R
| elfcpp::PF_W
);
4694 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4698 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
4699 p
!= input_objects
->dynobj_end();
4702 if (!(*p
)->is_needed() && (*p
)->as_needed())
4704 // This dynamic object was linked with --as-needed, but it
4709 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4712 if (parameters
->options().shared())
4714 const char* soname
= parameters
->options().soname();
4716 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4719 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4720 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4721 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4723 sym
= symtab
->lookup(parameters
->options().fini());
4724 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4725 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4727 // Look for .init_array, .preinit_array and .fini_array by checking
4729 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4730 p
!= this->section_list_
.end();
4732 switch((*p
)->type())
4734 case elfcpp::SHT_FINI_ARRAY
:
4735 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4736 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4738 case elfcpp::SHT_INIT_ARRAY
:
4739 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4740 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4742 case elfcpp::SHT_PREINIT_ARRAY
:
4743 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4744 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4750 // Add a DT_RPATH entry if needed.
4751 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4754 std::string rpath_val
;
4755 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4759 if (rpath_val
.empty())
4760 rpath_val
= p
->name();
4763 // Eliminate duplicates.
4764 General_options::Dir_list::const_iterator q
;
4765 for (q
= rpath
.begin(); q
!= p
; ++q
)
4766 if (q
->name() == p
->name())
4771 rpath_val
+= p
->name();
4776 if (!parameters
->options().enable_new_dtags())
4777 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4779 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4782 // Look for text segments that have dynamic relocations.
4783 bool have_textrel
= false;
4784 if (!this->script_options_
->saw_sections_clause())
4786 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4787 p
!= this->segment_list_
.end();
4790 if ((*p
)->type() == elfcpp::PT_LOAD
4791 && ((*p
)->flags() & elfcpp::PF_W
) == 0
4792 && (*p
)->has_dynamic_reloc())
4794 have_textrel
= true;
4801 // We don't know the section -> segment mapping, so we are
4802 // conservative and just look for readonly sections with
4803 // relocations. If those sections wind up in writable segments,
4804 // then we have created an unnecessary DT_TEXTREL entry.
4805 for (Section_list::const_iterator p
= this->section_list_
.begin();
4806 p
!= this->section_list_
.end();
4809 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4810 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4811 && (*p
)->has_dynamic_reloc())
4813 have_textrel
= true;
4819 if (parameters
->options().filter() != NULL
)
4820 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
4821 if (parameters
->options().any_auxiliary())
4823 for (options::String_set::const_iterator p
=
4824 parameters
->options().auxiliary_begin();
4825 p
!= parameters
->options().auxiliary_end();
4827 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
4830 // Add a DT_FLAGS entry if necessary.
4831 unsigned int flags
= 0;
4834 // Add a DT_TEXTREL for compatibility with older loaders.
4835 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4836 flags
|= elfcpp::DF_TEXTREL
;
4838 if (parameters
->options().text())
4839 gold_error(_("read-only segment has dynamic relocations"));
4840 else if (parameters
->options().warn_shared_textrel()
4841 && parameters
->options().shared())
4842 gold_warning(_("shared library text segment is not shareable"));
4844 if (parameters
->options().shared() && this->has_static_tls())
4845 flags
|= elfcpp::DF_STATIC_TLS
;
4846 if (parameters
->options().origin())
4847 flags
|= elfcpp::DF_ORIGIN
;
4848 if (parameters
->options().Bsymbolic())
4850 flags
|= elfcpp::DF_SYMBOLIC
;
4851 // Add DT_SYMBOLIC for compatibility with older loaders.
