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
),
364 symtab_section_(NULL
),
365 symtab_xindex_(NULL
),
366 dynsym_section_(NULL
),
367 dynsym_xindex_(NULL
),
368 dynamic_section_(NULL
),
369 dynamic_symbol_(NULL
),
371 eh_frame_section_(NULL
),
372 eh_frame_data_(NULL
),
373 added_eh_frame_data_(false),
374 eh_frame_hdr_section_(NULL
),
375 build_id_note_(NULL
),
379 output_file_size_(-1),
380 have_added_input_section_(false),
381 sections_are_attached_(false),
382 input_requires_executable_stack_(false),
383 input_with_gnu_stack_note_(false),
384 input_without_gnu_stack_note_(false),
385 has_static_tls_(false),
386 any_postprocessing_sections_(false),
387 resized_signatures_(false),
388 have_stabstr_section_(false),
389 incremental_inputs_(NULL
),
390 record_output_section_data_from_script_(false),
391 script_output_section_data_list_(),
392 segment_states_(NULL
),
393 relaxation_debug_check_(NULL
),
394 incremental_base_(NULL
),
397 // Make space for more than enough segments for a typical file.
398 // This is just for efficiency--it's OK if we wind up needing more.
399 this->segment_list_
.reserve(12);
401 // We expect two unattached Output_data objects: the file header and
402 // the segment headers.
403 this->special_output_list_
.reserve(2);
405 // Initialize structure needed for an incremental build.
406 if (parameters
->incremental())
407 this->incremental_inputs_
= new Incremental_inputs
;
409 // The section name pool is worth optimizing in all cases, because
410 // it is small, but there are often overlaps due to .rel sections.
411 this->namepool_
.set_optimize();
414 // For incremental links, record the base file to be modified.
417 Layout::set_incremental_base(Incremental_binary
* base
)
419 this->incremental_base_
= base
;
420 this->free_list_
.init(base
->output_file()->filesize(), true);
423 // Hash a key we use to look up an output section mapping.
426 Layout::Hash_key::operator()(const Layout::Key
& k
) const
428 return k
.first
+ k
.second
.first
+ k
.second
.second
;
431 // Returns whether the given section is in the list of
432 // debug-sections-used-by-some-version-of-gdb. Currently,
433 // we've checked versions of gdb up to and including 6.7.1.
435 static const char* gdb_sections
[] =
437 // ".debug_aranges", // not used by gdb as of 6.7.1
444 // ".debug_pubnames", // not used by gdb as of 6.7.1
449 static const char* lines_only_debug_sections
[] =
451 // ".debug_aranges", // not used by gdb as of 6.7.1
458 // ".debug_pubnames", // not used by gdb as of 6.7.1
464 is_gdb_debug_section(const char* str
)
466 // We can do this faster: binary search or a hashtable. But why bother?
467 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
468 if (strcmp(str
, gdb_sections
[i
]) == 0)
474 is_lines_only_debug_section(const char* str
)
476 // We can do this faster: binary search or a hashtable. But why bother?
478 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
480 if (strcmp(str
, lines_only_debug_sections
[i
]) == 0)
485 // Sometimes we compress sections. This is typically done for
486 // sections that are not part of normal program execution (such as
487 // .debug_* sections), and where the readers of these sections know
488 // how to deal with compressed sections. This routine doesn't say for
489 // certain whether we'll compress -- it depends on commandline options
490 // as well -- just whether this section is a candidate for compression.
491 // (The Output_compressed_section class decides whether to compress
492 // a given section, and picks the name of the compressed section.)
495 is_compressible_debug_section(const char* secname
)
497 return (is_prefix_of(".debug", secname
));
500 // We may see compressed debug sections in input files. Return TRUE
501 // if this is the name of a compressed debug section.
504 is_compressed_debug_section(const char* secname
)
506 return (is_prefix_of(".zdebug", secname
));
509 // Whether to include this section in the link.
511 template<int size
, bool big_endian
>
513 Layout::include_section(Sized_relobj
<size
, big_endian
>*, const char* name
,
514 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
516 if (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
)
519 switch (shdr
.get_sh_type())
521 case elfcpp::SHT_NULL
:
522 case elfcpp::SHT_SYMTAB
:
523 case elfcpp::SHT_DYNSYM
:
524 case elfcpp::SHT_HASH
:
525 case elfcpp::SHT_DYNAMIC
:
526 case elfcpp::SHT_SYMTAB_SHNDX
:
529 case elfcpp::SHT_STRTAB
:
530 // Discard the sections which have special meanings in the ELF
531 // ABI. Keep others (e.g., .stabstr). We could also do this by
532 // checking the sh_link fields of the appropriate sections.
533 return (strcmp(name
, ".dynstr") != 0
534 && strcmp(name
, ".strtab") != 0
535 && strcmp(name
, ".shstrtab") != 0);
537 case elfcpp::SHT_RELA
:
538 case elfcpp::SHT_REL
:
539 case elfcpp::SHT_GROUP
:
540 // If we are emitting relocations these should be handled
542 gold_assert(!parameters
->options().relocatable()
543 && !parameters
->options().emit_relocs());
546 case elfcpp::SHT_PROGBITS
:
547 if (parameters
->options().strip_debug()
548 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
550 if (is_debug_info_section(name
))
553 if (parameters
->options().strip_debug_non_line()
554 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
556 // Debugging sections can only be recognized by name.
557 if (is_prefix_of(".debug", name
)
558 && !is_lines_only_debug_section(name
))
561 if (parameters
->options().strip_debug_gdb()
562 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
564 // Debugging sections can only be recognized by name.
565 if (is_prefix_of(".debug", name
)
566 && !is_gdb_debug_section(name
))
569 if (parameters
->options().strip_lto_sections()
570 && !parameters
->options().relocatable()
571 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
573 // Ignore LTO sections containing intermediate code.
574 if (is_prefix_of(".gnu.lto_", name
))
577 // The GNU linker strips .gnu_debuglink sections, so we do too.
578 // This is a feature used to keep debugging information in
580 if (strcmp(name
, ".gnu_debuglink") == 0)
589 // Return an output section named NAME, or NULL if there is none.
592 Layout::find_output_section(const char* name
) const
594 for (Section_list::const_iterator p
= this->section_list_
.begin();
595 p
!= this->section_list_
.end();
597 if (strcmp((*p
)->name(), name
) == 0)
602 // Return an output segment of type TYPE, with segment flags SET set
603 // and segment flags CLEAR clear. Return NULL if there is none.
606 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
607 elfcpp::Elf_Word clear
) const
609 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
610 p
!= this->segment_list_
.end();
612 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
613 && ((*p
)->flags() & set
) == set
614 && ((*p
)->flags() & clear
) == 0)
619 // Return the output section to use for section NAME with type TYPE
620 // and section flags FLAGS. NAME must be canonicalized in the string
621 // pool, and NAME_KEY is the key. IS_INTERP is true if this is the
622 // .interp section. IS_DYNAMIC_LINKER_SECTION is true if this section
623 // is used by the dynamic linker. IS_RELRO is true for a relro
624 // section. IS_LAST_RELRO is true for the last relro section.
625 // IS_FIRST_NON_RELRO is true for the first non-relro section.
628 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
629 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
630 Output_section_order order
, bool is_relro
)
632 elfcpp::Elf_Xword lookup_flags
= flags
;
634 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
635 // read-write with read-only sections. Some other ELF linkers do
636 // not do this. FIXME: Perhaps there should be an option
638 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
640 const Key
key(name_key
, std::make_pair(type
, lookup_flags
));
641 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
642 std::pair
<Section_name_map::iterator
, bool> ins(
643 this->section_name_map_
.insert(v
));
646 return ins
.first
->second
;
649 // This is the first time we've seen this name/type/flags
650 // combination. For compatibility with the GNU linker, we
651 // combine sections with contents and zero flags with sections
652 // with non-zero flags. This is a workaround for cases where
653 // assembler code forgets to set section flags. FIXME: Perhaps
654 // there should be an option to control this.
655 Output_section
* os
= NULL
;
657 if (type
== elfcpp::SHT_PROGBITS
)
661 Output_section
* same_name
= this->find_output_section(name
);
662 if (same_name
!= NULL
663 && same_name
->type() == elfcpp::SHT_PROGBITS
664 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
667 else if ((flags
& elfcpp::SHF_TLS
) == 0)
669 elfcpp::Elf_Xword zero_flags
= 0;
670 const Key
zero_key(name_key
, std::make_pair(type
, zero_flags
));
671 Section_name_map::iterator p
=
672 this->section_name_map_
.find(zero_key
);
673 if (p
!= this->section_name_map_
.end())
679 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
681 ins
.first
->second
= os
;
686 // Pick the output section to use for section NAME, in input file
687 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
688 // linker created section. IS_INPUT_SECTION is true if we are
689 // choosing an output section for an input section found in a input
690 // file. IS_INTERP is true if this is the .interp section.
691 // IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
692 // dynamic linker. IS_RELRO is true for a relro section.
693 // IS_LAST_RELRO is true for the last relro section.
694 // IS_FIRST_NON_RELRO is true for the first non-relro section. This
695 // will return NULL if the input section should be discarded.
698 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
699 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
700 bool is_input_section
, Output_section_order order
,
703 // We should not see any input sections after we have attached
704 // sections to segments.
705 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
707 // Some flags in the input section should not be automatically
708 // copied to the output section.
709 flags
&= ~ (elfcpp::SHF_INFO_LINK
712 | elfcpp::SHF_STRINGS
);
714 // We only clear the SHF_LINK_ORDER flag in for
715 // a non-relocatable link.
716 if (!parameters
->options().relocatable())
717 flags
&= ~elfcpp::SHF_LINK_ORDER
;
719 if (this->script_options_
->saw_sections_clause())
721 // We are using a SECTIONS clause, so the output section is
722 // chosen based only on the name.
724 Script_sections
* ss
= this->script_options_
->script_sections();
725 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
726 Output_section
** output_section_slot
;
727 Script_sections::Section_type script_section_type
;
728 const char* orig_name
= name
;
729 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
730 &script_section_type
);
733 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
734 "because it is not allowed by the "
735 "SECTIONS clause of the linker script"),
737 // The SECTIONS clause says to discard this input section.
741 // We can only handle script section types ST_NONE and ST_NOLOAD.
742 switch (script_section_type
)
744 case Script_sections::ST_NONE
:
746 case Script_sections::ST_NOLOAD
:
747 flags
&= elfcpp::SHF_ALLOC
;
753 // If this is an orphan section--one not mentioned in the linker
754 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
755 // default processing below.
757 if (output_section_slot
!= NULL
)
759 if (*output_section_slot
!= NULL
)
761 (*output_section_slot
)->update_flags_for_input_section(flags
);
762 return *output_section_slot
;
765 // We don't put sections found in the linker script into
766 // SECTION_NAME_MAP_. That keeps us from getting confused
767 // if an orphan section is mapped to a section with the same
768 // name as one in the linker script.
770 name
= this->namepool_
.add(name
, false, NULL
);
772 Output_section
* os
= this->make_output_section(name
, type
, flags
,
775 os
->set_found_in_sections_clause();
777 // Special handling for NOLOAD sections.
778 if (script_section_type
== Script_sections::ST_NOLOAD
)
782 // The constructor of Output_section sets addresses of non-ALLOC
783 // sections to 0 by default. We don't want that for NOLOAD
784 // sections even if they have no SHF_ALLOC flag.
785 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
786 && os
->is_address_valid())
788 gold_assert(os
->address() == 0
789 && !os
->is_offset_valid()
790 && !os
->is_data_size_valid());
791 os
->reset_address_and_file_offset();
795 *output_section_slot
= os
;
800 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
802 size_t len
= strlen(name
);
803 char* uncompressed_name
= NULL
;
805 // Compressed debug sections should be mapped to the corresponding
806 // uncompressed section.
807 if (is_compressed_debug_section(name
))
809 uncompressed_name
= new char[len
];
810 uncompressed_name
[0] = '.';
811 gold_assert(name
[0] == '.' && name
[1] == 'z');
812 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
813 uncompressed_name
[len
- 1] = '\0';
815 name
= uncompressed_name
;
818 // Turn NAME from the name of the input section into the name of the
821 && !this->script_options_
->saw_sections_clause()
822 && !parameters
->options().relocatable())
823 name
= Layout::output_section_name(name
, &len
);
825 Stringpool::Key name_key
;
826 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
828 if (uncompressed_name
!= NULL
)
829 delete[] uncompressed_name
;
831 // Find or make the output section. The output section is selected
832 // based on the section name, type, and flags.
833 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
836 // For incremental links, record the initial fixed layout of a section
837 // from the base file, and return a pointer to the Output_section.
839 template<int size
, bool big_endian
>
841 Layout::init_fixed_output_section(const char* name
,
842 elfcpp::Shdr
<size
, big_endian
>& shdr
)
844 unsigned int sh_type
= shdr
.get_sh_type();
846 // We preserve the layout of PROGBITS, NOBITS, and NOTE sections.
847 // All others will be created from scratch and reallocated.
848 if (sh_type
!= elfcpp::SHT_PROGBITS
849 && sh_type
!= elfcpp::SHT_NOBITS
850 && sh_type
!= elfcpp::SHT_NOTE
)
853 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
854 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
855 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
856 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
857 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
858 shdr
.get_sh_addralign();
860 // Make the output section.
861 Stringpool::Key name_key
;
862 name
= this->namepool_
.add(name
, true, &name_key
);
863 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
864 sh_flags
, ORDER_INVALID
, false);
865 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
866 if (sh_type
!= elfcpp::SHT_NOBITS
)
867 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
871 // Return the output section to use for input section SHNDX, with name
872 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
873 // index of a relocation section which applies to this section, or 0
874 // if none, or -1U if more than one. RELOC_TYPE is the type of the
875 // relocation section if there is one. Set *OFF to the offset of this
876 // input section without the output section. Return NULL if the
877 // section should be discarded. Set *OFF to -1 if the section
878 // contents should not be written directly to the output file, but
879 // will instead receive special handling.
881 template<int size
, bool big_endian
>
883 Layout::layout(Sized_relobj
<size
, big_endian
>* object
, unsigned int shndx
,
884 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
885 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
889 if (!this->include_section(object
, name
, shdr
))
894 // Sometimes .init_array*, .preinit_array* and .fini_array* do not have
895 // correct section types. Force them here.
