1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
34 #include "libiberty.h"
38 #include "parameters.h"
42 #include "script-sections.h"
47 #include "compressed_output.h"
48 #include "reduced_debug_output.h"
50 #include "descriptors.h"
52 #include "incremental.h"
60 // The total number of free lists used.
61 unsigned int Free_list::num_lists
= 0;
62 // The total number of free list nodes used.
63 unsigned int Free_list::num_nodes
= 0;
64 // The total number of calls to Free_list::remove.
65 unsigned int Free_list::num_removes
= 0;
66 // The total number of nodes visited during calls to Free_list::remove.
67 unsigned int Free_list::num_remove_visits
= 0;
68 // The total number of calls to Free_list::allocate.
69 unsigned int Free_list::num_allocates
= 0;
70 // The total number of nodes visited during calls to Free_list::allocate.
71 unsigned int Free_list::num_allocate_visits
= 0;
73 // Initialize the free list. Creates a single free list node that
74 // describes the entire region of length LEN. If EXTEND is true,
75 // allocate() is allowed to extend the region beyond its initial
79 Free_list::init(off_t len
, bool extend
)
81 this->list_
.push_front(Free_list_node(0, len
));
82 this->last_remove_
= this->list_
.begin();
83 this->extend_
= extend
;
85 ++Free_list::num_lists
;
86 ++Free_list::num_nodes
;
89 // Remove a chunk from the free list. Because we start with a single
90 // node that covers the entire section, and remove chunks from it one
91 // at a time, we do not need to coalesce chunks or handle cases that
92 // span more than one free node. We expect to remove chunks from the
93 // free list in order, and we expect to have only a few chunks of free
94 // space left (corresponding to files that have changed since the last
95 // incremental link), so a simple linear list should provide sufficient
99 Free_list::remove(off_t start
, off_t end
)
103 gold_assert(start
< end
);
105 ++Free_list::num_removes
;
107 Iterator p
= this->last_remove_
;
108 if (p
->start_
> start
)
109 p
= this->list_
.begin();
111 for (; p
!= this->list_
.end(); ++p
)
113 ++Free_list::num_remove_visits
;
114 // Find a node that wholly contains the indicated region.
115 if (p
->start_
<= start
&& p
->end_
>= end
)
117 // Case 1: the indicated region spans the whole node.
118 // Add some fuzz to avoid creating tiny free chunks.
119 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
120 p
= this->list_
.erase(p
);
121 // Case 2: remove a chunk from the start of the node.
122 else if (p
->start_
+ 3 >= start
)
124 // Case 3: remove a chunk from the end of the node.
125 else if (p
->end_
<= end
+ 3)
127 // Case 4: remove a chunk from the middle, and split
128 // the node into two.
131 Free_list_node
newnode(p
->start_
, start
);
133 this->list_
.insert(p
, newnode
);
134 ++Free_list::num_nodes
;
136 this->last_remove_
= p
;
141 // Did not find a node containing the given chunk. This could happen
142 // because a small chunk was already removed due to the fuzz.
143 gold_debug(DEBUG_INCREMENTAL
,
144 "Free_list::remove(%d,%d) not found",
145 static_cast<int>(start
), static_cast<int>(end
));
148 // Allocate a chunk of size LEN from the free list. Returns -1ULL
149 // if a sufficiently large chunk of free space is not found.
150 // We use a simple first-fit algorithm.
153 Free_list::allocate(off_t len
, uint64_t align
, off_t minoff
)
155 gold_debug(DEBUG_INCREMENTAL
,
156 "Free_list::allocate(%08lx, %d, %08lx)",
157 static_cast<long>(len
), static_cast<int>(align
),
158 static_cast<long>(minoff
));
160 return align_address(minoff
, align
);
162 ++Free_list::num_allocates
;
164 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
166 ++Free_list::num_allocate_visits
;
167 off_t start
= p
->start_
> minoff
? p
->start_
: minoff
;
168 start
= align_address(start
, align
);
169 off_t end
= start
+ len
;
172 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
173 this->list_
.erase(p
);
174 else if (p
->start_
+ 3 >= start
)
176 else if (p
->end_
<= end
+ 3)
180 Free_list_node
newnode(p
->start_
, start
);
182 this->list_
.insert(p
, newnode
);
183 ++Free_list::num_nodes
;
191 // Dump the free list (for debugging).
195 gold_info("Free list:\n start end length\n");
196 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
197 gold_info(" %08lx %08lx %08lx", static_cast<long>(p
->start_
),
198 static_cast<long>(p
->end_
),
199 static_cast<long>(p
->end_
- p
->start_
));
202 // Print the statistics for the free lists.
204 Free_list::print_stats()
206 fprintf(stderr
, _("%s: total free lists: %u\n"),
207 program_name
, Free_list::num_lists
);
208 fprintf(stderr
, _("%s: total free list nodes: %u\n"),
209 program_name
, Free_list::num_nodes
);
210 fprintf(stderr
, _("%s: calls to Free_list::remove: %u\n"),
211 program_name
, Free_list::num_removes
);
212 fprintf(stderr
, _("%s: nodes visited: %u\n"),
213 program_name
, Free_list::num_remove_visits
);
214 fprintf(stderr
, _("%s: calls to Free_list::allocate: %u\n"),
215 program_name
, Free_list::num_allocates
);
216 fprintf(stderr
, _("%s: nodes visited: %u\n"),
217 program_name
, Free_list::num_allocate_visits
);
220 // Layout::Relaxation_debug_check methods.
222 // Check that sections and special data are in reset states.
223 // We do not save states for Output_sections and special Output_data.
224 // So we check that they have not assigned any addresses or offsets.
225 // clean_up_after_relaxation simply resets their addresses and offsets.
227 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
228 const Layout::Section_list
& sections
,
229 const Layout::Data_list
& special_outputs
)
231 for(Layout::Section_list::const_iterator p
= sections
.begin();
234 gold_assert((*p
)->address_and_file_offset_have_reset_values());
236 for(Layout::Data_list::const_iterator p
= special_outputs
.begin();
237 p
!= special_outputs
.end();
239 gold_assert((*p
)->address_and_file_offset_have_reset_values());
242 // Save information of SECTIONS for checking later.
245 Layout::Relaxation_debug_check::read_sections(
246 const Layout::Section_list
& sections
)
248 for(Layout::Section_list::const_iterator p
= sections
.begin();
252 Output_section
* os
= *p
;
254 info
.output_section
= os
;
255 info
.address
= os
->is_address_valid() ? os
->address() : 0;
256 info
.data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
257 info
.offset
= os
->is_offset_valid()? os
->offset() : -1 ;
258 this->section_infos_
.push_back(info
);
262 // Verify SECTIONS using previously recorded information.
265 Layout::Relaxation_debug_check::verify_sections(
266 const Layout::Section_list
& sections
)
269 for(Layout::Section_list::const_iterator p
= sections
.begin();
273 Output_section
* os
= *p
;
274 uint64_t address
= os
->is_address_valid() ? os
->address() : 0;
275 off_t data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
276 off_t offset
= os
->is_offset_valid()? os
->offset() : -1 ;
278 if (i
>= this->section_infos_
.size())
280 gold_fatal("Section_info of %s missing.\n", os
->name());
282 const Section_info
& info
= this->section_infos_
[i
];
283 if (os
!= info
.output_section
)
284 gold_fatal("Section order changed. Expecting %s but see %s\n",
285 info
.output_section
->name(), os
->name());
286 if (address
!= info
.address
287 || data_size
!= info
.data_size
288 || offset
!= info
.offset
)
289 gold_fatal("Section %s changed.\n", os
->name());
293 // Layout_task_runner methods.
295 // Lay out the sections. This is called after all the input objects
299 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
301 Layout
* layout
= this->layout_
;
302 off_t file_size
= layout
->finalize(this->input_objects_
,
307 // Now we know the final size of the output file and we know where
308 // each piece of information goes.
310 if (this->mapfile_
!= NULL
)
312 this->mapfile_
->print_discarded_sections(this->input_objects_
);
313 layout
->print_to_mapfile(this->mapfile_
);
317 if (layout
->incremental_base() == NULL
)
319 of
= new Output_file(parameters
->options().output_file_name());
320 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
321 of
->set_is_temporary();
326 of
= layout
->incremental_base()->output_file();
328 // Apply the incremental relocations for symbols whose values
329 // have changed. We do this before we resize the file and start
330 // writing anything else to it, so that we can read the old
331 // incremental information from the file before (possibly)
333 if (parameters
->incremental_update())
334 layout
->incremental_base()->apply_incremental_relocs(this->symtab_
,
338 of
->resize(file_size
);
341 // Queue up the final set of tasks.
342 gold::queue_final_tasks(this->options_
, this->input_objects_
,
343 this->symtab_
, layout
, workqueue
, of
);
348 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
349 : number_of_input_files_(number_of_input_files
),
350 script_options_(script_options
),
358 unattached_section_list_(),
359 special_output_list_(),
360 section_headers_(NULL
),
362 relro_segment_(NULL
),
363 interp_segment_(NULL
),
365 symtab_section_(NULL
),
366 symtab_xindex_(NULL
),
367 dynsym_section_(NULL
),
368 dynsym_xindex_(NULL
),
369 dynamic_section_(NULL
),
370 dynamic_symbol_(NULL
),
372 eh_frame_section_(NULL
),
373 eh_frame_data_(NULL
),
374 added_eh_frame_data_(false),
375 eh_frame_hdr_section_(NULL
),
376 build_id_note_(NULL
),
380 output_file_size_(-1),
381 have_added_input_section_(false),
382 sections_are_attached_(false),
383 input_requires_executable_stack_(false),
384 input_with_gnu_stack_note_(false),
385 input_without_gnu_stack_note_(false),
386 has_static_tls_(false),
387 any_postprocessing_sections_(false),
388 resized_signatures_(false),
389 have_stabstr_section_(false),
390 incremental_inputs_(NULL
),
391 record_output_section_data_from_script_(false),
392 script_output_section_data_list_(),
393 segment_states_(NULL
),
394 relaxation_debug_check_(NULL
),
395 incremental_base_(NULL
),
398 // Make space for more than enough segments for a typical file.
399 // This is just for efficiency--it's OK if we wind up needing more.
400 this->segment_list_
.reserve(12);
402 // We expect two unattached Output_data objects: the file header and
403 // the segment headers.
404 this->special_output_list_
.reserve(2);
406 // Initialize structure needed for an incremental build.
407 if (parameters
->incremental())
408 this->incremental_inputs_
= new Incremental_inputs
;
410 // The section name pool is worth optimizing in all cases, because
411 // it is small, but there are often overlaps due to .rel sections.
412 this->namepool_
.set_optimize();
415 // For incremental links, record the base file to be modified.
418 Layout::set_incremental_base(Incremental_binary
* base
)
420 this->incremental_base_
= base
;
421 this->free_list_
.init(base
->output_file()->filesize(), true);
424 // Hash a key we use to look up an output section mapping.
427 Layout::Hash_key::operator()(const Layout::Key
& k
) const
429 return k
.first
+ k
.second
.first
+ k
.second
.second
;
432 // Returns whether the given section is in the list of
433 // debug-sections-used-by-some-version-of-gdb. Currently,
434 // we've checked versions of gdb up to and including 6.7.1.
436 static const char* gdb_sections
[] =
438 // ".debug_aranges", // not used by gdb as of 6.7.1
445 // ".debug_pubnames", // not used by gdb as of 6.7.1
450 static const char* lines_only_debug_sections
[] =
452 // ".debug_aranges", // not used by gdb as of 6.7.1
459 // ".debug_pubnames", // not used by gdb as of 6.7.1
465 is_gdb_debug_section(const char* str
)
467 // We can do this faster: binary search or a hashtable. But why bother?
468 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
469 if (strcmp(str
, gdb_sections
[i
]) == 0)
475 is_lines_only_debug_section(const char* str
)
477 // We can do this faster: binary search or a hashtable. But why bother?
479 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
481 if (strcmp(str
, lines_only_debug_sections
[i
]) == 0)
486 // Sometimes we compress sections. This is typically done for
487 // sections that are not part of normal program execution (such as
488 // .debug_* sections), and where the readers of these sections know
489 // how to deal with compressed sections. This routine doesn't say for
490 // certain whether we'll compress -- it depends on commandline options
491 // as well -- just whether this section is a candidate for compression.
492 // (The Output_compressed_section class decides whether to compress
493 // a given section, and picks the name of the compressed section.)
496 is_compressible_debug_section(const char* secname
)
498 return (is_prefix_of(".debug", secname
));
501 // We may see compressed debug sections in input files. Return TRUE
502 // if this is the name of a compressed debug section.
505 is_compressed_debug_section(const char* secname
)
507 return (is_prefix_of(".zdebug", secname
));
510 // Whether to include this section in the link.
512 template<int size
, bool big_endian
>
514 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
515 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
517 if (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
)
520 switch (shdr
.get_sh_type())
522 case elfcpp::SHT_NULL
:
523 case elfcpp::SHT_SYMTAB
:
524 case elfcpp::SHT_DYNSYM
:
525 case elfcpp::SHT_HASH
:
526 case elfcpp::SHT_DYNAMIC
:
527 case elfcpp::SHT_SYMTAB_SHNDX
:
530 case elfcpp::SHT_STRTAB
:
531 // Discard the sections which have special meanings in the ELF
532 // ABI. Keep others (e.g., .stabstr). We could also do this by
533 // checking the sh_link fields of the appropriate sections.
534 return (strcmp(name
, ".dynstr") != 0
535 && strcmp(name
, ".strtab") != 0
536 && strcmp(name
, ".shstrtab") != 0);
538 case elfcpp::SHT_RELA
:
539 case elfcpp::SHT_REL
:
540 case elfcpp::SHT_GROUP
:
541 // If we are emitting relocations these should be handled
543 gold_assert(!parameters
->options().relocatable()
544 && !parameters
->options().emit_relocs());
547 case elfcpp::SHT_PROGBITS
:
548 if (parameters
->options().strip_debug()
549 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
551 if (is_debug_info_section(name
))
554 if (parameters
->options().strip_debug_non_line()
555 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
557 // Debugging sections can only be recognized by name.
558 if (is_prefix_of(".debug", name
)
559 && !is_lines_only_debug_section(name
))
562 if (parameters
->options().strip_debug_gdb()
563 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
565 // Debugging sections can only be recognized by name.
566 if (is_prefix_of(".debug", name
)
567 && !is_gdb_debug_section(name
))
570 if (parameters
->options().strip_lto_sections()
571 && !parameters
->options().relocatable()
572 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
574 // Ignore LTO sections containing intermediate code.
575 if (is_prefix_of(".gnu.lto_", name
))
578 // The GNU linker strips .gnu_debuglink sections, so we do too.
579 // This is a feature used to keep debugging information in
581 if (strcmp(name
, ".gnu_debuglink") == 0)
590 // Return an output section named NAME, or NULL if there is none.
593 Layout::find_output_section(const char* name
) const
595 for (Section_list::const_iterator p
= this->section_list_
.begin();
596 p
!= this->section_list_
.end();
598 if (strcmp((*p
)->name(), name
) == 0)
603 // Return an output segment of type TYPE, with segment flags SET set
604 // and segment flags CLEAR clear. Return NULL if there is none.
607 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
608 elfcpp::Elf_Word clear
) const
610 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
611 p
!= this->segment_list_
.end();
613 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
614 && ((*p
)->flags() & set
) == set
615 && ((*p
)->flags() & clear
) == 0)
620 // Return the output section to use for section NAME with type TYPE
621 // and section flags FLAGS. NAME must be canonicalized in the string
622 // pool, and NAME_KEY is the key. ORDER is where this should appear
623 // in the output sections. IS_RELRO is true for a relro section.
