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_file
<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_file
<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 elfcpp::Elf_Xword orig_flags
= os
->flags();
949 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
950 this->script_options_
->saw_sections_clause());
952 // If the flags changed, we may have to change the order.
953 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
955 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
956 elfcpp::Elf_Xword new_flags
=
957 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
958 if (orig_flags
!= new_flags
)
959 os
->set_order(this->default_section_order(os
, false));
962 this->have_added_input_section_
= true;
967 // Handle a relocation section when doing a relocatable link.
969 template<int size
, bool big_endian
>
971 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
973 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
974 Output_section
* data_section
,
975 Relocatable_relocs
* rr
)
977 gold_assert(parameters
->options().relocatable()
978 || parameters
->options().emit_relocs());
980 int sh_type
= shdr
.get_sh_type();
983 if (sh_type
== elfcpp::SHT_REL
)
985 else if (sh_type
== elfcpp::SHT_RELA
)
989 name
+= data_section
->name();
991 // In a relocatable link relocs for a grouped section must not be
992 // combined with other reloc sections.
994 if (!parameters
->options().relocatable()
995 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
996 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
997 shdr
.get_sh_flags(), false,
998 ORDER_INVALID
, false);
1001 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1002 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1003 ORDER_INVALID
, false);
1006 os
->set_should_link_to_symtab();
1007 os
->set_info_section(data_section
);
1009 Output_section_data
* posd
;
1010 if (sh_type
== elfcpp::SHT_REL
)
1012 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1013 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1017 else if (sh_type
== elfcpp::SHT_RELA
)
1019 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1020 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1027 os
->add_output_section_data(posd
);
1028 rr
->set_output_data(posd
);
1033 // Handle a group section when doing a relocatable link.
1035 template<int size
, bool big_endian
>
1037 Layout::layout_group(Symbol_table
* symtab
,
1038 Sized_relobj_file
<size
, big_endian
>* object
,
1040 const char* group_section_name
,
1041 const char* signature
,
1042 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1043 elfcpp::Elf_Word flags
,
1044 std::vector
<unsigned int>* shndxes
)
1046 gold_assert(parameters
->options().relocatable());
1047 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1048 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1049 Output_section
* os
= this->make_output_section(group_section_name
,
1051 shdr
.get_sh_flags(),
1052 ORDER_INVALID
, false);
1054 // We need to find a symbol with the signature in the symbol table.
1055 // If we don't find one now, we need to look again later.
1056 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1058 os
->set_info_symndx(sym
);
1061 // Reserve some space to minimize reallocations.
1062 if (this->group_signatures_
.empty())
1063 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1065 // We will wind up using a symbol whose name is the signature.
1066 // So just put the signature in the symbol name pool to save it.
1067 signature
= symtab
->canonicalize_name(signature
);
1068 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1071 os
->set_should_link_to_symtab();
1074 section_size_type entry_count
=
1075 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1076 Output_section_data
* posd
=
1077 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1079 os
->add_output_section_data(posd
);
1082 // Special GNU handling of sections name .eh_frame. They will
1083 // normally hold exception frame data as defined by the C++ ABI
1084 // (http://codesourcery.com/cxx-abi/).
1086 template<int size
, bool big_endian
>
1088 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1089 const unsigned char* symbols
,
1091 const unsigned char* symbol_names
,
1092 off_t symbol_names_size
,
1094 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1095 unsigned int reloc_shndx
, unsigned int reloc_type
,
1098 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
);
1099 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1101 const char* const name
= ".eh_frame";
1102 Output_section
* os
= this->choose_output_section(object
, name
,
1103 elfcpp::SHT_PROGBITS
,
1104 elfcpp::SHF_ALLOC
, false,
1105 ORDER_EHFRAME
, false);
1109 if (this->eh_frame_section_
== NULL
)
1111 this->eh_frame_section_
= os
;
1112 this->eh_frame_data_
= new Eh_frame();
1114 // For incremental linking, we do not optimize .eh_frame sections
1115 // or create a .eh_frame_hdr section.
1116 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1118 Output_section
* hdr_os
=
1119 this->choose_output_section(NULL
, ".eh_frame_hdr",
1120 elfcpp::SHT_PROGBITS
,
1121 elfcpp::SHF_ALLOC
, false,
1122 ORDER_EHFRAME
, false);
1126 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1127 this->eh_frame_data_
);
1128 hdr_os
->add_output_section_data(hdr_posd
);
1130 hdr_os
->set_after_input_sections();
1132 if (!this->script_options_
->saw_phdrs_clause())
1134 Output_segment
* hdr_oseg
;
1135 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1137 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1141 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1146 gold_assert(this->eh_frame_section_
== os
);
1148 if (!parameters
->incremental()
1149 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1158 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1160 // A writable .eh_frame section is a RELRO section.
1161 if ((shdr
.get_sh_flags() & elfcpp::SHF_WRITE
) != 0)
1164 // We found a .eh_frame section we are going to optimize, so now
1165 // we can add the set of optimized sections to the output
1166 // section. We need to postpone adding this until we've found a
1167 // section we can optimize so that the .eh_frame section in
1168 // crtbegin.o winds up at the start of the output section.
1169 if (!this->added_eh_frame_data_
)
1171 os
->add_output_section_data(this->eh_frame_data_
);
1172 this->added_eh_frame_data_
= true;
1178 // We couldn't handle this .eh_frame section for some reason.
1179 // Add it as a normal section.
1180 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1181 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1182 saw_sections_clause
);
1183 this->have_added_input_section_
= true;
1189 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1190 // the output section.
1193 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1194 elfcpp::Elf_Xword flags
,
1195 Output_section_data
* posd
,
1196 Output_section_order order
, bool is_relro
)
1198 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1199 false, order
, is_relro
);
1201 os
->add_output_section_data(posd
);
1205 // Map section flags to segment flags.
1208 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1210 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1211 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1212 ret
|= elfcpp::PF_W
;
1213 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1214 ret
|= elfcpp::PF_X
;
1218 // Make a new Output_section, and attach it to segments as
1219 // appropriate. ORDER is the order in which this section should
1220 // appear in the output segment. IS_RELRO is true if this is a relro
1221 // (read-only after relocations) section.
1224 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1225 elfcpp::Elf_Xword flags
,
1226 Output_section_order order
, bool is_relro
)
1229 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1230 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1231 && is_compressible_debug_section(name
))
1232 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1234 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1235 && parameters
->options().strip_debug_non_line()
1236 && strcmp(".debug_abbrev", name
) == 0)
1238 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1240 if (this->debug_info_
)
1241 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1243 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1244 && parameters
->options().strip_debug_non_line()
1245 && strcmp(".debug_info", name
) == 0)
1247 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1249 if (this->debug_abbrev_
)
1250 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1254 // FIXME: const_cast is ugly.
1255 Target
* target
= const_cast<Target
*>(¶meters
->target());
1256 os
= target
->make_output_section(name
, type
, flags
);
1259 // With -z relro, we have to recognize the special sections by name.
1260 // There is no other way.
1261 bool is_relro_local
= false;
1262 if (!this->script_options_
->saw_sections_clause()
1263 && parameters
->options().relro()
1264 && type
== elfcpp::SHT_PROGBITS
1265 && (flags
& elfcpp::SHF_ALLOC
) != 0
1266 && (flags
& elfcpp::SHF_WRITE
) != 0)
1268 if (strcmp(name
, ".data.rel.ro") == 0)
1270 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1273 is_relro_local
= true;
1275 else if (type
== elfcpp::SHT_INIT_ARRAY
1276 || type
== elfcpp::SHT_FINI_ARRAY
1277 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1279 else if (strcmp(name
, ".ctors") == 0
1280 || strcmp(name
, ".dtors") == 0
1281 || strcmp(name
, ".jcr") == 0)
1288 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1289 order
= this->default_section_order(os
, is_relro_local
);
1291 os
->set_order(order
);
1293 parameters
->target().new_output_section(os
);
1295 this->section_list_
.push_back(os
);
1297 // The GNU linker by default sorts some sections by priority, so we
1298 // do the same. We need to know that this might happen before we
1299 // attach any input sections.
1300 if (!this->script_options_
->saw_sections_clause()
1301 && (strcmp(name
, ".ctors") == 0
1302 || strcmp(name
, ".dtors") == 0
1303 || strcmp(name
, ".init_array") == 0
1304 || strcmp(name
, ".fini_array") == 0))
1305 os
->set_may_sort_attached_input_sections();
1307 // Check for .stab*str sections, as .stab* sections need to link to
1309 if (type
== elfcpp::SHT_STRTAB
1310 && !this->have_stabstr_section_
1311 && strncmp(name
, ".stab", 5) == 0
1312 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1313 this->have_stabstr_section_
= true;
1315 // If we have already attached the sections to segments, then we
1316 // need to attach this one now. This happens for sections created
1317 // directly by the linker.
1318 if (this->sections_are_attached_
)
1319 this->attach_section_to_segment(os
);
1324 // Return the default order in which a section should be placed in an
1325 // output segment. This function captures a lot of the ideas in
1326 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1327 // linker created section is normally set when the section is created;
1328 // this function is used for input sections.
1330 Output_section_order
1331 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1333 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1334 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1335 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1336 bool is_bss
= false;
1341 case elfcpp::SHT_PROGBITS
:
1343 case elfcpp::SHT_NOBITS
:
1346 case elfcpp::SHT_RELA
:
1347 case elfcpp::SHT_REL
:
1349 return ORDER_DYNAMIC_RELOCS
;
1351 case elfcpp::SHT_HASH
:
1352 case elfcpp::SHT_DYNAMIC
:
1353 case elfcpp::SHT_SHLIB
:
1354 case elfcpp::SHT_DYNSYM
:
1355 case elfcpp::SHT_GNU_HASH
:
1356 case elfcpp::SHT_GNU_verdef
:
1357 case elfcpp::SHT_GNU_verneed
:
1358 case elfcpp::SHT_GNU_versym
:
1360 return ORDER_DYNAMIC_LINKER
;
1362 case elfcpp::SHT_NOTE
:
1363 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1366 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1367 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1369 if (!is_bss
&& !is_write
)
1373 if (strcmp(os
->name(), ".init") == 0)
1375 else if (strcmp(os
->name(), ".fini") == 0)
1378 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1382 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1384 if (os
->is_small_section())
1385 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1386 if (os
->is_large_section())
1387 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1389 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1392 // Attach output sections to segments. This is called after we have
1393 // seen all the input sections.
1396 Layout::attach_sections_to_segments()
1398 for (Section_list::iterator p
= this->section_list_
.begin();
1399 p
!= this->section_list_
.end();
1401 this->attach_section_to_segment(*p
);
1403 this->sections_are_attached_
= true;
1406 // Attach an output section to a segment.
1409 Layout::attach_section_to_segment(Output_section
* os
)
1411 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1412 this->unattached_section_list_
.push_back(os
);
1414 this->attach_allocated_section_to_segment(os
);
1417 // Attach an allocated output section to a segment.
1420 Layout::attach_allocated_section_to_segment(Output_section
* os
)
1422 elfcpp::Elf_Xword flags
= os
->flags();
1423 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1425 if (parameters
->options().relocatable())
1428 // If we have a SECTIONS clause, we can't handle the attachment to
1429 // segments until after we've seen all the sections.