896 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
897 if (sh_type
== elfcpp::SHT_PROGBITS
)
899 static const char init_array_prefix
[] = ".init_array";
900 static const char preinit_array_prefix
[] = ".preinit_array";
901 static const char fini_array_prefix
[] = ".fini_array";
902 static size_t init_array_prefix_size
= sizeof(init_array_prefix
) - 1;
903 static size_t preinit_array_prefix_size
=
904 sizeof(preinit_array_prefix
) - 1;
905 static size_t fini_array_prefix_size
= sizeof(fini_array_prefix
) - 1;
907 if (strncmp(name
, init_array_prefix
, init_array_prefix_size
) == 0)
908 sh_type
= elfcpp::SHT_INIT_ARRAY
;
909 else if (strncmp(name
, preinit_array_prefix
, preinit_array_prefix_size
)
911 sh_type
= elfcpp::SHT_PREINIT_ARRAY
;
912 else if (strncmp(name
, fini_array_prefix
, fini_array_prefix_size
) == 0)
913 sh_type
= elfcpp::SHT_FINI_ARRAY
;
916 // In a relocatable link a grouped section must not be combined with
917 // any other sections.
918 if (parameters
->options().relocatable()
919 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
921 name
= this->namepool_
.add(name
, true, NULL
);
922 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
923 ORDER_INVALID
, false);
927 os
= this->choose_output_section(object
, name
, sh_type
,
928 shdr
.get_sh_flags(), true,
929 ORDER_INVALID
, false);
934 // By default the GNU linker sorts input sections whose names match
935 // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
936 // are sorted by name. This is used to implement constructor
937 // priority ordering. We are compatible.
938 if (!this->script_options_
->saw_sections_clause()
939 && (is_prefix_of(".ctors.", name
)
940 || is_prefix_of(".dtors.", name
)
941 || is_prefix_of(".init_array.", name
)
942 || is_prefix_of(".fini_array.", name
)))
943 os
->set_must_sort_attached_input_sections();
945 // FIXME: Handle SHF_LINK_ORDER somewhere.
947 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
948 this->script_options_
->saw_sections_clause());
949 this->have_added_input_section_
= true;
954 // Handle a relocation section when doing a relocatable link.
956 template<int size
, bool big_endian
>
958 Layout::layout_reloc(Sized_relobj
<size
, big_endian
>* object
,
960 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
961 Output_section
* data_section
,
962 Relocatable_relocs
* rr
)
964 gold_assert(parameters
->options().relocatable()
965 || parameters
->options().emit_relocs());
967 int sh_type
= shdr
.get_sh_type();
970 if (sh_type
== elfcpp::SHT_REL
)
972 else if (sh_type
== elfcpp::SHT_RELA
)
976 name
+= data_section
->name();
978 // In a relocatable link relocs for a grouped section must not be
979 // combined with other reloc sections.
981 if (!parameters
->options().relocatable()
982 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
983 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
984 shdr
.get_sh_flags(), false,
985 ORDER_INVALID
, false);
988 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
989 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
990 ORDER_INVALID
, false);
993 os
->set_should_link_to_symtab();
994 os
->set_info_section(data_section
);
996 Output_section_data
* posd
;
997 if (sh_type
== elfcpp::SHT_REL
)
999 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1000 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1004 else if (sh_type
== elfcpp::SHT_RELA
)
1006 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1007 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1014 os
->add_output_section_data(posd
);
1015 rr
->set_output_data(posd
);
1020 // Handle a group section when doing a relocatable link.
1022 template<int size
, bool big_endian
>
1024 Layout::layout_group(Symbol_table
* symtab
,
1025 Sized_relobj
<size
, big_endian
>* object
,
1027 const char* group_section_name
,
1028 const char* signature
,
1029 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1030 elfcpp::Elf_Word flags
,
1031 std::vector
<unsigned int>* shndxes
)
1033 gold_assert(parameters
->options().relocatable());
1034 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1035 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1036 Output_section
* os
= this->make_output_section(group_section_name
,
1038 shdr
.get_sh_flags(),
1039 ORDER_INVALID
, false);
1041 // We need to find a symbol with the signature in the symbol table.
1042 // If we don't find one now, we need to look again later.
1043 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1045 os
->set_info_symndx(sym
);
1048 // Reserve some space to minimize reallocations.
1049 if (this->group_signatures_
.empty())
1050 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1052 // We will wind up using a symbol whose name is the signature.
1053 // So just put the signature in the symbol name pool to save it.
1054 signature
= symtab
->canonicalize_name(signature
);
1055 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1058 os
->set_should_link_to_symtab();
1061 section_size_type entry_count
=
1062 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1063 Output_section_data
* posd
=
1064 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1066 os
->add_output_section_data(posd
);
1069 // Special GNU handling of sections name .eh_frame. They will
1070 // normally hold exception frame data as defined by the C++ ABI
1071 // (http://codesourcery.com/cxx-abi/).
1073 template<int size
, bool big_endian
>
1075 Layout::layout_eh_frame(Sized_relobj
<size
, big_endian
>* object
,
1076 const unsigned char* symbols
,
1078 const unsigned char* symbol_names
,
1079 off_t symbol_names_size
,
1081 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1082 unsigned int reloc_shndx
, unsigned int reloc_type
,
1085 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
);
1086 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1088 const char* const name
= ".eh_frame";
1089 Output_section
* os
= this->choose_output_section(object
, name
,
1090 elfcpp::SHT_PROGBITS
,
1091 elfcpp::SHF_ALLOC
, false,
1092 ORDER_EHFRAME
, false);
1096 if (this->eh_frame_section_
== NULL
)
1098 this->eh_frame_section_
= os
;
1099 this->eh_frame_data_
= new Eh_frame();
1101 // For incremental linking, we do not optimize .eh_frame sections
1102 // or create a .eh_frame_hdr section.
1103 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1105 Output_section
* hdr_os
=
1106 this->choose_output_section(NULL
, ".eh_frame_hdr",
1107 elfcpp::SHT_PROGBITS
,
1108 elfcpp::SHF_ALLOC
, false,
1109 ORDER_EHFRAME
, false);
1113 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1114 this->eh_frame_data_
);
1115 hdr_os
->add_output_section_data(hdr_posd
);
1117 hdr_os
->set_after_input_sections();
1119 if (!this->script_options_
->saw_phdrs_clause())
1121 Output_segment
* hdr_oseg
;
1122 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1124 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1128 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1133 gold_assert(this->eh_frame_section_
== os
);
1135 if (!parameters
->incremental()
1136 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1145 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1147 // A writable .eh_frame section is a RELRO section.
1148 if ((shdr
.get_sh_flags() & elfcpp::SHF_WRITE
) != 0)
1151 // We found a .eh_frame section we are going to optimize, so now
1152 // we can add the set of optimized sections to the output
1153 // section. We need to postpone adding this until we've found a
1154 // section we can optimize so that the .eh_frame section in
1155 // crtbegin.o winds up at the start of the output section.
1156 if (!this->added_eh_frame_data_
)
1158 os
->add_output_section_data(this->eh_frame_data_
);
1159 this->added_eh_frame_data_
= true;
1165 // We couldn't handle this .eh_frame section for some reason.
1166 // Add it as a normal section.
1167 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1168 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1169 saw_sections_clause
);
1170 this->have_added_input_section_
= true;
1176 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1177 // the output section.
1180 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1181 elfcpp::Elf_Xword flags
,
1182 Output_section_data
* posd
,
1183 Output_section_order order
, bool is_relro
)
1185 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1186 false, order
, is_relro
);
1188 os
->add_output_section_data(posd
);
1192 // Map section flags to segment flags.
1195 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1197 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1198 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1199 ret
|= elfcpp::PF_W
;
1200 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1201 ret
|= elfcpp::PF_X
;
1205 // Make a new Output_section, and attach it to segments as
1206 // appropriate. ORDER is the order in which this section should
1207 // appear in the output segment. IS_RELRO is true if this is a relro
1208 // (read-only after relocations) section.
1211 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1212 elfcpp::Elf_Xword flags
,
1213 Output_section_order order
, bool is_relro
)
1216 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1217 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1218 && is_compressible_debug_section(name
))
1219 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1221 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1222 && parameters
->options().strip_debug_non_line()
1223 && strcmp(".debug_abbrev", name
) == 0)
1225 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1227 if (this->debug_info_
)
1228 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1230 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1231 && parameters
->options().strip_debug_non_line()
1232 && strcmp(".debug_info", name
) == 0)
1234 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1236 if (this->debug_abbrev_
)
1237 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1241 // FIXME: const_cast is ugly.
1242 Target
* target
= const_cast<Target
*>(¶meters
->target());
1243 os
= target
->make_output_section(name
, type
, flags
);
1246 // With -z relro, we have to recognize the special sections by name.
1247 // There is no other way.
1248 bool is_relro_local
= false;
1249 if (!this->script_options_
->saw_sections_clause()
1250 && parameters
->options().relro()
1251 && type
== elfcpp::SHT_PROGBITS
1252 && (flags
& elfcpp::SHF_ALLOC
) != 0
1253 && (flags
& elfcpp::SHF_WRITE
) != 0)
1255 if (strcmp(name
, ".data.rel.ro") == 0)
1257 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1260 is_relro_local
= true;
1262 else if (type
== elfcpp::SHT_INIT_ARRAY
1263 || type
== elfcpp::SHT_FINI_ARRAY
1264 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1266 else if (strcmp(name
, ".ctors") == 0
1267 || strcmp(name
, ".dtors") == 0
1268 || strcmp(name
, ".jcr") == 0)
1275 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1276 order
= this->default_section_order(os
, is_relro_local
);
1278 os
->set_order(order
);
1280 parameters
->target().new_output_section(os
);
1282 this->section_list_
.push_back(os
);
1284 // The GNU linker by default sorts some sections by priority, so we
1285 // do the same. We need to know that this might happen before we
1286 // attach any input sections.
1287 if (!this->script_options_
->saw_sections_clause()
1288 && (strcmp(name
, ".ctors") == 0
1289 || strcmp(name
, ".dtors") == 0
1290 || strcmp(name
, ".init_array") == 0
1291 || strcmp(name
, ".fini_array") == 0))
1292 os
->set_may_sort_attached_input_sections();
1294 // Check for .stab*str sections, as .stab* sections need to link to
1296 if (type
== elfcpp::SHT_STRTAB
1297 && !this->have_stabstr_section_
1298 && strncmp(name
, ".stab", 5) == 0
1299 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1300 this->have_stabstr_section_
= true;
1302 // If we have already attached the sections to segments, then we
1303 // need to attach this one now. This happens for sections created
1304 // directly by the linker.
1305 if (this->sections_are_attached_
)
1306 this->attach_section_to_segment(os
);
1311 // Return the default order in which a section should be placed in an
1312 // output segment. This function captures a lot of the ideas in
1313 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1314 // linker created section is normally set when the section is created;
1315 // this function is used for input sections.
1317 Output_section_order
1318 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1320 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1321 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1322 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1323 bool is_bss
= false;
1328 case elfcpp::SHT_PROGBITS
:
1330 case elfcpp::SHT_NOBITS
:
1333 case elfcpp::SHT_RELA
:
1334 case elfcpp::SHT_REL
:
1336 return ORDER_DYNAMIC_RELOCS
;
1338 case elfcpp::SHT_HASH
:
1339 case elfcpp::SHT_DYNAMIC
:
1340 case elfcpp::SHT_SHLIB
:
1341 case elfcpp::SHT_DYNSYM
:
1342 case elfcpp::SHT_GNU_HASH
:
1343 case elfcpp::SHT_GNU_verdef
:
1344 case elfcpp::SHT_GNU_verneed
:
1345 case elfcpp::SHT_GNU_versym
:
1347 return ORDER_DYNAMIC_LINKER
;
1349 case elfcpp::SHT_NOTE
:
1350 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1353 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1354 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1356 if (!is_bss
&& !is_write
)
1360 if (strcmp(os
->name(), ".init") == 0)
1362 else if (strcmp(os
->name(), ".fini") == 0)
1365 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1369 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1371 if (os
->is_small_section())
1372 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1373 if (os
->is_large_section())
1374 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1376 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1379 // Attach output sections to segments. This is called after we have
1380 // seen all the input sections.
1383 Layout::attach_sections_to_segments()
1385 for (Section_list::iterator p
= this->section_list_
.begin();
1386 p
!= this->section_list_
.end();
1388 this->attach_section_to_segment(*p
);
1390 this->sections_are_attached_
= true;
1393 // Attach an output section to a segment.
1396 Layout::attach_section_to_segment(Output_section
* os
)
1398 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1399 this->unattached_section_list_
.push_back(os
);
1401 this->attach_allocated_section_to_segment(os
);
1404 // Attach an allocated output section to a segment.
1407 Layout::attach_allocated_section_to_segment(Output_section
* os
)
1409 elfcpp::Elf_Xword flags
= os
->flags();
1410 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1412 if (parameters
->options().relocatable())
1415 // If we have a SECTIONS clause, we can't handle the attachment to
1416 // segments until after we've seen all the sections.
1417 if (this->script_options_
->saw_sections_clause())
1420 gold_assert(!this->script_options_
->saw_phdrs_clause());
1422 // This output section goes into a PT_LOAD segment.
1424 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1426 // Check for --section-start.
1428 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1430 // In general the only thing we really care about for PT_LOAD
1431 // segments is whether or not they are writable or executable,
1432 // so that is how we search for them.
1433 // Large data sections also go into their own PT_LOAD segment.
1434 // People who need segments sorted on some other basis will
1435 // have to use a linker script.
1437 Segment_list::const_iterator p
;
1438 for (p
= this->segment_list_
.begin();
1439 p
!= this->segment_list_
.end();
1442 if ((*p
)->type() != elfcpp::PT_LOAD
)
1444 if (!parameters
->options().omagic()
1445 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1447 if (parameters
->options().rosegment()
1448 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1450 // If -Tbss was specified, we need to separate the data and BSS
1452 if (parameters
->options().user_set_Tbss())
1454 if ((os
->type() == elfcpp::SHT_NOBITS
)
1455 == (*p
)->has_any_data_sections())
1458 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1463 if ((*p
)->are_addresses_set())
1466 (*p
)->add_initial_output_data(os
);
1467 (*p
)->update_flags_for_output_section(seg_flags
);
1468 (*p
)->set_addresses(addr
, addr
);
1472 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1476 if (p
== this->segment_list_
.end())
1478 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1480 if (os
->is_large_data_section())
1481 oseg
->set_is_large_data_segment();
1482 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1484 oseg
->set_addresses(addr
, addr
);
1487 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1489 if (os
->type() == elfcpp::SHT_NOTE
)
1491 // See if we already have an equivalent PT_NOTE segment.