626 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
627 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
628 Output_section_order order
, bool is_relro
)
630 elfcpp::Elf_Xword lookup_flags
= flags
;
632 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
633 // read-write with read-only sections. Some other ELF linkers do
634 // not do this. FIXME: Perhaps there should be an option
636 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
638 const Key
key(name_key
, std::make_pair(type
, lookup_flags
));
639 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
640 std::pair
<Section_name_map::iterator
, bool> ins(
641 this->section_name_map_
.insert(v
));
644 return ins
.first
->second
;
647 // This is the first time we've seen this name/type/flags
648 // combination. For compatibility with the GNU linker, we
649 // combine sections with contents and zero flags with sections
650 // with non-zero flags. This is a workaround for cases where
651 // assembler code forgets to set section flags. FIXME: Perhaps
652 // there should be an option to control this.
653 Output_section
* os
= NULL
;
655 if (type
== elfcpp::SHT_PROGBITS
)
659 Output_section
* same_name
= this->find_output_section(name
);
660 if (same_name
!= NULL
661 && same_name
->type() == elfcpp::SHT_PROGBITS
662 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
665 else if ((flags
& elfcpp::SHF_TLS
) == 0)
667 elfcpp::Elf_Xword zero_flags
= 0;
668 const Key
zero_key(name_key
, std::make_pair(type
, zero_flags
));
669 Section_name_map::iterator p
=
670 this->section_name_map_
.find(zero_key
);
671 if (p
!= this->section_name_map_
.end())
677 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
679 ins
.first
->second
= os
;
684 // Pick the output section to use for section NAME, in input file
685 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
686 // linker created section. IS_INPUT_SECTION is true if we are
687 // choosing an output section for an input section found in a input
688 // file. ORDER is where this section should appear in the output
689 // sections. IS_RELRO is true for a relro section. This will return
690 // NULL if the input section should be discarded.
693 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
694 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
695 bool is_input_section
, Output_section_order order
,
698 // We should not see any input sections after we have attached
699 // sections to segments.
700 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
702 // Some flags in the input section should not be automatically
703 // copied to the output section.
704 flags
&= ~ (elfcpp::SHF_INFO_LINK
707 | elfcpp::SHF_STRINGS
);
709 // We only clear the SHF_LINK_ORDER flag in for
710 // a non-relocatable link.
711 if (!parameters
->options().relocatable())
712 flags
&= ~elfcpp::SHF_LINK_ORDER
;
714 if (this->script_options_
->saw_sections_clause())
716 // We are using a SECTIONS clause, so the output section is
717 // chosen based only on the name.
719 Script_sections
* ss
= this->script_options_
->script_sections();
720 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
721 Output_section
** output_section_slot
;
722 Script_sections::Section_type script_section_type
;
723 const char* orig_name
= name
;
724 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
725 &script_section_type
);
728 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
729 "because it is not allowed by the "
730 "SECTIONS clause of the linker script"),
732 // The SECTIONS clause says to discard this input section.
736 // We can only handle script section types ST_NONE and ST_NOLOAD.
737 switch (script_section_type
)
739 case Script_sections::ST_NONE
:
741 case Script_sections::ST_NOLOAD
:
742 flags
&= elfcpp::SHF_ALLOC
;
748 // If this is an orphan section--one not mentioned in the linker
749 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
750 // default processing below.
752 if (output_section_slot
!= NULL
)
754 if (*output_section_slot
!= NULL
)
756 (*output_section_slot
)->update_flags_for_input_section(flags
);
757 return *output_section_slot
;
760 // We don't put sections found in the linker script into
761 // SECTION_NAME_MAP_. That keeps us from getting confused
762 // if an orphan section is mapped to a section with the same
763 // name as one in the linker script.
765 name
= this->namepool_
.add(name
, false, NULL
);
767 Output_section
* os
= this->make_output_section(name
, type
, flags
,
770 os
->set_found_in_sections_clause();
772 // Special handling for NOLOAD sections.
773 if (script_section_type
== Script_sections::ST_NOLOAD
)
777 // The constructor of Output_section sets addresses of non-ALLOC
778 // sections to 0 by default. We don't want that for NOLOAD
779 // sections even if they have no SHF_ALLOC flag.
780 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
781 && os
->is_address_valid())
783 gold_assert(os
->address() == 0
784 && !os
->is_offset_valid()
785 && !os
->is_data_size_valid());
786 os
->reset_address_and_file_offset();
790 *output_section_slot
= os
;
795 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
797 size_t len
= strlen(name
);
798 char* uncompressed_name
= NULL
;
800 // Compressed debug sections should be mapped to the corresponding
801 // uncompressed section.
802 if (is_compressed_debug_section(name
))
804 uncompressed_name
= new char[len
];
805 uncompressed_name
[0] = '.';
806 gold_assert(name
[0] == '.' && name
[1] == 'z');
807 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
808 uncompressed_name
[len
- 1] = '\0';
810 name
= uncompressed_name
;
813 // Turn NAME from the name of the input section into the name of the
816 && !this->script_options_
->saw_sections_clause()
817 && !parameters
->options().relocatable())
818 name
= Layout::output_section_name(name
, &len
);
820 Stringpool::Key name_key
;
821 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
823 if (uncompressed_name
!= NULL
)
824 delete[] uncompressed_name
;
826 // Find or make the output section. The output section is selected
827 // based on the section name, type, and flags.
828 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
831 // For incremental links, record the initial fixed layout of a section
832 // from the base file, and return a pointer to the Output_section.
834 template<int size
, bool big_endian
>
836 Layout::init_fixed_output_section(const char* name
,
837 elfcpp::Shdr
<size
, big_endian
>& shdr
)
839 unsigned int sh_type
= shdr
.get_sh_type();
841 // We preserve the layout of PROGBITS, NOBITS, and NOTE sections.
842 // All others will be created from scratch and reallocated.
843 if (sh_type
!= elfcpp::SHT_PROGBITS
844 && sh_type
!= elfcpp::SHT_NOBITS
845 && sh_type
!= elfcpp::SHT_NOTE
)
848 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
849 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
850 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
851 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
852 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
853 shdr
.get_sh_addralign();
855 // Make the output section.
856 Stringpool::Key name_key
;
857 name
= this->namepool_
.add(name
, true, &name_key
);
858 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
859 sh_flags
, ORDER_INVALID
, false);
860 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
861 if (sh_type
!= elfcpp::SHT_NOBITS
)
862 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
866 // Return the output section to use for input section SHNDX, with name
867 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
868 // index of a relocation section which applies to this section, or 0
869 // if none, or -1U if more than one. RELOC_TYPE is the type of the
870 // relocation section if there is one. Set *OFF to the offset of this
871 // input section without the output section. Return NULL if the
872 // section should be discarded. Set *OFF to -1 if the section
873 // contents should not be written directly to the output file, but
874 // will instead receive special handling.
876 template<int size
, bool big_endian
>
878 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
879 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
880 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
884 if (!this->include_section(object
, name
, shdr
))
889 // Sometimes .init_array*, .preinit_array* and .fini_array* do not have
890 // correct section types. Force them here.
891 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
892 if (sh_type
== elfcpp::SHT_PROGBITS
)
894 static const char init_array_prefix
[] = ".init_array";
895 static const char preinit_array_prefix
[] = ".preinit_array";
896 static const char fini_array_prefix
[] = ".fini_array";
897 static size_t init_array_prefix_size
= sizeof(init_array_prefix
) - 1;
898 static size_t preinit_array_prefix_size
=
899 sizeof(preinit_array_prefix
) - 1;
900 static size_t fini_array_prefix_size
= sizeof(fini_array_prefix
) - 1;
902 if (strncmp(name
, init_array_prefix
, init_array_prefix_size
) == 0)
903 sh_type
= elfcpp::SHT_INIT_ARRAY
;
904 else if (strncmp(name
, preinit_array_prefix
, preinit_array_prefix_size
)
906 sh_type
= elfcpp::SHT_PREINIT_ARRAY
;
907 else if (strncmp(name
, fini_array_prefix
, fini_array_prefix_size
) == 0)
908 sh_type
= elfcpp::SHT_FINI_ARRAY
;
911 // In a relocatable link a grouped section must not be combined with
912 // any other sections.
913 if (parameters
->options().relocatable()
914 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
916 name
= this->namepool_
.add(name
, true, NULL
);
917 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
918 ORDER_INVALID
, false);
922 os
= this->choose_output_section(object
, name
, sh_type
,
923 shdr
.get_sh_flags(), true,
924 ORDER_INVALID
, false);
929 // By default the GNU linker sorts input sections whose names match
930 // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
931 // are sorted by name. This is used to implement constructor
932 // priority ordering. We are compatible.
933 if (!this->script_options_
->saw_sections_clause()
934 && (is_prefix_of(".ctors.", name
)
935 || is_prefix_of(".dtors.", name
)
936 || is_prefix_of(".init_array.", name
)
937 || is_prefix_of(".fini_array.", name
)))
938 os
->set_must_sort_attached_input_sections();
940 // FIXME: Handle SHF_LINK_ORDER somewhere.
942 elfcpp::Elf_Xword orig_flags
= os
->flags();
944 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
945 this->script_options_
->saw_sections_clause());
947 // If the flags changed, we may have to change the order.
948 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
950 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
951 elfcpp::Elf_Xword new_flags
=
952 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
953 if (orig_flags
!= new_flags
)
954 os
->set_order(this->default_section_order(os
, false));
957 this->have_added_input_section_
= true;
962 // Handle a relocation section when doing a relocatable link.
964 template<int size
, bool big_endian
>
966 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
968 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
969 Output_section
* data_section
,
970 Relocatable_relocs
* rr
)
972 gold_assert(parameters
->options().relocatable()
973 || parameters
->options().emit_relocs());
975 int sh_type
= shdr
.get_sh_type();
978 if (sh_type
== elfcpp::SHT_REL
)
980 else if (sh_type
== elfcpp::SHT_RELA
)
984 name
+= data_section
->name();
986 // In a relocatable link relocs for a grouped section must not be
987 // combined with other reloc sections.
989 if (!parameters
->options().relocatable()
990 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
991 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
992 shdr
.get_sh_flags(), false,
993 ORDER_INVALID
, false);
996 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
997 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
998 ORDER_INVALID
, false);
1001 os
->set_should_link_to_symtab();
1002 os
->set_info_section(data_section
);
1004 Output_section_data
* posd
;
1005 if (sh_type
== elfcpp::SHT_REL
)
1007 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1008 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1012 else if (sh_type
== elfcpp::SHT_RELA
)
1014 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1015 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1022 os
->add_output_section_data(posd
);
1023 rr
->set_output_data(posd
);
1028 // Handle a group section when doing a relocatable link.
1030 template<int size
, bool big_endian
>
1032 Layout::layout_group(Symbol_table
* symtab
,
1033 Sized_relobj_file
<size
, big_endian
>* object
,
1035 const char* group_section_name
,
1036 const char* signature
,
1037 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1038 elfcpp::Elf_Word flags
,
1039 std::vector
<unsigned int>* shndxes
)
1041 gold_assert(parameters
->options().relocatable());
1042 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1043 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1044 Output_section
* os
= this->make_output_section(group_section_name
,
1046 shdr
.get_sh_flags(),
1047 ORDER_INVALID
, false);
1049 // We need to find a symbol with the signature in the symbol table.
1050 // If we don't find one now, we need to look again later.
1051 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1053 os
->set_info_symndx(sym
);
1056 // Reserve some space to minimize reallocations.
1057 if (this->group_signatures_
.empty())
1058 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1060 // We will wind up using a symbol whose name is the signature.
1061 // So just put the signature in the symbol name pool to save it.
1062 signature
= symtab
->canonicalize_name(signature
);
1063 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1066 os
->set_should_link_to_symtab();
1069 section_size_type entry_count
=
1070 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1071 Output_section_data
* posd
=
1072 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1074 os
->add_output_section_data(posd
);
1077 // Special GNU handling of sections name .eh_frame. They will
1078 // normally hold exception frame data as defined by the C++ ABI
1079 // (http://codesourcery.com/cxx-abi/).
1081 template<int size
, bool big_endian
>
1083 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1084 const unsigned char* symbols
,
1086 const unsigned char* symbol_names
,
1087 off_t symbol_names_size
,
1089 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1090 unsigned int reloc_shndx
, unsigned int reloc_type
,
1093 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
);
1094 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1096 const char* const name
= ".eh_frame";
1097 Output_section
* os
= this->choose_output_section(object
, name
,
1098 elfcpp::SHT_PROGBITS
,
1099 elfcpp::SHF_ALLOC
, false,
1100 ORDER_EHFRAME
, false);
1104 if (this->eh_frame_section_
== NULL
)
1106 this->eh_frame_section_
= os
;
1107 this->eh_frame_data_
= new Eh_frame();
1109 // For incremental linking, we do not optimize .eh_frame sections
1110 // or create a .eh_frame_hdr section.
1111 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1113 Output_section
* hdr_os
=
1114 this->choose_output_section(NULL
, ".eh_frame_hdr",
1115 elfcpp::SHT_PROGBITS
,
1116 elfcpp::SHF_ALLOC
, false,
1117 ORDER_EHFRAME
, false);
1121 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1122 this->eh_frame_data_
);
1123 hdr_os
->add_output_section_data(hdr_posd
);
1125 hdr_os
->set_after_input_sections();
1127 if (!this->script_options_
->saw_phdrs_clause())
1129 Output_segment
* hdr_oseg
;
1130 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1132 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1136 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1141 gold_assert(this->eh_frame_section_
== os
);
1143 if (!parameters
->incremental()
1144 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1153 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1155 // A writable .eh_frame section is a RELRO section.
1156 if ((shdr
.get_sh_flags() & elfcpp::SHF_WRITE
) != 0)
1159 // We found a .eh_frame section we are going to optimize, so now
1160 // we can add the set of optimized sections to the output
1161 // section. We need to postpone adding this until we've found a
1162 // section we can optimize so that the .eh_frame section in
1163 // crtbegin.o winds up at the start of the output section.
1164 if (!this->added_eh_frame_data_
)
1166 os
->add_output_section_data(this->eh_frame_data_
);
1167 this->added_eh_frame_data_
= true;
1173 // We couldn't handle this .eh_frame section for some reason.
1174 // Add it as a normal section.
1175 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1176 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1177 saw_sections_clause
);
1178 this->have_added_input_section_
= true;
1184 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1185 // the output section.
1188 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1189 elfcpp::Elf_Xword flags
,
1190 Output_section_data
* posd
,
1191 Output_section_order order
, bool is_relro
)
1193 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1194 false, order
, is_relro
);
1196 os
->add_output_section_data(posd
);
1200 // Map section flags to segment flags.
1203 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1205 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1206 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1207 ret
|= elfcpp::PF_W
;
1208 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1209 ret
|= elfcpp::PF_X
;
1213 // Make a new Output_section, and attach it to segments as
1214 // appropriate. ORDER is the order in which this section should
1215 // appear in the output segment. IS_RELRO is true if this is a relro
1216 // (read-only after relocations) section.
1219 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1220 elfcpp::Elf_Xword flags
,
1221 Output_section_order order
, bool is_relro
)
1224 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1225 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1226 && is_compressible_debug_section(name
))
1227 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1229 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1230 && parameters
->options().strip_debug_non_line()
1231 && strcmp(".debug_abbrev", name
) == 0)
1233 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1235 if (this->debug_info_
)
1236 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1238 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1239 && parameters
->options().strip_debug_non_line()
1240 && strcmp(".debug_info", name
) == 0)
1242 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1244 if (this->debug_abbrev_
)
1245 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1249 // FIXME: const_cast is ugly.