1430 if (this->script_options_
->saw_sections_clause())
1433 gold_assert(!this->script_options_
->saw_phdrs_clause());
1435 // This output section goes into a PT_LOAD segment.
1437 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1439 // Check for --section-start.
1441 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1443 // In general the only thing we really care about for PT_LOAD
1444 // segments is whether or not they are writable or executable,
1445 // so that is how we search for them.
1446 // Large data sections also go into their own PT_LOAD segment.
1447 // People who need segments sorted on some other basis will
1448 // have to use a linker script.
1450 Segment_list::const_iterator p
;
1451 for (p
= this->segment_list_
.begin();
1452 p
!= this->segment_list_
.end();
1455 if ((*p
)->type() != elfcpp::PT_LOAD
)
1457 if (!parameters
->options().omagic()
1458 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1460 if (parameters
->options().rosegment()
1461 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1463 // If -Tbss was specified, we need to separate the data and BSS
1465 if (parameters
->options().user_set_Tbss())
1467 if ((os
->type() == elfcpp::SHT_NOBITS
)
1468 == (*p
)->has_any_data_sections())
1471 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1476 if ((*p
)->are_addresses_set())
1479 (*p
)->add_initial_output_data(os
);
1480 (*p
)->update_flags_for_output_section(seg_flags
);
1481 (*p
)->set_addresses(addr
, addr
);
1485 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1489 if (p
== this->segment_list_
.end())
1491 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1493 if (os
->is_large_data_section())
1494 oseg
->set_is_large_data_segment();
1495 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1497 oseg
->set_addresses(addr
, addr
);
1500 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1502 if (os
->type() == elfcpp::SHT_NOTE
)
1504 // See if we already have an equivalent PT_NOTE segment.
1505 for (p
= this->segment_list_
.begin();
1506 p
!= segment_list_
.end();
1509 if ((*p
)->type() == elfcpp::PT_NOTE
1510 && (((*p
)->flags() & elfcpp::PF_W
)
1511 == (seg_flags
& elfcpp::PF_W
)))
1513 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1518 if (p
== this->segment_list_
.end())
1520 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1522 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1526 // If we see a loadable SHF_TLS section, we create a PT_TLS
1527 // segment. There can only be one such segment.
1528 if ((flags
& elfcpp::SHF_TLS
) != 0)
1530 if (this->tls_segment_
== NULL
)
1531 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1532 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1535 // If -z relro is in effect, and we see a relro section, we create a
1536 // PT_GNU_RELRO segment. There can only be one such segment.
1537 if (os
->is_relro() && parameters
->options().relro())
1539 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1540 if (this->relro_segment_
== NULL
)
1541 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1542 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1546 // Make an output section for a script.
1549 Layout::make_output_section_for_script(
1551 Script_sections::Section_type section_type
)
1553 name
= this->namepool_
.add(name
, false, NULL
);
1554 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
1555 if (section_type
== Script_sections::ST_NOLOAD
)
1557 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1558 sh_flags
, ORDER_INVALID
,
1560 os
->set_found_in_sections_clause();
1561 if (section_type
== Script_sections::ST_NOLOAD
)
1562 os
->set_is_noload();
1566 // Return the number of segments we expect to see.
1569 Layout::expected_segment_count() const
1571 size_t ret
= this->segment_list_
.size();
1573 // If we didn't see a SECTIONS clause in a linker script, we should
1574 // already have the complete list of segments. Otherwise we ask the
1575 // SECTIONS clause how many segments it expects, and add in the ones
1576 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1578 if (!this->script_options_
->saw_sections_clause())
1582 const Script_sections
* ss
= this->script_options_
->script_sections();
1583 return ret
+ ss
->expected_segment_count(this);
1587 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
1588 // is whether we saw a .note.GNU-stack section in the object file.
1589 // GNU_STACK_FLAGS is the section flags. The flags give the
1590 // protection required for stack memory. We record this in an
1591 // executable as a PT_GNU_STACK segment. If an object file does not
1592 // have a .note.GNU-stack segment, we must assume that it is an old
1593 // object. On some targets that will force an executable stack.
1596 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
1599 if (!seen_gnu_stack
)
1601 this->input_without_gnu_stack_note_
= true;
1602 if (parameters
->options().warn_execstack()
1603 && parameters
->target().is_default_stack_executable())
1604 gold_warning(_("%s: missing .note.GNU-stack section"
1605 " implies executable stack"),
1606 obj
->name().c_str());
1610 this->input_with_gnu_stack_note_
= true;
1611 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
1613 this->input_requires_executable_stack_
= true;
1614 if (parameters
->options().warn_execstack()
1615 || parameters
->options().is_stack_executable())
1616 gold_warning(_("%s: requires executable stack"),
1617 obj
->name().c_str());
1622 // Create automatic note sections.
1625 Layout::create_notes()
1627 this->create_gold_note();
1628 this->create_executable_stack_info();
1629 this->create_build_id();
1632 // Create the dynamic sections which are needed before we read the
1636 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
1638 if (parameters
->doing_static_link())
1641 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
1642 elfcpp::SHT_DYNAMIC
,
1644 | elfcpp::SHF_WRITE
),
1648 this->dynamic_symbol_
=
1649 symtab
->define_in_output_data("_DYNAMIC", NULL
, Symbol_table::PREDEFINED
,
1650 this->dynamic_section_
, 0, 0,
1651 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
1652 elfcpp::STV_HIDDEN
, 0, false, false);
1654 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
1656 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
1659 // For each output section whose name can be represented as C symbol,
1660 // define __start and __stop symbols for the section. This is a GNU
1664 Layout::define_section_symbols(Symbol_table
* symtab
)
1666 for (Section_list::const_iterator p
= this->section_list_
.begin();
1667 p
!= this->section_list_
.end();
1670 const char* const name
= (*p
)->name();
1671 if (is_cident(name
))
1673 const std::string
name_string(name
);
1674 const std::string
start_name(cident_section_start_prefix
1676 const std::string
stop_name(cident_section_stop_prefix
1679 symtab
->define_in_output_data(start_name
.c_str(),
1681 Symbol_table::PREDEFINED
,
1687 elfcpp::STV_DEFAULT
,
1689 false, // offset_is_from_end
1690 true); // only_if_ref
1692 symtab
->define_in_output_data(stop_name
.c_str(),
1694 Symbol_table::PREDEFINED
,
1700 elfcpp::STV_DEFAULT
,
1702 true, // offset_is_from_end
1703 true); // only_if_ref
1708 // Define symbols for group signatures.
1711 Layout::define_group_signatures(Symbol_table
* symtab
)
1713 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
1714 p
!= this->group_signatures_
.end();
1717 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
1719 p
->section
->set_info_symndx(sym
);
1722 // Force the name of the group section to the group
1723 // signature, and use the group's section symbol as the
1724 // signature symbol.
1725 if (strcmp(p
->section
->name(), p
->signature
) != 0)
1727 const char* name
= this->namepool_
.add(p
->signature
,
1729 p
->section
->set_name(name
);
1731 p
->section
->set_needs_symtab_index();
1732 p
->section
->set_info_section_symndx(p
->section
);
1736 this->group_signatures_
.clear();
1739 // Find the first read-only PT_LOAD segment, creating one if
1743 Layout::find_first_load_seg()
1745 Output_segment
* best
= NULL
;
1746 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1747 p
!= this->segment_list_
.end();
1750 if ((*p
)->type() == elfcpp::PT_LOAD
1751 && ((*p
)->flags() & elfcpp::PF_R
) != 0
1752 && (parameters
->options().omagic()
1753 || ((*p
)->flags() & elfcpp::PF_W
) == 0))
1755 if (best
== NULL
|| this->segment_precedes(*p
, best
))
1762 gold_assert(!this->script_options_
->saw_phdrs_clause());
1764 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
1769 // Save states of all current output segments. Store saved states
1770 // in SEGMENT_STATES.
1773 Layout::save_segments(Segment_states
* segment_states
)
1775 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1776 p
!= this->segment_list_
.end();
1779 Output_segment
* segment
= *p
;
1781 Output_segment
* copy
= new Output_segment(*segment
);
1782 (*segment_states
)[segment
] = copy
;
1786 // Restore states of output segments and delete any segment not found in
1790 Layout::restore_segments(const Segment_states
* segment_states
)
1792 // Go through the segment list and remove any segment added in the
1794 this->tls_segment_
= NULL
;
1795 this->relro_segment_
= NULL
;
1796 Segment_list::iterator list_iter
= this->segment_list_
.begin();
1797 while (list_iter
!= this->segment_list_
.end())
1799 Output_segment
* segment
= *list_iter
;
1800 Segment_states::const_iterator states_iter
=
1801 segment_states
->find(segment
);
1802 if (states_iter
!= segment_states
->end())
1804 const Output_segment
* copy
= states_iter
->second
;
1805 // Shallow copy to restore states.
1808 // Also fix up TLS and RELRO segment pointers as appropriate.
1809 if (segment
->type() == elfcpp::PT_TLS
)
1810 this->tls_segment_
= segment
;
1811 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
1812 this->relro_segment_
= segment
;
1818 list_iter
= this->segment_list_
.erase(list_iter
);
1819 // This is a segment created during section layout. It should be
1820 // safe to remove it since we should have removed all pointers to it.
1826 // Clean up after relaxation so that sections can be laid out again.
1829 Layout::clean_up_after_relaxation()
1831 // Restore the segments to point state just prior to the relaxation loop.
1832 Script_sections
* script_section
= this->script_options_
->script_sections();
1833 script_section
->release_segments();
1834 this->restore_segments(this->segment_states_
);
1836 // Reset section addresses and file offsets
1837 for (Section_list::iterator p
= this->section_list_
.begin();
1838 p
!= this->section_list_
.end();
1841 (*p
)->restore_states();
1843 // If an input section changes size because of relaxation,
1844 // we need to adjust the section offsets of all input sections.
1845 // after such a section.
1846 if ((*p
)->section_offsets_need_adjustment())
1847 (*p
)->adjust_section_offsets();
1849 (*p
)->reset_address_and_file_offset();
1852 // Reset special output object address and file offsets.
1853 for (Data_list::iterator p
= this->special_output_list_
.begin();
1854 p
!= this->special_output_list_
.end();
1856 (*p
)->reset_address_and_file_offset();
1858 // A linker script may have created some output section data objects.
1859 // They are useless now.
1860 for (Output_section_data_list::const_iterator p
=
1861 this->script_output_section_data_list_
.begin();
1862 p
!= this->script_output_section_data_list_
.end();
1865 this->script_output_section_data_list_
.clear();
1868 // Prepare for relaxation.
1871 Layout::prepare_for_relaxation()
1873 // Create an relaxation debug check if in debugging mode.
1874 if (is_debugging_enabled(DEBUG_RELAXATION
))
1875 this->relaxation_debug_check_
= new Relaxation_debug_check();
1877 // Save segment states.
1878 this->segment_states_
= new Segment_states();
1879 this->save_segments(this->segment_states_
);
1881 for(Section_list::const_iterator p
= this->section_list_
.begin();
1882 p
!= this->section_list_
.end();
1884 (*p
)->save_states();
1886 if (is_debugging_enabled(DEBUG_RELAXATION
))
1887 this->relaxation_debug_check_
->check_output_data_for_reset_values(
1888 this->section_list_
, this->special_output_list_
);
1890 // Also enable recording of output section data from scripts.