4852 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4854 if (parameters
->options().now())
4855 flags
|= elfcpp::DF_BIND_NOW
;
4857 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4860 if (parameters
->options().initfirst())
4861 flags
|= elfcpp::DF_1_INITFIRST
;
4862 if (parameters
->options().interpose())
4863 flags
|= elfcpp::DF_1_INTERPOSE
;
4864 if (parameters
->options().loadfltr())
4865 flags
|= elfcpp::DF_1_LOADFLTR
;
4866 if (parameters
->options().nodefaultlib())
4867 flags
|= elfcpp::DF_1_NODEFLIB
;
4868 if (parameters
->options().nodelete())
4869 flags
|= elfcpp::DF_1_NODELETE
;
4870 if (parameters
->options().nodlopen())
4871 flags
|= elfcpp::DF_1_NOOPEN
;
4872 if (parameters
->options().nodump())
4873 flags
|= elfcpp::DF_1_NODUMP
;
4874 if (!parameters
->options().shared())
4875 flags
&= ~(elfcpp::DF_1_INITFIRST
4876 | elfcpp::DF_1_NODELETE
4877 | elfcpp::DF_1_NOOPEN
);
4878 if (parameters
->options().origin())
4879 flags
|= elfcpp::DF_1_ORIGIN
;
4880 if (parameters
->options().now())
4881 flags
|= elfcpp::DF_1_NOW
;
4882 if (parameters
->options().Bgroup())
4883 flags
|= elfcpp::DF_1_GROUP
;
4885 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4888 // Set the size of the _DYNAMIC symbol table to be the size of the
4892 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4894 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4897 odyn
->finalize_data_size();
4898 if (this->dynamic_symbol_
== NULL
)
4900 off_t data_size
= odyn
->data_size();
4901 const int size
= parameters
->target().get_size();
4903 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4904 else if (size
== 64)
4905 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4910 // The mapping of input section name prefixes to output section names.
4911 // In some cases one prefix is itself a prefix of another prefix; in
4912 // such a case the longer prefix must come first. These prefixes are
4913 // based on the GNU linker default ELF linker script.
4915 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4916 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4917 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4919 MAPPING_INIT(".text.", ".text"),
4920 MAPPING_INIT(".rodata.", ".rodata"),
4921 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4922 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4923 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4924 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4925 MAPPING_INIT(".data.", ".data"),
4926 MAPPING_INIT(".bss.", ".bss"),
4927 MAPPING_INIT(".tdata.", ".tdata"),
4928 MAPPING_INIT(".tbss.", ".tbss"),
4929 MAPPING_INIT(".init_array.", ".init_array"),
4930 MAPPING_INIT(".fini_array.", ".fini_array"),
4931 MAPPING_INIT(".sdata.", ".sdata"),
4932 MAPPING_INIT(".sbss.", ".sbss"),
4933 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4934 // differently depending on whether it is creating a shared library.
4935 MAPPING_INIT(".sdata2.", ".sdata"),
4936 MAPPING_INIT(".sbss2.", ".sbss"),
4937 MAPPING_INIT(".lrodata.", ".lrodata"),
4938 MAPPING_INIT(".ldata.", ".ldata"),
4939 MAPPING_INIT(".lbss.", ".lbss"),
4940 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4941 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4942 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4943 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4944 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4945 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4946 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4947 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4948 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4949 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4950 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4951 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4952 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4953 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4954 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4955 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4956 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4957 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4958 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4959 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4960 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4963 #undef MAPPING_INIT_EXACT
4965 const int Layout::section_name_mapping_count
=
4966 (sizeof(Layout::section_name_mapping
)
4967 / sizeof(Layout::section_name_mapping
[0]));
4969 // Choose the output section name to use given an input section name.
4970 // Set *PLEN to the length of the name. *PLEN is initialized to the
4974 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
4977 // gcc 4.3 generates the following sorts of section names when it
4978 // needs a section name specific to a function:
4984 // .data.rel.local.FN
4986 // .data.rel.ro.local.FN
4993 // The GNU linker maps all of those to the part before the .FN,
4994 // except that .data.rel.local.FN is mapped to .data, and
4995 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4996 // beginning with .data.rel.ro.local are grouped together.
4998 // For an anonymous namespace, the string FN can contain a '.'.