1250 Target
* target
= const_cast<Target
*>(¶meters
->target());
1251 os
= target
->make_output_section(name
, type
, flags
);
1254 // With -z relro, we have to recognize the special sections by name.
1255 // There is no other way.
1256 bool is_relro_local
= false;
1257 if (!this->script_options_
->saw_sections_clause()
1258 && parameters
->options().relro()
1259 && type
== elfcpp::SHT_PROGBITS
1260 && (flags
& elfcpp::SHF_ALLOC
) != 0
1261 && (flags
& elfcpp::SHF_WRITE
) != 0)
1263 if (strcmp(name
, ".data.rel.ro") == 0)
1265 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1268 is_relro_local
= true;
1270 else if (type
== elfcpp::SHT_INIT_ARRAY
1271 || type
== elfcpp::SHT_FINI_ARRAY
1272 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1274 else if (strcmp(name
, ".ctors") == 0
1275 || strcmp(name
, ".dtors") == 0
1276 || strcmp(name
, ".jcr") == 0)
1283 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1284 order
= this->default_section_order(os
, is_relro_local
);
1286 os
->set_order(order
);
1288 parameters
->target().new_output_section(os
);
1290 this->section_list_
.push_back(os
);
1292 // The GNU linker by default sorts some sections by priority, so we
1293 // do the same. We need to know that this might happen before we
1294 // attach any input sections.
1295 if (!this->script_options_
->saw_sections_clause()
1296 && (strcmp(name
, ".ctors") == 0
1297 || strcmp(name
, ".dtors") == 0
1298 || strcmp(name
, ".init_array") == 0
1299 || strcmp(name
, ".fini_array") == 0))
1300 os
->set_may_sort_attached_input_sections();
1302 // Check for .stab*str sections, as .stab* sections need to link to
1304 if (type
== elfcpp::SHT_STRTAB
1305 && !this->have_stabstr_section_
1306 && strncmp(name
, ".stab", 5) == 0
1307 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1308 this->have_stabstr_section_
= true;
1310 // If we have already attached the sections to segments, then we
1311 // need to attach this one now. This happens for sections created
1312 // directly by the linker.
1313 if (this->sections_are_attached_
)
1314 this->attach_section_to_segment(os
);
1319 // Return the default order in which a section should be placed in an
1320 // output segment. This function captures a lot of the ideas in
1321 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1322 // linker created section is normally set when the section is created;
1323 // this function is used for input sections.
1325 Output_section_order
1326 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1328 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1329 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1330 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1331 bool is_bss
= false;
1336 case elfcpp::SHT_PROGBITS
:
1338 case elfcpp::SHT_NOBITS
:
1341 case elfcpp::SHT_RELA
:
1342 case elfcpp::SHT_REL
:
1344 return ORDER_DYNAMIC_RELOCS
;
1346 case elfcpp::SHT_HASH
:
1347 case elfcpp::SHT_DYNAMIC
:
1348 case elfcpp::SHT_SHLIB
:
1349 case elfcpp::SHT_DYNSYM
:
1350 case elfcpp::SHT_GNU_HASH
:
1351 case elfcpp::SHT_GNU_verdef
:
1352 case elfcpp::SHT_GNU_verneed
:
1353 case elfcpp::SHT_GNU_versym
:
1355 return ORDER_DYNAMIC_LINKER
;
1357 case elfcpp::SHT_NOTE
:
1358 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1361 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1362 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1364 if (!is_bss
&& !is_write
)
1368 if (strcmp(os
->name(), ".init") == 0)
1370 else if (strcmp(os
->name(), ".fini") == 0)
1373 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1377 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1379 if (os
->is_small_section())
1380 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1381 if (os
->is_large_section())
1382 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1384 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1387 // Attach output sections to segments. This is called after we have
1388 // seen all the input sections.
1391 Layout::attach_sections_to_segments()
1393 for (Section_list::iterator p
= this->section_list_
.begin();
1394 p
!= this->section_list_
.end();
1396 this->attach_section_to_segment(*p
);
1398 this->sections_are_attached_
= true;
1401 // Attach an output section to a segment.
1404 Layout::attach_section_to_segment(Output_section
* os
)
1406 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1407 this->unattached_section_list_
.push_back(os
);
1409 this->attach_allocated_section_to_segment(os
);
1412 // Attach an allocated output section to a segment.
1415 Layout::attach_allocated_section_to_segment(Output_section
* os
)
1417 elfcpp::Elf_Xword flags
= os
->flags();
1418 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1420 if (parameters
->options().relocatable())
1423 // If we have a SECTIONS clause, we can't handle the attachment to
1424 // segments until after we've seen all the sections.
1425 if (this->script_options_
->saw_sections_clause())
1428 gold_assert(!this->script_options_
->saw_phdrs_clause());
1430 // This output section goes into a PT_LOAD segment.
1432 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1434 // Check for --section-start.
1436 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1438 // In general the only thing we really care about for PT_LOAD
1439 // segments is whether or not they are writable or executable,
1440 // so that is how we search for them.
1441 // Large data sections also go into their own PT_LOAD segment.
1442 // People who need segments sorted on some other basis will
1443 // have to use a linker script.
1445 Segment_list::const_iterator p
;
1446 for (p
= this->segment_list_
.begin();
1447 p
!= this->segment_list_
.end();
1450 if ((*p
)->type() != elfcpp::PT_LOAD
)
1452 if (!parameters
->options().omagic()
1453 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1455 if (parameters
->options().rosegment()
1456 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1458 // If -Tbss was specified, we need to separate the data and BSS
1460 if (parameters
->options().user_set_Tbss())
1462 if ((os
->type() == elfcpp::SHT_NOBITS
)
1463 == (*p
)->has_any_data_sections())
1466 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1471 if ((*p
)->are_addresses_set())
1474 (*p
)->add_initial_output_data(os
);
1475 (*p
)->update_flags_for_output_section(seg_flags
);
1476 (*p
)->set_addresses(addr
, addr
);
1480 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1484 if (p
== this->segment_list_
.end())
1486 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1488 if (os
->is_large_data_section())
1489 oseg
->set_is_large_data_segment();
1490 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1492 oseg
->set_addresses(addr
, addr
);
1495 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1497 if (os
->type() == elfcpp::SHT_NOTE
)
1499 // See if we already have an equivalent PT_NOTE segment.
1500 for (p
= this->segment_list_
.begin();
1501 p
!= segment_list_
.end();
1504 if ((*p
)->type() == elfcpp::PT_NOTE
1505 && (((*p
)->flags() & elfcpp::PF_W
)
1506 == (seg_flags
& elfcpp::PF_W
)))
1508 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1513 if (p
== this->segment_list_
.end())
1515 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1517 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1521 // If we see a loadable SHF_TLS section, we create a PT_TLS
1522 // segment. There can only be one such segment.
1523 if ((flags
& elfcpp::SHF_TLS
) != 0)
1525 if (this->tls_segment_
== NULL
)
1526 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1527 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1530 // If -z relro is in effect, and we see a relro section, we create a
1531 // PT_GNU_RELRO segment. There can only be one such segment.
1532 if (os
->is_relro() && parameters
->options().relro())
1534 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1535 if (this->relro_segment_
== NULL
)
1536 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1537 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1540 // If we are making a shared library, and we see a section named
1541 // .interp, and the -dynamic-linker option was not used, then put
1542 // the .interp section into a PT_INTERP segment. This is for GNU ld
1543 // compatibility. If making an executable, or if the
1544 // -dynamic-linker option was used, we will create the section and
1545 // segment in Layout::create_interp.
1546 if (strcmp(os
->name(), ".interp") == 0
1547 && parameters
->options().shared()
1548 && parameters
->options().dynamic_linker() == NULL
)
1550 if (this->interp_segment_
== NULL
)
1551 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
1552 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1556 // Make an output section for a script.
1559 Layout::make_output_section_for_script(
1561 Script_sections::Section_type section_type
)
1563 name
= this->namepool_
.add(name
, false, NULL
);
1564 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
1565 if (section_type
== Script_sections::ST_NOLOAD
)
1567 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1568 sh_flags
, ORDER_INVALID
,
1570 os
->set_found_in_sections_clause();
1571 if (section_type
== Script_sections::ST_NOLOAD
)
1572 os
->set_is_noload();
1576 // Return the number of segments we expect to see.
1579 Layout::expected_segment_count() const
1581 size_t ret
= this->segment_list_
.size();
1583 // If we didn't see a SECTIONS clause in a linker script, we should
1584 // already have the complete list of segments. Otherwise we ask the
1585 // SECTIONS clause how many segments it expects, and add in the ones
1586 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1588 if (!this->script_options_
->saw_sections_clause())
1592 const Script_sections
* ss
= this->script_options_
->script_sections();
1593 return ret
+ ss
->expected_segment_count(this);
1597 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
1598 // is whether we saw a .note.GNU-stack section in the object file.
1599 // GNU_STACK_FLAGS is the section flags. The flags give the
1600 // protection required for stack memory. We record this in an
1601 // executable as a PT_GNU_STACK segment. If an object file does not
1602 // have a .note.GNU-stack segment, we must assume that it is an old
1603 // object. On some targets that will force an executable stack.
1606 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
1609 if (!seen_gnu_stack
)
1611 this->input_without_gnu_stack_note_
= true;
1612 if (parameters
->options().warn_execstack()
1613 && parameters
->target().is_default_stack_executable())
1614 gold_warning(_("%s: missing .note.GNU-stack section"
1615 " implies executable stack"),
1616 obj
->name().c_str());
1620 this->input_with_gnu_stack_note_
= true;
1621 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
1623 this->input_requires_executable_stack_
= true;
1624 if (parameters
->options().warn_execstack()
1625 || parameters
->options().is_stack_executable())
1626 gold_warning(_("%s: requires executable stack"),
1627 obj
->name().c_str());
1632 // Create automatic note sections.
1635 Layout::create_notes()
1637 this->create_gold_note();
1638 this->create_executable_stack_info();
1639 this->create_build_id();
1642 // Create the dynamic sections which are needed before we read the
1646 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
1648 if (parameters
->doing_static_link())
1651 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
1652 elfcpp::SHT_DYNAMIC
,
1654 | elfcpp::SHF_WRITE
),
1658 this->dynamic_symbol_
=
1659 symtab
->define_in_output_data("_DYNAMIC", NULL
, Symbol_table::PREDEFINED
,
1660 this->dynamic_section_
, 0, 0,
1661 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
1662 elfcpp::STV_HIDDEN
, 0, false, false);
1664 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
1666 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
1669 // For each output section whose name can be represented as C symbol,
1670 // define __start and __stop symbols for the section. This is a GNU
1674 Layout::define_section_symbols(Symbol_table
* symtab
)
1676 for (Section_list::const_iterator p
= this->section_list_
.begin();
1677 p
!= this->section_list_
.end();
1680 const char* const name
= (*p
)->name();
1681 if (is_cident(name
))
1683 const std::string
name_string(name
);
1684 const std::string
start_name(cident_section_start_prefix
1686 const std::string
stop_name(cident_section_stop_prefix
1689 symtab
->define_in_output_data(start_name
.c_str(),
1691 Symbol_table::PREDEFINED
,
1697 elfcpp::STV_DEFAULT
,
1699 false, // offset_is_from_end
1700 true); // only_if_ref
1702 symtab
->define_in_output_data(stop_name
.c_str(),
1704 Symbol_table::PREDEFINED
,
1710 elfcpp::STV_DEFAULT
,
1712 true, // offset_is_from_end
1713 true); // only_if_ref
1718 // Define symbols for group signatures.
1721 Layout::define_group_signatures(Symbol_table
* symtab
)
1723 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
1724 p
!= this->group_signatures_
.end();
1727 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
1729 p
->section
->set_info_symndx(sym
);
1732 // Force the name of the group section to the group
1733 // signature, and use the group's section symbol as the
1734 // signature symbol.
1735 if (strcmp(p
->section
->name(), p
->signature
) != 0)
1737 const char* name
= this->namepool_
.add(p
->signature
,
1739 p
->section
->set_name(name
);
1741 p
->section
->set_needs_symtab_index();
1742 p
->section
->set_info_section_symndx(p
->section
);
1746 this->group_signatures_
.clear();
1749 // Find the first read-only PT_LOAD segment, creating one if
1753 Layout::find_first_load_seg()
1755 Output_segment
* best
= NULL
;
1756 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1757 p
!= this->segment_list_
.end();
1760 if ((*p
)->type() == elfcpp::PT_LOAD
1761 && ((*p
)->flags() & elfcpp::PF_R
) != 0
1762 && (parameters
->options().omagic()
1763 || ((*p
)->flags() & elfcpp::PF_W
) == 0))
1765 if (best
== NULL
|| this->segment_precedes(*p
, best
))
1772 gold_assert(!this->script_options_
->saw_phdrs_clause());
1774 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
1779 // Save states of all current output segments. Store saved states
1780 // in SEGMENT_STATES.
1783 Layout::save_segments(Segment_states
* segment_states
)
1785 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1786 p
!= this->segment_list_
.end();
1789 Output_segment
* segment
= *p
;
1791 Output_segment
* copy
= new Output_segment(*segment
);
1792 (*segment_states
)[segment
] = copy
;
1796 // Restore states of output segments and delete any segment not found in
1800 Layout::restore_segments(const Segment_states
* segment_states
)
1802 // Go through the segment list and remove any segment added in the
1804 this->tls_segment_
= NULL
;
1805 this->relro_segment_
= NULL
;
1806 Segment_list::iterator list_iter
= this->segment_list_
.begin();
1807 while (list_iter
!= this->segment_list_
.end())
1809 Output_segment
* segment
= *list_iter
;
1810 Segment_states::const_iterator states_iter
=
1811 segment_states
->find(segment
);
1812 if (states_iter
!= segment_states
->end())
1814 const Output_segment
* copy
= states_iter
->second
;
1815 // Shallow copy to restore states.
1818 // Also fix up TLS and RELRO segment pointers as appropriate.
1819 if (segment
->type() == elfcpp::PT_TLS
)
1820 this->tls_segment_
= segment
;
1821 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
1822 this->relro_segment_
= segment
;
1828 list_iter
= this->segment_list_
.erase(list_iter
);
1829 // This is a segment created during section layout. It should be
1830 // safe to remove it since we should have removed all pointers to it.
1836 // Clean up after relaxation so that sections can be laid out again.
1839 Layout::clean_up_after_relaxation()
1841 // Restore the segments to point state just prior to the relaxation loop.
1842 Script_sections
* script_section
= this->script_options_
->script_sections();
1843 script_section
->release_segments();
1844 this->restore_segments(this->segment_states_
);
1846 // Reset section addresses and file offsets
1847 for (Section_list::iterator p
= this->section_list_
.begin();
1848 p
!= this->section_list_
.end();
1851 (*p
)->restore_states();
1853 // If an input section changes size because of relaxation,
1854 // we need to adjust the section offsets of all input sections.
1855 // after such a section.
1856 if ((*p
)->section_offsets_need_adjustment())
1857 (*p
)->adjust_section_offsets();
1859 (*p
)->reset_address_and_file_offset();
1862 // Reset special output object address and file offsets.
1863 for (Data_list::iterator p
= this->special_output_list_
.begin();
1864 p
!= this->special_output_list_
.end();
1866 (*p
)->reset_address_and_file_offset();
1868 // A linker script may have created some output section data objects.
1869 // They are useless now.
1870 for (Output_section_data_list::const_iterator p
=
1871 this->script_output_section_data_list_
.begin();
1872 p
!= this->script_output_section_data_list_
.end();
1875 this->script_output_section_data_list_
.clear();
1878 // Prepare for relaxation.