1891 this->record_output_section_data_from_script_
= true;
1894 // Relaxation loop body: If target has no relaxation, this runs only once
1895 // Otherwise, the target relaxation hook is called at the end of
1896 // each iteration. If the hook returns true, it means re-layout of
1897 // section is required.
1899 // The number of segments created by a linking script without a PHDRS
1900 // clause may be affected by section sizes and alignments. There is
1901 // a remote chance that relaxation causes different number of PT_LOAD
1902 // segments are created and sections are attached to different segments.
1903 // Therefore, we always throw away all segments created during section
1904 // layout. In order to be able to restart the section layout, we keep
1905 // a copy of the segment list right before the relaxation loop and use
1906 // that to restore the segments.
1908 // PASS is the current relaxation pass number.
1909 // SYMTAB is a symbol table.
1910 // PLOAD_SEG is the address of a pointer for the load segment.
1911 // PHDR_SEG is a pointer to the PHDR segment.
1912 // SEGMENT_HEADERS points to the output segment header.
1913 // FILE_HEADER points to the output file header.
1914 // PSHNDX is the address to store the output section index.
1917 Layout::relaxation_loop_body(
1920 Symbol_table
* symtab
,
1921 Output_segment
** pload_seg
,
1922 Output_segment
* phdr_seg
,
1923 Output_segment_headers
* segment_headers
,
1924 Output_file_header
* file_header
,
1925 unsigned int* pshndx
)
1927 // If this is not the first iteration, we need to clean up after
1928 // relaxation so that we can lay out the sections again.
1930 this->clean_up_after_relaxation();
1932 // If there is a SECTIONS clause, put all the input sections into
1933 // the required order.
1934 Output_segment
* load_seg
;
1935 if (this->script_options_
->saw_sections_clause())
1936 load_seg
= this->set_section_addresses_from_script(symtab
);
1937 else if (parameters
->options().relocatable())
1940 load_seg
= this->find_first_load_seg();
1942 if (parameters
->options().oformat_enum()
1943 != General_options::OBJECT_FORMAT_ELF
)
1946 // If the user set the address of the text segment, that may not be
1947 // compatible with putting the segment headers and file headers into
1949 if (parameters
->options().user_set_Ttext())
1952 gold_assert(phdr_seg
== NULL
1954 || this->script_options_
->saw_sections_clause());
1956 // If the address of the load segment we found has been set by
1957 // --section-start rather than by a script, then adjust the VMA and
1958 // LMA downward if possible to include the file and section headers.
1959 uint64_t header_gap
= 0;
1960 if (load_seg
!= NULL
1961 && load_seg
->are_addresses_set()
1962 && !this->script_options_
->saw_sections_clause()
1963 && !parameters
->options().relocatable())
1965 file_header
->finalize_data_size();
1966 segment_headers
->finalize_data_size();
1967 size_t sizeof_headers
= (file_header
->data_size()
1968 + segment_headers
->data_size());
1969 const uint64_t abi_pagesize
= target
->abi_pagesize();
1970 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
1971 hdr_paddr
&= ~(abi_pagesize
- 1);
1972 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
1973 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
1977 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
1978 load_seg
->paddr() - subtract
);
1979 header_gap
= subtract
- sizeof_headers
;
1983 // Lay out the segment headers.
1984 if (!parameters
->options().relocatable())
1986 gold_assert(segment_headers
!= NULL
);
1987 if (header_gap
!= 0 && load_seg
!= NULL
)
1989 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
1990 load_seg
->add_initial_output_data(z
);
1992 if (load_seg
!= NULL
)
1993 load_seg
->add_initial_output_data(segment_headers
);
1994 if (phdr_seg
!= NULL
)
1995 phdr_seg
->add_initial_output_data(segment_headers
);
1998 // Lay out the file header.
1999 if (load_seg
!= NULL
)
2000 load_seg
->add_initial_output_data(file_header
);
2002 if (this->script_options_
->saw_phdrs_clause()
2003 && !parameters
->options().relocatable())
2005 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2006 // clause in a linker script.
2007 Script_sections
* ss
= this->script_options_
->script_sections();
2008 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2011 // We set the output section indexes in set_segment_offsets and
2012 // set_section_indexes.
2015 // Set the file offsets of all the segments, and all the sections
2018 if (!parameters
->options().relocatable())
2019 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2021 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2023 // Verify that the dummy relaxation does not change anything.
2024 if (is_debugging_enabled(DEBUG_RELAXATION
))
2027 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2029 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2032 *pload_seg
= load_seg
;
2036 // Search the list of patterns and find the postion of the given section
2037 // name in the output section. If the section name matches a glob
2038 // pattern and a non-glob name, then the non-glob position takes
2039 // precedence. Return 0 if no match is found.
2042 Layout::find_section_order_index(const std::string
& section_name
)
2044 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2045 map_it
= this->input_section_position_
.find(section_name
);
2046 if (map_it
!= this->input_section_position_
.end())
2047 return map_it
->second
;
2049 // Absolute match failed. Linear search the glob patterns.
2050 std::vector
<std::string
>::iterator it
;
2051 for (it
= this->input_section_glob_
.begin();
2052 it
!= this->input_section_glob_
.end();
2055 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2057 map_it
= this->input_section_position_
.find(*it
);
2058 gold_assert(map_it
!= this->input_section_position_
.end());
2059 return map_it
->second
;
2065 // Read the sequence of input sections from the file specified with
2066 // --section-ordering-file.
2069 Layout::read_layout_from_file()
2071 const char* filename
= parameters
->options().section_ordering_file();
2077 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2078 filename
, strerror(errno
));
2080 std::getline(in
, line
); // this chops off the trailing \n, if any
2081 unsigned int position
= 1;
2085 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2086 line
.resize(line
.length() - 1);
2087 // Ignore comments, beginning with '#'
2090 std::getline(in
, line
);
2093 this->input_section_position_
[line
] = position
;
2094 // Store all glob patterns in a vector.
2095 if (is_wildcard_string(line
.c_str()))
2096 this->input_section_glob_
.push_back(line
);
2098 std::getline(in
, line
);
2102 // Finalize the layout. When this is called, we have created all the
2103 // output sections and all the output segments which are based on
2104 // input sections. We have several things to do, and we have to do
2105 // them in the right order, so that we get the right results correctly
2108 // 1) Finalize the list of output segments and create the segment
2111 // 2) Finalize the dynamic symbol table and associated sections.
2113 // 3) Determine the final file offset of all the output segments.
2115 // 4) Determine the final file offset of all the SHF_ALLOC output
2118 // 5) Create the symbol table sections and the section name table
2121 // 6) Finalize the symbol table: set symbol values to their final
2122 // value and make a final determination of which symbols are going
2123 // into the output symbol table.
2125 // 7) Create the section table header.
2127 // 8) Determine the final file offset of all the output sections which
2128 // are not SHF_ALLOC, including the section table header.
2130 // 9) Finalize the ELF file header.
2132 // This function returns the size of the output file.
2135 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2136 Target
* target
, const Task
* task
)
2138 target
->finalize_sections(this, input_objects
, symtab
);
2140 this->count_local_symbols(task
, input_objects
);
2142 this->link_stabs_sections();
2144 Output_segment
* phdr_seg
= NULL
;
2145 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2147 // There was a dynamic object in the link. We need to create
2148 // some information for the dynamic linker.
2150 // Create the PT_PHDR segment which will hold the program
2152 if (!this->script_options_
->saw_phdrs_clause())
2153 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2155 // Create the dynamic symbol table, including the hash table.
2156 Output_section
* dynstr
;
2157 std::vector
<Symbol
*> dynamic_symbols
;
2158 unsigned int local_dynamic_count
;
2159 Versions
versions(*this->script_options()->version_script_info(),
2161 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2162 &local_dynamic_count
, &dynamic_symbols
,
2165 // Create the .interp section to hold the name of the
2166 // interpreter, and put it in a PT_INTERP segment.
2167 if (!parameters
->options().shared())
2168 this->create_interp(target
);
2170 // Finish the .dynamic section to hold the dynamic data, and put
2171 // it in a PT_DYNAMIC segment.
2172 this->finish_dynamic_section(input_objects
, symtab
);
2174 // We should have added everything we need to the dynamic string
2176 this->dynpool_
.set_string_offsets();
2178 // Create the version sections. We can't do this until the
2179 // dynamic string table is complete.
2180 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2181 dynamic_symbols
, dynstr
);
2183 // Set the size of the _DYNAMIC symbol. We can't do this until
2184 // after we call create_version_sections.
2185 this->set_dynamic_symbol_size(symtab
);
2188 // Create segment headers.
2189 Output_segment_headers
* segment_headers
=
2190 (parameters
->options().relocatable()
2192 : new Output_segment_headers(this->segment_list_
));
2194 // Lay out the file header.
2195 Output_file_header
* file_header
2196 = new Output_file_header(target
, symtab
, segment_headers
,
2197 parameters
->options().entry());
2199 this->special_output_list_
.push_back(file_header
);
2200 if (segment_headers
!= NULL
)
2201 this->special_output_list_
.push_back(segment_headers
);
2203 // Find approriate places for orphan output sections if we are using
2205 if (this->script_options_
->saw_sections_clause())
2206 this->place_orphan_sections_in_script();
2208 Output_segment
* load_seg
;
2213 // Take a snapshot of the section layout as needed.
2214 if (target
->may_relax())
2215 this->prepare_for_relaxation();
2217 // Run the relaxation loop to lay out sections.
2220 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2221 phdr_seg
, segment_headers
, file_header
,
2225 while (target
->may_relax()
2226 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2228 // Set the file offsets of all the non-data sections we've seen so
2229 // far which don't have to wait for the input sections. We need
2230 // this in order to finalize local symbols in non-allocated
2232 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2234 // Set the section indexes of all unallocated sections seen so far,
2235 // in case any of them are somehow referenced by a symbol.
2236 shndx
= this->set_section_indexes(shndx
);
2238 // Create the symbol table sections.
2239 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2240 if (!parameters
->doing_static_link())
2241 this->assign_local_dynsym_offsets(input_objects
);
2243 // Process any symbol assignments from a linker script. This must
2244 // be called after the symbol table has been finalized.
2245 this->script_options_
->finalize_symbols(symtab
, this);
2247 // Create the incremental inputs sections.
2248 if (this->incremental_inputs_
)
2250 this->incremental_inputs_
->finalize();
2251 this->create_incremental_info_sections(symtab
);
2254 // Create the .shstrtab section.
2255 Output_section
* shstrtab_section
= this->create_shstrtab();
2257 // Set the file offsets of the rest of the non-data sections which
2258 // don't have to wait for the input sections.
2259 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2261 // Now that all sections have been created, set the section indexes
2262 // for any sections which haven't been done yet.
2263 shndx
= this->set_section_indexes(shndx
);
2265 // Create the section table header.
2266 this->create_shdrs(shstrtab_section
, &off
);
2268 // If there are no sections which require postprocessing, we can
2269 // handle the section names now, and avoid a resize later.
2270 if (!this->any_postprocessing_sections_
)
2272 off
= this->set_section_offsets(off
,
2273 POSTPROCESSING_SECTIONS_PASS
);
2275 this->set_section_offsets(off
,
2276 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2279 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2281 // Now we know exactly where everything goes in the output file
2282 // (except for non-allocated sections which require postprocessing).