1492 for (p
= this->segment_list_
.begin();
1493 p
!= segment_list_
.end();
1496 if ((*p
)->type() == elfcpp::PT_NOTE
1497 && (((*p
)->flags() & elfcpp::PF_W
)
1498 == (seg_flags
& elfcpp::PF_W
)))
1500 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1505 if (p
== this->segment_list_
.end())
1507 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1509 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1513 // If we see a loadable SHF_TLS section, we create a PT_TLS
1514 // segment. There can only be one such segment.
1515 if ((flags
& elfcpp::SHF_TLS
) != 0)
1517 if (this->tls_segment_
== NULL
)
1518 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1519 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1522 // If -z relro is in effect, and we see a relro section, we create a
1523 // PT_GNU_RELRO segment. There can only be one such segment.
1524 if (os
->is_relro() && parameters
->options().relro())
1526 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1527 if (this->relro_segment_
== NULL
)
1528 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1529 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1533 // Make an output section for a script.
1536 Layout::make_output_section_for_script(
1538 Script_sections::Section_type section_type
)
1540 name
= this->namepool_
.add(name
, false, NULL
);
1541 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
1542 if (section_type
== Script_sections::ST_NOLOAD
)
1544 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1545 sh_flags
, ORDER_INVALID
,
1547 os
->set_found_in_sections_clause();
1548 if (section_type
== Script_sections::ST_NOLOAD
)
1549 os
->set_is_noload();
1553 // Return the number of segments we expect to see.
1556 Layout::expected_segment_count() const
1558 size_t ret
= this->segment_list_
.size();
1560 // If we didn't see a SECTIONS clause in a linker script, we should
1561 // already have the complete list of segments. Otherwise we ask the
1562 // SECTIONS clause how many segments it expects, and add in the ones
1563 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1565 if (!this->script_options_
->saw_sections_clause())
1569 const Script_sections
* ss
= this->script_options_
->script_sections();
1570 return ret
+ ss
->expected_segment_count(this);
1574 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
1575 // is whether we saw a .note.GNU-stack section in the object file.
1576 // GNU_STACK_FLAGS is the section flags. The flags give the
1577 // protection required for stack memory. We record this in an
1578 // executable as a PT_GNU_STACK segment. If an object file does not
1579 // have a .note.GNU-stack segment, we must assume that it is an old
1580 // object. On some targets that will force an executable stack.
1583 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
1586 if (!seen_gnu_stack
)
1588 this->input_without_gnu_stack_note_
= true;
1589 if (parameters
->options().warn_execstack()
1590 && parameters
->target().is_default_stack_executable())
1591 gold_warning(_("%s: missing .note.GNU-stack section"
1592 " implies executable stack"),
1593 obj
->name().c_str());
1597 this->input_with_gnu_stack_note_
= true;
1598 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
1600 this->input_requires_executable_stack_
= true;
1601 if (parameters
->options().warn_execstack()
1602 || parameters
->options().is_stack_executable())
1603 gold_warning(_("%s: requires executable stack"),
1604 obj
->name().c_str());
1609 // Create automatic note sections.
1612 Layout::create_notes()
1614 this->create_gold_note();
1615 this->create_executable_stack_info();
1616 this->create_build_id();
1619 // Create the dynamic sections which are needed before we read the
1623 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
1625 if (parameters
->doing_static_link())
1628 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
1629 elfcpp::SHT_DYNAMIC
,
1631 | elfcpp::SHF_WRITE
),
1635 this->dynamic_symbol_
=
1636 symtab
->define_in_output_data("_DYNAMIC", NULL
, Symbol_table::PREDEFINED
,
1637 this->dynamic_section_
, 0, 0,
1638 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
1639 elfcpp::STV_HIDDEN
, 0, false, false);
1641 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
1643 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
1646 // For each output section whose name can be represented as C symbol,
1647 // define __start and __stop symbols for the section. This is a GNU
1651 Layout::define_section_symbols(Symbol_table
* symtab
)
1653 for (Section_list::const_iterator p
= this->section_list_
.begin();
1654 p
!= this->section_list_
.end();
1657 const char* const name
= (*p
)->name();
1658 if (is_cident(name
))
1660 const std::string
name_string(name
);
1661 const std::string
start_name(cident_section_start_prefix
1663 const std::string
stop_name(cident_section_stop_prefix
1666 symtab
->define_in_output_data(start_name
.c_str(),
1668 Symbol_table::PREDEFINED
,
1674 elfcpp::STV_DEFAULT
,
1676 false, // offset_is_from_end
1677 true); // only_if_ref
1679 symtab
->define_in_output_data(stop_name
.c_str(),
1681 Symbol_table::PREDEFINED
,
1687 elfcpp::STV_DEFAULT
,
1689 true, // offset_is_from_end
1690 true); // only_if_ref
1695 // Define symbols for group signatures.
1698 Layout::define_group_signatures(Symbol_table
* symtab
)
1700 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
1701 p
!= this->group_signatures_
.end();
1704 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
1706 p
->section
->set_info_symndx(sym
);
1709 // Force the name of the group section to the group
1710 // signature, and use the group's section symbol as the
1711 // signature symbol.
1712 if (strcmp(p
->section
->name(), p
->signature
) != 0)
1714 const char* name
= this->namepool_
.add(p
->signature
,
1716 p
->section
->set_name(name
);
1718 p
->section
->set_needs_symtab_index();
1719 p
->section
->set_info_section_symndx(p
->section
);
1723 this->group_signatures_
.clear();
1726 // Find the first read-only PT_LOAD segment, creating one if
1730 Layout::find_first_load_seg()
1732 Output_segment
* best
= NULL
;
1733 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1734 p
!= this->segment_list_
.end();
1737 if ((*p
)->type() == elfcpp::PT_LOAD
1738 && ((*p
)->flags() & elfcpp::PF_R
) != 0
1739 && (parameters
->options().omagic()
1740 || ((*p
)->flags() & elfcpp::PF_W
) == 0))
1742 if (best
== NULL
|| this->segment_precedes(*p
, best
))
1749 gold_assert(!this->script_options_
->saw_phdrs_clause());
1751 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
1756 // Save states of all current output segments. Store saved states
1757 // in SEGMENT_STATES.
1760 Layout::save_segments(Segment_states
* segment_states
)
1762 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1763 p
!= this->segment_list_
.end();
1766 Output_segment
* segment
= *p
;
1768 Output_segment
* copy
= new Output_segment(*segment
);
1769 (*segment_states
)[segment
] = copy
;
1773 // Restore states of output segments and delete any segment not found in
1777 Layout::restore_segments(const Segment_states
* segment_states
)
1779 // Go through the segment list and remove any segment added in the
1781 this->tls_segment_
= NULL
;
1782 this->relro_segment_
= NULL
;
1783 Segment_list::iterator list_iter
= this->segment_list_
.begin();
1784 while (list_iter
!= this->segment_list_
.end())
1786 Output_segment
* segment
= *list_iter
;
1787 Segment_states::const_iterator states_iter
=
1788 segment_states
->find(segment
);
1789 if (states_iter
!= segment_states
->end())
1791 const Output_segment
* copy
= states_iter
->second
;
1792 // Shallow copy to restore states.
1795 // Also fix up TLS and RELRO segment pointers as appropriate.
1796 if (segment
->type() == elfcpp::PT_TLS
)
1797 this->tls_segment_
= segment
;
1798 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
1799 this->relro_segment_
= segment
;
1805 list_iter
= this->segment_list_
.erase(list_iter
);
1806 // This is a segment created during section layout. It should be
1807 // safe to remove it since we should have removed all pointers to it.
1813 // Clean up after relaxation so that sections can be laid out again.
1816 Layout::clean_up_after_relaxation()
1818 // Restore the segments to point state just prior to the relaxation loop.
1819 Script_sections
* script_section
= this->script_options_
->script_sections();
1820 script_section
->release_segments();
1821 this->restore_segments(this->segment_states_
);
1823 // Reset section addresses and file offsets
1824 for (Section_list::iterator p
= this->section_list_
.begin();
1825 p
!= this->section_list_
.end();
1828 (*p
)->restore_states();
1830 // If an input section changes size because of relaxation,
1831 // we need to adjust the section offsets of all input sections.
1832 // after such a section.
1833 if ((*p
)->section_offsets_need_adjustment())
1834 (*p
)->adjust_section_offsets();
1836 (*p
)->reset_address_and_file_offset();
1839 // Reset special output object address and file offsets.
1840 for (Data_list::iterator p
= this->special_output_list_
.begin();
1841 p
!= this->special_output_list_
.end();
1843 (*p
)->reset_address_and_file_offset();
1845 // A linker script may have created some output section data objects.
1846 // They are useless now.
1847 for (Output_section_data_list::const_iterator p
=
1848 this->script_output_section_data_list_
.begin();
1849 p
!= this->script_output_section_data_list_
.end();
1852 this->script_output_section_data_list_
.clear();
1855 // Prepare for relaxation.
1858 Layout::prepare_for_relaxation()
1860 // Create an relaxation debug check if in debugging mode.
1861 if (is_debugging_enabled(DEBUG_RELAXATION
))
1862 this->relaxation_debug_check_
= new Relaxation_debug_check();
1864 // Save segment states.
1865 this->segment_states_
= new Segment_states();
1866 this->save_segments(this->segment_states_
);
1868 for(Section_list::const_iterator p
= this->section_list_
.begin();
1869 p
!= this->section_list_
.end();
1871 (*p
)->save_states();
1873 if (is_debugging_enabled(DEBUG_RELAXATION
))
1874 this->relaxation_debug_check_
->check_output_data_for_reset_values(
1875 this->section_list_
, this->special_output_list_
);
1877 // Also enable recording of output section data from scripts.
1878 this->record_output_section_data_from_script_
= true;
1881 // Relaxation loop body: If target has no relaxation, this runs only once
1882 // Otherwise, the target relaxation hook is called at the end of
1883 // each iteration. If the hook returns true, it means re-layout of
1884 // section is required.
1886 // The number of segments created by a linking script without a PHDRS
1887 // clause may be affected by section sizes and alignments. There is
1888 // a remote chance that relaxation causes different number of PT_LOAD
1889 // segments are created and sections are attached to different segments.
1890 // Therefore, we always throw away all segments created during section
1891 // layout. In order to be able to restart the section layout, we keep
1892 // a copy of the segment list right before the relaxation loop and use
1893 // that to restore the segments.
1895 // PASS is the current relaxation pass number.
1896 // SYMTAB is a symbol table.
1897 // PLOAD_SEG is the address of a pointer for the load segment.
1898 // PHDR_SEG is a pointer to the PHDR segment.
1899 // SEGMENT_HEADERS points to the output segment header.
1900 // FILE_HEADER points to the output file header.
1901 // PSHNDX is the address to store the output section index.
1904 Layout::relaxation_loop_body(
1907 Symbol_table
* symtab
,
1908 Output_segment
** pload_seg
,
1909 Output_segment
* phdr_seg
,
1910 Output_segment_headers
* segment_headers
,
1911 Output_file_header
* file_header
,
1912 unsigned int* pshndx
)
1914 // If this is not the first iteration, we need to clean up after
1915 // relaxation so that we can lay out the sections again.
1917 this->clean_up_after_relaxation();
1919 // If there is a SECTIONS clause, put all the input sections into
1920 // the required order.
1921 Output_segment
* load_seg
;
1922 if (this->script_options_
->saw_sections_clause())
1923 load_seg
= this->set_section_addresses_from_script(symtab
);
1924 else if (parameters
->options().relocatable())
1927 load_seg
= this->find_first_load_seg();
1929 if (parameters
->options().oformat_enum()
1930 != General_options::OBJECT_FORMAT_ELF
)
1933 // If the user set the address of the text segment, that may not be
1934 // compatible with putting the segment headers and file headers into
1936 if (parameters
->options().user_set_Ttext())
1939 gold_assert(phdr_seg
== NULL
1941 || this->script_options_
->saw_sections_clause());
1943 // If the address of the load segment we found has been set by
1944 // --section-start rather than by a script, then adjust the VMA and
1945 // LMA downward if possible to include the file and section headers.
1946 uint64_t header_gap
= 0;
1947 if (load_seg
!= NULL
1948 && load_seg
->are_addresses_set()
1949 && !this->script_options_
->saw_sections_clause()
1950 && !parameters
->options().relocatable())
1952 file_header
->finalize_data_size();
1953 segment_headers
->finalize_data_size();
1954 size_t sizeof_headers
= (file_header
->data_size()
1955 + segment_headers
->data_size());
1956 const uint64_t abi_pagesize
= target
->abi_pagesize();
1957 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
1958 hdr_paddr
&= ~(abi_pagesize
- 1);
1959 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
1960 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
1964 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
1965 load_seg
->paddr() - subtract
);
1966 header_gap
= subtract
- sizeof_headers
;
1970 // Lay out the segment headers.
1971 if (!parameters
->options().relocatable())
1973 gold_assert(segment_headers
!= NULL
);
1974 if (header_gap
!= 0 && load_seg
!= NULL
)
1976 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
1977 load_seg
->add_initial_output_data(z
);
1979 if (load_seg
!= NULL
)
1980 load_seg
->add_initial_output_data(segment_headers
);
1981 if (phdr_seg
!= NULL
)
1982 phdr_seg
->add_initial_output_data(segment_headers
);
1985 // Lay out the file header.
1986 if (load_seg
!= NULL
)
1987 load_seg
->add_initial_output_data(file_header
);
1989 if (this->script_options_
->saw_phdrs_clause()
1990 && !parameters
->options().relocatable())
1992 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1993 // clause in a linker script.
1994 Script_sections
* ss
= this->script_options_
->script_sections();
1995 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
1998 // We set the output section indexes in set_segment_offsets and
1999 // set_section_indexes.
2002 // Set the file offsets of all the segments, and all the sections
2005 if (!parameters
->options().relocatable())
2006 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2008 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2010 // Verify that the dummy relaxation does not change anything.
2011 if (is_debugging_enabled(DEBUG_RELAXATION
))
2014 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2016 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2019 *pload_seg
= load_seg
;
2023 // Search the list of patterns and find the postion of the given section
2024 // name in the output section. If the section name matches a glob
2025 // pattern and a non-glob name, then the non-glob position takes
2026 // precedence. Return 0 if no match is found.
2029 Layout::find_section_order_index(const std::string
& section_name
)
2031 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2032 map_it
= this->input_section_position_
.find(section_name
);
2033 if (map_it
!= this->input_section_position_
.end())
2034 return map_it
->second
;
2036 // Absolute match failed. Linear search the glob patterns.