5000 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5001 // GNU linker maps to .rodata.
5003 // The .data.rel.ro sections are used with -z relro. The sections
5004 // are recognized by name. We use the same names that the GNU
5005 // linker does for these sections.
5007 // It is hard to handle this in a principled way, so we don't even
5008 // try. We use a table of mappings. If the input section name is
5009 // not found in the table, we simply use it as the output section
5012 const Section_name_mapping
* psnm
= section_name_mapping
;
5013 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
5015 if (psnm
->fromlen
> 0)
5017 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
5019 *plen
= psnm
->tolen
;
5025 if (strcmp(name
, psnm
->from
) == 0)
5027 *plen
= psnm
->tolen
;
5033 // As an additional complication, .ctors sections are output in
5034 // either .ctors or .init_array sections, and .dtors sections are
5035 // output in either .dtors or .fini_array sections.
5036 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
5038 if (parameters
->options().ctors_in_init_array())
5041 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5046 return name
[1] == 'c' ? ".ctors" : ".dtors";
5049 if (parameters
->options().ctors_in_init_array()
5050 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
5052 // To make .init_array/.fini_array work with gcc we must exclude
5053 // .ctors and .dtors sections from the crtbegin and crtend
5056 || (!Layout::match_file_name(relobj
, "crtbegin")
5057 && !Layout::match_file_name(relobj
, "crtend")))
5060 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5067 // Return true if RELOBJ is an input file whose base name matches
5068 // FILE_NAME. The base name must have an extension of ".o", and must
5069 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5070 // to match crtbegin.o as well as crtbeginS.o without getting confused
5071 // by other possibilities. Overall matching the file name this way is
5072 // a dreadful hack, but the GNU linker does it in order to better
5073 // support gcc, and we need to be compatible.
5076 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
5078 const std::string
& file_name(relobj
->name());
5079 const char* base_name
= lbasename(file_name
.c_str());
5080 size_t match_len
= strlen(match
);
5081 if (strncmp(base_name
, match
, match_len
) != 0)
5083 size_t base_len
= strlen(base_name
);
5084 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
5086 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
5089 // Check if a comdat group or .gnu.linkonce section with the given
5090 // NAME is selected for the link. If there is already a section,
5091 // *KEPT_SECTION is set to point to the existing section and the
5092 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5093 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5094 // *KEPT_SECTION is set to the internal copy and the function returns
5098 Layout::find_or_add_kept_section(const std::string
& name
,
5103 Kept_section
** kept_section
)
5105 // It's normal to see a couple of entries here, for the x86 thunk
5106 // sections. If we see more than a few, we're linking a C++
5107 // program, and we resize to get more space to minimize rehashing.
5108 if (this->signatures_
.size() > 4
5109 && !this->resized_signatures_
)
5111 reserve_unordered_map(&this->signatures_
,
5112 this->number_of_input_files_
* 64);
5113 this->resized_signatures_
= true;
5116 Kept_section candidate
;
5117 std::pair
<Signatures::iterator
, bool> ins
=
5118 this->signatures_
.insert(std::make_pair(name
, candidate
));
5120 if (kept_section
!= NULL
)
5121 *kept_section
= &ins
.first
->second
;
5124 // This is the first time we've seen this signature.
5125 ins
.first
->second
.set_object(object
);
5126 ins
.first
->second
.set_shndx(shndx
);
5128 ins
.first
->second
.set_is_comdat();
5130 ins
.first
->second
.set_is_group_name();
5134 // We have already seen this signature.
5136 if (ins
.first
->second
.is_group_name())
5138 // We've already seen a real section group with this signature.
5139 // If the kept group is from a plugin object, and we're in the
5140 // replacement phase, accept the new one as a replacement.