1881 Layout::prepare_for_relaxation()
1883 // Create an relaxation debug check if in debugging mode.
1884 if (is_debugging_enabled(DEBUG_RELAXATION
))
1885 this->relaxation_debug_check_
= new Relaxation_debug_check();
1887 // Save segment states.
1888 this->segment_states_
= new Segment_states();
1889 this->save_segments(this->segment_states_
);
1891 for(Section_list::const_iterator p
= this->section_list_
.begin();
1892 p
!= this->section_list_
.end();
1894 (*p
)->save_states();
1896 if (is_debugging_enabled(DEBUG_RELAXATION
))
1897 this->relaxation_debug_check_
->check_output_data_for_reset_values(
1898 this->section_list_
, this->special_output_list_
);
1900 // Also enable recording of output section data from scripts.
1901 this->record_output_section_data_from_script_
= true;
1904 // Relaxation loop body: If target has no relaxation, this runs only once
1905 // Otherwise, the target relaxation hook is called at the end of
1906 // each iteration. If the hook returns true, it means re-layout of
1907 // section is required.
1909 // The number of segments created by a linking script without a PHDRS
1910 // clause may be affected by section sizes and alignments. There is
1911 // a remote chance that relaxation causes different number of PT_LOAD
1912 // segments are created and sections are attached to different segments.
1913 // Therefore, we always throw away all segments created during section
1914 // layout. In order to be able to restart the section layout, we keep
1915 // a copy of the segment list right before the relaxation loop and use
1916 // that to restore the segments.
1918 // PASS is the current relaxation pass number.
1919 // SYMTAB is a symbol table.
1920 // PLOAD_SEG is the address of a pointer for the load segment.
1921 // PHDR_SEG is a pointer to the PHDR segment.
1922 // SEGMENT_HEADERS points to the output segment header.
1923 // FILE_HEADER points to the output file header.
1924 // PSHNDX is the address to store the output section index.
1927 Layout::relaxation_loop_body(
1930 Symbol_table
* symtab
,
1931 Output_segment
** pload_seg
,
1932 Output_segment
* phdr_seg
,
1933 Output_segment_headers
* segment_headers
,
1934 Output_file_header
* file_header
,
1935 unsigned int* pshndx
)
1937 // If this is not the first iteration, we need to clean up after
1938 // relaxation so that we can lay out the sections again.
1940 this->clean_up_after_relaxation();
1942 // If there is a SECTIONS clause, put all the input sections into
1943 // the required order.
1944 Output_segment
* load_seg
;
1945 if (this->script_options_
->saw_sections_clause())
1946 load_seg
= this->set_section_addresses_from_script(symtab
);
1947 else if (parameters
->options().relocatable())
1950 load_seg
= this->find_first_load_seg();
1952 if (parameters
->options().oformat_enum()
1953 != General_options::OBJECT_FORMAT_ELF
)
1956 // If the user set the address of the text segment, that may not be
1957 // compatible with putting the segment headers and file headers into
1959 if (parameters
->options().user_set_Ttext())
1962 gold_assert(phdr_seg
== NULL
1964 || this->script_options_
->saw_sections_clause());
1966 // If the address of the load segment we found has been set by
1967 // --section-start rather than by a script, then adjust the VMA and
1968 // LMA downward if possible to include the file and section headers.
1969 uint64_t header_gap
= 0;
1970 if (load_seg
!= NULL
1971 && load_seg
->are_addresses_set()
1972 && !this->script_options_
->saw_sections_clause()
1973 && !parameters
->options().relocatable())
1975 file_header
->finalize_data_size();
1976 segment_headers
->finalize_data_size();
1977 size_t sizeof_headers
= (file_header
->data_size()
1978 + segment_headers
->data_size());
1979 const uint64_t abi_pagesize
= target
->abi_pagesize();
1980 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
1981 hdr_paddr
&= ~(abi_pagesize
- 1);
1982 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
1983 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
1987 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
1988 load_seg
->paddr() - subtract
);
1989 header_gap
= subtract
- sizeof_headers
;
1993 // Lay out the segment headers.
1994 if (!parameters
->options().relocatable())
1996 gold_assert(segment_headers
!= NULL
);
1997 if (header_gap
!= 0 && load_seg
!= NULL
)
1999 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2000 load_seg
->add_initial_output_data(z
);
2002 if (load_seg
!= NULL
)
2003 load_seg
->add_initial_output_data(segment_headers
);
2004 if (phdr_seg
!= NULL
)
2005 phdr_seg
->add_initial_output_data(segment_headers
);
2008 // Lay out the file header.
2009 if (load_seg
!= NULL
)
2010 load_seg
->add_initial_output_data(file_header
);
2012 if (this->script_options_
->saw_phdrs_clause()
2013 && !parameters
->options().relocatable())
2015 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2016 // clause in a linker script.
2017 Script_sections
* ss
= this->script_options_
->script_sections();
2018 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2021 // We set the output section indexes in set_segment_offsets and
2022 // set_section_indexes.
2025 // Set the file offsets of all the segments, and all the sections
2028 if (!parameters
->options().relocatable())
2029 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2031 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2033 // Verify that the dummy relaxation does not change anything.
2034 if (is_debugging_enabled(DEBUG_RELAXATION
))
2037 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2039 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2042 *pload_seg
= load_seg
;
2046 // Search the list of patterns and find the postion of the given section
2047 // name in the output section. If the section name matches a glob
2048 // pattern and a non-glob name, then the non-glob position takes
2049 // precedence. Return 0 if no match is found.
2052 Layout::find_section_order_index(const std::string
& section_name
)
2054 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2055 map_it
= this->input_section_position_
.find(section_name
);
2056 if (map_it
!= this->input_section_position_
.end())
2057 return map_it
->second
;
2059 // Absolute match failed. Linear search the glob patterns.
2060 std::vector
<std::string
>::iterator it
;
2061 for (it
= this->input_section_glob_
.begin();
2062 it
!= this->input_section_glob_
.end();
2065 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2067 map_it
= this->input_section_position_
.find(*it
);
2068 gold_assert(map_it
!= this->input_section_position_
.end());
2069 return map_it
->second
;
2075 // Read the sequence of input sections from the file specified with
2076 // --section-ordering-file.
2079 Layout::read_layout_from_file()
2081 const char* filename
= parameters
->options().section_ordering_file();
2087 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2088 filename
, strerror(errno
));
2090 std::getline(in
, line
); // this chops off the trailing \n, if any
2091 unsigned int position
= 1;
2095 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2096 line
.resize(line
.length() - 1);
2097 // Ignore comments, beginning with '#'
2100 std::getline(in
, line
);
2103 this->input_section_position_
[line
] = position
;
2104 // Store all glob patterns in a vector.
2105 if (is_wildcard_string(line
.c_str()))
2106 this->input_section_glob_
.push_back(line
);
2108 std::getline(in
, line
);
2112 // Finalize the layout. When this is called, we have created all the
2113 // output sections and all the output segments which are based on
2114 // input sections. We have several things to do, and we have to do
2115 // them in the right order, so that we get the right results correctly
2118 // 1) Finalize the list of output segments and create the segment
2121 // 2) Finalize the dynamic symbol table and associated sections.
2123 // 3) Determine the final file offset of all the output segments.
2125 // 4) Determine the final file offset of all the SHF_ALLOC output
2128 // 5) Create the symbol table sections and the section name table
2131 // 6) Finalize the symbol table: set symbol values to their final
2132 // value and make a final determination of which symbols are going
2133 // into the output symbol table.
2135 // 7) Create the section table header.
2137 // 8) Determine the final file offset of all the output sections which
2138 // are not SHF_ALLOC, including the section table header.
2140 // 9) Finalize the ELF file header.
2142 // This function returns the size of the output file.
2145 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2146 Target
* target
, const Task
* task
)
2148 target
->finalize_sections(this, input_objects
, symtab
);
2150 this->count_local_symbols(task
, input_objects
);
2152 this->link_stabs_sections();
2154 Output_segment
* phdr_seg
= NULL
;
2155 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2157 // There was a dynamic object in the link. We need to create
2158 // some information for the dynamic linker.
2160 // Create the PT_PHDR segment which will hold the program
2162 if (!this->script_options_
->saw_phdrs_clause())
2163 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2165 // Create the dynamic symbol table, including the hash table.
2166 Output_section
* dynstr
;
2167 std::vector
<Symbol
*> dynamic_symbols
;
2168 unsigned int local_dynamic_count
;
2169 Versions
versions(*this->script_options()->version_script_info(),
2171 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2172 &local_dynamic_count
, &dynamic_symbols
,
2175 // Create the .interp section to hold the name of the
2176 // interpreter, and put it in a PT_INTERP segment.
2177 if (!parameters
->options().shared()
2178 || parameters
->options().dynamic_linker() != NULL
)
2179 this->create_interp(target
);
2181 // Finish the .dynamic section to hold the dynamic data, and put
2182 // it in a PT_DYNAMIC segment.
2183 this->finish_dynamic_section(input_objects
, symtab
);
2185 // We should have added everything we need to the dynamic string
2187 this->dynpool_
.set_string_offsets();
2189 // Create the version sections. We can't do this until the
2190 // dynamic string table is complete.
2191 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2192 dynamic_symbols
, dynstr
);
2194 // Set the size of the _DYNAMIC symbol. We can't do this until
2195 // after we call create_version_sections.
2196 this->set_dynamic_symbol_size(symtab
);
2199 // Create segment headers.
2200 Output_segment_headers
* segment_headers
=
2201 (parameters
->options().relocatable()
2203 : new Output_segment_headers(this->segment_list_
));
2205 // Lay out the file header.
2206 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
2209 this->special_output_list_
.push_back(file_header
);
2210 if (segment_headers
!= NULL
)
2211 this->special_output_list_
.push_back(segment_headers
);
2213 // Find approriate places for orphan output sections if we are using
2215 if (this->script_options_
->saw_sections_clause())
2216 this->place_orphan_sections_in_script();
2218 Output_segment
* load_seg
;
2223 // Take a snapshot of the section layout as needed.
2224 if (target
->may_relax())
2225 this->prepare_for_relaxation();
2227 // Run the relaxation loop to lay out sections.
2230 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2231 phdr_seg
, segment_headers
, file_header
,
2235 while (target
->may_relax()
2236 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2238 // Set the file offsets of all the non-data sections we've seen so
2239 // far which don't have to wait for the input sections. We need
2240 // this in order to finalize local symbols in non-allocated
2242 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2244 // Set the section indexes of all unallocated sections seen so far,
2245 // in case any of them are somehow referenced by a symbol.
2246 shndx
= this->set_section_indexes(shndx
);
2248 // Create the symbol table sections.
2249 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2250 if (!parameters
->doing_static_link())
2251 this->assign_local_dynsym_offsets(input_objects
);
2253 // Process any symbol assignments from a linker script. This must
2254 // be called after the symbol table has been finalized.
2255 this->script_options_
->finalize_symbols(symtab
, this);
2257 // Create the incremental inputs sections.
2258 if (this->incremental_inputs_
)
2260 this->incremental_inputs_
->finalize();
2261 this->create_incremental_info_sections(symtab
);
2264 // Create the .shstrtab section.
2265 Output_section
* shstrtab_section
= this->create_shstrtab();
2267 // Set the file offsets of the rest of the non-data sections which
2268 // don't have to wait for the input sections.
2269 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2271 // Now that all sections have been created, set the section indexes
2272 // for any sections which haven't been done yet.
2273 shndx
= this->set_section_indexes(shndx
);
2275 // Create the section table header.
2276 this->create_shdrs(shstrtab_section
, &off
);
2278 // If there are no sections which require postprocessing, we can
2279 // handle the section names now, and avoid a resize later.
2280 if (!this->any_postprocessing_sections_
)
2282 off
= this->set_section_offsets(off
,
2283 POSTPROCESSING_SECTIONS_PASS
);
2285 this->set_section_offsets(off
,
2286 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2289 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2291 // Now we know exactly where everything goes in the output file
2292 // (except for non-allocated sections which require postprocessing).
2293 Output_data::layout_complete();
2295 this->output_file_size_
= off
;
2300 // Create a note header following the format defined in the ELF ABI.
2301 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2302 // of the section to create, DESCSZ is the size of the descriptor.
2303 // ALLOCATE is true if the section should be allocated in memory.
2304 // This returns the new note section. It sets *TRAILING_PADDING to
2305 // the number of trailing zero bytes required.
2308 Layout::create_note(const char* name
, int note_type
,
2309 const char* section_name
, size_t descsz
,
2310 bool allocate
, size_t* trailing_padding
)
2312 // Authorities all agree that the values in a .note field should
2313 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2314 // they differ on what the alignment is for 64-bit binaries.
2315 // The GABI says unambiguously they take 8-byte alignment:
2316 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2317 // Other documentation says alignment should always be 4 bytes:
2318 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2319 // GNU ld and GNU readelf both support the latter (at least as of
2320 // version 2.16.91), and glibc always generates the latter for
2321 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2323 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2324 const int size
= parameters
->target().get_size();
2326 const int size
= 32;
2329 // The contents of the .note section.
2330 size_t namesz
= strlen(name
) + 1;
2331 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2332 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2334 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2336 unsigned char* buffer
= new unsigned char[notehdrsz
];
2337 memset(buffer
, 0, notehdrsz
);
2339 bool is_big_endian
= parameters
->target().is_big_endian();
2345 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2346 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2347 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2351 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2352 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2353 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2356 else if (size
== 64)
2360 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2361 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2362 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2366 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2367 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2368 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2374 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2376 elfcpp::Elf_Xword flags
= 0;
2377 Output_section_order order
= ORDER_INVALID
;
2380 flags
= elfcpp::SHF_ALLOC
;
2381 order
= ORDER_RO_NOTE
;
2383 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2385 flags
, false, order
, false);
2389 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2392 os
->add_output_section_data(posd
);
2394 *trailing_padding
= aligned_descsz
- descsz
;
2399 // For an executable or shared library, create a note to record the
2400 // version of gold used to create the binary.
2403 Layout::create_gold_note()
2405 if (parameters
->options().relocatable()
2406 || parameters
->incremental_update())
2409 std::string desc
= std::string("gold ") + gold::get_version_string();
2411 size_t trailing_padding
;
2412 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2413 ".note.gnu.gold-version", desc
.size(),
2414 false, &trailing_padding
);
2418 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2419 os
->add_output_section_data(posd
);
2421 if (trailing_padding
> 0)
2423 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2424 os
->add_output_section_data(posd
);
2428 // Record whether the stack should be executable. This can be set
2429 // from the command line using the -z execstack or -z noexecstack
2430 // options. Otherwise, if any input file has a .note.GNU-stack
2431 // section with the SHF_EXECINSTR flag set, the stack should be
2432 // executable. Otherwise, if at least one input file a
2433 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2434 // section, we use the target default for whether the stack should be
2435 // executable. Otherwise, we don't generate a stack note. When
2436 // generating a object file, we create a .note.GNU-stack section with
2437 // the appropriate marking. When generating an executable or shared
2438 // library, we create a PT_GNU_STACK segment.
2441 Layout::create_executable_stack_info()
2443 bool is_stack_executable
;
2444 if (parameters
->options().is_execstack_set())
2445 is_stack_executable
= parameters
->options().is_stack_executable();
2446 else if (!this->input_with_gnu_stack_note_
)
2450 if (this->input_requires_executable_stack_
)
2451 is_stack_executable
= true;
2452 else if (this->input_without_gnu_stack_note_
)
2453 is_stack_executable
=
2454 parameters
->target().is_default_stack_executable();
2456 is_stack_executable
= false;
2459 if (parameters
->options().relocatable())
2461 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2462 elfcpp::Elf_Xword flags
= 0;
2463 if (is_stack_executable
)
2464 flags
|= elfcpp::SHF_EXECINSTR
;
2465 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2466 ORDER_INVALID
, false);
2470 if (this->script_options_
->saw_phdrs_clause())
2472 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2473 if (is_stack_executable
)
2474 flags
|= elfcpp::PF_X
;
2475 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2479 // If --build-id was used, set up the build ID note.