2037 std::vector
<std::string
>::iterator it
;
2038 for (it
= this->input_section_glob_
.begin();
2039 it
!= this->input_section_glob_
.end();
2042 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2044 map_it
= this->input_section_position_
.find(*it
);
2045 gold_assert(map_it
!= this->input_section_position_
.end());
2046 return map_it
->second
;
2052 // Read the sequence of input sections from the file specified with
2053 // --section-ordering-file.
2056 Layout::read_layout_from_file()
2058 const char* filename
= parameters
->options().section_ordering_file();
2064 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2065 filename
, strerror(errno
));
2067 std::getline(in
, line
); // this chops off the trailing \n, if any
2068 unsigned int position
= 1;
2072 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2073 line
.resize(line
.length() - 1);
2074 // Ignore comments, beginning with '#'
2077 std::getline(in
, line
);
2080 this->input_section_position_
[line
] = position
;
2081 // Store all glob patterns in a vector.
2082 if (is_wildcard_string(line
.c_str()))
2083 this->input_section_glob_
.push_back(line
);
2085 std::getline(in
, line
);
2089 // Finalize the layout. When this is called, we have created all the
2090 // output sections and all the output segments which are based on
2091 // input sections. We have several things to do, and we have to do
2092 // them in the right order, so that we get the right results correctly
2095 // 1) Finalize the list of output segments and create the segment
2098 // 2) Finalize the dynamic symbol table and associated sections.
2100 // 3) Determine the final file offset of all the output segments.
2102 // 4) Determine the final file offset of all the SHF_ALLOC output
2105 // 5) Create the symbol table sections and the section name table
2108 // 6) Finalize the symbol table: set symbol values to their final
2109 // value and make a final determination of which symbols are going
2110 // into the output symbol table.
2112 // 7) Create the section table header.
2114 // 8) Determine the final file offset of all the output sections which
2115 // are not SHF_ALLOC, including the section table header.
2117 // 9) Finalize the ELF file header.
2119 // This function returns the size of the output file.
2122 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2123 Target
* target
, const Task
* task
)
2125 target
->finalize_sections(this, input_objects
, symtab
);
2127 this->count_local_symbols(task
, input_objects
);
2129 this->link_stabs_sections();
2131 Output_segment
* phdr_seg
= NULL
;
2132 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2134 // There was a dynamic object in the link. We need to create
2135 // some information for the dynamic linker.
2137 // Create the PT_PHDR segment which will hold the program
2139 if (!this->script_options_
->saw_phdrs_clause())
2140 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2142 // Create the dynamic symbol table, including the hash table.
2143 Output_section
* dynstr
;
2144 std::vector
<Symbol
*> dynamic_symbols
;
2145 unsigned int local_dynamic_count
;
2146 Versions
versions(*this->script_options()->version_script_info(),
2148 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2149 &local_dynamic_count
, &dynamic_symbols
,
2152 // Create the .interp section to hold the name of the
2153 // interpreter, and put it in a PT_INTERP segment.
2154 if (!parameters
->options().shared())
2155 this->create_interp(target
);
2157 // Finish the .dynamic section to hold the dynamic data, and put
2158 // it in a PT_DYNAMIC segment.
2159 this->finish_dynamic_section(input_objects
, symtab
);
2161 // We should have added everything we need to the dynamic string
2163 this->dynpool_
.set_string_offsets();
2165 // Create the version sections. We can't do this until the
2166 // dynamic string table is complete.
2167 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2168 dynamic_symbols
, dynstr
);
2170 // Set the size of the _DYNAMIC symbol. We can't do this until
2171 // after we call create_version_sections.
2172 this->set_dynamic_symbol_size(symtab
);
2175 // Create segment headers.
2176 Output_segment_headers
* segment_headers
=
2177 (parameters
->options().relocatable()
2179 : new Output_segment_headers(this->segment_list_
));
2181 // Lay out the file header.
2182 Output_file_header
* file_header
2183 = new Output_file_header(target
, symtab
, segment_headers
,
2184 parameters
->options().entry());
2186 this->special_output_list_
.push_back(file_header
);
2187 if (segment_headers
!= NULL
)
2188 this->special_output_list_
.push_back(segment_headers
);
2190 // Find approriate places for orphan output sections if we are using
2192 if (this->script_options_
->saw_sections_clause())
2193 this->place_orphan_sections_in_script();
2195 Output_segment
* load_seg
;
2200 // Take a snapshot of the section layout as needed.
2201 if (target
->may_relax())
2202 this->prepare_for_relaxation();
2204 // Run the relaxation loop to lay out sections.
2207 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2208 phdr_seg
, segment_headers
, file_header
,
2212 while (target
->may_relax()
2213 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2215 // Set the file offsets of all the non-data sections we've seen so
2216 // far which don't have to wait for the input sections. We need
2217 // this in order to finalize local symbols in non-allocated
2219 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2221 // Set the section indexes of all unallocated sections seen so far,
2222 // in case any of them are somehow referenced by a symbol.
2223 shndx
= this->set_section_indexes(shndx
);
2225 // Create the symbol table sections.
2226 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2227 if (!parameters
->doing_static_link())
2228 this->assign_local_dynsym_offsets(input_objects
);
2230 // Process any symbol assignments from a linker script. This must
2231 // be called after the symbol table has been finalized.
2232 this->script_options_
->finalize_symbols(symtab
, this);
2234 // Create the incremental inputs sections.
2235 if (this->incremental_inputs_
)
2237 this->incremental_inputs_
->finalize();
2238 this->create_incremental_info_sections(symtab
);
2241 // Create the .shstrtab section.
2242 Output_section
* shstrtab_section
= this->create_shstrtab();
2244 // Set the file offsets of the rest of the non-data sections which
2245 // don't have to wait for the input sections.
2246 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2248 // Now that all sections have been created, set the section indexes
2249 // for any sections which haven't been done yet.
2250 shndx
= this->set_section_indexes(shndx
);
2252 // Create the section table header.
2253 this->create_shdrs(shstrtab_section
, &off
);
2255 // If there are no sections which require postprocessing, we can
2256 // handle the section names now, and avoid a resize later.
2257 if (!this->any_postprocessing_sections_
)
2259 off
= this->set_section_offsets(off
,
2260 POSTPROCESSING_SECTIONS_PASS
);
2262 this->set_section_offsets(off
,
2263 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2266 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2268 // Now we know exactly where everything goes in the output file
2269 // (except for non-allocated sections which require postprocessing).
2270 Output_data::layout_complete();
2272 this->output_file_size_
= off
;
2277 // Create a note header following the format defined in the ELF ABI.
2278 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2279 // of the section to create, DESCSZ is the size of the descriptor.
2280 // ALLOCATE is true if the section should be allocated in memory.
2281 // This returns the new note section. It sets *TRAILING_PADDING to
2282 // the number of trailing zero bytes required.
2285 Layout::create_note(const char* name
, int note_type
,
2286 const char* section_name
, size_t descsz
,
2287 bool allocate
, size_t* trailing_padding
)
2289 // Authorities all agree that the values in a .note field should
2290 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2291 // they differ on what the alignment is for 64-bit binaries.
2292 // The GABI says unambiguously they take 8-byte alignment:
2293 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2294 // Other documentation says alignment should always be 4 bytes:
2295 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2296 // GNU ld and GNU readelf both support the latter (at least as of
2297 // version 2.16.91), and glibc always generates the latter for
2298 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2300 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2301 const int size
= parameters
->target().get_size();
2303 const int size
= 32;
2306 // The contents of the .note section.
2307 size_t namesz
= strlen(name
) + 1;
2308 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2309 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2311 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2313 unsigned char* buffer
= new unsigned char[notehdrsz
];
2314 memset(buffer
, 0, notehdrsz
);
2316 bool is_big_endian
= parameters
->target().is_big_endian();
2322 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2323 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2324 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2328 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2329 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2330 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2333 else if (size
== 64)
2337 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2338 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2339 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2343 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2344 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2345 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2351 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2353 elfcpp::Elf_Xword flags
= 0;
2354 Output_section_order order
= ORDER_INVALID
;
2357 flags
= elfcpp::SHF_ALLOC
;
2358 order
= ORDER_RO_NOTE
;
2360 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2362 flags
, false, order
, false);
2366 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2369 os
->add_output_section_data(posd
);
2371 *trailing_padding
= aligned_descsz
- descsz
;
2376 // For an executable or shared library, create a note to record the
2377 // version of gold used to create the binary.
2380 Layout::create_gold_note()
2382 if (parameters
->options().relocatable()
2383 || parameters
->incremental_update())
2386 std::string desc
= std::string("gold ") + gold::get_version_string();
2388 size_t trailing_padding
;
2389 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2390 ".note.gnu.gold-version", desc
.size(),
2391 false, &trailing_padding
);
2395 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2396 os
->add_output_section_data(posd
);
2398 if (trailing_padding
> 0)
2400 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2401 os
->add_output_section_data(posd
);
2405 // Record whether the stack should be executable. This can be set
2406 // from the command line using the -z execstack or -z noexecstack
2407 // options. Otherwise, if any input file has a .note.GNU-stack
2408 // section with the SHF_EXECINSTR flag set, the stack should be
2409 // executable. Otherwise, if at least one input file a
2410 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2411 // section, we use the target default for whether the stack should be
2412 // executable. Otherwise, we don't generate a stack note. When
2413 // generating a object file, we create a .note.GNU-stack section with
2414 // the appropriate marking. When generating an executable or shared
2415 // library, we create a PT_GNU_STACK segment.
2418 Layout::create_executable_stack_info()
2420 bool is_stack_executable
;
2421 if (parameters
->options().is_execstack_set())
2422 is_stack_executable
= parameters
->options().is_stack_executable();
2423 else if (!this->input_with_gnu_stack_note_
)
2427 if (this->input_requires_executable_stack_
)
2428 is_stack_executable
= true;
2429 else if (this->input_without_gnu_stack_note_
)
2430 is_stack_executable
=
2431 parameters
->target().is_default_stack_executable();
2433 is_stack_executable
= false;
2436 if (parameters
->options().relocatable())
2438 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2439 elfcpp::Elf_Xword flags
= 0;
2440 if (is_stack_executable
)
2441 flags
|= elfcpp::SHF_EXECINSTR
;
2442 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2443 ORDER_INVALID
, false);
2447 if (this->script_options_
->saw_phdrs_clause())
2449 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2450 if (is_stack_executable
)
2451 flags
|= elfcpp::PF_X
;
2452 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2456 // If --build-id was used, set up the build ID note.
2459 Layout::create_build_id()
2461 if (!parameters
->options().user_set_build_id())
2464 const char* style
= parameters
->options().build_id();
2465 if (strcmp(style
, "none") == 0)
2468 // Set DESCSZ to the size of the note descriptor. When possible,
2469 // set DESC to the note descriptor contents.
2472 if (strcmp(style
, "md5") == 0)
2474 else if (strcmp(style
, "sha1") == 0)
2476 else if (strcmp(style
, "uuid") == 0)
2478 const size_t uuidsz
= 128 / 8;
2480 char buffer
[uuidsz
];
2481 memset(buffer
, 0, uuidsz
);
2483 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2485 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2489 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2490 release_descriptor(descriptor
, true);
2492 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
2493 else if (static_cast<size_t>(got
) != uuidsz
)
2494 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2498 desc
.assign(buffer
, uuidsz
);
2501 else if (strncmp(style
, "0x", 2) == 0)
2504 const char* p
= style
+ 2;
2507 if (hex_p(p
[0]) && hex_p(p
[1]))
2509 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
2513 else if (*p
== '-' || *p
== ':')
2516 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2519 descsz
= desc
.size();
2522 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2525 size_t trailing_padding
;
2526 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2527 ".note.gnu.build-id", descsz
, true,
2534 // We know the value already, so we fill it in now.
2535 gold_assert(desc
.size() == descsz
);
2537 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2538 os
->add_output_section_data(posd
);
2540 if (trailing_padding
!= 0)
2542 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2543 os
->add_output_section_data(posd
);
2548 // We need to compute a checksum after we have completed the
2550 gold_assert(trailing_padding
== 0);
2551 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
2552 os
->add_output_section_data(this->build_id_note_
);
2556 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2557 // field of the former should point to the latter. I'm not sure who
2558 // started this, but the GNU linker does it, and some tools depend
2562 Layout::link_stabs_sections()
2564 if (!this->have_stabstr_section_
)
2567 for (Section_list::iterator p
= this->section_list_
.begin();
2568 p
!= this->section_list_
.end();
2571 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
2574 const char* name
= (*p
)->name();
2575 if (strncmp(name
, ".stab", 5) != 0)
2578 size_t len
= strlen(name
);
2579 if (strcmp(name
+ len
- 3, "str") != 0)
2582 std::string
stab_name(name
, len
- 3);
2583 Output_section
* stab_sec
;
2584 stab_sec
= this->find_output_section(stab_name
.c_str());
2585 if (stab_sec
!= NULL
)
2586 stab_sec
->set_link_section(*p
);
2590 // Create .gnu_incremental_inputs and related sections needed
2591 // for the next run of incremental linking to check what has changed.
2594 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
2596 Incremental_inputs
* incr
= this->incremental_inputs_
;
2598 gold_assert(incr
!= NULL
);
2600 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2601 incr
->create_data_sections(symtab
);
2603 // Add the .gnu_incremental_inputs section.
2604 const char* incremental_inputs_name
=
2605 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
2606 Output_section
* incremental_inputs_os
=
2607 this->make_output_section(incremental_inputs_name
,
2608 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
2609 ORDER_INVALID
, false);
2610 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
2612 // Add the .gnu_incremental_symtab section.
2613 const char* incremental_symtab_name
=
2614 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
2615 Output_section
* incremental_symtab_os
=
2616 this->make_output_section(incremental_symtab_name
,
2617 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
2618 ORDER_INVALID
, false);
2619 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
2620 incremental_symtab_os
->set_entsize(4);
2622 // Add the .gnu_incremental_relocs section.
2623 const char* incremental_relocs_name
=
2624 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
2625 Output_section
* incremental_relocs_os
=
2626 this->make_output_section(incremental_relocs_name
,
2627 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
2628 ORDER_INVALID
, false);
2629 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
2630 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
2632 // Add the .gnu_incremental_got_plt section.
2633 const char* incremental_got_plt_name
=
2634 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
2635 Output_section
* incremental_got_plt_os
=
2636 this->make_output_section(incremental_got_plt_name
,
2637 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
2638 ORDER_INVALID
, false);
2639 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
2641 // Add the .gnu_incremental_strtab section.