5141 if (ins
.first
->second
.object() == NULL
5142 && parameters
->options().plugins()->in_replacement_phase())
5144 ins
.first
->second
.set_object(object
);
5145 ins
.first
->second
.set_shndx(shndx
);
5150 else if (is_group_name
)
5152 // This is a real section group, and we've already seen a
5153 // linkonce section with this signature. Record that we've seen
5154 // a section group, and don't include this section group.
5155 ins
.first
->second
.set_is_group_name();
5160 // We've already seen a linkonce section and this is a linkonce
5161 // section. These don't block each other--this may be the same
5162 // symbol name with different section types.
5167 // Store the allocated sections into the section list.
5170 Layout::get_allocated_sections(Section_list
* section_list
) const
5172 for (Section_list::const_iterator p
= this->section_list_
.begin();
5173 p
!= this->section_list_
.end();
5175 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5176 section_list
->push_back(*p
);
5179 // Store the executable sections into the section list.
5182 Layout::get_executable_sections(Section_list
* section_list
) const
5184 for (Section_list::const_iterator p
= this->section_list_
.begin();
5185 p
!= this->section_list_
.end();
5187 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5188 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5189 section_list
->push_back(*p
);
5192 // Create an output segment.
5195 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5197 gold_assert(!parameters
->options().relocatable());
5198 Output_segment
* oseg
= new Output_segment(type
, flags
);
5199 this->segment_list_
.push_back(oseg
);
5201 if (type
== elfcpp::PT_TLS
)
5202 this->tls_segment_
= oseg
;
5203 else if (type
== elfcpp::PT_GNU_RELRO
)
5204 this->relro_segment_
= oseg
;
5205 else if (type
== elfcpp::PT_INTERP
)
5206 this->interp_segment_
= oseg
;
5211 // Return the file offset of the normal symbol table.
5214 Layout::symtab_section_offset() const
5216 if (this->symtab_section_
!= NULL
)
5217 return this->symtab_section_
->offset();
5221 // Return the section index of the normal symbol table. It may have
5222 // been stripped by the -s/--strip-all option.
5225 Layout::symtab_section_shndx() const
5227 if (this->symtab_section_
!= NULL
)
5228 return this->symtab_section_
->out_shndx();
5232 // Write out the Output_sections. Most won't have anything to write,
5233 // since most of the data will come from input sections which are
5234 // handled elsewhere. But some Output_sections do have Output_data.
5237 Layout::write_output_sections(Output_file
* of
) const
5239 for (Section_list::const_iterator p
= this->section_list_
.begin();
5240 p
!= this->section_list_
.end();
5243 if (!(*p
)->after_input_sections())
5248 // Write out data not associated with a section or the symbol table.
5251 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5253 if (!parameters
->options().strip_all())
5255 const Output_section
* symtab_section
= this->symtab_section_
;
5256 for (Section_list::const_iterator p
= this->section_list_
.begin();
5257 p
!= this->section_list_
.end();
5260 if ((*p
)->needs_symtab_index())
5262 gold_assert(symtab_section
!= NULL
);
5263 unsigned int index
= (*p
)->symtab_index();
5264 gold_assert(index
> 0 && index
!= -1U);
5265 off_t off
= (symtab_section
->offset()
5266 + index
* symtab_section
->entsize());
5267 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5272 const Output_section
* dynsym_section
= this->dynsym_section_
;
5273 for (Section_list::const_iterator p
= this->section_list_
.begin();
5274 p
!= this->section_list_
.end();
5277 if ((*p
)->needs_dynsym_index())
5279 gold_assert(dynsym_section
!= NULL
);
5280 unsigned int index
= (*p
)->dynsym_index();
5281 gold_assert(index
> 0 && index
!= -1U);
5282 off_t off
= (dynsym_section
->offset()
5283 + index
* dynsym_section
->entsize());
5284 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5288 // Write out the Output_data which are not in an Output_section.
5289 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5290 p
!= this->special_output_list_
.end();
5294 // Write out the Output_data which are not in an Output_section
5295 // and are regenerated in each iteration of relaxation.