2482 Layout::create_build_id()
2484 if (!parameters
->options().user_set_build_id())
2487 const char* style
= parameters
->options().build_id();
2488 if (strcmp(style
, "none") == 0)
2491 // Set DESCSZ to the size of the note descriptor. When possible,
2492 // set DESC to the note descriptor contents.
2495 if (strcmp(style
, "md5") == 0)
2497 else if (strcmp(style
, "sha1") == 0)
2499 else if (strcmp(style
, "uuid") == 0)
2501 const size_t uuidsz
= 128 / 8;
2503 char buffer
[uuidsz
];
2504 memset(buffer
, 0, uuidsz
);
2506 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2508 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2512 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2513 release_descriptor(descriptor
, true);
2515 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
2516 else if (static_cast<size_t>(got
) != uuidsz
)
2517 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2521 desc
.assign(buffer
, uuidsz
);
2524 else if (strncmp(style
, "0x", 2) == 0)
2527 const char* p
= style
+ 2;
2530 if (hex_p(p
[0]) && hex_p(p
[1]))
2532 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
2536 else if (*p
== '-' || *p
== ':')
2539 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2542 descsz
= desc
.size();
2545 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2548 size_t trailing_padding
;
2549 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2550 ".note.gnu.build-id", descsz
, true,
2557 // We know the value already, so we fill it in now.
2558 gold_assert(desc
.size() == descsz
);
2560 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2561 os
->add_output_section_data(posd
);
2563 if (trailing_padding
!= 0)
2565 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2566 os
->add_output_section_data(posd
);
2571 // We need to compute a checksum after we have completed the
2573 gold_assert(trailing_padding
== 0);
2574 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
2575 os
->add_output_section_data(this->build_id_note_
);
2579 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2580 // field of the former should point to the latter. I'm not sure who
2581 // started this, but the GNU linker does it, and some tools depend
2585 Layout::link_stabs_sections()
2587 if (!this->have_stabstr_section_
)
2590 for (Section_list::iterator p
= this->section_list_
.begin();
2591 p
!= this->section_list_
.end();
2594 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
2597 const char* name
= (*p
)->name();
2598 if (strncmp(name
, ".stab", 5) != 0)
2601 size_t len
= strlen(name
);
2602 if (strcmp(name
+ len
- 3, "str") != 0)
2605 std::string
stab_name(name
, len
- 3);
2606 Output_section
* stab_sec
;
2607 stab_sec
= this->find_output_section(stab_name
.c_str());
2608 if (stab_sec
!= NULL
)
2609 stab_sec
->set_link_section(*p
);
2613 // Create .gnu_incremental_inputs and related sections needed
2614 // for the next run of incremental linking to check what has changed.
2617 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
2619 Incremental_inputs
* incr
= this->incremental_inputs_
;
2621 gold_assert(incr
!= NULL
);
2623 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2624 incr
->create_data_sections(symtab
);
2626 // Add the .gnu_incremental_inputs section.
2627 const char* incremental_inputs_name
=
2628 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
2629 Output_section
* incremental_inputs_os
=
2630 this->make_output_section(incremental_inputs_name
,
2631 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
2632 ORDER_INVALID
, false);
2633 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
2635 // Add the .gnu_incremental_symtab section.
2636 const char* incremental_symtab_name
=
2637 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
2638 Output_section
* incremental_symtab_os
=
2639 this->make_output_section(incremental_symtab_name
,
2640 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
2641 ORDER_INVALID
, false);
2642 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
2643 incremental_symtab_os
->set_entsize(4);
2645 // Add the .gnu_incremental_relocs section.
2646 const char* incremental_relocs_name
=
2647 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
2648 Output_section
* incremental_relocs_os
=
2649 this->make_output_section(incremental_relocs_name
,
2650 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
2651 ORDER_INVALID
, false);
2652 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
2653 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
2655 // Add the .gnu_incremental_got_plt section.
2656 const char* incremental_got_plt_name
=
2657 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
2658 Output_section
* incremental_got_plt_os
=
2659 this->make_output_section(incremental_got_plt_name
,
2660 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
2661 ORDER_INVALID
, false);
2662 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
2664 // Add the .gnu_incremental_strtab section.
2665 const char* incremental_strtab_name
=
2666 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
2667 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
2668 elfcpp::SHT_STRTAB
, 0,
2669 ORDER_INVALID
, false);
2670 Output_data_strtab
* strtab_data
=
2671 new Output_data_strtab(incr
->get_stringpool());
2672 incremental_strtab_os
->add_output_section_data(strtab_data
);
2674 incremental_inputs_os
->set_after_input_sections();
2675 incremental_symtab_os
->set_after_input_sections();
2676 incremental_relocs_os
->set_after_input_sections();
2677 incremental_got_plt_os
->set_after_input_sections();
2679 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
2680 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
2681 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
2682 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
2685 // Return whether SEG1 should be before SEG2 in the output file. This
2686 // is based entirely on the segment type and flags. When this is
2687 // called the segment addresses has normally not yet been set.
2690 Layout::segment_precedes(const Output_segment
* seg1
,
2691 const Output_segment
* seg2
)
2693 elfcpp::Elf_Word type1
= seg1
->type();
2694 elfcpp::Elf_Word type2
= seg2
->type();
2696 // The single PT_PHDR segment is required to precede any loadable
2697 // segment. We simply make it always first.
2698 if (type1
== elfcpp::PT_PHDR
)
2700 gold_assert(type2
!= elfcpp::PT_PHDR
);
2703 if (type2
== elfcpp::PT_PHDR
)
2706 // The single PT_INTERP segment is required to precede any loadable
2707 // segment. We simply make it always second.
2708 if (type1
== elfcpp::PT_INTERP
)
2710 gold_assert(type2
!= elfcpp::PT_INTERP
);
2713 if (type2
== elfcpp::PT_INTERP
)
2716 // We then put PT_LOAD segments before any other segments.
2717 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
2719 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
2722 // We put the PT_TLS segment last except for the PT_GNU_RELRO
2723 // segment, because that is where the dynamic linker expects to find
2724 // it (this is just for efficiency; other positions would also work
2726 if (type1
== elfcpp::PT_TLS
2727 && type2
!= elfcpp::PT_TLS
2728 && type2
!= elfcpp::PT_GNU_RELRO
)
2730 if (type2
== elfcpp::PT_TLS
2731 && type1
!= elfcpp::PT_TLS
2732 && type1
!= elfcpp::PT_GNU_RELRO
)
2735 // We put the PT_GNU_RELRO segment last, because that is where the
2736 // dynamic linker expects to find it (as with PT_TLS, this is just
2738 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
2740 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
2743 const elfcpp::Elf_Word flags1
= seg1
->flags();
2744 const elfcpp::Elf_Word flags2
= seg2
->flags();
2746 // The order of non-PT_LOAD segments is unimportant. We simply sort
2747 // by the numeric segment type and flags values. There should not
2748 // be more than one segment with the same type and flags.
2749 if (type1
!= elfcpp::PT_LOAD
)
2752 return type1
< type2
;
2753 gold_assert(flags1
!= flags2
);
2754 return flags1
< flags2
;
2757 // If the addresses are set already, sort by load address.
2758 if (seg1
->are_addresses_set())
2760 if (!seg2
->are_addresses_set())
2763 unsigned int section_count1
= seg1
->output_section_count();
2764 unsigned int section_count2
= seg2
->output_section_count();
2765 if (section_count1
== 0 && section_count2
> 0)
2767 if (section_count1
> 0 && section_count2
== 0)
2770 uint64_t paddr1
= (seg1
->are_addresses_set()
2772 : seg1
->first_section_load_address());
2773 uint64_t paddr2
= (seg2
->are_addresses_set()
2775 : seg2
->first_section_load_address());
2777 if (paddr1
!= paddr2
)
2778 return paddr1
< paddr2
;
2780 else if (seg2
->are_addresses_set())
2783 // A segment which holds large data comes after a segment which does
2784 // not hold large data.
2785 if (seg1
->is_large_data_segment())
2787 if (!seg2
->is_large_data_segment())
2790 else if (seg2
->is_large_data_segment())
2793 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
2794 // segments come before writable segments. Then writable segments
2795 // with data come before writable segments without data. Then
2796 // executable segments come before non-executable segments. Then
2797 // the unlikely case of a non-readable segment comes before the
2798 // normal case of a readable segment. If there are multiple
2799 // segments with the same type and flags, we require that the
2800 // address be set, and we sort by virtual address and then physical
2802 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
2803 return (flags1
& elfcpp::PF_W
) == 0;
2804 if ((flags1
& elfcpp::PF_W
) != 0
2805 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
2806 return seg1
->has_any_data_sections();
2807 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
2808 return (flags1
& elfcpp::PF_X
) != 0;
2809 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
2810 return (flags1
& elfcpp::PF_R
) == 0;
2812 // We shouldn't get here--we shouldn't create segments which we
2813 // can't distinguish.
2817 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2820 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
2822 uint64_t unsigned_off
= off
;
2823 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
2824 | (addr
& (abi_pagesize
- 1)));
2825 if (aligned_off
< unsigned_off
)
2826 aligned_off
+= abi_pagesize
;
2830 // Set the file offsets of all the segments, and all the sections they
2831 // contain. They have all been created. LOAD_SEG must be be laid out
2832 // first. Return the offset of the data to follow.
2835 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
2836 unsigned int* pshndx
)
2838 // Sort them into the final order.
2839 std::sort(this->segment_list_
.begin(), this->segment_list_
.end(),
2840 Layout::Compare_segments());
2842 // Find the PT_LOAD segments, and set their addresses and offsets
2843 // and their section's addresses and offsets.
2845 if (parameters
->options().user_set_Ttext())
2846 addr
= parameters
->options().Ttext();
2847 else if (parameters
->options().output_is_position_independent())
2850 addr
= target
->default_text_segment_address();
2853 // If LOAD_SEG is NULL, then the file header and segment headers
2854 // will not be loadable. But they still need to be at offset 0 in
2855 // the file. Set their offsets now.
2856 if (load_seg
== NULL
)
2858 for (Data_list::iterator p
= this->special_output_list_
.begin();
2859 p
!= this->special_output_list_
.end();
2862 off
= align_address(off
, (*p
)->addralign());
2863 (*p
)->set_address_and_file_offset(0, off
);
2864 off
+= (*p
)->data_size();
2868 unsigned int increase_relro
= this->increase_relro_
;
2869 if (this->script_options_
->saw_sections_clause())
2872 const bool check_sections
= parameters
->options().check_sections();
2873 Output_segment
* last_load_segment
= NULL
;
2875 for (Segment_list::iterator p
= this->segment_list_
.begin();
2876 p
!= this->segment_list_
.end();
2879 if ((*p
)->type() == elfcpp::PT_LOAD
)
2881 if (load_seg
!= NULL
&& load_seg
!= *p
)
2885 bool are_addresses_set
= (*p
)->are_addresses_set();
2886 if (are_addresses_set
)
2888 // When it comes to setting file offsets, we care about
2889 // the physical address.
2890 addr
= (*p
)->paddr();
2892 else if (parameters
->options().user_set_Tdata()
2893 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2894 && (!parameters
->options().user_set_Tbss()
2895 || (*p
)->has_any_data_sections()))
2897 addr
= parameters
->options().Tdata();
2898 are_addresses_set
= true;
2900 else if (parameters
->options().user_set_Tbss()
2901 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2902 && !(*p
)->has_any_data_sections())
2904 addr
= parameters
->options().Tbss();
2905 are_addresses_set
= true;
2908 uint64_t orig_addr
= addr
;
2909 uint64_t orig_off
= off
;
2911 uint64_t aligned_addr
= 0;
2912 uint64_t abi_pagesize
= target
->abi_pagesize();
2913 uint64_t common_pagesize
= target
->common_pagesize();
2915 if (!parameters
->options().nmagic()
2916 && !parameters
->options().omagic())
2917 (*p
)->set_minimum_p_align(common_pagesize
);
2919 if (!are_addresses_set
)
2921 // Skip the address forward one page, maintaining the same
2922 // position within the page. This lets us store both segments
2923 // overlapping on a single page in the file, but the loader will
2924 // put them on different pages in memory. We will revisit this
2925 // decision once we know the size of the segment.
2927 addr
= align_address(addr
, (*p
)->maximum_alignment());
2928 aligned_addr
= addr
;
2930 if ((addr
& (abi_pagesize
- 1)) != 0)
2931 addr
= addr
+ abi_pagesize
;
2933 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2936 if (!parameters
->options().nmagic()
2937 && !parameters
->options().omagic())
2938 off
= align_file_offset(off
, addr
, abi_pagesize
);
2939 else if (load_seg
== NULL
)
2941 // This is -N or -n with a section script which prevents
2942 // us from using a load segment. We need to ensure that
2943 // the file offset is aligned to the alignment of the
2944 // segment. This is because the linker script
2945 // implicitly assumed a zero offset. If we don't align
2946 // here, then the alignment of the sections in the
2947 // linker script may not match the alignment of the
2948 // sections in the set_section_addresses call below,
2949 // causing an error about dot moving backward.
2950 off
= align_address(off
, (*p
)->maximum_alignment());
2953 unsigned int shndx_hold
= *pshndx
;
2954 bool has_relro
= false;
2955 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
2960 // Now that we know the size of this segment, we may be able
2961 // to save a page in memory, at the cost of wasting some
2962 // file space, by instead aligning to the start of a new
2963 // page. Here we use the real machine page size rather than
2964 // the ABI mandated page size. If the segment has been
2965 // aligned so that the relro data ends at a page boundary,
2966 // we do not try to realign it.
2968 if (!are_addresses_set
2970 && aligned_addr
!= addr
2971 && !parameters
->incremental())
2973 uint64_t first_off
= (common_pagesize
2975 & (common_pagesize
- 1)));
2976 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
2979 && ((aligned_addr
& ~ (common_pagesize
- 1))
2980 != (new_addr
& ~ (common_pagesize
- 1)))
2981 && first_off
+ last_off
<= common_pagesize
)
2983 *pshndx
= shndx_hold
;
2984 addr
= align_address(aligned_addr
, common_pagesize
);
2985 addr
= align_address(addr
, (*p
)->maximum_alignment());
2986 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2987 off
= align_file_offset(off
, addr
, abi_pagesize
);
2989 increase_relro
= this->increase_relro_
;
2990 if (this->script_options_
->saw_sections_clause())
2994 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
3003 // Implement --check-sections. We know that the segments
3004 // are sorted by LMA.
3005 if (check_sections
&& last_load_segment
!= NULL
)
3007 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
3008 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3011 unsigned long long lb1
= last_load_segment
->paddr();
3012 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3013 unsigned long long lb2
= (*p
)->paddr();
3014 unsigned long long le2
= lb2
+ (*p
)->memsz();
3015 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3016 "[0x%llx -> 0x%llx]"),
3017 lb1
, le1
, lb2
, le2
);
3020 last_load_segment
= *p
;
3024 // Handle the non-PT_LOAD segments, setting their offsets from their
3025 // section's offsets.
3026 for (Segment_list::iterator p
= this->segment_list_
.begin();
3027 p
!= this->segment_list_
.end();
3030 if ((*p
)->type() != elfcpp::PT_LOAD
)
3031 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3036 // Set the TLS offsets for each section in the PT_TLS segment.