2642 const char* incremental_strtab_name
=
2643 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
2644 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
2645 elfcpp::SHT_STRTAB
, 0,
2646 ORDER_INVALID
, false);
2647 Output_data_strtab
* strtab_data
=
2648 new Output_data_strtab(incr
->get_stringpool());
2649 incremental_strtab_os
->add_output_section_data(strtab_data
);
2651 incremental_inputs_os
->set_after_input_sections();
2652 incremental_symtab_os
->set_after_input_sections();
2653 incremental_relocs_os
->set_after_input_sections();
2654 incremental_got_plt_os
->set_after_input_sections();
2656 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
2657 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
2658 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
2659 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
2662 // Return whether SEG1 should be before SEG2 in the output file. This
2663 // is based entirely on the segment type and flags. When this is
2664 // called the segment addresses has normally not yet been set.
2667 Layout::segment_precedes(const Output_segment
* seg1
,
2668 const Output_segment
* seg2
)
2670 elfcpp::Elf_Word type1
= seg1
->type();
2671 elfcpp::Elf_Word type2
= seg2
->type();
2673 // The single PT_PHDR segment is required to precede any loadable
2674 // segment. We simply make it always first.
2675 if (type1
== elfcpp::PT_PHDR
)
2677 gold_assert(type2
!= elfcpp::PT_PHDR
);
2680 if (type2
== elfcpp::PT_PHDR
)
2683 // The single PT_INTERP segment is required to precede any loadable
2684 // segment. We simply make it always second.
2685 if (type1
== elfcpp::PT_INTERP
)
2687 gold_assert(type2
!= elfcpp::PT_INTERP
);
2690 if (type2
== elfcpp::PT_INTERP
)
2693 // We then put PT_LOAD segments before any other segments.
2694 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
2696 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
2699 // We put the PT_TLS segment last except for the PT_GNU_RELRO
2700 // segment, because that is where the dynamic linker expects to find
2701 // it (this is just for efficiency; other positions would also work
2703 if (type1
== elfcpp::PT_TLS
2704 && type2
!= elfcpp::PT_TLS
2705 && type2
!= elfcpp::PT_GNU_RELRO
)
2707 if (type2
== elfcpp::PT_TLS
2708 && type1
!= elfcpp::PT_TLS
2709 && type1
!= elfcpp::PT_GNU_RELRO
)
2712 // We put the PT_GNU_RELRO segment last, because that is where the
2713 // dynamic linker expects to find it (as with PT_TLS, this is just
2715 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
2717 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
2720 const elfcpp::Elf_Word flags1
= seg1
->flags();
2721 const elfcpp::Elf_Word flags2
= seg2
->flags();
2723 // The order of non-PT_LOAD segments is unimportant. We simply sort
2724 // by the numeric segment type and flags values. There should not
2725 // be more than one segment with the same type and flags.
2726 if (type1
!= elfcpp::PT_LOAD
)
2729 return type1
< type2
;
2730 gold_assert(flags1
!= flags2
);
2731 return flags1
< flags2
;
2734 // If the addresses are set already, sort by load address.
2735 if (seg1
->are_addresses_set())
2737 if (!seg2
->are_addresses_set())
2740 unsigned int section_count1
= seg1
->output_section_count();
2741 unsigned int section_count2
= seg2
->output_section_count();
2742 if (section_count1
== 0 && section_count2
> 0)
2744 if (section_count1
> 0 && section_count2
== 0)
2747 uint64_t paddr1
= (seg1
->are_addresses_set()
2749 : seg1
->first_section_load_address());
2750 uint64_t paddr2
= (seg2
->are_addresses_set()
2752 : seg2
->first_section_load_address());
2754 if (paddr1
!= paddr2
)
2755 return paddr1
< paddr2
;
2757 else if (seg2
->are_addresses_set())
2760 // A segment which holds large data comes after a segment which does
2761 // not hold large data.
2762 if (seg1
->is_large_data_segment())
2764 if (!seg2
->is_large_data_segment())
2767 else if (seg2
->is_large_data_segment())
2770 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
2771 // segments come before writable segments. Then writable segments
2772 // with data come before writable segments without data. Then
2773 // executable segments come before non-executable segments. Then
2774 // the unlikely case of a non-readable segment comes before the
2775 // normal case of a readable segment. If there are multiple
2776 // segments with the same type and flags, we require that the
2777 // address be set, and we sort by virtual address and then physical
2779 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
2780 return (flags1
& elfcpp::PF_W
) == 0;
2781 if ((flags1
& elfcpp::PF_W
) != 0
2782 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
2783 return seg1
->has_any_data_sections();
2784 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
2785 return (flags1
& elfcpp::PF_X
) != 0;
2786 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
2787 return (flags1
& elfcpp::PF_R
) == 0;
2789 // We shouldn't get here--we shouldn't create segments which we
2790 // can't distinguish.
2794 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2797 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
2799 uint64_t unsigned_off
= off
;
2800 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
2801 | (addr
& (abi_pagesize
- 1)));
2802 if (aligned_off
< unsigned_off
)
2803 aligned_off
+= abi_pagesize
;
2807 // Set the file offsets of all the segments, and all the sections they
2808 // contain. They have all been created. LOAD_SEG must be be laid out
2809 // first. Return the offset of the data to follow.
2812 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
2813 unsigned int* pshndx
)
2815 // Sort them into the final order.
2816 std::sort(this->segment_list_
.begin(), this->segment_list_
.end(),
2817 Layout::Compare_segments());
2819 // Find the PT_LOAD segments, and set their addresses and offsets
2820 // and their section's addresses and offsets.
2822 if (parameters
->options().user_set_Ttext())
2823 addr
= parameters
->options().Ttext();
2824 else if (parameters
->options().output_is_position_independent())
2827 addr
= target
->default_text_segment_address();
2830 // If LOAD_SEG is NULL, then the file header and segment headers
2831 // will not be loadable. But they still need to be at offset 0 in
2832 // the file. Set their offsets now.
2833 if (load_seg
== NULL
)
2835 for (Data_list::iterator p
= this->special_output_list_
.begin();
2836 p
!= this->special_output_list_
.end();
2839 off
= align_address(off
, (*p
)->addralign());
2840 (*p
)->set_address_and_file_offset(0, off
);
2841 off
+= (*p
)->data_size();
2845 unsigned int increase_relro
= this->increase_relro_
;
2846 if (this->script_options_
->saw_sections_clause())
2849 const bool check_sections
= parameters
->options().check_sections();
2850 Output_segment
* last_load_segment
= NULL
;
2852 for (Segment_list::iterator p
= this->segment_list_
.begin();
2853 p
!= this->segment_list_
.end();
2856 if ((*p
)->type() == elfcpp::PT_LOAD
)
2858 if (load_seg
!= NULL
&& load_seg
!= *p
)
2862 bool are_addresses_set
= (*p
)->are_addresses_set();
2863 if (are_addresses_set
)
2865 // When it comes to setting file offsets, we care about
2866 // the physical address.
2867 addr
= (*p
)->paddr();
2869 else if (parameters
->options().user_set_Tdata()
2870 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2871 && (!parameters
->options().user_set_Tbss()
2872 || (*p
)->has_any_data_sections()))
2874 addr
= parameters
->options().Tdata();
2875 are_addresses_set
= true;
2877 else if (parameters
->options().user_set_Tbss()
2878 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2879 && !(*p
)->has_any_data_sections())
2881 addr
= parameters
->options().Tbss();
2882 are_addresses_set
= true;
2885 uint64_t orig_addr
= addr
;
2886 uint64_t orig_off
= off
;
2888 uint64_t aligned_addr
= 0;
2889 uint64_t abi_pagesize
= target
->abi_pagesize();
2890 uint64_t common_pagesize
= target
->common_pagesize();
2892 if (!parameters
->options().nmagic()
2893 && !parameters
->options().omagic())
2894 (*p
)->set_minimum_p_align(common_pagesize
);
2896 if (!are_addresses_set
)
2898 // Skip the address forward one page, maintaining the same
2899 // position within the page. This lets us store both segments
2900 // overlapping on a single page in the file, but the loader will
2901 // put them on different pages in memory. We will revisit this
2902 // decision once we know the size of the segment.
2904 addr
= align_address(addr
, (*p
)->maximum_alignment());
2905 aligned_addr
= addr
;
2907 if ((addr
& (abi_pagesize
- 1)) != 0)
2908 addr
= addr
+ abi_pagesize
;
2910 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2913 if (!parameters
->options().nmagic()
2914 && !parameters
->options().omagic())
2915 off
= align_file_offset(off
, addr
, abi_pagesize
);
2916 else if (load_seg
== NULL
)
2918 // This is -N or -n with a section script which prevents
2919 // us from using a load segment. We need to ensure that
2920 // the file offset is aligned to the alignment of the
2921 // segment. This is because the linker script
2922 // implicitly assumed a zero offset. If we don't align
2923 // here, then the alignment of the sections in the
2924 // linker script may not match the alignment of the
2925 // sections in the set_section_addresses call below,
2926 // causing an error about dot moving backward.
2927 off
= align_address(off
, (*p
)->maximum_alignment());
2930 unsigned int shndx_hold
= *pshndx
;
2931 bool has_relro
= false;
2932 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
2937 // Now that we know the size of this segment, we may be able
2938 // to save a page in memory, at the cost of wasting some
2939 // file space, by instead aligning to the start of a new
2940 // page. Here we use the real machine page size rather than
2941 // the ABI mandated page size. If the segment has been
2942 // aligned so that the relro data ends at a page boundary,
2943 // we do not try to realign it.
2945 if (!are_addresses_set
2947 && aligned_addr
!= addr
2948 && !parameters
->incremental_update())
2950 uint64_t first_off
= (common_pagesize
2952 & (common_pagesize
- 1)));
2953 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
2956 && ((aligned_addr
& ~ (common_pagesize
- 1))
2957 != (new_addr
& ~ (common_pagesize
- 1)))
2958 && first_off
+ last_off
<= common_pagesize
)
2960 *pshndx
= shndx_hold
;
2961 addr
= align_address(aligned_addr
, common_pagesize
);
2962 addr
= align_address(addr
, (*p
)->maximum_alignment());
2963 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2964 off
= align_file_offset(off
, addr
, abi_pagesize
);
2966 increase_relro
= this->increase_relro_
;
2967 if (this->script_options_
->saw_sections_clause())
2971 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
2980 // Implement --check-sections. We know that the segments
2981 // are sorted by LMA.
2982 if (check_sections
&& last_load_segment
!= NULL
)
2984 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
2985 if (last_load_segment
->paddr() + last_load_segment
->memsz()
2988 unsigned long long lb1
= last_load_segment
->paddr();
2989 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
2990 unsigned long long lb2
= (*p
)->paddr();
2991 unsigned long long le2
= lb2
+ (*p
)->memsz();
2992 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
2993 "[0x%llx -> 0x%llx]"),
2994 lb1
, le1
, lb2
, le2
);
2997 last_load_segment
= *p
;
3001 // Handle the non-PT_LOAD segments, setting their offsets from their
3002 // section's offsets.
3003 for (Segment_list::iterator p
= this->segment_list_
.begin();
3004 p
!= this->segment_list_
.end();
3007 if ((*p
)->type() != elfcpp::PT_LOAD
)
3008 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3013 // Set the TLS offsets for each section in the PT_TLS segment.
3014 if (this->tls_segment_
!= NULL
)
3015 this->tls_segment_
->set_tls_offsets();
3020 // Set the offsets of all the allocated sections when doing a
3021 // relocatable link. This does the same jobs as set_segment_offsets,
3022 // only for a relocatable link.
3025 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3026 unsigned int* pshndx
)
3030 file_header
->set_address_and_file_offset(0, 0);
3031 off
+= file_header
->data_size();
3033 for (Section_list::iterator p
= this->section_list_
.begin();
3034 p
!= this->section_list_
.end();
3037 // We skip unallocated sections here, except that group sections
3038 // have to come first.
3039 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3040 && (*p
)->type() != elfcpp::SHT_GROUP
)
3043 off
= align_address(off
, (*p
)->addralign());
3045 // The linker script might have set the address.
3046 if (!(*p
)->is_address_valid())
3047 (*p
)->set_address(0);
3048 (*p
)->set_file_offset(off
);
3049 (*p
)->finalize_data_size();
3050 off
+= (*p
)->data_size();
3052 (*p
)->set_out_shndx(*pshndx
);
3059 // Set the file offset of all the sections not associated with a
3063 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3065 off_t startoff
= off
;
3068 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3069 p
!= this->unattached_section_list_
.end();
3072 // The symtab section is handled in create_symtab_sections.
3073 if (*p
== this->symtab_section_
)
3076 // If we've already set the data size, don't set it again.
3077 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3080 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3081 && (*p
)->requires_postprocessing())
3083 (*p
)->create_postprocessing_buffer();
3084 this->any_postprocessing_sections_
= true;
3087 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3088 && (*p
)->after_input_sections())
3090 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3091 && (!(*p
)->after_input_sections()
3092 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3094 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3095 && (!(*p
)->after_input_sections()
3096 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3099 if (!parameters
->incremental_update())
3101 off
= align_address(off
, (*p
)->addralign());
3102 (*p
)->set_file_offset(off
);
3103 (*p
)->finalize_data_size();
3107 // Incremental update: allocate file space from free list.
3108 (*p
)->pre_finalize_data_size();
3109 off_t current_size
= (*p
)->current_data_size();
3110 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3113 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3114 this->free_list_
.dump();
3115 gold_assert((*p
)->output_section() != NULL
);
3116 gold_fatal(_("out of patch space for section %s; "
3117 "relink with --incremental-full"),
3118 (*p
)->output_section()->name());
3120 (*p
)->set_file_offset(off
);
3121 (*p
)->finalize_data_size();
3122 if ((*p
)->data_size() > current_size
)
3124 gold_assert((*p
)->output_section() != NULL
);
3125 gold_fatal(_("%s: section changed size; "
3126 "relink with --incremental-full"),
3127 (*p
)->output_section()->name());
3129 gold_debug(DEBUG_INCREMENTAL
,
3130 "set_section_offsets: %08lx %08lx %s",
3131 static_cast<long>(off
),
3132 static_cast<long>((*p
)->data_size()),
3133 ((*p
)->output_section() != NULL
3134 ? (*p
)->output_section()->name() : "(special)"));
3137 off
+= (*p
)->data_size();
3141 // At this point the name must be set.
3142 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3143 this->namepool_
.add((*p
)->name(), false, NULL
);
3148 // Set the section indexes of all the sections not associated with a
3152 Layout::set_section_indexes(unsigned int shndx
)
3154 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3155 p
!= this->unattached_section_list_
.end();
3158 if (!(*p
)->has_out_shndx())
3160 (*p
)->set_out_shndx(shndx
);
3167 // Set the section addresses according to the linker script. This is
3168 // only called when we see a SECTIONS clause. This returns the
3169 // program segment which should hold the file header and segment
3170 // headers, if any. It will return NULL if they should not be in a
3174 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3176 Script_sections
* ss
= this->script_options_
->script_sections();
3177 gold_assert(ss
->saw_sections_clause());
3178 return this->script_options_
->set_section_addresses(symtab
, this);
3181 // Place the orphan sections in the linker script.