2283 Output_data::layout_complete();
2285 this->output_file_size_
= off
;
2290 // Create a note header following the format defined in the ELF ABI.
2291 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2292 // of the section to create, DESCSZ is the size of the descriptor.
2293 // ALLOCATE is true if the section should be allocated in memory.
2294 // This returns the new note section. It sets *TRAILING_PADDING to
2295 // the number of trailing zero bytes required.
2298 Layout::create_note(const char* name
, int note_type
,
2299 const char* section_name
, size_t descsz
,
2300 bool allocate
, size_t* trailing_padding
)
2302 // Authorities all agree that the values in a .note field should
2303 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2304 // they differ on what the alignment is for 64-bit binaries.
2305 // The GABI says unambiguously they take 8-byte alignment:
2306 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2307 // Other documentation says alignment should always be 4 bytes:
2308 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2309 // GNU ld and GNU readelf both support the latter (at least as of
2310 // version 2.16.91), and glibc always generates the latter for
2311 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2313 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2314 const int size
= parameters
->target().get_size();
2316 const int size
= 32;
2319 // The contents of the .note section.
2320 size_t namesz
= strlen(name
) + 1;
2321 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2322 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2324 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2326 unsigned char* buffer
= new unsigned char[notehdrsz
];
2327 memset(buffer
, 0, notehdrsz
);
2329 bool is_big_endian
= parameters
->target().is_big_endian();
2335 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2336 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2337 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2341 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2342 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2343 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2346 else if (size
== 64)
2350 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2351 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2352 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2356 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2357 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2358 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2364 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2366 elfcpp::Elf_Xword flags
= 0;
2367 Output_section_order order
= ORDER_INVALID
;
2370 flags
= elfcpp::SHF_ALLOC
;
2371 order
= ORDER_RO_NOTE
;
2373 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2375 flags
, false, order
, false);
2379 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2382 os
->add_output_section_data(posd
);
2384 *trailing_padding
= aligned_descsz
- descsz
;
2389 // For an executable or shared library, create a note to record the
2390 // version of gold used to create the binary.
2393 Layout::create_gold_note()
2395 if (parameters
->options().relocatable()
2396 || parameters
->incremental_update())
2399 std::string desc
= std::string("gold ") + gold::get_version_string();
2401 size_t trailing_padding
;
2402 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2403 ".note.gnu.gold-version", desc
.size(),
2404 false, &trailing_padding
);
2408 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2409 os
->add_output_section_data(posd
);
2411 if (trailing_padding
> 0)
2413 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2414 os
->add_output_section_data(posd
);
2418 // Record whether the stack should be executable. This can be set
2419 // from the command line using the -z execstack or -z noexecstack
2420 // options. Otherwise, if any input file has a .note.GNU-stack
2421 // section with the SHF_EXECINSTR flag set, the stack should be
2422 // executable. Otherwise, if at least one input file a
2423 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2424 // section, we use the target default for whether the stack should be
2425 // executable. Otherwise, we don't generate a stack note. When
2426 // generating a object file, we create a .note.GNU-stack section with
2427 // the appropriate marking. When generating an executable or shared
2428 // library, we create a PT_GNU_STACK segment.
2431 Layout::create_executable_stack_info()
2433 bool is_stack_executable
;
2434 if (parameters
->options().is_execstack_set())
2435 is_stack_executable
= parameters
->options().is_stack_executable();
2436 else if (!this->input_with_gnu_stack_note_
)
2440 if (this->input_requires_executable_stack_
)
2441 is_stack_executable
= true;
2442 else if (this->input_without_gnu_stack_note_
)
2443 is_stack_executable
=
2444 parameters
->target().is_default_stack_executable();
2446 is_stack_executable
= false;
2449 if (parameters
->options().relocatable())
2451 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2452 elfcpp::Elf_Xword flags
= 0;
2453 if (is_stack_executable
)
2454 flags
|= elfcpp::SHF_EXECINSTR
;
2455 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2456 ORDER_INVALID
, false);
2460 if (this->script_options_
->saw_phdrs_clause())
2462 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2463 if (is_stack_executable
)
2464 flags
|= elfcpp::PF_X
;
2465 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2469 // If --build-id was used, set up the build ID note.
2472 Layout::create_build_id()
2474 if (!parameters
->options().user_set_build_id())
2477 const char* style
= parameters
->options().build_id();
2478 if (strcmp(style
, "none") == 0)
2481 // Set DESCSZ to the size of the note descriptor. When possible,
2482 // set DESC to the note descriptor contents.
2485 if (strcmp(style
, "md5") == 0)
2487 else if (strcmp(style
, "sha1") == 0)
2489 else if (strcmp(style
, "uuid") == 0)
2491 const size_t uuidsz
= 128 / 8;
2493 char buffer
[uuidsz
];
2494 memset(buffer
, 0, uuidsz
);
2496 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2498 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2502 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2503 release_descriptor(descriptor
, true);
2505 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
2506 else if (static_cast<size_t>(got
) != uuidsz
)
2507 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2511 desc
.assign(buffer
, uuidsz
);
2514 else if (strncmp(style
, "0x", 2) == 0)
2517 const char* p
= style
+ 2;
2520 if (hex_p(p
[0]) && hex_p(p
[1]))
2522 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
2526 else if (*p
== '-' || *p
== ':')
2529 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2532 descsz
= desc
.size();
2535 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2538 size_t trailing_padding
;
2539 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2540 ".note.gnu.build-id", descsz
, true,
2547 // We know the value already, so we fill it in now.
2548 gold_assert(desc
.size() == descsz
);
2550 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2551 os
->add_output_section_data(posd
);
2553 if (trailing_padding
!= 0)
2555 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2556 os
->add_output_section_data(posd
);
2561 // We need to compute a checksum after we have completed the
2563 gold_assert(trailing_padding
== 0);
2564 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
2565 os
->add_output_section_data(this->build_id_note_
);
2569 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2570 // field of the former should point to the latter. I'm not sure who
2571 // started this, but the GNU linker does it, and some tools depend
2575 Layout::link_stabs_sections()
2577 if (!this->have_stabstr_section_
)
2580 for (Section_list::iterator p
= this->section_list_
.begin();
2581 p
!= this->section_list_
.end();
2584 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
2587 const char* name
= (*p
)->name();
2588 if (strncmp(name
, ".stab", 5) != 0)
2591 size_t len
= strlen(name
);
2592 if (strcmp(name
+ len
- 3, "str") != 0)
2595 std::string
stab_name(name
, len
- 3);
2596 Output_section
* stab_sec
;
2597 stab_sec
= this->find_output_section(stab_name
.c_str());
2598 if (stab_sec
!= NULL
)
2599 stab_sec
->set_link_section(*p
);
2603 // Create .gnu_incremental_inputs and related sections needed
2604 // for the next run of incremental linking to check what has changed.
2607 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
2609 Incremental_inputs
* incr
= this->incremental_inputs_
;
2611 gold_assert(incr
!= NULL
);
2613 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2614 incr
->create_data_sections(symtab
);
2616 // Add the .gnu_incremental_inputs section.
2617 const char* incremental_inputs_name
=
2618 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
2619 Output_section
* incremental_inputs_os
=
2620 this->make_output_section(incremental_inputs_name
,
2621 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
2622 ORDER_INVALID
, false);
2623 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
2625 // Add the .gnu_incremental_symtab section.
2626 const char* incremental_symtab_name
=
2627 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
2628 Output_section
* incremental_symtab_os
=
2629 this->make_output_section(incremental_symtab_name
,
2630 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
2631 ORDER_INVALID
, false);
2632 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
2633 incremental_symtab_os
->set_entsize(4);
2635 // Add the .gnu_incremental_relocs section.
2636 const char* incremental_relocs_name
=
2637 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
2638 Output_section
* incremental_relocs_os
=
2639 this->make_output_section(incremental_relocs_name
,
2640 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
2641 ORDER_INVALID
, false);
2642 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
2643 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
2645 // Add the .gnu_incremental_got_plt section.
2646 const char* incremental_got_plt_name
=
2647 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
2648 Output_section
* incremental_got_plt_os
=
2649 this->make_output_section(incremental_got_plt_name
,
2650 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
2651 ORDER_INVALID
, false);
2652 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
2654 // Add the .gnu_incremental_strtab section.
2655 const char* incremental_strtab_name
=
2656 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
2657 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
2658 elfcpp::SHT_STRTAB
, 0,
2659 ORDER_INVALID
, false);
2660 Output_data_strtab
* strtab_data
=
2661 new Output_data_strtab(incr
->get_stringpool());
2662 incremental_strtab_os
->add_output_section_data(strtab_data
);
2664 incremental_inputs_os
->set_after_input_sections();
2665 incremental_symtab_os
->set_after_input_sections();
2666 incremental_relocs_os
->set_after_input_sections();
2667 incremental_got_plt_os
->set_after_input_sections();
2669 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
2670 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
2671 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
2672 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
2675 // Return whether SEG1 should be before SEG2 in the output file. This
2676 // is based entirely on the segment type and flags. When this is
2677 // called the segment addresses has normally not yet been set.
2680 Layout::segment_precedes(const Output_segment
* seg1
,
2681 const Output_segment
* seg2
)
2683 elfcpp::Elf_Word type1
= seg1
->type();
2684 elfcpp::Elf_Word type2
= seg2
->type();
2686 // The single PT_PHDR segment is required to precede any loadable
2687 // segment. We simply make it always first.
2688 if (type1
== elfcpp::PT_PHDR
)
2690 gold_assert(type2
!= elfcpp::PT_PHDR
);
2693 if (type2
== elfcpp::PT_PHDR
)
2696 // The single PT_INTERP segment is required to precede any loadable
2697 // segment. We simply make it always second.
2698 if (type1
== elfcpp::PT_INTERP
)
2700 gold_assert(type2
!= elfcpp::PT_INTERP
);
2703 if (type2
== elfcpp::PT_INTERP
)
2706 // We then put PT_LOAD segments before any other segments.
2707 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
2709 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
2712 // We put the PT_TLS segment last except for the PT_GNU_RELRO
2713 // segment, because that is where the dynamic linker expects to find
2714 // it (this is just for efficiency; other positions would also work
2716 if (type1
== elfcpp::PT_TLS
2717 && type2
!= elfcpp::PT_TLS
2718 && type2
!= elfcpp::PT_GNU_RELRO
)
2720 if (type2
== elfcpp::PT_TLS
2721 && type1
!= elfcpp::PT_TLS
2722 && type1
!= elfcpp::PT_GNU_RELRO
)
2725 // We put the PT_GNU_RELRO segment last, because that is where the
2726 // dynamic linker expects to find it (as with PT_TLS, this is just
2728 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
2730 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
2733 const elfcpp::Elf_Word flags1
= seg1
->flags();
2734 const elfcpp::Elf_Word flags2
= seg2
->flags();
2736 // The order of non-PT_LOAD segments is unimportant. We simply sort
2737 // by the numeric segment type and flags values. There should not
2738 // be more than one segment with the same type and flags.
2739 if (type1
!= elfcpp::PT_LOAD
)
2742 return type1
< type2
;
2743 gold_assert(flags1
!= flags2
);
2744 return flags1
< flags2
;
2747 // If the addresses are set already, sort by load address.