5296 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
5297 p
!= this->relax_output_list_
.end();
5302 // Write out the Output_sections which can only be written after the
5303 // input sections are complete.
5306 Layout::write_sections_after_input_sections(Output_file
* of
)
5308 // Determine the final section offsets, and thus the final output
5309 // file size. Note we finalize the .shstrab last, to allow the
5310 // after_input_section sections to modify their section-names before
5312 if (this->any_postprocessing_sections_
)
5314 off_t off
= this->output_file_size_
;
5315 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5317 // Now that we've finalized the names, we can finalize the shstrab.
5319 this->set_section_offsets(off
,
5320 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5322 if (off
> this->output_file_size_
)
5325 this->output_file_size_
= off
;
5329 for (Section_list::const_iterator p
= this->section_list_
.begin();
5330 p
!= this->section_list_
.end();
5333 if ((*p
)->after_input_sections())
5337 this->section_headers_
->write(of
);
5340 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5341 // or as a "tree" where each chunk of the string is hashed and then those
5342 // hashes are put into a (much smaller) string which is hashed with sha1.
5343 // We compute a checksum over the entire file because that is simplest.
5346 Layout::queue_build_id_tasks(Workqueue
* workqueue
, Task_token
* build_id_blocker
,
5349 const size_t filesize
= (this->output_file_size() <= 0 ? 0
5350 : static_cast<size_t>(this->output_file_size()));
5351 if (this->build_id_note_
!= NULL
5352 && strcmp(parameters
->options().build_id(), "tree") == 0
5353 && parameters
->options().build_id_chunk_size_for_treehash() > 0
5356 parameters
->options().build_id_min_file_size_for_treehash()))
5358 static const size_t MD5_OUTPUT_SIZE_IN_BYTES
= 16;
5359 const size_t chunk_size
=
5360 parameters
->options().build_id_chunk_size_for_treehash();
5361 const size_t num_hashes
= ((filesize
- 1) / chunk_size
) + 1;
5362 Task_token
* post_hash_tasks_blocker
= new Task_token(true);
5363 post_hash_tasks_blocker
->add_blockers(num_hashes
);
5364 this->size_of_array_of_hashes_
= num_hashes
* MD5_OUTPUT_SIZE_IN_BYTES
;
5365 const unsigned char* src
= of
->get_input_view(0, filesize
);
5366 this->input_view_
= src
;
5367 unsigned char *dst
= new unsigned char[this->size_of_array_of_hashes_
];
5368 this->array_of_hashes_
= dst
;
5369 for (size_t i
= 0, src_offset
= 0; i
< num_hashes
;
5370 i
++, dst
+= MD5_OUTPUT_SIZE_IN_BYTES
, src_offset
+= chunk_size
)
5372 size_t size
= std::min(chunk_size
, filesize
- src_offset
);
5373 workqueue
->queue(new Hash_task(src
+ src_offset
,
5377 post_hash_tasks_blocker
));
5379 return post_hash_tasks_blocker
;
5381 return build_id_blocker
;
5384 // If a tree-style build ID was requested, the parallel part of that computation
5385 // is already done, and the final hash-of-hashes is computed here. For other
5386 // types of build IDs, all the work is done here.
5389 Layout::write_build_id(Output_file
* of
) const
5391 if (this->build_id_note_
== NULL
)
5394 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5395 this->build_id_note_
->data_size());
5397 if (this->array_of_hashes_
== NULL
)
5399 const size_t output_file_size
= this->output_file_size();
5400 const unsigned char* iv
= of
->get_input_view(0, output_file_size
);
5401 const char* style
= parameters
->options().build_id();
5403 // If we get here with style == "tree" then the output must be
5404 // too small for chunking, and we use SHA-1 in that case.
5405 if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
5406 sha1_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5407 else if (strcmp(style
, "md5") == 0)
5408 md5_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5412 of
->free_input_view(0, output_file_size
, iv
);
5416 // Non-overlapping substrings of the output file have been hashed.