3184 Layout::place_orphan_sections_in_script()
3186 Script_sections
* ss
= this->script_options_
->script_sections();
3187 gold_assert(ss
->saw_sections_clause());
3189 // Place each orphaned output section in the script.
3190 for (Section_list::iterator p
= this->section_list_
.begin();
3191 p
!= this->section_list_
.end();
3194 if (!(*p
)->found_in_sections_clause())
3195 ss
->place_orphan(*p
);
3199 // Count the local symbols in the regular symbol table and the dynamic
3200 // symbol table, and build the respective string pools.
3203 Layout::count_local_symbols(const Task
* task
,
3204 const Input_objects
* input_objects
)
3206 // First, figure out an upper bound on the number of symbols we'll
3207 // be inserting into each pool. This helps us create the pools with
3208 // the right size, to avoid unnecessary hashtable resizing.
3209 unsigned int symbol_count
= 0;
3210 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3211 p
!= input_objects
->relobj_end();
3213 symbol_count
+= (*p
)->local_symbol_count();
3215 // Go from "upper bound" to "estimate." We overcount for two
3216 // reasons: we double-count symbols that occur in more than one
3217 // object file, and we count symbols that are dropped from the
3218 // output. Add it all together and assume we overcount by 100%.
3221 // We assume all symbols will go into both the sympool and dynpool.
3222 this->sympool_
.reserve(symbol_count
);
3223 this->dynpool_
.reserve(symbol_count
);
3225 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3226 p
!= input_objects
->relobj_end();
3229 Task_lock_obj
<Object
> tlo(task
, *p
);
3230 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3234 // Create the symbol table sections. Here we also set the final
3235 // values of the symbols. At this point all the loadable sections are
3236 // fully laid out. SHNUM is the number of sections so far.
3239 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3240 Symbol_table
* symtab
,
3246 if (parameters
->target().get_size() == 32)
3248 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3251 else if (parameters
->target().get_size() == 64)
3253 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3259 // Compute file offsets relative to the start of the symtab section.
3262 // Save space for the dummy symbol at the start of the section. We
3263 // never bother to write this out--it will just be left as zero.
3265 unsigned int local_symbol_index
= 1;
3267 // Add STT_SECTION symbols for each Output section which needs one.
3268 for (Section_list::iterator p
= this->section_list_
.begin();
3269 p
!= this->section_list_
.end();
3272 if (!(*p
)->needs_symtab_index())
3273 (*p
)->set_symtab_index(-1U);
3276 (*p
)->set_symtab_index(local_symbol_index
);
3277 ++local_symbol_index
;
3282 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3283 p
!= input_objects
->relobj_end();
3286 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3288 off
+= (index
- local_symbol_index
) * symsize
;
3289 local_symbol_index
= index
;
3292 unsigned int local_symcount
= local_symbol_index
;
3293 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3296 size_t dyn_global_index
;
3298 if (this->dynsym_section_
== NULL
)
3301 dyn_global_index
= 0;
3306 dyn_global_index
= this->dynsym_section_
->info();
3307 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3308 dynoff
= this->dynsym_section_
->offset() + locsize
;
3309 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3310 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3311 == this->dynsym_section_
->data_size() - locsize
);
3314 off_t global_off
= off
;
3315 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3316 &this->sympool_
, &local_symcount
);
3318 if (!parameters
->options().strip_all())
3320 this->sympool_
.set_string_offsets();
3322 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3323 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3327 this->symtab_section_
= osymtab
;
3329 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3331 osymtab
->add_output_section_data(pos
);
3333 // We generate a .symtab_shndx section if we have more than
3334 // SHN_LORESERVE sections. Technically it is possible that we
3335 // don't need one, because it is possible that there are no
3336 // symbols in any of sections with indexes larger than
3337 // SHN_LORESERVE. That is probably unusual, though, and it is
3338 // easier to always create one than to compute section indexes
3339 // twice (once here, once when writing out the symbols).
3340 if (shnum
>= elfcpp::SHN_LORESERVE
)
3342 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3344 Output_section
* osymtab_xindex
=
3345 this->make_output_section(symtab_xindex_name
,
3346 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3347 ORDER_INVALID
, false);
3349 size_t symcount
= off
/ symsize
;
3350 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3352 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3354 osymtab_xindex
->set_link_section(osymtab
);
3355 osymtab_xindex
->set_addralign(4);
3356 osymtab_xindex
->set_entsize(4);
3358 osymtab_xindex
->set_after_input_sections();
3360 // This tells the driver code to wait until the symbol table
3361 // has written out before writing out the postprocessing
3362 // sections, including the .symtab_shndx section.
3363 this->any_postprocessing_sections_
= true;
3366 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3367 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3372 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3373 ostrtab
->add_output_section_data(pstr
);
3376 if (!parameters
->incremental_update())
3377 symtab_off
= align_address(*poff
, align
);
3380 symtab_off
= this->allocate(off
, align
, *poff
);
3382 gold_fatal(_("out of patch space for symbol table; "
3383 "relink with --incremental-full"));
3384 gold_debug(DEBUG_INCREMENTAL
,
3385 "create_symtab_sections: %08lx %08lx .symtab",
3386 static_cast<long>(symtab_off
),
3387 static_cast<long>(off
));
3390 symtab
->set_file_offset(symtab_off
+ global_off
);
3391 osymtab
->set_file_offset(symtab_off
);
3392 osymtab
->finalize_data_size();
3393 osymtab
->set_link_section(ostrtab
);
3394 osymtab
->set_info(local_symcount
);
3395 osymtab
->set_entsize(symsize
);
3397 if (symtab_off
+ off
> *poff
)
3398 *poff
= symtab_off
+ off
;
3402 // Create the .shstrtab section, which holds the names of the
3403 // sections. At the time this is called, we have created all the
3404 // output sections except .shstrtab itself.
3407 Layout::create_shstrtab()
3409 // FIXME: We don't need to create a .shstrtab section if we are
3410 // stripping everything.
3412 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
3414 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
3415 ORDER_INVALID
, false);
3417 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
3419 // We can't write out this section until we've set all the
3420 // section names, and we don't set the names of compressed
3421 // output sections until relocations are complete. FIXME: With
3422 // the current names we use, this is unnecessary.
3423 os
->set_after_input_sections();
3426 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
3427 os
->add_output_section_data(posd
);
3432 // Create the section headers. SIZE is 32 or 64. OFF is the file
3436 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
3438 Output_section_headers
* oshdrs
;
3439 oshdrs
= new Output_section_headers(this,
3440 &this->segment_list_
,
3441 &this->section_list_
,
3442 &this->unattached_section_list_
,
3446 if (!parameters
->incremental_update())
3447 off
= align_address(*poff
, oshdrs
->addralign());
3450 oshdrs
->pre_finalize_data_size();
3451 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
3453 gold_fatal(_("out of patch space for section header table; "
3454 "relink with --incremental-full"));
3455 gold_debug(DEBUG_INCREMENTAL
,
3456 "create_shdrs: %08lx %08lx (section header table)",
3457 static_cast<long>(off
),
3458 static_cast<long>(off
+ oshdrs
->data_size()));
3460 oshdrs
->set_address_and_file_offset(0, off
);
3461 off
+= oshdrs
->data_size();
3464 this->section_headers_
= oshdrs
;
3467 // Count the allocated sections.
3470 Layout::allocated_output_section_count() const
3472 size_t section_count
= 0;
3473 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3474 p
!= this->segment_list_
.end();
3476 section_count
+= (*p
)->output_section_count();
3477 return section_count
;
3480 // Create the dynamic symbol table.
3483 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
3484 Symbol_table
* symtab
,
3485 Output_section
** pdynstr
,
3486 unsigned int* plocal_dynamic_count
,
3487 std::vector
<Symbol
*>* pdynamic_symbols
,
3488 Versions
* pversions
)
3490 // Count all the symbols in the dynamic symbol table, and set the
3491 // dynamic symbol indexes.
3493 // Skip symbol 0, which is always all zeroes.
3494 unsigned int index
= 1;
3496 // Add STT_SECTION symbols for each Output section which needs one.
3497 for (Section_list::iterator p
= this->section_list_
.begin();
3498 p
!= this->section_list_
.end();
3501 if (!(*p
)->needs_dynsym_index())
3502 (*p
)->set_dynsym_index(-1U);
3505 (*p
)->set_dynsym_index(index
);
3510 // Count the local symbols that need to go in the dynamic symbol table,
3511 // and set the dynamic symbol indexes.
3512 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3513 p
!= input_objects
->relobj_end();
3516 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
3520 unsigned int local_symcount
= index
;
3521 *plocal_dynamic_count
= local_symcount
;
3523 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
3524 &this->dynpool_
, pversions
);
3528 const int size
= parameters
->target().get_size();
3531 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3534 else if (size
== 64)
3536 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3542 // Create the dynamic symbol table section.
3544 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
3548 ORDER_DYNAMIC_LINKER
,
3551 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
3554 dynsym
->add_output_section_data(odata
);
3556 dynsym
->set_info(local_symcount
);
3557 dynsym
->set_entsize(symsize
);
3558 dynsym
->set_addralign(align
);
3560 this->dynsym_section_
= dynsym
;
3562 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3563 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
3564 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
3566 // If there are more than SHN_LORESERVE allocated sections, we
3567 // create a .dynsym_shndx section. It is possible that we don't
3568 // need one, because it is possible that there are no dynamic
3569 // symbols in any of the sections with indexes larger than
3570 // SHN_LORESERVE. This is probably unusual, though, and at this
3571 // time we don't know the actual section indexes so it is
3572 // inconvenient to check.
3573 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
3575 Output_section
* dynsym_xindex
=
3576 this->choose_output_section(NULL
, ".dynsym_shndx",
3577 elfcpp::SHT_SYMTAB_SHNDX
,
3579 false, ORDER_DYNAMIC_LINKER
, false);
3581 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
3583 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
3585 dynsym_xindex
->set_link_section(dynsym
);
3586 dynsym_xindex
->set_addralign(4);
3587 dynsym_xindex
->set_entsize(4);
3589 dynsym_xindex
->set_after_input_sections();
3591 // This tells the driver code to wait until the symbol table has
3592 // written out before writing out the postprocessing sections,
3593 // including the .dynsym_shndx section.
3594 this->any_postprocessing_sections_
= true;
3597 // Create the dynamic string table section.
3599 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
3603 ORDER_DYNAMIC_LINKER
,
3606 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
3607 dynstr
->add_output_section_data(strdata
);
3609 dynsym
->set_link_section(dynstr
);
3610 this->dynamic_section_
->set_link_section(dynstr
);
3612 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
3613 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
3617 // Create the hash tables.
3619 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
3620 || strcmp(parameters
->options().hash_style(), "both") == 0)
3622 unsigned char* phash
;
3623 unsigned int hashlen
;
3624 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
3627 Output_section
* hashsec
=
3628 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
3629 elfcpp::SHF_ALLOC
, false,
3630 ORDER_DYNAMIC_LINKER
, false);
3632 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3636 hashsec
->add_output_section_data(hashdata
);
3638 hashsec
->set_link_section(dynsym
);
3639 hashsec
->set_entsize(4);
3641 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
3644 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
3645 || strcmp(parameters
->options().hash_style(), "both") == 0)
3647 unsigned char* phash
;
3648 unsigned int hashlen
;
3649 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
3652 Output_section
* hashsec
=
3653 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
3654 elfcpp::SHF_ALLOC
, false,
3655 ORDER_DYNAMIC_LINKER
, false);
3657 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3661 hashsec
->add_output_section_data(hashdata
);
3663 hashsec
->set_link_section(dynsym
);
3665 // For a 64-bit target, the entries in .gnu.hash do not have a
3666 // uniform size, so we only set the entry size for a 32-bit
3668 if (parameters
->target().get_size() == 32)
3669 hashsec
->set_entsize(4);
3671 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
3675 // Assign offsets to each local portion of the dynamic symbol table.
3678 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
3680 Output_section
* dynsym
= this->dynsym_section_
;
3681 gold_assert(dynsym
!= NULL
);
3683 off_t off
= dynsym
->offset();
3685 // Skip the dummy symbol at the start of the section.
3686 off
+= dynsym
->entsize();
3688 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3689 p
!= input_objects
->relobj_end();
3692 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
3693 off
+= count
* dynsym
->entsize();
3697 // Create the version sections.
3700 Layout::create_version_sections(const Versions
* versions
,
3701 const Symbol_table
* symtab
,
3702 unsigned int local_symcount
,
3703 const std::vector
<Symbol
*>& dynamic_symbols
,
3704 const Output_section
* dynstr
)
3706 if (!versions
->any_defs() && !versions
->any_needs())
3709 switch (parameters
->size_and_endianness())
3711 #ifdef HAVE_TARGET_32_LITTLE
3712 case Parameters::TARGET_32_LITTLE
:
3713 this->sized_create_version_sections
<32, false>(versions
, symtab
,
3715 dynamic_symbols
, dynstr
);
3718 #ifdef HAVE_TARGET_32_BIG
3719 case Parameters::TARGET_32_BIG
:
3720 this->sized_create_version_sections
<32, true>(versions
, symtab
,
3722 dynamic_symbols
, dynstr
);
3725 #ifdef HAVE_TARGET_64_LITTLE
3726 case Parameters::TARGET_64_LITTLE
:
3727 this->sized_create_version_sections
<64, false>(versions
, symtab
,
3729 dynamic_symbols
, dynstr
);
3732 #ifdef HAVE_TARGET_64_BIG
3733 case Parameters::TARGET_64_BIG
:
3734 this->sized_create_version_sections
<64, true>(versions
, symtab
,
3736 dynamic_symbols
, dynstr
);
3744 // Create the version sections, sized version.