3037 if (this->tls_segment_
!= NULL
)
3038 this->tls_segment_
->set_tls_offsets();
3043 // Set the offsets of all the allocated sections when doing a
3044 // relocatable link. This does the same jobs as set_segment_offsets,
3045 // only for a relocatable link.
3048 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3049 unsigned int* pshndx
)
3053 file_header
->set_address_and_file_offset(0, 0);
3054 off
+= file_header
->data_size();
3056 for (Section_list::iterator p
= this->section_list_
.begin();
3057 p
!= this->section_list_
.end();
3060 // We skip unallocated sections here, except that group sections
3061 // have to come first.
3062 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3063 && (*p
)->type() != elfcpp::SHT_GROUP
)
3066 off
= align_address(off
, (*p
)->addralign());
3068 // The linker script might have set the address.
3069 if (!(*p
)->is_address_valid())
3070 (*p
)->set_address(0);
3071 (*p
)->set_file_offset(off
);
3072 (*p
)->finalize_data_size();
3073 off
+= (*p
)->data_size();
3075 (*p
)->set_out_shndx(*pshndx
);
3082 // Set the file offset of all the sections not associated with a
3086 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3088 off_t startoff
= off
;
3091 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3092 p
!= this->unattached_section_list_
.end();
3095 // The symtab section is handled in create_symtab_sections.
3096 if (*p
== this->symtab_section_
)
3099 // If we've already set the data size, don't set it again.
3100 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3103 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3104 && (*p
)->requires_postprocessing())
3106 (*p
)->create_postprocessing_buffer();
3107 this->any_postprocessing_sections_
= true;
3110 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3111 && (*p
)->after_input_sections())
3113 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3114 && (!(*p
)->after_input_sections()
3115 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3117 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3118 && (!(*p
)->after_input_sections()
3119 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3122 if (!parameters
->incremental_update())
3124 off
= align_address(off
, (*p
)->addralign());
3125 (*p
)->set_file_offset(off
);
3126 (*p
)->finalize_data_size();
3130 // Incremental update: allocate file space from free list.
3131 (*p
)->pre_finalize_data_size();
3132 off_t current_size
= (*p
)->current_data_size();
3133 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3136 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3137 this->free_list_
.dump();
3138 gold_assert((*p
)->output_section() != NULL
);
3139 gold_fallback(_("out of patch space for section %s; "
3140 "relink with --incremental-full"),
3141 (*p
)->output_section()->name());
3143 (*p
)->set_file_offset(off
);
3144 (*p
)->finalize_data_size();
3145 if ((*p
)->data_size() > current_size
)
3147 gold_assert((*p
)->output_section() != NULL
);
3148 gold_fallback(_("%s: section changed size; "
3149 "relink with --incremental-full"),
3150 (*p
)->output_section()->name());
3152 gold_debug(DEBUG_INCREMENTAL
,
3153 "set_section_offsets: %08lx %08lx %s",
3154 static_cast<long>(off
),
3155 static_cast<long>((*p
)->data_size()),
3156 ((*p
)->output_section() != NULL
3157 ? (*p
)->output_section()->name() : "(special)"));
3160 off
+= (*p
)->data_size();
3164 // At this point the name must be set.
3165 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3166 this->namepool_
.add((*p
)->name(), false, NULL
);
3171 // Set the section indexes of all the sections not associated with a
3175 Layout::set_section_indexes(unsigned int shndx
)
3177 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3178 p
!= this->unattached_section_list_
.end();
3181 if (!(*p
)->has_out_shndx())
3183 (*p
)->set_out_shndx(shndx
);
3190 // Set the section addresses according to the linker script. This is
3191 // only called when we see a SECTIONS clause. This returns the
3192 // program segment which should hold the file header and segment
3193 // headers, if any. It will return NULL if they should not be in a
3197 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3199 Script_sections
* ss
= this->script_options_
->script_sections();
3200 gold_assert(ss
->saw_sections_clause());
3201 return this->script_options_
->set_section_addresses(symtab
, this);
3204 // Place the orphan sections in the linker script.
3207 Layout::place_orphan_sections_in_script()
3209 Script_sections
* ss
= this->script_options_
->script_sections();
3210 gold_assert(ss
->saw_sections_clause());
3212 // Place each orphaned output section in the script.
3213 for (Section_list::iterator p
= this->section_list_
.begin();
3214 p
!= this->section_list_
.end();
3217 if (!(*p
)->found_in_sections_clause())
3218 ss
->place_orphan(*p
);
3222 // Count the local symbols in the regular symbol table and the dynamic
3223 // symbol table, and build the respective string pools.
3226 Layout::count_local_symbols(const Task
* task
,
3227 const Input_objects
* input_objects
)
3229 // First, figure out an upper bound on the number of symbols we'll
3230 // be inserting into each pool. This helps us create the pools with
3231 // the right size, to avoid unnecessary hashtable resizing.
3232 unsigned int symbol_count
= 0;
3233 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3234 p
!= input_objects
->relobj_end();
3236 symbol_count
+= (*p
)->local_symbol_count();
3238 // Go from "upper bound" to "estimate." We overcount for two
3239 // reasons: we double-count symbols that occur in more than one
3240 // object file, and we count symbols that are dropped from the
3241 // output. Add it all together and assume we overcount by 100%.
3244 // We assume all symbols will go into both the sympool and dynpool.
3245 this->sympool_
.reserve(symbol_count
);
3246 this->dynpool_
.reserve(symbol_count
);
3248 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3249 p
!= input_objects
->relobj_end();
3252 Task_lock_obj
<Object
> tlo(task
, *p
);
3253 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3257 // Create the symbol table sections. Here we also set the final
3258 // values of the symbols. At this point all the loadable sections are
3259 // fully laid out. SHNUM is the number of sections so far.
3262 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3263 Symbol_table
* symtab
,
3269 if (parameters
->target().get_size() == 32)
3271 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3274 else if (parameters
->target().get_size() == 64)
3276 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3282 // Compute file offsets relative to the start of the symtab section.
3285 // Save space for the dummy symbol at the start of the section. We
3286 // never bother to write this out--it will just be left as zero.
3288 unsigned int local_symbol_index
= 1;
3290 // Add STT_SECTION symbols for each Output section which needs one.
3291 for (Section_list::iterator p
= this->section_list_
.begin();
3292 p
!= this->section_list_
.end();
3295 if (!(*p
)->needs_symtab_index())
3296 (*p
)->set_symtab_index(-1U);
3299 (*p
)->set_symtab_index(local_symbol_index
);
3300 ++local_symbol_index
;
3305 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3306 p
!= input_objects
->relobj_end();
3309 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3311 off
+= (index
- local_symbol_index
) * symsize
;
3312 local_symbol_index
= index
;
3315 unsigned int local_symcount
= local_symbol_index
;
3316 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3319 size_t dyn_global_index
;
3321 if (this->dynsym_section_
== NULL
)
3324 dyn_global_index
= 0;
3329 dyn_global_index
= this->dynsym_section_
->info();
3330 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3331 dynoff
= this->dynsym_section_
->offset() + locsize
;
3332 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3333 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3334 == this->dynsym_section_
->data_size() - locsize
);
3337 off_t global_off
= off
;
3338 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3339 &this->sympool_
, &local_symcount
);
3341 if (!parameters
->options().strip_all())
3343 this->sympool_
.set_string_offsets();
3345 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3346 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3350 this->symtab_section_
= osymtab
;
3352 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3354 osymtab
->add_output_section_data(pos
);
3356 // We generate a .symtab_shndx section if we have more than
3357 // SHN_LORESERVE sections. Technically it is possible that we
3358 // don't need one, because it is possible that there are no
3359 // symbols in any of sections with indexes larger than
3360 // SHN_LORESERVE. That is probably unusual, though, and it is
3361 // easier to always create one than to compute section indexes
3362 // twice (once here, once when writing out the symbols).
3363 if (shnum
>= elfcpp::SHN_LORESERVE
)
3365 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3367 Output_section
* osymtab_xindex
=
3368 this->make_output_section(symtab_xindex_name
,
3369 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3370 ORDER_INVALID
, false);
3372 size_t symcount
= off
/ symsize
;
3373 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3375 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3377 osymtab_xindex
->set_link_section(osymtab
);
3378 osymtab_xindex
->set_addralign(4);
3379 osymtab_xindex
->set_entsize(4);
3381 osymtab_xindex
->set_after_input_sections();
3383 // This tells the driver code to wait until the symbol table
3384 // has written out before writing out the postprocessing
3385 // sections, including the .symtab_shndx section.
3386 this->any_postprocessing_sections_
= true;
3389 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3390 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3395 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3396 ostrtab
->add_output_section_data(pstr
);
3399 if (!parameters
->incremental_update())
3400 symtab_off
= align_address(*poff
, align
);
3403 symtab_off
= this->allocate(off
, align
, *poff
);
3405 gold_fallback(_("out of patch space for symbol table; "
3406 "relink with --incremental-full"));
3407 gold_debug(DEBUG_INCREMENTAL
,
3408 "create_symtab_sections: %08lx %08lx .symtab",
3409 static_cast<long>(symtab_off
),
3410 static_cast<long>(off
));
3413 symtab
->set_file_offset(symtab_off
+ global_off
);
3414 osymtab
->set_file_offset(symtab_off
);
3415 osymtab
->finalize_data_size();
3416 osymtab
->set_link_section(ostrtab
);
3417 osymtab
->set_info(local_symcount
);
3418 osymtab
->set_entsize(symsize
);
3420 if (symtab_off
+ off
> *poff
)
3421 *poff
= symtab_off
+ off
;
3425 // Create the .shstrtab section, which holds the names of the
3426 // sections. At the time this is called, we have created all the
3427 // output sections except .shstrtab itself.
3430 Layout::create_shstrtab()
3432 // FIXME: We don't need to create a .shstrtab section if we are
3433 // stripping everything.
3435 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
3437 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
3438 ORDER_INVALID
, false);
3440 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
3442 // We can't write out this section until we've set all the
3443 // section names, and we don't set the names of compressed
3444 // output sections until relocations are complete. FIXME: With
3445 // the current names we use, this is unnecessary.
3446 os
->set_after_input_sections();
3449 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
3450 os
->add_output_section_data(posd
);
3455 // Create the section headers. SIZE is 32 or 64. OFF is the file
3459 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
3461 Output_section_headers
* oshdrs
;
3462 oshdrs
= new Output_section_headers(this,
3463 &this->segment_list_
,
3464 &this->section_list_
,
3465 &this->unattached_section_list_
,
3469 if (!parameters
->incremental_update())
3470 off
= align_address(*poff
, oshdrs
->addralign());
3473 oshdrs
->pre_finalize_data_size();
3474 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
3476 gold_fallback(_("out of patch space for section header table; "
3477 "relink with --incremental-full"));
3478 gold_debug(DEBUG_INCREMENTAL
,
3479 "create_shdrs: %08lx %08lx (section header table)",
3480 static_cast<long>(off
),
3481 static_cast<long>(off
+ oshdrs
->data_size()));
3483 oshdrs
->set_address_and_file_offset(0, off
);
3484 off
+= oshdrs
->data_size();
3487 this->section_headers_
= oshdrs
;
3490 // Count the allocated sections.
3493 Layout::allocated_output_section_count() const
3495 size_t section_count
= 0;
3496 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3497 p
!= this->segment_list_
.end();
3499 section_count
+= (*p
)->output_section_count();
3500 return section_count
;
3503 // Create the dynamic symbol table.
3506 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
3507 Symbol_table
* symtab
,
3508 Output_section
** pdynstr
,
3509 unsigned int* plocal_dynamic_count
,
3510 std::vector
<Symbol
*>* pdynamic_symbols
,
3511 Versions
* pversions
)
3513 // Count all the symbols in the dynamic symbol table, and set the
3514 // dynamic symbol indexes.
3516 // Skip symbol 0, which is always all zeroes.
3517 unsigned int index
= 1;
3519 // Add STT_SECTION symbols for each Output section which needs one.
3520 for (Section_list::iterator p
= this->section_list_
.begin();
3521 p
!= this->section_list_
.end();
3524 if (!(*p
)->needs_dynsym_index())
3525 (*p
)->set_dynsym_index(-1U);
3528 (*p
)->set_dynsym_index(index
);
3533 // Count the local symbols that need to go in the dynamic symbol table,
3534 // and set the dynamic symbol indexes.
3535 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3536 p
!= input_objects
->relobj_end();
3539 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
3543 unsigned int local_symcount
= index
;
3544 *plocal_dynamic_count
= local_symcount
;
3546 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
3547 &this->dynpool_
, pversions
);
3551 const int size
= parameters
->target().get_size();
3554 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3557 else if (size
== 64)
3559 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3565 // Create the dynamic symbol table section.
3567 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
3571 ORDER_DYNAMIC_LINKER
,
3574 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
3577 dynsym
->add_output_section_data(odata
);
3579 dynsym
->set_info(local_symcount
);
3580 dynsym
->set_entsize(symsize
);
3581 dynsym
->set_addralign(align
);
3583 this->dynsym_section_
= dynsym
;
3585 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3586 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
3587 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
3589 // If there are more than SHN_LORESERVE allocated sections, we
3590 // create a .dynsym_shndx section. It is possible that we don't
3591 // need one, because it is possible that there are no dynamic
3592 // symbols in any of the sections with indexes larger than
3593 // SHN_LORESERVE. This is probably unusual, though, and at this
3594 // time we don't know the actual section indexes so it is
3595 // inconvenient to check.
3596 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
3598 Output_section
* dynsym_xindex
=
3599 this->choose_output_section(NULL
, ".dynsym_shndx",
3600 elfcpp::SHT_SYMTAB_SHNDX
,
3602 false, ORDER_DYNAMIC_LINKER
, false);
3604 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
3606 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
3608 dynsym_xindex
->set_link_section(dynsym
);
3609 dynsym_xindex
->set_addralign(4);
3610 dynsym_xindex
->set_entsize(4);
3612 dynsym_xindex
->set_after_input_sections();
3614 // This tells the driver code to wait until the symbol table has
3615 // written out before writing out the postprocessing sections,
3616 // including the .dynsym_shndx section.
3617 this->any_postprocessing_sections_
= true;
3620 // Create the dynamic string table section.
3622 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
3626 ORDER_DYNAMIC_LINKER
,
3629 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
3630 dynstr
->add_output_section_data(strdata
);
3632 dynsym
->set_link_section(dynstr
);
3633 this->dynamic_section_
->set_link_section(dynstr
);
3635 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
3636 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
3640 // Create the hash tables.
3642 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
3643 || strcmp(parameters
->options().hash_style(), "both") == 0)
3645 unsigned char* phash
;
3646 unsigned int hashlen
;
3647 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
3650 Output_section
* hashsec
=
3651 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
3652 elfcpp::SHF_ALLOC
, false,
3653 ORDER_DYNAMIC_LINKER
, false);
3655 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3659 hashsec
->add_output_section_data(hashdata
);
3661 hashsec
->set_link_section(dynsym
);
3662 hashsec
->set_entsize(4);
3664 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
3667 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
3668 || strcmp(parameters
->options().hash_style(), "both") == 0)
3670 unsigned char* phash
;
3671 unsigned int hashlen
;
3672 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
3675 Output_section
* hashsec
=
3676 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
3677 elfcpp::SHF_ALLOC
, false,
3678 ORDER_DYNAMIC_LINKER
, false);
3680 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3684 hashsec
->add_output_section_data(hashdata
);
3686 hashsec
->set_link_section(dynsym
);
3688 // For a 64-bit target, the entries in .gnu.hash do not have a
3689 // uniform size, so we only set the entry size for a 32-bit
3691 if (parameters
->target().get_size() == 32)
3692 hashsec
->set_entsize(4);
3694 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
3698 // Assign offsets to each local portion of the dynamic symbol table.