5417 // Compute SHA-1 hash of the hashes.
5418 sha1_buffer(reinterpret_cast<const char*>(this->array_of_hashes_
),
5419 this->size_of_array_of_hashes_
, ov
);
5420 delete[] this->array_of_hashes_
;
5421 of
->free_input_view(0, this->output_file_size(), this->input_view_
);
5424 of
->write_output_view(this->build_id_note_
->offset(),
5425 this->build_id_note_
->data_size(),
5429 // Write out a binary file. This is called after the link is
5430 // complete. IN is the temporary output file we used to generate the
5431 // ELF code. We simply walk through the segments, read them from
5432 // their file offset in IN, and write them to their load address in
5433 // the output file. FIXME: with a bit more work, we could support
5434 // S-records and/or Intel hex format here.
5437 Layout::write_binary(Output_file
* in
) const
5439 gold_assert(parameters
->options().oformat_enum()
5440 == General_options::OBJECT_FORMAT_BINARY
);
5442 // Get the size of the binary file.
5443 uint64_t max_load_address
= 0;
5444 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5445 p
!= this->segment_list_
.end();
5448 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5450 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5451 if (max_paddr
> max_load_address
)
5452 max_load_address
= max_paddr
;
5456 Output_file
out(parameters
->options().output_file_name());
5457 out
.open(max_load_address
);
5459 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5460 p
!= this->segment_list_
.end();
5463 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5465 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5467 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5469 memcpy(vout
, vin
, (*p
)->filesz());
5470 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5471 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5478 // Print the output sections to the map file.
5481 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5483 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5484 p
!= this->segment_list_
.end();
5486 (*p
)->print_sections_to_mapfile(mapfile
);
5489 // Print statistical information to stderr. This is used for --stats.
5492 Layout::print_stats() const
5494 this->namepool_
.print_stats("section name pool");
5495 this->sympool_
.print_stats("output symbol name pool");
5496 this->dynpool_
.print_stats("dynamic name pool");
5498 for (Section_list::const_iterator p
= this->section_list_
.begin();
5499 p
!= this->section_list_
.end();
5501 (*p
)->print_merge_stats();
5504 // Write_sections_task methods.
5506 // We can always run this task.
5509 Write_sections_task::is_runnable()
5514 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5518 Write_sections_task::locks(Task_locker
* tl
)
5520 tl
->add(this, this->output_sections_blocker_
);
5521 tl
->add(this, this->final_blocker_
);
5524 // Run the task--write out the data.
5527 Write_sections_task::run(Workqueue
*)
5529 this->layout_
->write_output_sections(this->of_
);
5532 // Write_data_task methods.
5534 // We can always run this task.
5537 Write_data_task::is_runnable()
5542 // We need to unlock FINAL_BLOCKER when finished.
5545 Write_data_task::locks(Task_locker
* tl
)
5547 tl
->add(this, this->final_blocker_
);
5550 // Run the task--write out the data.
5553 Write_data_task::run(Workqueue
*)
5555 this->layout_
->write_data(this->symtab_
, this->of_
);
5558 // Write_symbols_task methods.
5560 // We can always run this task.
5563 Write_symbols_task::is_runnable()
5568 // We need to unlock FINAL_BLOCKER when finished.
5571 Write_symbols_task::locks(Task_locker
* tl
)
5573 tl
->add(this, this->final_blocker_
);
5576 // Run the task--write out the symbols.
5579 Write_symbols_task::run(Workqueue
*)
5581 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
5582 this->layout_
->symtab_xindex(),
5583 this->layout_
->dynsym_xindex(), this->of_
);
5586 // Write_after_input_sections_task methods.
5588 // We can only run this task after the input sections have completed.
5591 Write_after_input_sections_task::is_runnable()
5593 if (this->input_sections_blocker_
->is_blocked())
5594 return this->input_sections_blocker_
;
5598 // We need to unlock FINAL_BLOCKER when finished.