2748 if (seg1
->are_addresses_set())
2750 if (!seg2
->are_addresses_set())
2753 unsigned int section_count1
= seg1
->output_section_count();
2754 unsigned int section_count2
= seg2
->output_section_count();
2755 if (section_count1
== 0 && section_count2
> 0)
2757 if (section_count1
> 0 && section_count2
== 0)
2760 uint64_t paddr1
= (seg1
->are_addresses_set()
2762 : seg1
->first_section_load_address());
2763 uint64_t paddr2
= (seg2
->are_addresses_set()
2765 : seg2
->first_section_load_address());
2767 if (paddr1
!= paddr2
)
2768 return paddr1
< paddr2
;
2770 else if (seg2
->are_addresses_set())
2773 // A segment which holds large data comes after a segment which does
2774 // not hold large data.
2775 if (seg1
->is_large_data_segment())
2777 if (!seg2
->is_large_data_segment())
2780 else if (seg2
->is_large_data_segment())
2783 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
2784 // segments come before writable segments. Then writable segments
2785 // with data come before writable segments without data. Then
2786 // executable segments come before non-executable segments. Then
2787 // the unlikely case of a non-readable segment comes before the
2788 // normal case of a readable segment. If there are multiple
2789 // segments with the same type and flags, we require that the
2790 // address be set, and we sort by virtual address and then physical
2792 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
2793 return (flags1
& elfcpp::PF_W
) == 0;
2794 if ((flags1
& elfcpp::PF_W
) != 0
2795 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
2796 return seg1
->has_any_data_sections();
2797 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
2798 return (flags1
& elfcpp::PF_X
) != 0;
2799 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
2800 return (flags1
& elfcpp::PF_R
) == 0;
2802 // We shouldn't get here--we shouldn't create segments which we
2803 // can't distinguish.
2807 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2810 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
2812 uint64_t unsigned_off
= off
;
2813 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
2814 | (addr
& (abi_pagesize
- 1)));
2815 if (aligned_off
< unsigned_off
)
2816 aligned_off
+= abi_pagesize
;
2820 // Set the file offsets of all the segments, and all the sections they
2821 // contain. They have all been created. LOAD_SEG must be be laid out
2822 // first. Return the offset of the data to follow.
2825 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
2826 unsigned int* pshndx
)
2828 // Sort them into the final order.
2829 std::sort(this->segment_list_
.begin(), this->segment_list_
.end(),
2830 Layout::Compare_segments());
2832 // Find the PT_LOAD segments, and set their addresses and offsets
2833 // and their section's addresses and offsets.
2835 if (parameters
->options().user_set_Ttext())
2836 addr
= parameters
->options().Ttext();
2837 else if (parameters
->options().output_is_position_independent())
2840 addr
= target
->default_text_segment_address();
2843 // If LOAD_SEG is NULL, then the file header and segment headers
2844 // will not be loadable. But they still need to be at offset 0 in
2845 // the file. Set their offsets now.
2846 if (load_seg
== NULL
)
2848 for (Data_list::iterator p
= this->special_output_list_
.begin();
2849 p
!= this->special_output_list_
.end();
2852 off
= align_address(off
, (*p
)->addralign());
2853 (*p
)->set_address_and_file_offset(0, off
);
2854 off
+= (*p
)->data_size();
2858 unsigned int increase_relro
= this->increase_relro_
;
2859 if (this->script_options_
->saw_sections_clause())
2862 const bool check_sections
= parameters
->options().check_sections();
2863 Output_segment
* last_load_segment
= NULL
;
2865 for (Segment_list::iterator p
= this->segment_list_
.begin();
2866 p
!= this->segment_list_
.end();
2869 if ((*p
)->type() == elfcpp::PT_LOAD
)
2871 if (load_seg
!= NULL
&& load_seg
!= *p
)
2875 bool are_addresses_set
= (*p
)->are_addresses_set();
2876 if (are_addresses_set
)
2878 // When it comes to setting file offsets, we care about
2879 // the physical address.
2880 addr
= (*p
)->paddr();
2882 else if (parameters
->options().user_set_Tdata()
2883 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2884 && (!parameters
->options().user_set_Tbss()
2885 || (*p
)->has_any_data_sections()))
2887 addr
= parameters
->options().Tdata();
2888 are_addresses_set
= true;
2890 else if (parameters
->options().user_set_Tbss()
2891 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2892 && !(*p
)->has_any_data_sections())
2894 addr
= parameters
->options().Tbss();
2895 are_addresses_set
= true;
2898 uint64_t orig_addr
= addr
;
2899 uint64_t orig_off
= off
;
2901 uint64_t aligned_addr
= 0;
2902 uint64_t abi_pagesize
= target
->abi_pagesize();
2903 uint64_t common_pagesize
= target
->common_pagesize();
2905 if (!parameters
->options().nmagic()
2906 && !parameters
->options().omagic())
2907 (*p
)->set_minimum_p_align(common_pagesize
);
2909 if (!are_addresses_set
)
2911 // Skip the address forward one page, maintaining the same
2912 // position within the page. This lets us store both segments
2913 // overlapping on a single page in the file, but the loader will
2914 // put them on different pages in memory. We will revisit this
2915 // decision once we know the size of the segment.
2917 addr
= align_address(addr
, (*p
)->maximum_alignment());
2918 aligned_addr
= addr
;
2920 if ((addr
& (abi_pagesize
- 1)) != 0)
2921 addr
= addr
+ abi_pagesize
;
2923 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2926 if (!parameters
->options().nmagic()
2927 && !parameters
->options().omagic())
2928 off
= align_file_offset(off
, addr
, abi_pagesize
);
2929 else if (load_seg
== NULL
)
2931 // This is -N or -n with a section script which prevents
2932 // us from using a load segment. We need to ensure that
2933 // the file offset is aligned to the alignment of the
2934 // segment. This is because the linker script
2935 // implicitly assumed a zero offset. If we don't align
2936 // here, then the alignment of the sections in the
2937 // linker script may not match the alignment of the
2938 // sections in the set_section_addresses call below,
2939 // causing an error about dot moving backward.
2940 off
= align_address(off
, (*p
)->maximum_alignment());
2943 unsigned int shndx_hold
= *pshndx
;
2944 bool has_relro
= false;
2945 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
2950 // Now that we know the size of this segment, we may be able
2951 // to save a page in memory, at the cost of wasting some
2952 // file space, by instead aligning to the start of a new
2953 // page. Here we use the real machine page size rather than
2954 // the ABI mandated page size. If the segment has been
2955 // aligned so that the relro data ends at a page boundary,
2956 // we do not try to realign it.
2958 if (!are_addresses_set
2960 && aligned_addr
!= addr
2961 && !parameters
->incremental_update())
2963 uint64_t first_off
= (common_pagesize
2965 & (common_pagesize
- 1)));
2966 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
2969 && ((aligned_addr
& ~ (common_pagesize
- 1))
2970 != (new_addr
& ~ (common_pagesize
- 1)))
2971 && first_off
+ last_off
<= common_pagesize
)
2973 *pshndx
= shndx_hold
;
2974 addr
= align_address(aligned_addr
, common_pagesize
);
2975 addr
= align_address(addr
, (*p
)->maximum_alignment());
2976 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2977 off
= align_file_offset(off
, addr
, abi_pagesize
);
2979 increase_relro
= this->increase_relro_
;
2980 if (this->script_options_
->saw_sections_clause())
2984 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
2993 // Implement --check-sections. We know that the segments
2994 // are sorted by LMA.
2995 if (check_sections
&& last_load_segment
!= NULL
)
2997 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
2998 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3001 unsigned long long lb1
= last_load_segment
->paddr();
3002 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3003 unsigned long long lb2
= (*p
)->paddr();
3004 unsigned long long le2
= lb2
+ (*p
)->memsz();
3005 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3006 "[0x%llx -> 0x%llx]"),
3007 lb1
, le1
, lb2
, le2
);
3010 last_load_segment
= *p
;
3014 // Handle the non-PT_LOAD segments, setting their offsets from their
3015 // section's offsets.
3016 for (Segment_list::iterator p
= this->segment_list_
.begin();
3017 p
!= this->segment_list_
.end();
3020 if ((*p
)->type() != elfcpp::PT_LOAD
)
3021 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3026 // Set the TLS offsets for each section in the PT_TLS segment.
3027 if (this->tls_segment_
!= NULL
)
3028 this->tls_segment_
->set_tls_offsets();
3033 // Set the offsets of all the allocated sections when doing a
3034 // relocatable link. This does the same jobs as set_segment_offsets,
3035 // only for a relocatable link.
3038 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3039 unsigned int* pshndx
)
3043 file_header
->set_address_and_file_offset(0, 0);
3044 off
+= file_header
->data_size();
3046 for (Section_list::iterator p
= this->section_list_
.begin();
3047 p
!= this->section_list_
.end();
3050 // We skip unallocated sections here, except that group sections
3051 // have to come first.
3052 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3053 && (*p
)->type() != elfcpp::SHT_GROUP
)
3056 off
= align_address(off
, (*p
)->addralign());
3058 // The linker script might have set the address.
3059 if (!(*p
)->is_address_valid())
3060 (*p
)->set_address(0);
3061 (*p
)->set_file_offset(off
);
3062 (*p
)->finalize_data_size();
3063 off
+= (*p
)->data_size();
3065 (*p
)->set_out_shndx(*pshndx
);
3072 // Set the file offset of all the sections not associated with a
3076 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3078 off_t startoff
= off
;
3081 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3082 p
!= this->unattached_section_list_
.end();
3085 // The symtab section is handled in create_symtab_sections.
3086 if (*p
== this->symtab_section_
)
3089 // If we've already set the data size, don't set it again.
3090 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3093 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3094 && (*p
)->requires_postprocessing())
3096 (*p
)->create_postprocessing_buffer();
3097 this->any_postprocessing_sections_
= true;
3100 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3101 && (*p
)->after_input_sections())
3103 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3104 && (!(*p
)->after_input_sections()
3105 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3107 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3108 && (!(*p
)->after_input_sections()
3109 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3112 if (!parameters
->incremental_update())
3114 off
= align_address(off
, (*p
)->addralign());
3115 (*p
)->set_file_offset(off
);
3116 (*p
)->finalize_data_size();
3120 // Incremental update: allocate file space from free list.
3121 (*p
)->pre_finalize_data_size();
3122 off_t current_size
= (*p
)->current_data_size();
3123 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3126 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3127 this->free_list_
.dump();
3128 gold_assert((*p
)->output_section() != NULL
);
3129 gold_fatal(_("out of patch space for section %s; "
3130 "relink with --incremental-full"),
3131 (*p
)->output_section()->name());
3133 (*p
)->set_file_offset(off
);
3134 (*p
)->finalize_data_size();
3135 if ((*p
)->data_size() > current_size
)
3137 gold_assert((*p
)->output_section() != NULL
);
3138 gold_fatal(_("%s: section changed size; "
3139 "relink with --incremental-full"),
3140 (*p
)->output_section()->name());
3142 gold_debug(DEBUG_INCREMENTAL
,
3143 "set_section_offsets: %08lx %08lx %s",
3144 static_cast<long>(off
),
3145 static_cast<long>((*p
)->data_size()),
3146 ((*p
)->output_section() != NULL
3147 ? (*p
)->output_section()->name() : "(special)"));
3150 off
+= (*p
)->data_size();
3154 // At this point the name must be set.