3746 template<int size
, bool big_endian
>
3748 Layout::sized_create_version_sections(
3749 const Versions
* versions
,
3750 const Symbol_table
* symtab
,
3751 unsigned int local_symcount
,
3752 const std::vector
<Symbol
*>& dynamic_symbols
,
3753 const Output_section
* dynstr
)
3755 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
3756 elfcpp::SHT_GNU_versym
,
3759 ORDER_DYNAMIC_LINKER
,
3762 unsigned char* vbuf
;
3764 versions
->symbol_section_contents
<size
, big_endian
>(symtab
, &this->dynpool_
,
3769 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
3772 vsec
->add_output_section_data(vdata
);
3773 vsec
->set_entsize(2);
3774 vsec
->set_link_section(this->dynsym_section_
);
3776 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3777 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
3779 if (versions
->any_defs())
3781 Output_section
* vdsec
;
3782 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
3783 elfcpp::SHT_GNU_verdef
,
3785 false, ORDER_DYNAMIC_LINKER
, false);
3787 unsigned char* vdbuf
;
3788 unsigned int vdsize
;
3789 unsigned int vdentries
;
3790 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
, &vdbuf
,
3791 &vdsize
, &vdentries
);
3793 Output_section_data
* vddata
=
3794 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
3796 vdsec
->add_output_section_data(vddata
);
3797 vdsec
->set_link_section(dynstr
);
3798 vdsec
->set_info(vdentries
);
3800 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
3801 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
3804 if (versions
->any_needs())
3806 Output_section
* vnsec
;
3807 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
3808 elfcpp::SHT_GNU_verneed
,
3810 false, ORDER_DYNAMIC_LINKER
, false);
3812 unsigned char* vnbuf
;
3813 unsigned int vnsize
;
3814 unsigned int vnentries
;
3815 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
3819 Output_section_data
* vndata
=
3820 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
3822 vnsec
->add_output_section_data(vndata
);
3823 vnsec
->set_link_section(dynstr
);
3824 vnsec
->set_info(vnentries
);
3826 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
3827 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
3831 // Create the .interp section and PT_INTERP segment.
3834 Layout::create_interp(const Target
* target
)
3836 const char* interp
= parameters
->options().dynamic_linker();
3839 interp
= target
->dynamic_linker();
3840 gold_assert(interp
!= NULL
);
3843 size_t len
= strlen(interp
) + 1;
3845 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
3847 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
3848 elfcpp::SHT_PROGBITS
,
3850 false, ORDER_INTERP
,
3852 osec
->add_output_section_data(odata
);
3854 if (!this->script_options_
->saw_phdrs_clause())
3856 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_INTERP
,
3858 oseg
->add_output_section_to_nonload(osec
, elfcpp::PF_R
);
3862 // Add dynamic tags for the PLT and the dynamic relocs. This is
3863 // called by the target-specific code. This does nothing if not doing
3866 // USE_REL is true for REL relocs rather than RELA relocs.
3868 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3870 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3871 // and we also set DT_PLTREL. We use PLT_REL's output section, since
3872 // some targets have multiple reloc sections in PLT_REL.
3874 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3875 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3877 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3881 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
3882 const Output_data
* plt_rel
,
3883 const Output_data_reloc_generic
* dyn_rel
,
3884 bool add_debug
, bool dynrel_includes_plt
)
3886 Output_data_dynamic
* odyn
= this->dynamic_data_
;
3890 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
3891 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
3893 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
3895 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
3896 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
3897 odyn
->add_constant(elfcpp::DT_PLTREL
,
3898 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
3901 if (dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
3903 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
3905 if (plt_rel
!= NULL
&& dynrel_includes_plt
)
3906 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3909 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3911 const int size
= parameters
->target().get_size();
3916 rel_tag
= elfcpp::DT_RELENT
;
3918 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
3919 else if (size
== 64)
3920 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
3926 rel_tag
= elfcpp::DT_RELAENT
;
3928 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
3929 else if (size
== 64)
3930 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
3934 odyn
->add_constant(rel_tag
, rel_size
);
3936 if (parameters
->options().combreloc())
3938 size_t c
= dyn_rel
->relative_reloc_count();
3940 odyn
->add_constant((use_rel
3941 ? elfcpp::DT_RELCOUNT
3942 : elfcpp::DT_RELACOUNT
),
3947 if (add_debug
&& !parameters
->options().shared())
3949 // The value of the DT_DEBUG tag is filled in by the dynamic
3950 // linker at run time, and used by the debugger.
3951 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
3955 // Finish the .dynamic section and PT_DYNAMIC segment.
3958 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
3959 const Symbol_table
* symtab
)
3961 if (!this->script_options_
->saw_phdrs_clause())
3963 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
3966 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
3967 elfcpp::PF_R
| elfcpp::PF_W
);
3970 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3972 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
3973 p
!= input_objects
->dynobj_end();
3976 if (!(*p
)->is_needed()
3977 && !(*p
)->is_incremental()
3978 && (*p
)->input_file()->options().as_needed())
3980 // This dynamic object was linked with --as-needed, but it
3985 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
3988 if (parameters
->options().shared())
3990 const char* soname
= parameters
->options().soname();
3992 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
3995 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
3996 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
3997 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
3999 sym
= symtab
->lookup(parameters
->options().fini());
4000 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4001 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4003 // Look for .init_array, .preinit_array and .fini_array by checking
4005 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4006 p
!= this->section_list_
.end();
4008 switch((*p
)->type())
4010 case elfcpp::SHT_FINI_ARRAY
:
4011 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4012 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4014 case elfcpp::SHT_INIT_ARRAY
:
4015 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4016 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4018 case elfcpp::SHT_PREINIT_ARRAY
:
4019 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4020 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4026 // Add a DT_RPATH entry if needed.
4027 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4030 std::string rpath_val
;
4031 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4035 if (rpath_val
.empty())
4036 rpath_val
= p
->name();
4039 // Eliminate duplicates.
4040 General_options::Dir_list::const_iterator q
;
4041 for (q
= rpath
.begin(); q
!= p
; ++q
)
4042 if (q
->name() == p
->name())
4047 rpath_val
+= p
->name();
4052 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4053 if (parameters
->options().enable_new_dtags())
4054 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4057 // Look for text segments that have dynamic relocations.
4058 bool have_textrel
= false;
4059 if (!this->script_options_
->saw_sections_clause())
4061 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4062 p
!= this->segment_list_
.end();
4065 if (((*p
)->flags() & elfcpp::PF_W
) == 0
4066 && (*p
)->has_dynamic_reloc())
4068 have_textrel
= true;
4075 // We don't know the section -> segment mapping, so we are
4076 // conservative and just look for readonly sections with
4077 // relocations. If those sections wind up in writable segments,
4078 // then we have created an unnecessary DT_TEXTREL entry.
4079 for (Section_list::const_iterator p
= this->section_list_
.begin();
4080 p
!= this->section_list_
.end();
4083 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4084 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4085 && ((*p
)->has_dynamic_reloc()))
4087 have_textrel
= true;
4093 // Add a DT_FLAGS entry. We add it even if no flags are set so that
4094 // post-link tools can easily modify these flags if desired.
4095 unsigned int flags
= 0;
4098 // Add a DT_TEXTREL for compatibility with older loaders.
4099 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4100 flags
|= elfcpp::DF_TEXTREL
;
4102 if (parameters
->options().text())
4103 gold_error(_("read-only segment has dynamic relocations"));
4104 else if (parameters
->options().warn_shared_textrel()
4105 && parameters
->options().shared())
4106 gold_warning(_("shared library text segment is not shareable"));
4108 if (parameters
->options().shared() && this->has_static_tls())
4109 flags
|= elfcpp::DF_STATIC_TLS
;
4110 if (parameters
->options().origin())
4111 flags
|= elfcpp::DF_ORIGIN
;
4112 if (parameters
->options().Bsymbolic())
4114 flags
|= elfcpp::DF_SYMBOLIC
;
4115 // Add DT_SYMBOLIC for compatibility with older loaders.
4116 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4118 if (parameters
->options().now())
4119 flags
|= elfcpp::DF_BIND_NOW
;
4120 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4123 if (parameters
->options().initfirst())
4124 flags
|= elfcpp::DF_1_INITFIRST
;
4125 if (parameters
->options().interpose())
4126 flags
|= elfcpp::DF_1_INTERPOSE
;
4127 if (parameters
->options().loadfltr())
4128 flags
|= elfcpp::DF_1_LOADFLTR
;
4129 if (parameters
->options().nodefaultlib())
4130 flags
|= elfcpp::DF_1_NODEFLIB
;
4131 if (parameters
->options().nodelete())
4132 flags
|= elfcpp::DF_1_NODELETE
;
4133 if (parameters
->options().nodlopen())
4134 flags
|= elfcpp::DF_1_NOOPEN
;
4135 if (parameters
->options().nodump())
4136 flags
|= elfcpp::DF_1_NODUMP
;
4137 if (!parameters
->options().shared())
4138 flags
&= ~(elfcpp::DF_1_INITFIRST
4139 | elfcpp::DF_1_NODELETE
4140 | elfcpp::DF_1_NOOPEN
);
4141 if (parameters
->options().origin())
4142 flags
|= elfcpp::DF_1_ORIGIN
;
4143 if (parameters
->options().now())
4144 flags
|= elfcpp::DF_1_NOW
;
4146 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4149 // Set the size of the _DYNAMIC symbol table to be the size of the
4153 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4155 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4156 odyn
->finalize_data_size();
4157 off_t data_size
= odyn
->data_size();
4158 const int size
= parameters
->target().get_size();
4160 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4161 else if (size
== 64)
4162 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4167 // The mapping of input section name prefixes to output section names.
4168 // In some cases one prefix is itself a prefix of another prefix; in
4169 // such a case the longer prefix must come first. These prefixes are
4170 // based on the GNU linker default ELF linker script.
4172 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4173 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4175 MAPPING_INIT(".text.", ".text"),
4176 MAPPING_INIT(".ctors.", ".ctors"),
4177 MAPPING_INIT(".dtors.", ".dtors"),
4178 MAPPING_INIT(".rodata.", ".rodata"),
4179 MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
4180 MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
4181 MAPPING_INIT(".data.", ".data"),
4182 MAPPING_INIT(".bss.", ".bss"),
4183 MAPPING_INIT(".tdata.", ".tdata"),
4184 MAPPING_INIT(".tbss.", ".tbss"),
4185 MAPPING_INIT(".init_array.", ".init_array"),
4186 MAPPING_INIT(".fini_array.", ".fini_array"),
4187 MAPPING_INIT(".sdata.", ".sdata"),
4188 MAPPING_INIT(".sbss.", ".sbss"),
4189 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4190 // differently depending on whether it is creating a shared library.
4191 MAPPING_INIT(".sdata2.", ".sdata"),
4192 MAPPING_INIT(".sbss2.", ".sbss"),
4193 MAPPING_INIT(".lrodata.", ".lrodata"),
4194 MAPPING_INIT(".ldata.", ".ldata"),
4195 MAPPING_INIT(".lbss.", ".lbss"),
4196 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4197 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4198 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4199 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4200 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4201 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4202 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4203 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4204 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4205 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4206 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4207 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4208 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4209 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4210 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4211 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4212 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4213 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4214 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4215 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4216 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4220 const int Layout::section_name_mapping_count
=
4221 (sizeof(Layout::section_name_mapping
)
4222 / sizeof(Layout::section_name_mapping
[0]));
4224 // Choose the output section name to use given an input section name.
4225 // Set *PLEN to the length of the name. *PLEN is initialized to the
4229 Layout::output_section_name(const char* name
, size_t* plen
)
4231 // gcc 4.3 generates the following sorts of section names when it
4232 // needs a section name specific to a function:
4238 // .data.rel.local.FN
4240 // .data.rel.ro.local.FN
4247 // The GNU linker maps all of those to the part before the .FN,
4248 // except that .data.rel.local.FN is mapped to .data, and
4249 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4250 // beginning with .data.rel.ro.local are grouped together.
4252 // For an anonymous namespace, the string FN can contain a '.'.
4254 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4255 // GNU linker maps to .rodata.
4257 // The .data.rel.ro sections are used with -z relro. The sections
4258 // are recognized by name. We use the same names that the GNU
4259 // linker does for these sections.
4261 // It is hard to handle this in a principled way, so we don't even
4262 // try. We use a table of mappings. If the input section name is
4263 // not found in the table, we simply use it as the output section
4266 const Section_name_mapping
* psnm
= section_name_mapping
;
4267 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4269 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4271 *plen
= psnm
->tolen
;
4279 // Check if a comdat group or .gnu.linkonce section with the given
4280 // NAME is selected for the link. If there is already a section,
4281 // *KEPT_SECTION is set to point to the existing section and the
4282 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4283 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4284 // *KEPT_SECTION is set to the internal copy and the function returns
4288 Layout::find_or_add_kept_section(const std::string
& name
,
4293 Kept_section
** kept_section
)
4295 // It's normal to see a couple of entries here, for the x86 thunk
4296 // sections. If we see more than a few, we're linking a C++
4297 // program, and we resize to get more space to minimize rehashing.
4298 if (this->signatures_
.size() > 4
4299 && !this->resized_signatures_
)
4301 reserve_unordered_map(&this->signatures_
,
4302 this->number_of_input_files_
* 64);
4303 this->resized_signatures_
= true;
4306 Kept_section candidate
;
4307 std::pair
<Signatures::iterator
, bool> ins
=
4308 this->signatures_
.insert(std::make_pair(name
, candidate
));
4310 if (kept_section
!= NULL
)
4311 *kept_section
= &ins
.first
->second
;
4314 // This is the first time we've seen this signature.
4315 ins
.first
->second
.set_object(object
);
4316 ins
.first
->second
.set_shndx(shndx
);
4318 ins
.first
->second
.set_is_comdat();
4320 ins
.first
->second
.set_is_group_name();
4324 // We have already seen this signature.
4326 if (ins
.first
->second
.is_group_name())
4328 // We've already seen a real section group with this signature.
4329 // If the kept group is from a plugin object, and we're in the
4330 // replacement phase, accept the new one as a replacement.
4331 if (ins
.first
->second
.object() == NULL
4332 && parameters
->options().plugins()->in_replacement_phase())
4334 ins
.first
->second
.set_object(object
);
4335 ins
.first
->second
.set_shndx(shndx
);
4340 else if (is_group_name
)
4342 // This is a real section group, and we've already seen a
4343 // linkonce section with this signature. Record that we've seen
4344 // a section group, and don't include this section group.
4345 ins
.first
->second
.set_is_group_name();
4350 // We've already seen a linkonce section and this is a linkonce
4351 // section. These don't block each other--this may be the same
4352 // symbol name with different section types.
4357 // Store the allocated sections into the section list.
4360 Layout::get_allocated_sections(Section_list
* section_list
) const
4362 for (Section_list::const_iterator p
= this->section_list_
.begin();
4363 p
!= this->section_list_
.end();
4365 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
4366 section_list
->push_back(*p
);
4369 // Create an output segment.