5601 Write_after_input_sections_task::locks(Task_locker
* tl
)
5603 tl
->add(this, this->final_blocker_
);
5609 Write_after_input_sections_task::run(Workqueue
*)
5611 this->layout_
->write_sections_after_input_sections(this->of_
);
5614 // Close_task_runner methods.
5616 // Finish up the build ID computation, if necessary, and write a binary file,
5617 // if necessary. Then close the output file.
5620 Close_task_runner::run(Workqueue
*, const Task
*)
5622 // At this point the multi-threaded part of the build ID computation,
5623 // if any, is done. See queue_build_id_tasks().
5624 this->layout_
->write_build_id(this->of_
);
5626 // If we've been asked to create a binary file, we do so here.
5627 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
5628 this->layout_
->write_binary(this->of_
);
5633 // Instantiate the templates we need. We could use the configure
5634 // script to restrict this to only the ones for implemented targets.
5636 #ifdef HAVE_TARGET_32_LITTLE
5639 Layout::init_fixed_output_section
<32, false>(
5641 elfcpp::Shdr
<32, false>& shdr
);
5644 #ifdef HAVE_TARGET_32_BIG
5647 Layout::init_fixed_output_section
<32, true>(
5649 elfcpp::Shdr
<32, true>& shdr
);
5652 #ifdef HAVE_TARGET_64_LITTLE
5655 Layout::init_fixed_output_section
<64, false>(
5657 elfcpp::Shdr
<64, false>& shdr
);
5660 #ifdef HAVE_TARGET_64_BIG
5663 Layout::init_fixed_output_section
<64, true>(
5665 elfcpp::Shdr
<64, true>& shdr
);
5668 #ifdef HAVE_TARGET_32_LITTLE
5671 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
5674 const elfcpp::Shdr
<32, false>& shdr
,
5675 unsigned int, unsigned int, off_t
*);
5678 #ifdef HAVE_TARGET_32_BIG
5681 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
5684 const elfcpp::Shdr
<32, true>& shdr
,
5685 unsigned int, unsigned int, off_t
*);
5688 #ifdef HAVE_TARGET_64_LITTLE
5691 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
5694 const elfcpp::Shdr
<64, false>& shdr
,
5695 unsigned int, unsigned int, off_t
*);
5698 #ifdef HAVE_TARGET_64_BIG
5701 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
5704 const elfcpp::Shdr
<64, true>& shdr
,
5705 unsigned int, unsigned int, off_t
*);
5708 #ifdef HAVE_TARGET_32_LITTLE
5711 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
5712 unsigned int reloc_shndx
,
5713 const elfcpp::Shdr
<32, false>& shdr
,
5714 Output_section
* data_section
,
5715 Relocatable_relocs
* rr
);
5718 #ifdef HAVE_TARGET_32_BIG
5721 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
5722 unsigned int reloc_shndx
,
5723 const elfcpp::Shdr
<32, true>& shdr
,
5724 Output_section
* data_section
,
5725 Relocatable_relocs
* rr
);
5728 #ifdef HAVE_TARGET_64_LITTLE
5731 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
5732 unsigned int reloc_shndx
,
5733 const elfcpp::Shdr
<64, false>& shdr
,
5734 Output_section
* data_section
,
5735 Relocatable_relocs
* rr
);
5738 #ifdef HAVE_TARGET_64_BIG
5741 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
5742 unsigned int reloc_shndx
,
5743 const elfcpp::Shdr
<64, true>& shdr
,
5744 Output_section
* data_section
,
5745 Relocatable_relocs
* rr
);
5748 #ifdef HAVE_TARGET_32_LITTLE
5751 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
5752 Sized_relobj_file
<32, false>* object
,
5754 const char* group_section_name