3155 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3156 this->namepool_
.add((*p
)->name(), false, NULL
);
3161 // Set the section indexes of all the sections not associated with a
3165 Layout::set_section_indexes(unsigned int shndx
)
3167 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3168 p
!= this->unattached_section_list_
.end();
3171 if (!(*p
)->has_out_shndx())
3173 (*p
)->set_out_shndx(shndx
);
3180 // Set the section addresses according to the linker script. This is
3181 // only called when we see a SECTIONS clause. This returns the
3182 // program segment which should hold the file header and segment
3183 // headers, if any. It will return NULL if they should not be in a
3187 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3189 Script_sections
* ss
= this->script_options_
->script_sections();
3190 gold_assert(ss
->saw_sections_clause());
3191 return this->script_options_
->set_section_addresses(symtab
, this);
3194 // Place the orphan sections in the linker script.
3197 Layout::place_orphan_sections_in_script()
3199 Script_sections
* ss
= this->script_options_
->script_sections();
3200 gold_assert(ss
->saw_sections_clause());
3202 // Place each orphaned output section in the script.
3203 for (Section_list::iterator p
= this->section_list_
.begin();
3204 p
!= this->section_list_
.end();
3207 if (!(*p
)->found_in_sections_clause())
3208 ss
->place_orphan(*p
);
3212 // Count the local symbols in the regular symbol table and the dynamic
3213 // symbol table, and build the respective string pools.
3216 Layout::count_local_symbols(const Task
* task
,
3217 const Input_objects
* input_objects
)
3219 // First, figure out an upper bound on the number of symbols we'll
3220 // be inserting into each pool. This helps us create the pools with
3221 // the right size, to avoid unnecessary hashtable resizing.
3222 unsigned int symbol_count
= 0;
3223 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3224 p
!= input_objects
->relobj_end();
3226 symbol_count
+= (*p
)->local_symbol_count();
3228 // Go from "upper bound" to "estimate." We overcount for two
3229 // reasons: we double-count symbols that occur in more than one
3230 // object file, and we count symbols that are dropped from the
3231 // output. Add it all together and assume we overcount by 100%.
3234 // We assume all symbols will go into both the sympool and dynpool.
3235 this->sympool_
.reserve(symbol_count
);
3236 this->dynpool_
.reserve(symbol_count
);
3238 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3239 p
!= input_objects
->relobj_end();
3242 Task_lock_obj
<Object
> tlo(task
, *p
);
3243 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3247 // Create the symbol table sections. Here we also set the final
3248 // values of the symbols. At this point all the loadable sections are
3249 // fully laid out. SHNUM is the number of sections so far.
3252 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3253 Symbol_table
* symtab
,
3259 if (parameters
->target().get_size() == 32)
3261 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3264 else if (parameters
->target().get_size() == 64)
3266 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3272 // Compute file offsets relative to the start of the symtab section.
3275 // Save space for the dummy symbol at the start of the section. We
3276 // never bother to write this out--it will just be left as zero.
3278 unsigned int local_symbol_index
= 1;
3280 // Add STT_SECTION symbols for each Output section which needs one.
3281 for (Section_list::iterator p
= this->section_list_
.begin();
3282 p
!= this->section_list_
.end();
3285 if (!(*p
)->needs_symtab_index())
3286 (*p
)->set_symtab_index(-1U);
3289 (*p
)->set_symtab_index(local_symbol_index
);
3290 ++local_symbol_index
;
3295 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3296 p
!= input_objects
->relobj_end();
3299 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3301 off
+= (index
- local_symbol_index
) * symsize
;
3302 local_symbol_index
= index
;
3305 unsigned int local_symcount
= local_symbol_index
;
3306 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3309 size_t dyn_global_index
;
3311 if (this->dynsym_section_
== NULL
)
3314 dyn_global_index
= 0;
3319 dyn_global_index
= this->dynsym_section_
->info();
3320 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3321 dynoff
= this->dynsym_section_
->offset() + locsize
;
3322 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3323 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3324 == this->dynsym_section_
->data_size() - locsize
);
3327 off_t global_off
= off
;
3328 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3329 &this->sympool_
, &local_symcount
);
3331 if (!parameters
->options().strip_all())
3333 this->sympool_
.set_string_offsets();
3335 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3336 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3340 this->symtab_section_
= osymtab
;
3342 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3344 osymtab
->add_output_section_data(pos
);
3346 // We generate a .symtab_shndx section if we have more than
3347 // SHN_LORESERVE sections. Technically it is possible that we
3348 // don't need one, because it is possible that there are no
3349 // symbols in any of sections with indexes larger than
3350 // SHN_LORESERVE. That is probably unusual, though, and it is
3351 // easier to always create one than to compute section indexes
3352 // twice (once here, once when writing out the symbols).
3353 if (shnum
>= elfcpp::SHN_LORESERVE
)
3355 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3357 Output_section
* osymtab_xindex
=
3358 this->make_output_section(symtab_xindex_name
,
3359 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3360 ORDER_INVALID
, false);
3362 size_t symcount
= off
/ symsize
;
3363 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3365 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3367 osymtab_xindex
->set_link_section(osymtab
);
3368 osymtab_xindex
->set_addralign(4);
3369 osymtab_xindex
->set_entsize(4);
3371 osymtab_xindex
->set_after_input_sections();
3373 // This tells the driver code to wait until the symbol table
3374 // has written out before writing out the postprocessing
3375 // sections, including the .symtab_shndx section.
3376 this->any_postprocessing_sections_
= true;
3379 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3380 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3385 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3386 ostrtab
->add_output_section_data(pstr
);
3389 if (!parameters
->incremental_update())
3390 symtab_off
= align_address(*poff
, align
);
3393 symtab_off
= this->allocate(off
, align
, *poff
);
3395 gold_fatal(_("out of patch space for symbol table; "
3396 "relink with --incremental-full"));
3397 gold_debug(DEBUG_INCREMENTAL
,
3398 "create_symtab_sections: %08lx %08lx .symtab",
3399 static_cast<long>(symtab_off
),
3400 static_cast<long>(off
));
3403 symtab
->set_file_offset(symtab_off
+ global_off
);
3404 osymtab
->set_file_offset(symtab_off
);
3405 osymtab
->finalize_data_size();
3406 osymtab
->set_link_section(ostrtab
);
3407 osymtab
->set_info(local_symcount
);
3408 osymtab
->set_entsize(symsize
);
3410 if (symtab_off
+ off
> *poff
)
3411 *poff
= symtab_off
+ off
;
3415 // Create the .shstrtab section, which holds the names of the
3416 // sections. At the time this is called, we have created all the
3417 // output sections except .shstrtab itself.
3420 Layout::create_shstrtab()
3422 // FIXME: We don't need to create a .shstrtab section if we are
3423 // stripping everything.
3425 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
3427 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
3428 ORDER_INVALID
, false);
3430 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
3432 // We can't write out this section until we've set all the
3433 // section names, and we don't set the names of compressed
3434 // output sections until relocations are complete. FIXME: With
3435 // the current names we use, this is unnecessary.
3436 os
->set_after_input_sections();
3439 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
3440 os
->add_output_section_data(posd
);
3445 // Create the section headers. SIZE is 32 or 64. OFF is the file
3449 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
3451 Output_section_headers
* oshdrs
;
3452 oshdrs
= new Output_section_headers(this,
3453 &this->segment_list_
,
3454 &this->section_list_
,
3455 &this->unattached_section_list_
,
3459 if (!parameters
->incremental_update())
3460 off
= align_address(*poff
, oshdrs
->addralign());
3463 oshdrs
->pre_finalize_data_size();
3464 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
3466 gold_fatal(_("out of patch space for section header table; "
3467 "relink with --incremental-full"));
3468 gold_debug(DEBUG_INCREMENTAL
,
3469 "create_shdrs: %08lx %08lx (section header table)",
3470 static_cast<long>(off
),
3471 static_cast<long>(off
+ oshdrs
->data_size()));
3473 oshdrs
->set_address_and_file_offset(0, off
);
3474 off
+= oshdrs
->data_size();
3477 this->section_headers_
= oshdrs
;
3480 // Count the allocated sections.
3483 Layout::allocated_output_section_count() const
3485 size_t section_count
= 0;
3486 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3487 p
!= this->segment_list_
.end();
3489 section_count
+= (*p
)->output_section_count();
3490 return section_count
;
3493 // Create the dynamic symbol table.
3496 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
3497 Symbol_table
* symtab
,
3498 Output_section
** pdynstr
,
3499 unsigned int* plocal_dynamic_count
,
3500 std::vector
<Symbol
*>* pdynamic_symbols
,
3501 Versions
* pversions
)
3503 // Count all the symbols in the dynamic symbol table, and set the
3504 // dynamic symbol indexes.
3506 // Skip symbol 0, which is always all zeroes.
3507 unsigned int index
= 1;
3509 // Add STT_SECTION symbols for each Output section which needs one.
3510 for (Section_list::iterator p
= this->section_list_
.begin();
3511 p
!= this->section_list_
.end();
3514 if (!(*p
)->needs_dynsym_index())
3515 (*p
)->set_dynsym_index(-1U);
3518 (*p
)->set_dynsym_index(index
);
3523 // Count the local symbols that need to go in the dynamic symbol table,
3524 // and set the dynamic symbol indexes.
3525 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3526 p
!= input_objects
->relobj_end();
3529 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
3533 unsigned int local_symcount
= index
;
3534 *plocal_dynamic_count
= local_symcount
;
3536 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
3537 &this->dynpool_
, pversions
);
3541 const int size
= parameters
->target().get_size();
3544 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3547 else if (size
== 64)
3549 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3555 // Create the dynamic symbol table section.
3557 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
3561 ORDER_DYNAMIC_LINKER
,
3564 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
3567 dynsym
->add_output_section_data(odata
);
3569 dynsym
->set_info(local_symcount
);
3570 dynsym
->set_entsize(symsize
);
3571 dynsym
->set_addralign(align
);
3573 this->dynsym_section_
= dynsym
;
3575 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3576 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
3577 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
3579 // If there are more than SHN_LORESERVE allocated sections, we
3580 // create a .dynsym_shndx section. It is possible that we don't
3581 // need one, because it is possible that there are no dynamic
3582 // symbols in any of the sections with indexes larger than
3583 // SHN_LORESERVE. This is probably unusual, though, and at this
3584 // time we don't know the actual section indexes so it is
3585 // inconvenient to check.
3586 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
3588 Output_section
* dynsym_xindex
=
3589 this->choose_output_section(NULL
, ".dynsym_shndx",
3590 elfcpp::SHT_SYMTAB_SHNDX
,
3592 false, ORDER_DYNAMIC_LINKER
, false);
3594 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
3596 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
3598 dynsym_xindex
->set_link_section(dynsym
);
3599 dynsym_xindex
->set_addralign(4);
3600 dynsym_xindex
->set_entsize(4);
3602 dynsym_xindex
->set_after_input_sections();
3604 // This tells the driver code to wait until the symbol table has
3605 // written out before writing out the postprocessing sections,
3606 // including the .dynsym_shndx section.
3607 this->any_postprocessing_sections_
= true;
3610 // Create the dynamic string table section.