3701 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
3703 Output_section
* dynsym
= this->dynsym_section_
;
3704 gold_assert(dynsym
!= NULL
);
3706 off_t off
= dynsym
->offset();
3708 // Skip the dummy symbol at the start of the section.
3709 off
+= dynsym
->entsize();
3711 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3712 p
!= input_objects
->relobj_end();
3715 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
3716 off
+= count
* dynsym
->entsize();
3720 // Create the version sections.
3723 Layout::create_version_sections(const Versions
* versions
,
3724 const Symbol_table
* symtab
,
3725 unsigned int local_symcount
,
3726 const std::vector
<Symbol
*>& dynamic_symbols
,
3727 const Output_section
* dynstr
)
3729 if (!versions
->any_defs() && !versions
->any_needs())
3732 switch (parameters
->size_and_endianness())
3734 #ifdef HAVE_TARGET_32_LITTLE
3735 case Parameters::TARGET_32_LITTLE
:
3736 this->sized_create_version_sections
<32, false>(versions
, symtab
,
3738 dynamic_symbols
, dynstr
);
3741 #ifdef HAVE_TARGET_32_BIG
3742 case Parameters::TARGET_32_BIG
:
3743 this->sized_create_version_sections
<32, true>(versions
, symtab
,
3745 dynamic_symbols
, dynstr
);
3748 #ifdef HAVE_TARGET_64_LITTLE
3749 case Parameters::TARGET_64_LITTLE
:
3750 this->sized_create_version_sections
<64, false>(versions
, symtab
,
3752 dynamic_symbols
, dynstr
);
3755 #ifdef HAVE_TARGET_64_BIG
3756 case Parameters::TARGET_64_BIG
:
3757 this->sized_create_version_sections
<64, true>(versions
, symtab
,
3759 dynamic_symbols
, dynstr
);
3767 // Create the version sections, sized version.
3769 template<int size
, bool big_endian
>
3771 Layout::sized_create_version_sections(
3772 const Versions
* versions
,
3773 const Symbol_table
* symtab
,
3774 unsigned int local_symcount
,
3775 const std::vector
<Symbol
*>& dynamic_symbols
,
3776 const Output_section
* dynstr
)
3778 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
3779 elfcpp::SHT_GNU_versym
,
3782 ORDER_DYNAMIC_LINKER
,
3785 unsigned char* vbuf
;
3787 versions
->symbol_section_contents
<size
, big_endian
>(symtab
, &this->dynpool_
,
3792 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
3795 vsec
->add_output_section_data(vdata
);
3796 vsec
->set_entsize(2);
3797 vsec
->set_link_section(this->dynsym_section_
);
3799 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3800 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
3802 if (versions
->any_defs())
3804 Output_section
* vdsec
;
3805 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
3806 elfcpp::SHT_GNU_verdef
,
3808 false, ORDER_DYNAMIC_LINKER
, false);
3810 unsigned char* vdbuf
;
3811 unsigned int vdsize
;
3812 unsigned int vdentries
;
3813 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
, &vdbuf
,
3814 &vdsize
, &vdentries
);
3816 Output_section_data
* vddata
=
3817 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
3819 vdsec
->add_output_section_data(vddata
);
3820 vdsec
->set_link_section(dynstr
);
3821 vdsec
->set_info(vdentries
);
3823 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
3824 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
3827 if (versions
->any_needs())
3829 Output_section
* vnsec
;
3830 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
3831 elfcpp::SHT_GNU_verneed
,
3833 false, ORDER_DYNAMIC_LINKER
, false);
3835 unsigned char* vnbuf
;
3836 unsigned int vnsize
;
3837 unsigned int vnentries
;
3838 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
3842 Output_section_data
* vndata
=
3843 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
3845 vnsec
->add_output_section_data(vndata
);
3846 vnsec
->set_link_section(dynstr
);
3847 vnsec
->set_info(vnentries
);
3849 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
3850 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
3854 // Create the .interp section and PT_INTERP segment.
3857 Layout::create_interp(const Target
* target
)
3859 gold_assert(this->interp_segment_
== NULL
);
3861 const char* interp
= parameters
->options().dynamic_linker();
3864 interp
= target
->dynamic_linker();
3865 gold_assert(interp
!= NULL
);
3868 size_t len
= strlen(interp
) + 1;
3870 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
3872 Output_section
* osec
;
3874 // If we are using a SECTIONS clause, let it decide where the
3875 // .interp section should go. Otherwise always create a new section
3876 // so that this .interp section does not get confused with any
3877 // section of the same name in the program.
3878 if (this->script_options_
->saw_sections_clause())
3879 osec
= this->choose_output_section(NULL
, ".interp", elfcpp::SHT_PROGBITS
,
3880 elfcpp::SHF_ALLOC
, false, ORDER_INTERP
,
3884 const char* n
= this->namepool_
.add("interp", false, NULL
);
3885 osec
= this->make_output_section(n
, elfcpp::SHT_PROGBITS
,
3886 elfcpp::SHF_ALLOC
, ORDER_INTERP
, false);
3889 osec
->add_output_section_data(odata
);
3891 if (!this->script_options_
->saw_phdrs_clause())
3893 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_INTERP
,
3895 oseg
->add_output_section_to_nonload(osec
, elfcpp::PF_R
);
3899 // Add dynamic tags for the PLT and the dynamic relocs. This is
3900 // called by the target-specific code. This does nothing if not doing
3903 // USE_REL is true for REL relocs rather than RELA relocs.
3905 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3907 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3908 // and we also set DT_PLTREL. We use PLT_REL's output section, since
3909 // some targets have multiple reloc sections in PLT_REL.
3911 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3912 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3914 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3918 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
3919 const Output_data
* plt_rel
,
3920 const Output_data_reloc_generic
* dyn_rel
,
3921 bool add_debug
, bool dynrel_includes_plt
)
3923 Output_data_dynamic
* odyn
= this->dynamic_data_
;
3927 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
3928 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
3930 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
3932 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
3933 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
3934 odyn
->add_constant(elfcpp::DT_PLTREL
,
3935 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
3938 if (dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
3940 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
3942 if (plt_rel
!= NULL
&& dynrel_includes_plt
)
3943 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3946 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3948 const int size
= parameters
->target().get_size();
3953 rel_tag
= elfcpp::DT_RELENT
;
3955 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
3956 else if (size
== 64)
3957 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
3963 rel_tag
= elfcpp::DT_RELAENT
;
3965 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
3966 else if (size
== 64)
3967 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
3971 odyn
->add_constant(rel_tag
, rel_size
);
3973 if (parameters
->options().combreloc())
3975 size_t c
= dyn_rel
->relative_reloc_count();
3977 odyn
->add_constant((use_rel
3978 ? elfcpp::DT_RELCOUNT
3979 : elfcpp::DT_RELACOUNT
),
3984 if (add_debug
&& !parameters
->options().shared())
3986 // The value of the DT_DEBUG tag is filled in by the dynamic
3987 // linker at run time, and used by the debugger.
3988 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
3992 // Finish the .dynamic section and PT_DYNAMIC segment.
3995 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
3996 const Symbol_table
* symtab
)
3998 if (!this->script_options_
->saw_phdrs_clause())
4000 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
4003 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
4004 elfcpp::PF_R
| elfcpp::PF_W
);
4007 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4009 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
4010 p
!= input_objects
->dynobj_end();
4013 if (!(*p
)->is_needed() && (*p
)->as_needed())
4015 // This dynamic object was linked with --as-needed, but it
4020 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4023 if (parameters
->options().shared())
4025 const char* soname
= parameters
->options().soname();
4027 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4030 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4031 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4032 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4034 sym
= symtab
->lookup(parameters
->options().fini());
4035 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4036 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4038 // Look for .init_array, .preinit_array and .fini_array by checking
4040 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4041 p
!= this->section_list_
.end();
4043 switch((*p
)->type())
4045 case elfcpp::SHT_FINI_ARRAY
:
4046 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4047 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4049 case elfcpp::SHT_INIT_ARRAY
:
4050 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4051 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4053 case elfcpp::SHT_PREINIT_ARRAY
:
4054 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4055 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4061 // Add a DT_RPATH entry if needed.
4062 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4065 std::string rpath_val
;
4066 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4070 if (rpath_val
.empty())
4071 rpath_val
= p
->name();
4074 // Eliminate duplicates.
4075 General_options::Dir_list::const_iterator q
;
4076 for (q
= rpath
.begin(); q
!= p
; ++q
)
4077 if (q
->name() == p
->name())
4082 rpath_val
+= p
->name();
4087 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4088 if (parameters
->options().enable_new_dtags())
4089 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4092 // Look for text segments that have dynamic relocations.
4093 bool have_textrel
= false;
4094 if (!this->script_options_
->saw_sections_clause())
4096 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4097 p
!= this->segment_list_
.end();
4100 if (((*p
)->flags() & elfcpp::PF_W
) == 0
4101 && (*p
)->has_dynamic_reloc())
4103 have_textrel
= true;
4110 // We don't know the section -> segment mapping, so we are
4111 // conservative and just look for readonly sections with
4112 // relocations. If those sections wind up in writable segments,
4113 // then we have created an unnecessary DT_TEXTREL entry.
4114 for (Section_list::const_iterator p
= this->section_list_
.begin();
4115 p
!= this->section_list_
.end();
4118 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4119 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4120 && ((*p
)->has_dynamic_reloc()))
4122 have_textrel
= true;
4128 // Add a DT_FLAGS entry. We add it even if no flags are set so that
4129 // post-link tools can easily modify these flags if desired.
4130 unsigned int flags
= 0;
4133 // Add a DT_TEXTREL for compatibility with older loaders.
4134 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4135 flags
|= elfcpp::DF_TEXTREL
;
4137 if (parameters
->options().text())
4138 gold_error(_("read-only segment has dynamic relocations"));
4139 else if (parameters
->options().warn_shared_textrel()
4140 && parameters
->options().shared())
4141 gold_warning(_("shared library text segment is not shareable"));
4143 if (parameters
->options().shared() && this->has_static_tls())
4144 flags
|= elfcpp::DF_STATIC_TLS
;
4145 if (parameters
->options().origin())
4146 flags
|= elfcpp::DF_ORIGIN
;
4147 if (parameters
->options().Bsymbolic())
4149 flags
|= elfcpp::DF_SYMBOLIC
;
4150 // Add DT_SYMBOLIC for compatibility with older loaders.
4151 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4153 if (parameters
->options().now())
4154 flags
|= elfcpp::DF_BIND_NOW
;
4155 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4158 if (parameters
->options().initfirst())
4159 flags
|= elfcpp::DF_1_INITFIRST
;
4160 if (parameters
->options().interpose())
4161 flags
|= elfcpp::DF_1_INTERPOSE
;
4162 if (parameters
->options().loadfltr())
4163 flags
|= elfcpp::DF_1_LOADFLTR
;
4164 if (parameters
->options().nodefaultlib())
4165 flags
|= elfcpp::DF_1_NODEFLIB
;
4166 if (parameters
->options().nodelete())
4167 flags
|= elfcpp::DF_1_NODELETE
;
4168 if (parameters
->options().nodlopen())
4169 flags
|= elfcpp::DF_1_NOOPEN
;
4170 if (parameters
->options().nodump())
4171 flags
|= elfcpp::DF_1_NODUMP
;
4172 if (!parameters
->options().shared())
4173 flags
&= ~(elfcpp::DF_1_INITFIRST
4174 | elfcpp::DF_1_NODELETE
4175 | elfcpp::DF_1_NOOPEN
);
4176 if (parameters
->options().origin())
4177 flags
|= elfcpp::DF_1_ORIGIN
;
4178 if (parameters
->options().now())
4179 flags
|= elfcpp::DF_1_NOW
;
4181 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4184 // Set the size of the _DYNAMIC symbol table to be the size of the
4188 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4190 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4191 odyn
->finalize_data_size();
4192 off_t data_size
= odyn
->data_size();
4193 const int size
= parameters
->target().get_size();
4195 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4196 else if (size
== 64)
4197 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4202 // The mapping of input section name prefixes to output section names.
4203 // In some cases one prefix is itself a prefix of another prefix; in
4204 // such a case the longer prefix must come first. These prefixes are
4205 // based on the GNU linker default ELF linker script.
4207 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4208 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4210 MAPPING_INIT(".text.", ".text"),
4211 MAPPING_INIT(".ctors.", ".ctors"),
4212 MAPPING_INIT(".dtors.", ".dtors"),
4213 MAPPING_INIT(".rodata.", ".rodata"),
4214 MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
4215 MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
4216 MAPPING_INIT(".data.", ".data"),
4217 MAPPING_INIT(".bss.", ".bss"),
4218 MAPPING_INIT(".tdata.", ".tdata"),
4219 MAPPING_INIT(".tbss.", ".tbss"),
4220 MAPPING_INIT(".init_array.", ".init_array"),
4221 MAPPING_INIT(".fini_array.", ".fini_array"),
4222 MAPPING_INIT(".sdata.", ".sdata"),
4223 MAPPING_INIT(".sbss.", ".sbss"),
4224 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4225 // differently depending on whether it is creating a shared library.
4226 MAPPING_INIT(".sdata2.", ".sdata"),
4227 MAPPING_INIT(".sbss2.", ".sbss"),
4228 MAPPING_INIT(".lrodata.", ".lrodata"),
4229 MAPPING_INIT(".ldata.", ".ldata"),
4230 MAPPING_INIT(".lbss.", ".lbss"),
4231 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4232 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4233 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4234 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4235 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4236 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4237 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4238 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4239 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4240 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4241 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4242 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4243 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4244 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4245 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4246 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4247 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4248 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4249 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4250 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4251 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4255 const int Layout::section_name_mapping_count
=
4256 (sizeof(Layout::section_name_mapping
)
4257 / sizeof(Layout::section_name_mapping
[0]));
4259 // Choose the output section name to use given an input section name.
4260 // Set *PLEN to the length of the name. *PLEN is initialized to the
4264 Layout::output_section_name(const char* name
, size_t* plen
)
4266 // gcc 4.3 generates the following sorts of section names when it
4267 // needs a section name specific to a function:
4273 // .data.rel.local.FN
4275 // .data.rel.ro.local.FN
4282 // The GNU linker maps all of those to the part before the .FN,
4283 // except that .data.rel.local.FN is mapped to .data, and
4284 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4285 // beginning with .data.rel.ro.local are grouped together.
4287 // For an anonymous namespace, the string FN can contain a '.'.
4289 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4290 // GNU linker maps to .rodata.
4292 // The .data.rel.ro sections are used with -z relro. The sections
4293 // are recognized by name. We use the same names that the GNU
4294 // linker does for these sections.
4296 // It is hard to handle this in a principled way, so we don't even
4297 // try. We use a table of mappings. If the input section name is
4298 // not found in the table, we simply use it as the output section
4301 const Section_name_mapping
* psnm
= section_name_mapping
;
4302 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4304 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4306 *plen
= psnm
->tolen
;
4314 // Check if a comdat group or .gnu.linkonce section with the given
4315 // NAME is selected for the link. If there is already a section,
4316 // *KEPT_SECTION is set to point to the existing section and the
4317 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4318 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4319 // *KEPT_SECTION is set to the internal copy and the function returns
4323 Layout::find_or_add_kept_section(const std::string
& name
,
4328 Kept_section
** kept_section
)
4330 // It's normal to see a couple of entries here, for the x86 thunk
4331 // sections. If we see more than a few, we're linking a C++
4332 // program, and we resize to get more space to minimize rehashing.