,
5755 const char* signature
,
5756 const elfcpp::Shdr
<32, false>& shdr
,
5757 elfcpp::Elf_Word flags
,
5758 std::vector
<unsigned int>* shndxes
);
5761 #ifdef HAVE_TARGET_32_BIG
5764 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
5765 Sized_relobj_file
<32, true>* object
,
5767 const char* group_section_name
,
5768 const char* signature
,
5769 const elfcpp::Shdr
<32, true>& shdr
,
5770 elfcpp::Elf_Word flags
,
5771 std::vector
<unsigned int>* shndxes
);
5774 #ifdef HAVE_TARGET_64_LITTLE
5777 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
5778 Sized_relobj_file
<64, false>* object
,
5780 const char* group_section_name
,
5781 const char* signature
,
5782 const elfcpp::Shdr
<64, false>& shdr
,
5783 elfcpp::Elf_Word flags
,
5784 std::vector
<unsigned int>* shndxes
);
5787 #ifdef HAVE_TARGET_64_BIG
5790 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
5791 Sized_relobj_file
<64, true>* object
,
5793 const char* group_section_name
,
5794 const char* signature
,
5795 const elfcpp::Shdr
<64, true>& shdr
,
5796 elfcpp::Elf_Word flags
,
5797 std::vector
<unsigned int>* shndxes
);
5800 #ifdef HAVE_TARGET_32_LITTLE
5803 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
5804 const unsigned char* symbols
,
5806 const unsigned char* symbol_names
,
5807 off_t symbol_names_size
,
5809 const elfcpp::Shdr
<32, false>& shdr
,
5810 unsigned int reloc_shndx
,
5811 unsigned int reloc_type
,
5815 #ifdef HAVE_TARGET_32_BIG
5818 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
5819 const unsigned char* symbols
,
5821 const unsigned char* symbol_names
,
5822 off_t symbol_names_size
,
5824 const elfcpp::Shdr
<32, true>& shdr
,
5825 unsigned int reloc_shndx
,
5826 unsigned int reloc_type
,
5830 #ifdef HAVE_TARGET_64_LITTLE
5833 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
5834 const unsigned char* symbols
,
5836 const unsigned char* symbol_names
,
5837 off_t symbol_names_size
,
5839 const elfcpp::Shdr
<64, false>& shdr
,
5840 unsigned int reloc_shndx
,
5841 unsigned int reloc_type
,
5845 #ifdef HAVE_TARGET_64_BIG
5848 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
5849 const unsigned char* symbols
,
5851 const unsigned char* symbol_names
,
5852 off_t symbol_names_size
,
5854 const elfcpp::Shdr
<64, true>& shdr
,
5855 unsigned int reloc_shndx
,
5856 unsigned int reloc_type
,
5860 #ifdef HAVE_TARGET_32_LITTLE
5863 Layout::add_to_gdb_index(bool is_type_unit
,
5864 Sized_relobj
<32, false>* object
,
5865 const unsigned char* symbols
,
5868 unsigned int reloc_shndx
,
5869 unsigned int reloc_type
);
5872 #ifdef HAVE_TARGET_32_BIG
5875 Layout::add_to_gdb_index(bool is_type_unit
,
5876 Sized_relobj
<32, true>* object
,
5877 const unsigned char* symbols
,
5880 unsigned int reloc_shndx
,
5881 unsigned int reloc_type
);
5884 #ifdef HAVE_TARGET_64_LITTLE
5887 Layout::add_to_gdb_index(bool is_type_unit
,
5888 Sized_relobj
<64, false>* object
,
5889 const unsigned char* symbols
,
5892 unsigned int reloc_shndx
,
5893 unsigned int reloc_type
);
5896 #ifdef HAVE_TARGET_64_BIG
5899 Layout::add_to_gdb_index(bool is_type_unit
,
5900 Sized_relobj
<64, true>* object
,
5901 const unsigned char* symbols
,
5904 unsigned int reloc_shndx
,
5905 unsigned int reloc_type
);
5908 } // End namespace gold.