3612 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
3616 ORDER_DYNAMIC_LINKER
,
3619 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
3620 dynstr
->add_output_section_data(strdata
);
3622 dynsym
->set_link_section(dynstr
);
3623 this->dynamic_section_
->set_link_section(dynstr
);
3625 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
3626 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
3630 // Create the hash tables.
3632 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
3633 || strcmp(parameters
->options().hash_style(), "both") == 0)
3635 unsigned char* phash
;
3636 unsigned int hashlen
;
3637 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
3640 Output_section
* hashsec
=
3641 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
3642 elfcpp::SHF_ALLOC
, false,
3643 ORDER_DYNAMIC_LINKER
, false);
3645 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3649 hashsec
->add_output_section_data(hashdata
);
3651 hashsec
->set_link_section(dynsym
);
3652 hashsec
->set_entsize(4);
3654 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
3657 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
3658 || strcmp(parameters
->options().hash_style(), "both") == 0)
3660 unsigned char* phash
;
3661 unsigned int hashlen
;
3662 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
3665 Output_section
* hashsec
=
3666 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
3667 elfcpp::SHF_ALLOC
, false,
3668 ORDER_DYNAMIC_LINKER
, false);
3670 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3674 hashsec
->add_output_section_data(hashdata
);
3676 hashsec
->set_link_section(dynsym
);
3678 // For a 64-bit target, the entries in .gnu.hash do not have a
3679 // uniform size, so we only set the entry size for a 32-bit
3681 if (parameters
->target().get_size() == 32)
3682 hashsec
->set_entsize(4);
3684 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
3688 // Assign offsets to each local portion of the dynamic symbol table.
3691 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
3693 Output_section
* dynsym
= this->dynsym_section_
;
3694 gold_assert(dynsym
!= NULL
);
3696 off_t off
= dynsym
->offset();
3698 // Skip the dummy symbol at the start of the section.
3699 off
+= dynsym
->entsize();
3701 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3702 p
!= input_objects
->relobj_end();
3705 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
3706 off
+= count
* dynsym
->entsize();
3710 // Create the version sections.
3713 Layout::create_version_sections(const Versions
* versions
,
3714 const Symbol_table
* symtab
,
3715 unsigned int local_symcount
,
3716 const std::vector
<Symbol
*>& dynamic_symbols
,
3717 const Output_section
* dynstr
)
3719 if (!versions
->any_defs() && !versions
->any_needs())
3722 switch (parameters
->size_and_endianness())
3724 #ifdef HAVE_TARGET_32_LITTLE
3725 case Parameters::TARGET_32_LITTLE
:
3726 this->sized_create_version_sections
<32, false>(versions
, symtab
,
3728 dynamic_symbols
, dynstr
);
3731 #ifdef HAVE_TARGET_32_BIG
3732 case Parameters::TARGET_32_BIG
:
3733 this->sized_create_version_sections
<32, true>(versions
, symtab
,
3735 dynamic_symbols
, dynstr
);
3738 #ifdef HAVE_TARGET_64_LITTLE
3739 case Parameters::TARGET_64_LITTLE
:
3740 this->sized_create_version_sections
<64, false>(versions
, symtab
,
3742 dynamic_symbols
, dynstr
);
3745 #ifdef HAVE_TARGET_64_BIG
3746 case Parameters::TARGET_64_BIG
:
3747 this->sized_create_version_sections
<64, true>(versions
, symtab
,
3749 dynamic_symbols
, dynstr
);
3757 // Create the version sections, sized version.
3759 template<int size
, bool big_endian
>
3761 Layout::sized_create_version_sections(
3762 const Versions
* versions
,
3763 const Symbol_table
* symtab
,
3764 unsigned int local_symcount
,
3765 const std::vector
<Symbol
*>& dynamic_symbols
,
3766 const Output_section
* dynstr
)
3768 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
3769 elfcpp::SHT_GNU_versym
,
3772 ORDER_DYNAMIC_LINKER
,
3775 unsigned char* vbuf
;
3777 versions
->symbol_section_contents
<size
, big_endian
>(symtab
, &this->dynpool_
,
3782 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
3785 vsec
->add_output_section_data(vdata
);
3786 vsec
->set_entsize(2);
3787 vsec
->set_link_section(this->dynsym_section_
);
3789 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3790 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
3792 if (versions
->any_defs())
3794 Output_section
* vdsec
;
3795 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
3796 elfcpp::SHT_GNU_verdef
,
3798 false, ORDER_DYNAMIC_LINKER
, false);
3800 unsigned char* vdbuf
;
3801 unsigned int vdsize
;
3802 unsigned int vdentries
;
3803 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
, &vdbuf
,
3804 &vdsize
, &vdentries
);
3806 Output_section_data
* vddata
=
3807 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
3809 vdsec
->add_output_section_data(vddata
);
3810 vdsec
->set_link_section(dynstr
);
3811 vdsec
->set_info(vdentries
);
3813 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
3814 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
3817 if (versions
->any_needs())
3819 Output_section
* vnsec
;
3820 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
3821 elfcpp::SHT_GNU_verneed
,
3823 false, ORDER_DYNAMIC_LINKER
, false);
3825 unsigned char* vnbuf
;
3826 unsigned int vnsize
;
3827 unsigned int vnentries
;
3828 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
3832 Output_section_data
* vndata
=
3833 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
3835 vnsec
->add_output_section_data(vndata
);
3836 vnsec
->set_link_section(dynstr
);
3837 vnsec
->set_info(vnentries
);
3839 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
3840 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
3844 // Create the .interp section and PT_INTERP segment.
3847 Layout::create_interp(const Target
* target
)
3849 const char* interp
= parameters
->options().dynamic_linker();
3852 interp
= target
->dynamic_linker();
3853 gold_assert(interp
!= NULL
);
3856 size_t len
= strlen(interp
) + 1;
3858 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
3860 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
3861 elfcpp::SHT_PROGBITS
,
3863 false, ORDER_INTERP
,
3865 osec
->add_output_section_data(odata
);
3867 if (!this->script_options_
->saw_phdrs_clause())
3869 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_INTERP
,
3871 oseg
->add_output_section_to_nonload(osec
, elfcpp::PF_R
);
3875 // Add dynamic tags for the PLT and the dynamic relocs. This is
3876 // called by the target-specific code. This does nothing if not doing
3879 // USE_REL is true for REL relocs rather than RELA relocs.
3881 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3883 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3884 // and we also set DT_PLTREL. We use PLT_REL's output section, since
3885 // some targets have multiple reloc sections in PLT_REL.
3887 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3888 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3890 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3894 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
3895 const Output_data
* plt_rel
,
3896 const Output_data_reloc_generic
* dyn_rel
,
3897 bool add_debug
, bool dynrel_includes_plt
)
3899 Output_data_dynamic
* odyn
= this->dynamic_data_
;
3903 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
3904 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
3906 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
3908 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
3909 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
3910 odyn
->add_constant(elfcpp::DT_PLTREL
,
3911 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
3914 if (dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
3916 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
3918 if (plt_rel
!= NULL
&& dynrel_includes_plt
)
3919 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3922 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3924 const int size
= parameters
->target().get_size();
3929 rel_tag
= elfcpp::DT_RELENT
;
3931 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
3932 else if (size
== 64)
3933 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
3939 rel_tag
= elfcpp::DT_RELAENT
;
3941 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
3942 else if (size
== 64)
3943 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
3947 odyn
->add_constant(rel_tag
, rel_size
);
3949 if (parameters
->options().combreloc())
3951 size_t c
= dyn_rel
->relative_reloc_count();
3953 odyn
->add_constant((use_rel
3954 ? elfcpp::DT_RELCOUNT
3955 : elfcpp::DT_RELACOUNT
),
3960 if (add_debug
&& !parameters
->options().shared())
3962 // The value of the DT_DEBUG tag is filled in by the dynamic
3963 // linker at run time, and used by the debugger.
3964 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
3968 // Finish the .dynamic section and PT_DYNAMIC segment.
3971 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
3972 const Symbol_table
* symtab
)
3974 if (!this->script_options_
->saw_phdrs_clause())
3976 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
3979 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
3980 elfcpp::PF_R
| elfcpp::PF_W
);
3983 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3985 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
3986 p
!= input_objects
->dynobj_end();
3989 if (!(*p
)->is_needed()
3990 && !(*p
)->is_incremental()
3991 && (*p
)->input_file()->options().as_needed())
3993 // This dynamic object was linked with --as-needed, but it
3998 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4001 if (parameters
->options().shared())
4003 const char* soname
= parameters
->options().soname();
4005 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4008 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4009 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4010 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4012 sym
= symtab
->lookup(parameters
->options().fini());
4013 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4014 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4016 // Look for .init_array, .preinit_array and .fini_array by checking
4018 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4019 p
!= this->section_list_
.end();
4021 switch((*p
)->type())
4023 case elfcpp::SHT_FINI_ARRAY
:
4024 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4025 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4027 case elfcpp::SHT_INIT_ARRAY
:
4028 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4029 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4031 case elfcpp::SHT_PREINIT_ARRAY
:
4032 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4033 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4039 // Add a DT_RPATH entry if needed.
4040 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4043 std::string rpath_val
;
4044 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4048 if (rpath_val
.empty())
4049 rpath_val
= p
->name();
4052 // Eliminate duplicates.
4053 General_options::Dir_list::const_iterator q
;
4054 for (q
= rpath
.begin(); q
!= p
; ++q
)
4055 if (q
->name() == p
->name())
4060 rpath_val
+= p
->name();
4065 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4066 if (parameters
->options().enable_new_dtags())
4067 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4070 // Look for text segments that have dynamic relocations.
4071 bool have_textrel
= false;
4072 if (!this->script_options_
->saw_sections_clause())
4074 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4075 p
!= this->segment_list_
.end();
4078 if (((*p
)->flags() & elfcpp::PF_W
) == 0
4079 && (*p
)->has_dynamic_reloc())
4081 have_textrel
= true;
4088 // We don't know the section -> segment mapping, so we are
4089 // conservative and just look for readonly sections with
4090 // relocations. If those sections wind up in writable segments,
4091 // then we have created an unnecessary DT_TEXTREL entry.
4092 for (Section_list::const_iterator p
= this->section_list_
.begin();
4093 p
!= this->section_list_
.end();
4096 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4097 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4098 && ((*p
)->has_dynamic_reloc()))
4100 have_textrel
= true;
4106 // Add a DT_FLAGS entry. We add it even if no flags are set so that
4107 // post-link tools can easily modify these flags if desired.
4108 unsigned int flags
= 0;
4111 // Add a DT_TEXTREL for compatibility with older loaders.
4112 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4113 flags
|= elfcpp::DF_TEXTREL
;
4115 if (parameters
->options().text())
4116 gold_error(_("read-only segment has dynamic relocations"));
4117 else if (parameters
->options().warn_shared_textrel()
4118 && parameters
->options().shared())
4119 gold_warning(_("shared library text segment is not shareable"));
4121 if (parameters
->options().shared() && this->has_static_tls())
4122 flags
|= elfcpp::DF_STATIC_TLS
;
4123 if (parameters
->options().origin())
4124 flags
|= elfcpp::DF_ORIGIN
;
4125 if (parameters
->options().Bsymbolic())
4127 flags
|= elfcpp::DF_SYMBOLIC
;
4128 // Add DT_SYMBOLIC for compatibility with older loaders.