4333 if (this->signatures_
.size() > 4
4334 && !this->resized_signatures_
)
4336 reserve_unordered_map(&this->signatures_
,
4337 this->number_of_input_files_
* 64);
4338 this->resized_signatures_
= true;
4341 Kept_section candidate
;
4342 std::pair
<Signatures::iterator
, bool> ins
=
4343 this->signatures_
.insert(std::make_pair(name
, candidate
));
4345 if (kept_section
!= NULL
)
4346 *kept_section
= &ins
.first
->second
;
4349 // This is the first time we've seen this signature.
4350 ins
.first
->second
.set_object(object
);
4351 ins
.first
->second
.set_shndx(shndx
);
4353 ins
.first
->second
.set_is_comdat();
4355 ins
.first
->second
.set_is_group_name();
4359 // We have already seen this signature.
4361 if (ins
.first
->second
.is_group_name())
4363 // We've already seen a real section group with this signature.
4364 // If the kept group is from a plugin object, and we're in the
4365 // replacement phase, accept the new one as a replacement.
4366 if (ins
.first
->second
.object() == NULL
4367 && parameters
->options().plugins()->in_replacement_phase())
4369 ins
.first
->second
.set_object(object
);
4370 ins
.first
->second
.set_shndx(shndx
);
4375 else if (is_group_name
)
4377 // This is a real section group, and we've already seen a
4378 // linkonce section with this signature. Record that we've seen
4379 // a section group, and don't include this section group.
4380 ins
.first
->second
.set_is_group_name();
4385 // We've already seen a linkonce section and this is a linkonce
4386 // section. These don't block each other--this may be the same
4387 // symbol name with different section types.
4392 // Store the allocated sections into the section list.
4395 Layout::get_allocated_sections(Section_list
* section_list
) const
4397 for (Section_list::const_iterator p
= this->section_list_
.begin();
4398 p
!= this->section_list_
.end();
4400 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
4401 section_list
->push_back(*p
);
4404 // Create an output segment.
4407 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
4409 gold_assert(!parameters
->options().relocatable());
4410 Output_segment
* oseg
= new Output_segment(type
, flags
);
4411 this->segment_list_
.push_back(oseg
);
4413 if (type
== elfcpp::PT_TLS
)
4414 this->tls_segment_
= oseg
;
4415 else if (type
== elfcpp::PT_GNU_RELRO
)
4416 this->relro_segment_
= oseg
;
4417 else if (type
== elfcpp::PT_INTERP
)
4418 this->interp_segment_
= oseg
;
4423 // Return the file offset of the normal symbol table.
4426 Layout::symtab_section_offset() const
4428 if (this->symtab_section_
!= NULL
)
4429 return this->symtab_section_
->offset();
4433 // Write out the Output_sections. Most won't have anything to write,
4434 // since most of the data will come from input sections which are
4435 // handled elsewhere. But some Output_sections do have Output_data.
4438 Layout::write_output_sections(Output_file
* of
) const
4440 for (Section_list::const_iterator p
= this->section_list_
.begin();
4441 p
!= this->section_list_
.end();
4444 if (!(*p
)->after_input_sections())
4449 // Write out data not associated with a section or the symbol table.
4452 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
4454 if (!parameters
->options().strip_all())
4456 const Output_section
* symtab_section
= this->symtab_section_
;
4457 for (Section_list::const_iterator p
= this->section_list_
.begin();
4458 p
!= this->section_list_
.end();
4461 if ((*p
)->needs_symtab_index())
4463 gold_assert(symtab_section
!= NULL
);
4464 unsigned int index
= (*p
)->symtab_index();
4465 gold_assert(index
> 0 && index
!= -1U);
4466 off_t off
= (symtab_section
->offset()
4467 + index
* symtab_section
->entsize());
4468 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
4473 const Output_section
* dynsym_section
= this->dynsym_section_
;
4474 for (Section_list::const_iterator p
= this->section_list_
.begin();
4475 p
!= this->section_list_
.end();
4478 if ((*p
)->needs_dynsym_index())
4480 gold_assert(dynsym_section
!= NULL
);
4481 unsigned int index
= (*p
)->dynsym_index();
4482 gold_assert(index
> 0 && index
!= -1U);
4483 off_t off
= (dynsym_section
->offset()
4484 + index
* dynsym_section
->entsize());
4485 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
4489 // Write out the Output_data which are not in an Output_section.
4490 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
4491 p
!= this->special_output_list_
.end();
4496 // Write out the Output_sections which can only be written after the
4497 // input sections are complete.
4500 Layout::write_sections_after_input_sections(Output_file
* of
)
4502 // Determine the final section offsets, and thus the final output
4503 // file size. Note we finalize the .shstrab last, to allow the
4504 // after_input_section sections to modify their section-names before
4506 if (this->any_postprocessing_sections_
)
4508 off_t off
= this->output_file_size_
;
4509 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
4511 // Now that we've finalized the names, we can finalize the shstrab.
4513 this->set_section_offsets(off
,
4514 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
4516 if (off
> this->output_file_size_
)
4519 this->output_file_size_
= off
;
4523 for (Section_list::const_iterator p
= this->section_list_
.begin();
4524 p
!= this->section_list_
.end();
4527 if ((*p
)->after_input_sections())
4531 this->section_headers_
->write(of
);
4534 // If the build ID requires computing a checksum, do so here, and
4535 // write it out. We compute a checksum over the entire file because
4536 // that is simplest.
4539 Layout::write_build_id(Output_file
* of
) const
4541 if (this->build_id_note_
== NULL
)
4544 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
4546 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
4547 this->build_id_note_
->data_size());
4549 const char* style
= parameters
->options().build_id();
4550 if (strcmp(style
, "sha1") == 0)
4553 sha1_init_ctx(&ctx
);
4554 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
4555 sha1_finish_ctx(&ctx
, ov
);
4557 else if (strcmp(style
, "md5") == 0)
4561 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
4562 md5_finish_ctx(&ctx
, ov
);
4567 of
->write_output_view(this->build_id_note_
->offset(),
4568 this->build_id_note_
->data_size(),
4571 of
->free_input_view(0, this->output_file_size_
, iv
);
4574 // Write out a binary file. This is called after the link is
4575 // complete. IN is the temporary output file we used to generate the
4576 // ELF code. We simply walk through the segments, read them from
4577 // their file offset in IN, and write them to their load address in
4578 // the output file. FIXME: with a bit more work, we could support
4579 // S-records and/or Intel hex format here.
4582 Layout::write_binary(Output_file
* in
) const
4584 gold_assert(parameters
->options().oformat_enum()
4585 == General_options::OBJECT_FORMAT_BINARY
);
4587 // Get the size of the binary file.
4588 uint64_t max_load_address
= 0;
4589 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4590 p
!= this->segment_list_
.end();
4593 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4595 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
4596 if (max_paddr
> max_load_address
)
4597 max_load_address
= max_paddr
;
4601 Output_file
out(parameters
->options().output_file_name());
4602 out
.open(max_load_address
);
4604 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4605 p
!= this->segment_list_
.end();
4608 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4610 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
4612 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
4614 memcpy(vout
, vin
, (*p
)->filesz());
4615 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
4616 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
4623 // Print the output sections to the map file.
4626 Layout::print_to_mapfile(Mapfile
* mapfile
) const
4628 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4629 p
!= this->segment_list_
.end();
4631 (*p
)->print_sections_to_mapfile(mapfile
);
4634 // Print statistical information to stderr. This is used for --stats.
4637 Layout::print_stats() const
4639 this->namepool_
.print_stats("section name pool");
4640 this->sympool_
.print_stats("output symbol name pool");
4641 this->dynpool_
.print_stats("dynamic name pool");
4643 for (Section_list::const_iterator p
= this->section_list_
.begin();
4644 p
!= this->section_list_
.end();
4646 (*p
)->print_merge_stats();
4649 // Write_sections_task methods.
4651 // We can always run this task.
4654 Write_sections_task::is_runnable()
4659 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4663 Write_sections_task::locks(Task_locker
* tl
)
4665 tl
->add(this, this->output_sections_blocker_
);
4666 tl
->add(this, this->final_blocker_
);
4669 // Run the task--write out the data.
4672 Write_sections_task::run(Workqueue
*)
4674 this->layout_
->write_output_sections(this->of_
);
4677 // Write_data_task methods.
4679 // We can always run this task.
4682 Write_data_task::is_runnable()
4687 // We need to unlock FINAL_BLOCKER when finished.
4690 Write_data_task::locks(Task_locker
* tl
)
4692 tl
->add(this, this->final_blocker_
);
4695 // Run the task--write out the data.
4698 Write_data_task::run(Workqueue
*)
4700 this->layout_
->write_data(this->symtab_
, this->of_
);
4703 // Write_symbols_task methods.
4705 // We can always run this task.
4708 Write_symbols_task::is_runnable()
4713 // We need to unlock FINAL_BLOCKER when finished.
4716 Write_symbols_task::locks(Task_locker
* tl
)
4718 tl
->add(this, this->final_blocker_
);
4721 // Run the task--write out the symbols.
4724 Write_symbols_task::run(Workqueue
*)
4726 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
4727 this->layout_
->symtab_xindex(),
4728 this->layout_
->dynsym_xindex(), this->of_
);
4731 // Write_after_input_sections_task methods.
4733 // We can only run this task after the input sections have completed.
4736 Write_after_input_sections_task::is_runnable()
4738 if (this->input_sections_blocker_
->is_blocked())
4739 return this->input_sections_blocker_
;
4743 // We need to unlock FINAL_BLOCKER when finished.
4746 Write_after_input_sections_task::locks(Task_locker
* tl
)
4748 tl
->add(this, this->final_blocker_
);
4754 Write_after_input_sections_task::run(Workqueue
*)
4756 this->layout_
->write_sections_after_input_sections(this->of_
);
4759 // Close_task_runner methods.
4761 // Run the task--close the file.
4764 Close_task_runner::run(Workqueue
*, const Task
*)
4766 // If we need to compute a checksum for the BUILD if, we do so here.
4767 this->layout_
->write_build_id(this->of_
);
4769 // If we've been asked to create a binary file, we do so here.
4770 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
4771 this->layout_
->write_binary(this->of_
);
4776 // Instantiate the templates we need. We could use the configure
4777 // script to restrict this to only the ones for implemented targets.
4779 #ifdef HAVE_TARGET_32_LITTLE
4782 Layout::init_fixed_output_section
<32, false>(
4784 elfcpp::Shdr
<32, false>& shdr
);
4787 #ifdef HAVE_TARGET_32_BIG
4790 Layout::init_fixed_output_section
<32, true>(
4792 elfcpp::Shdr
<32, true>& shdr
);
4795 #ifdef HAVE_TARGET_64_LITTLE
4798 Layout::init_fixed_output_section
<64, false>(
4800 elfcpp::Shdr
<64, false>& shdr
);
4803 #ifdef HAVE_TARGET_64_BIG
4806 Layout::init_fixed_output_section
<64, true>(
4808 elfcpp::Shdr
<64, true>& shdr
);
4811 #ifdef HAVE_TARGET_32_LITTLE
4814 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
4817 const elfcpp::Shdr
<32, false>& shdr
,
4818 unsigned int, unsigned int, off_t
*);
4821 #ifdef HAVE_TARGET_32_BIG
4824 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
4827 const elfcpp::Shdr
<32, true>& shdr
,
4828 unsigned int, unsigned int, off_t
*);
4831 #ifdef HAVE_TARGET_64_LITTLE
4834 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
4837 const elfcpp::Shdr
<64, false>& shdr
,
4838 unsigned int, unsigned int, off_t
*);
4841 #ifdef HAVE_TARGET_64_BIG
4844 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
4847 const elfcpp::Shdr
<64, true>& shdr
,
4848 unsigned int, unsigned int, off_t
*);
4851 #ifdef HAVE_TARGET_32_LITTLE
4854 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
4855 unsigned int reloc_shndx
,
4856 const elfcpp::Shdr
<32, false>& shdr
,
4857 Output_section
* data_section
,
4858 Relocatable_relocs
* rr
);
4861 #ifdef HAVE_TARGET_32_BIG
4864 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
4865 unsigned int reloc_shndx
,
4866 const elfcpp::Shdr
<32, true>& shdr
,
4867 Output_section
* data_section
,
4868 Relocatable_relocs
* rr
);
4871 #ifdef HAVE_TARGET_64_LITTLE
4874 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
4875 unsigned int reloc_shndx
,
4876 const elfcpp::Shdr
<64, false>& shdr
,
4877 Output_section
* data_section
,
4878 Relocatable_relocs
* rr
);
4881 #ifdef HAVE_TARGET_64_BIG
4884 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
4885 unsigned int reloc_shndx
,
4886 const elfcpp::Shdr
<64, true>& shdr
,
4887 Output_section
* data_section
,
4888 Relocatable_relocs
* rr
);
4891 #ifdef HAVE_TARGET_32_LITTLE
4894 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
4895 Sized_relobj_file
<32, false>* object
,
4897 const char* group_section_name
,
4898 const char* signature
,
4899 const elfcpp::Shdr
<32, false>& shdr
,
4900 elfcpp::Elf_Word flags
,
4901 std::vector
<unsigned int>* shndxes
);
4904 #ifdef HAVE_TARGET_32_BIG
4907 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
4908 Sized_relobj_file
<32, true>* object
,
4910 const char* group_section_name
,
4911 const char* signature
,
4912 const elfcpp::Shdr
<32, true>& shdr
,
4913 elfcpp::Elf_Word flags
,
4914 std::vector
<unsigned int>* shndxes
);
4917 #ifdef HAVE_TARGET_64_LITTLE
4920 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
4921 Sized_relobj_file
<64, false>* object
,
4923 const char* group_section_name
,
4924 const char* signature
,
4925 const elfcpp::Shdr
<64, false>& shdr
,
4926 elfcpp::Elf_Word flags
,
4927 std::vector
<unsigned int>* shndxes
);
4930 #ifdef HAVE_TARGET_64_BIG
4933 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
4934 Sized_relobj_file
<64, true>* object
,
4936 const char* group_section_name
,
4937 const char* signature
,
4938 const elfcpp::Shdr
<64, true>& shdr
,
4939 elfcpp::Elf_Word flags
,
4940 std::vector
<unsigned int>* shndxes
);
4943 #ifdef HAVE_TARGET_32_LITTLE
4946 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
4947 const unsigned char* symbols
,
4949 const unsigned char* symbol_names
,
4950 off_t symbol_names_size
,
4952 const elfcpp::Shdr
<32, false>& shdr
,
4953 unsigned int reloc_shndx
,
4954 unsigned int reloc_type
,
4958 #ifdef HAVE_TARGET_32_BIG
4961 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
4962 const unsigned char* symbols
,
4964 const unsigned char* symbol_names
,
4965 off_t symbol_names_size
,
4967 const elfcpp::Shdr
<32, true>& shdr
,
4968 unsigned int reloc_shndx
,
4969 unsigned int reloc_type
,
4973 #ifdef HAVE_TARGET_64_LITTLE
4976 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
4977 const unsigned char* symbols
,
4979 const unsigned char* symbol_names
,
4980 off_t symbol_names_size
,
4982 const elfcpp::Shdr
<64, false>& shdr
,
4983 unsigned int reloc_shndx
,
4984 unsigned int reloc_type
,
4988 #ifdef HAVE_TARGET_64_BIG
4991 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
4992 const unsigned char* symbols
,
4994 const unsigned char* symbol_names
,
4995 off_t symbol_names_size
,
4997 const elfcpp::Shdr
<64, true>& shdr
,
4998 unsigned int reloc_shndx
,
4999 unsigned int reloc_type
,
5003 } // End namespace gold.