4372 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
4374 gold_assert(!parameters
->options().relocatable());
4375 Output_segment
* oseg
= new Output_segment(type
, flags
);
4376 this->segment_list_
.push_back(oseg
);
4378 if (type
== elfcpp::PT_TLS
)
4379 this->tls_segment_
= oseg
;
4380 else if (type
== elfcpp::PT_GNU_RELRO
)
4381 this->relro_segment_
= oseg
;
4386 // Return the file offset of the normal symbol table.
4389 Layout::symtab_section_offset() const
4391 if (this->symtab_section_
!= NULL
)
4392 return this->symtab_section_
->offset();
4396 // Write out the Output_sections. Most won't have anything to write,
4397 // since most of the data will come from input sections which are
4398 // handled elsewhere. But some Output_sections do have Output_data.
4401 Layout::write_output_sections(Output_file
* of
) const
4403 for (Section_list::const_iterator p
= this->section_list_
.begin();
4404 p
!= this->section_list_
.end();
4407 if (!(*p
)->after_input_sections())
4412 // Write out data not associated with a section or the symbol table.
4415 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
4417 if (!parameters
->options().strip_all())
4419 const Output_section
* symtab_section
= this->symtab_section_
;
4420 for (Section_list::const_iterator p
= this->section_list_
.begin();
4421 p
!= this->section_list_
.end();
4424 if ((*p
)->needs_symtab_index())
4426 gold_assert(symtab_section
!= NULL
);
4427 unsigned int index
= (*p
)->symtab_index();
4428 gold_assert(index
> 0 && index
!= -1U);
4429 off_t off
= (symtab_section
->offset()
4430 + index
* symtab_section
->entsize());
4431 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
4436 const Output_section
* dynsym_section
= this->dynsym_section_
;
4437 for (Section_list::const_iterator p
= this->section_list_
.begin();
4438 p
!= this->section_list_
.end();
4441 if ((*p
)->needs_dynsym_index())
4443 gold_assert(dynsym_section
!= NULL
);
4444 unsigned int index
= (*p
)->dynsym_index();
4445 gold_assert(index
> 0 && index
!= -1U);
4446 off_t off
= (dynsym_section
->offset()
4447 + index
* dynsym_section
->entsize());
4448 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
4452 // Write out the Output_data which are not in an Output_section.
4453 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
4454 p
!= this->special_output_list_
.end();
4459 // Write out the Output_sections which can only be written after the
4460 // input sections are complete.
4463 Layout::write_sections_after_input_sections(Output_file
* of
)
4465 // Determine the final section offsets, and thus the final output
4466 // file size. Note we finalize the .shstrab last, to allow the
4467 // after_input_section sections to modify their section-names before
4469 if (this->any_postprocessing_sections_
)
4471 off_t off
= this->output_file_size_
;
4472 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
4474 // Now that we've finalized the names, we can finalize the shstrab.
4476 this->set_section_offsets(off
,
4477 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
4479 if (off
> this->output_file_size_
)
4482 this->output_file_size_
= off
;
4486 for (Section_list::const_iterator p
= this->section_list_
.begin();
4487 p
!= this->section_list_
.end();
4490 if ((*p
)->after_input_sections())
4494 this->section_headers_
->write(of
);
4497 // If the build ID requires computing a checksum, do so here, and
4498 // write it out. We compute a checksum over the entire file because
4499 // that is simplest.
4502 Layout::write_build_id(Output_file
* of
) const
4504 if (this->build_id_note_
== NULL
)
4507 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
4509 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
4510 this->build_id_note_
->data_size());
4512 const char* style
= parameters
->options().build_id();
4513 if (strcmp(style
, "sha1") == 0)
4516 sha1_init_ctx(&ctx
);
4517 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
4518 sha1_finish_ctx(&ctx
, ov
);
4520 else if (strcmp(style
, "md5") == 0)
4524 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
4525 md5_finish_ctx(&ctx
, ov
);
4530 of
->write_output_view(this->build_id_note_
->offset(),
4531 this->build_id_note_
->data_size(),
4534 of
->free_input_view(0, this->output_file_size_
, iv
);
4537 // Write out a binary file. This is called after the link is
4538 // complete. IN is the temporary output file we used to generate the
4539 // ELF code. We simply walk through the segments, read them from
4540 // their file offset in IN, and write them to their load address in
4541 // the output file. FIXME: with a bit more work, we could support
4542 // S-records and/or Intel hex format here.
4545 Layout::write_binary(Output_file
* in
) const
4547 gold_assert(parameters
->options().oformat_enum()
4548 == General_options::OBJECT_FORMAT_BINARY
);
4550 // Get the size of the binary file.
4551 uint64_t max_load_address
= 0;
4552 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4553 p
!= this->segment_list_
.end();
4556 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4558 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
4559 if (max_paddr
> max_load_address
)
4560 max_load_address
= max_paddr
;
4564 Output_file
out(parameters
->options().output_file_name());
4565 out
.open(max_load_address
);
4567 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4568 p
!= this->segment_list_
.end();
4571 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4573 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
4575 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
4577 memcpy(vout
, vin
, (*p
)->filesz());
4578 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
4579 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
4586 // Print the output sections to the map file.
4589 Layout::print_to_mapfile(Mapfile
* mapfile
) const
4591 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4592 p
!= this->segment_list_
.end();
4594 (*p
)->print_sections_to_mapfile(mapfile
);
4597 // Print statistical information to stderr. This is used for --stats.
4600 Layout::print_stats() const
4602 this->namepool_
.print_stats("section name pool");
4603 this->sympool_
.print_stats("output symbol name pool");
4604 this->dynpool_
.print_stats("dynamic name pool");
4606 for (Section_list::const_iterator p
= this->section_list_
.begin();
4607 p
!= this->section_list_
.end();
4609 (*p
)->print_merge_stats();
4612 // Write_sections_task methods.
4614 // We can always run this task.
4617 Write_sections_task::is_runnable()
4622 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4626 Write_sections_task::locks(Task_locker
* tl
)
4628 tl
->add(this, this->output_sections_blocker_
);
4629 tl
->add(this, this->final_blocker_
);
4632 // Run the task--write out the data.
4635 Write_sections_task::run(Workqueue
*)
4637 this->layout_
->write_output_sections(this->of_
);
4640 // Write_data_task methods.
4642 // We can always run this task.
4645 Write_data_task::is_runnable()
4650 // We need to unlock FINAL_BLOCKER when finished.
4653 Write_data_task::locks(Task_locker
* tl
)
4655 tl
->add(this, this->final_blocker_
);
4658 // Run the task--write out the data.
4661 Write_data_task::run(Workqueue
*)
4663 this->layout_
->write_data(this->symtab_
, this->of_
);
4666 // Write_symbols_task methods.
4668 // We can always run this task.
4671 Write_symbols_task::is_runnable()
4676 // We need to unlock FINAL_BLOCKER when finished.
4679 Write_symbols_task::locks(Task_locker
* tl
)
4681 tl
->add(this, this->final_blocker_
);
4684 // Run the task--write out the symbols.
4687 Write_symbols_task::run(Workqueue
*)
4689 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
4690 this->layout_
->symtab_xindex(),
4691 this->layout_
->dynsym_xindex(), this->of_
);
4694 // Write_after_input_sections_task methods.
4696 // We can only run this task after the input sections have completed.
4699 Write_after_input_sections_task::is_runnable()
4701 if (this->input_sections_blocker_
->is_blocked())
4702 return this->input_sections_blocker_
;
4706 // We need to unlock FINAL_BLOCKER when finished.
4709 Write_after_input_sections_task::locks(Task_locker
* tl
)
4711 tl
->add(this, this->final_blocker_
);
4717 Write_after_input_sections_task::run(Workqueue
*)
4719 this->layout_
->write_sections_after_input_sections(this->of_
);
4722 // Close_task_runner methods.
4724 // Run the task--close the file.
4727 Close_task_runner::run(Workqueue
*, const Task
*)
4729 // If we need to compute a checksum for the BUILD if, we do so here.
4730 this->layout_
->write_build_id(this->of_
);
4732 // If we've been asked to create a binary file, we do so here.
4733 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
4734 this->layout_
->write_binary(this->of_
);
4739 // Instantiate the templates we need. We could use the configure
4740 // script to restrict this to only the ones for implemented targets.
4742 #ifdef HAVE_TARGET_32_LITTLE
4745 Layout::init_fixed_output_section
<32, false>(
4747 elfcpp::Shdr
<32, false>& shdr
);
4750 #ifdef HAVE_TARGET_32_BIG
4753 Layout::init_fixed_output_section
<32, true>(
4755 elfcpp::Shdr
<32, true>& shdr
);
4758 #ifdef HAVE_TARGET_64_LITTLE
4761 Layout::init_fixed_output_section
<64, false>(
4763 elfcpp::Shdr
<64, false>& shdr
);
4766 #ifdef HAVE_TARGET_64_BIG
4769 Layout::init_fixed_output_section
<64, true>(
4771 elfcpp::Shdr
<64, true>& shdr
);
4774 #ifdef HAVE_TARGET_32_LITTLE
4777 Layout::layout
<32, false>(Sized_relobj
<32, false>* object
, unsigned int shndx
,
4779 const elfcpp::Shdr
<32, false>& shdr
,
4780 unsigned int, unsigned int, off_t
*);
4783 #ifdef HAVE_TARGET_32_BIG
4786 Layout::layout
<32, true>(Sized_relobj
<32, true>* object
, unsigned int shndx
,
4788 const elfcpp::Shdr
<32, true>& shdr
,
4789 unsigned int, unsigned int, off_t
*);
4792 #ifdef HAVE_TARGET_64_LITTLE
4795 Layout::layout
<64, false>(Sized_relobj
<64, false>* object
, unsigned int shndx
,
4797 const elfcpp::Shdr
<64, false>& shdr
,
4798 unsigned int, unsigned int, off_t
*);
4801 #ifdef HAVE_TARGET_64_BIG
4804 Layout::layout
<64, true>(Sized_relobj
<64, true>* object
, unsigned int shndx
,
4806 const elfcpp::Shdr
<64, true>& shdr
,
4807 unsigned int, unsigned int, off_t
*);
4810 #ifdef HAVE_TARGET_32_LITTLE
4813 Layout::layout_reloc
<32, false>(Sized_relobj
<32, false>* object
,
4814 unsigned int reloc_shndx
,
4815 const elfcpp::Shdr
<32, false>& shdr
,
4816 Output_section
* data_section
,
4817 Relocatable_relocs
* rr
);
4820 #ifdef HAVE_TARGET_32_BIG
4823 Layout::layout_reloc
<32, true>(Sized_relobj
<32, true>* object
,
4824 unsigned int reloc_shndx
,
4825 const elfcpp::Shdr
<32, true>& shdr
,
4826 Output_section
* data_section
,
4827 Relocatable_relocs
* rr
);
4830 #ifdef HAVE_TARGET_64_LITTLE
4833 Layout::layout_reloc
<64, false>(Sized_relobj
<64, false>* object
,
4834 unsigned int reloc_shndx
,
4835 const elfcpp::Shdr
<64, false>& shdr
,
4836 Output_section
* data_section
,
4837 Relocatable_relocs
* rr
);
4840 #ifdef HAVE_TARGET_64_BIG
4843 Layout::layout_reloc
<64, true>(Sized_relobj
<64, true>* object
,
4844 unsigned int reloc_shndx
,
4845 const elfcpp::Shdr
<64, true>& shdr
,
4846 Output_section
* data_section
,
4847 Relocatable_relocs
* rr
);
4850 #ifdef HAVE_TARGET_32_LITTLE
4853 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
4854 Sized_relobj
<32, false>* object
,
4856 const char* group_section_name
,
4857 const char* signature
,
4858 const elfcpp::Shdr
<32, false>& shdr
,
4859 elfcpp::Elf_Word flags
,
4860 std::vector
<unsigned int>* shndxes
);
4863 #ifdef HAVE_TARGET_32_BIG
4866 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
4867 Sized_relobj
<32, true>* object
,
4869 const char* group_section_name
,
4870 const char* signature
,
4871 const elfcpp::Shdr
<32, true>& shdr
,
4872 elfcpp::Elf_Word flags
,
4873 std::vector
<unsigned int>* shndxes
);
4876 #ifdef HAVE_TARGET_64_LITTLE
4879 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
4880 Sized_relobj
<64, false>* object
,
4882 const char* group_section_name
,
4883 const char* signature
,
4884 const elfcpp::Shdr
<64, false>& shdr
,
4885 elfcpp::Elf_Word flags
,
4886 std::vector
<unsigned int>* shndxes
);
4889 #ifdef HAVE_TARGET_64_BIG
4892 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
4893 Sized_relobj
<64, true>* object
,
4895 const char* group_section_name
,
4896 const char* signature
,
4897 const elfcpp::Shdr
<64, true>& shdr
,
4898 elfcpp::Elf_Word flags
,
4899 std::vector
<unsigned int>* shndxes
);
4902 #ifdef HAVE_TARGET_32_LITTLE
4905 Layout::layout_eh_frame
<32, false>(Sized_relobj
<32, false>* object
,
4906 const unsigned char* symbols
,
4908 const unsigned char* symbol_names
,
4909 off_t symbol_names_size
,
4911 const elfcpp::Shdr
<32, false>& shdr
,
4912 unsigned int reloc_shndx
,
4913 unsigned int reloc_type
,
4917 #ifdef HAVE_TARGET_32_BIG
4920 Layout::layout_eh_frame
<32, true>(Sized_relobj
<32, true>* object
,
4921 const unsigned char* symbols
,
4923 const unsigned char* symbol_names
,
4924 off_t symbol_names_size
,
4926 const elfcpp::Shdr
<32, true>& shdr
,
4927 unsigned int reloc_shndx
,
4928 unsigned int reloc_type
,
4932 #ifdef HAVE_TARGET_64_LITTLE
4935 Layout::layout_eh_frame
<64, false>(Sized_relobj
<64, false>* object
,
4936 const unsigned char* symbols
,
4938 const unsigned char* symbol_names
,
4939 off_t symbol_names_size
,
4941 const elfcpp::Shdr
<64, false>& shdr
,
4942 unsigned int reloc_shndx
,
4943 unsigned int reloc_type
,
4947 #ifdef HAVE_TARGET_64_BIG
4950 Layout::layout_eh_frame
<64, true>(Sized_relobj
<64, true>* object
,
4951 const unsigned char* symbols
,
4953 const unsigned char* symbol_names
,
4954 off_t symbol_names_size
,
4956 const elfcpp::Shdr
<64, true>& shdr
,
4957 unsigned int reloc_shndx
,
4958 unsigned int reloc_type
,
4962 } // End namespace gold.