4129 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4131 if (parameters
->options().now())
4132 flags
|= elfcpp::DF_BIND_NOW
;
4133 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4136 if (parameters
->options().initfirst())
4137 flags
|= elfcpp::DF_1_INITFIRST
;
4138 if (parameters
->options().interpose())
4139 flags
|= elfcpp::DF_1_INTERPOSE
;
4140 if (parameters
->options().loadfltr())
4141 flags
|= elfcpp::DF_1_LOADFLTR
;
4142 if (parameters
->options().nodefaultlib())
4143 flags
|= elfcpp::DF_1_NODEFLIB
;
4144 if (parameters
->options().nodelete())
4145 flags
|= elfcpp::DF_1_NODELETE
;
4146 if (parameters
->options().nodlopen())
4147 flags
|= elfcpp::DF_1_NOOPEN
;
4148 if (parameters
->options().nodump())
4149 flags
|= elfcpp::DF_1_NODUMP
;
4150 if (!parameters
->options().shared())
4151 flags
&= ~(elfcpp::DF_1_INITFIRST
4152 | elfcpp::DF_1_NODELETE
4153 | elfcpp::DF_1_NOOPEN
);
4154 if (parameters
->options().origin())
4155 flags
|= elfcpp::DF_1_ORIGIN
;
4156 if (parameters
->options().now())
4157 flags
|= elfcpp::DF_1_NOW
;
4159 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4162 // Set the size of the _DYNAMIC symbol table to be the size of the
4166 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4168 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4169 odyn
->finalize_data_size();
4170 off_t data_size
= odyn
->data_size();
4171 const int size
= parameters
->target().get_size();
4173 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4174 else if (size
== 64)
4175 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4180 // The mapping of input section name prefixes to output section names.
4181 // In some cases one prefix is itself a prefix of another prefix; in
4182 // such a case the longer prefix must come first. These prefixes are
4183 // based on the GNU linker default ELF linker script.
4185 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4186 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4188 MAPPING_INIT(".text.", ".text"),
4189 MAPPING_INIT(".ctors.", ".ctors"),
4190 MAPPING_INIT(".dtors.", ".dtors"),
4191 MAPPING_INIT(".rodata.", ".rodata"),
4192 MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
4193 MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
4194 MAPPING_INIT(".data.", ".data"),
4195 MAPPING_INIT(".bss.", ".bss"),
4196 MAPPING_INIT(".tdata.", ".tdata"),
4197 MAPPING_INIT(".tbss.", ".tbss"),
4198 MAPPING_INIT(".init_array.", ".init_array"),
4199 MAPPING_INIT(".fini_array.", ".fini_array"),
4200 MAPPING_INIT(".sdata.", ".sdata"),
4201 MAPPING_INIT(".sbss.", ".sbss"),
4202 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4203 // differently depending on whether it is creating a shared library.
4204 MAPPING_INIT(".sdata2.", ".sdata"),
4205 MAPPING_INIT(".sbss2.", ".sbss"),
4206 MAPPING_INIT(".lrodata.", ".lrodata"),
4207 MAPPING_INIT(".ldata.", ".ldata"),
4208 MAPPING_INIT(".lbss.", ".lbss"),
4209 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4210 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4211 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4212 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4213 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4214 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4215 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4216 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4217 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4218 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4219 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4220 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4221 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4222 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4223 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4224 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4225 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4226 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4227 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4228 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4229 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4233 const int Layout::section_name_mapping_count
=
4234 (sizeof(Layout::section_name_mapping
)
4235 / sizeof(Layout::section_name_mapping
[0]));
4237 // Choose the output section name to use given an input section name.
4238 // Set *PLEN to the length of the name. *PLEN is initialized to the
4242 Layout::output_section_name(const char* name
, size_t* plen
)
4244 // gcc 4.3 generates the following sorts of section names when it
4245 // needs a section name specific to a function:
4251 // .data.rel.local.FN
4253 // .data.rel.ro.local.FN
4260 // The GNU linker maps all of those to the part before the .FN,
4261 // except that .data.rel.local.FN is mapped to .data, and
4262 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4263 // beginning with .data.rel.ro.local are grouped together.
4265 // For an anonymous namespace, the string FN can contain a '.'.
4267 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4268 // GNU linker maps to .rodata.
4270 // The .data.rel.ro sections are used with -z relro. The sections
4271 // are recognized by name. We use the same names that the GNU
4272 // linker does for these sections.
4274 // It is hard to handle this in a principled way, so we don't even
4275 // try. We use a table of mappings. If the input section name is
4276 // not found in the table, we simply use it as the output section
4279 const Section_name_mapping
* psnm
= section_name_mapping
;
4280 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4282 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4284 *plen
= psnm
->tolen
;
4292 // Check if a comdat group or .gnu.linkonce section with the given
4293 // NAME is selected for the link. If there is already a section,
4294 // *KEPT_SECTION is set to point to the existing section and the
4295 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4296 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4297 // *KEPT_SECTION is set to the internal copy and the function returns
4301 Layout::find_or_add_kept_section(const std::string
& name
,
4306 Kept_section
** kept_section
)
4308 // It's normal to see a couple of entries here, for the x86 thunk
4309 // sections. If we see more than a few, we're linking a C++
4310 // program, and we resize to get more space to minimize rehashing.
4311 if (this->signatures_
.size() > 4
4312 && !this->resized_signatures_
)
4314 reserve_unordered_map(&this->signatures_
,
4315 this->number_of_input_files_
* 64);
4316 this->resized_signatures_
= true;
4319 Kept_section candidate
;
4320 std::pair
<Signatures::iterator
, bool> ins
=
4321 this->signatures_
.insert(std::make_pair(name
, candidate
));
4323 if (kept_section
!= NULL
)
4324 *kept_section
= &ins
.first
->second
;
4327 // This is the first time we've seen this signature.
4328 ins
.first
->second
.set_object(object
);
4329 ins
.first
->second
.set_shndx(shndx
);
4331 ins
.first
->second
.set_is_comdat();
4333 ins
.first
->second
.set_is_group_name();
4337 // We have already seen this signature.
4339 if (ins
.first
->second
.is_group_name())
4341 // We've already seen a real section group with this signature.
4342 // If the kept group is from a plugin object, and we're in the
4343 // replacement phase, accept the new one as a replacement.
4344 if (ins
.first
->second
.object() == NULL
4345 && parameters
->options().plugins()->in_replacement_phase())
4347 ins
.first
->second
.set_object(object
);
4348 ins
.first
->second
.set_shndx(shndx
);
4353 else if (is_group_name
)
4355 // This is a real section group, and we've already seen a
4356 // linkonce section with this signature. Record that we've seen
4357 // a section group, and don't include this section group.
4358 ins
.first
->second
.set_is_group_name();
4363 // We've already seen a linkonce section and this is a linkonce
4364 // section. These don't block each other--this may be the same
4365 // symbol name with different section types.
4370 // Store the allocated sections into the section list.
4373 Layout::get_allocated_sections(Section_list
* section_list
) const
4375 for (Section_list::const_iterator p
= this->section_list_
.begin();
4376 p
!= this->section_list_
.end();
4378 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
4379 section_list
->push_back(*p
);
4382 // Create an output segment.
4385 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
4387 gold_assert(!parameters
->options().relocatable());
4388 Output_segment
* oseg
= new Output_segment(type
, flags
);
4389 this->segment_list_
.push_back(oseg
);
4391 if (type
== elfcpp::PT_TLS
)
4392 this->tls_segment_
= oseg
;
4393 else if (type
== elfcpp::PT_GNU_RELRO
)
4394 this->relro_segment_
= oseg
;
4399 // Return the file offset of the normal symbol table.
4402 Layout::symtab_section_offset() const
4404 if (this->symtab_section_
!= NULL
)
4405 return this->symtab_section_
->offset();
4409 // Write out the Output_sections. Most won't have anything to write,
4410 // since most of the data will come from input sections which are
4411 // handled elsewhere. But some Output_sections do have Output_data.
4414 Layout::write_output_sections(Output_file
* of
) const
4416 for (Section_list::const_iterator p
= this->section_list_
.begin();
4417 p
!= this->section_list_
.end();
4420 if (!(*p
)->after_input_sections())
4425 // Write out data not associated with a section or the symbol table.
4428 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
4430 if (!parameters
->options().strip_all())
4432 const Output_section
* symtab_section
= this->symtab_section_
;
4433 for (Section_list::const_iterator p
= this->section_list_
.begin();
4434 p
!= this->section_list_
.end();
4437 if ((*p
)->needs_symtab_index())
4439 gold_assert(symtab_section
!= NULL
);
4440 unsigned int index
= (*p
)->symtab_index();
4441 gold_assert(index
> 0 && index
!= -1U);
4442 off_t off
= (symtab_section
->offset()
4443 + index
* symtab_section
->entsize());
4444 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
4449 const Output_section
* dynsym_section
= this->dynsym_section_
;
4450 for (Section_list::const_iterator p
= this->section_list_
.begin();
4451 p
!= this->section_list_
.end();
4454 if ((*p
)->needs_dynsym_index())
4456 gold_assert(dynsym_section
!= NULL
);
4457 unsigned int index
= (*p
)->dynsym_index();
4458 gold_assert(index
> 0 && index
!= -1U);
4459 off_t off
= (dynsym_section
->offset()
4460 + index
* dynsym_section
->entsize());
4461 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
4465 // Write out the Output_data which are not in an Output_section.
4466 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
4467 p
!= this->special_output_list_
.end();
4472 // Write out the Output_sections which can only be written after the
4473 // input sections are complete.
4476 Layout::write_sections_after_input_sections(Output_file
* of
)
4478 // Determine the final section offsets, and thus the final output
4479 // file size. Note we finalize the .shstrab last, to allow the
4480 // after_input_section sections to modify their section-names before
4482 if (this->any_postprocessing_sections_
)
4484 off_t off
= this->output_file_size_
;
4485 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
4487 // Now that we've finalized the names, we can finalize the shstrab.
4489 this->set_section_offsets(off
,
4490 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
4492 if (off
> this->output_file_size_
)
4495 this->output_file_size_
= off
;
4499 for (Section_list::const_iterator p
= this->section_list_
.begin();
4500 p
!= this->section_list_
.end();
4503 if ((*p
)->after_input_sections())
4507 this->section_headers_
->write(of
);
4510 // If the build ID requires computing a checksum, do so here, and
4511 // write it out. We compute a checksum over the entire file because
4512 // that is simplest.
4515 Layout::write_build_id(Output_file
* of
) const
4517 if (this->build_id_note_
== NULL
)
4520 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
4522 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
4523 this->build_id_note_
->data_size());
4525 const char* style
= parameters
->options().build_id();
4526 if (strcmp(style
, "sha1") == 0)
4529 sha1_init_ctx(&ctx
);
4530 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
4531 sha1_finish_ctx(&ctx
, ov
);
4533 else if (strcmp(style
, "md5") == 0)
4537 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
4538 md5_finish_ctx(&ctx
, ov
);
4543 of
->write_output_view(this->build_id_note_
->offset(),
4544 this->build_id_note_
->data_size(),
4547 of
->free_input_view(0, this->output_file_size_
, iv
);
4550 // Write out a binary file. This is called after the link is
4551 // complete. IN is the temporary output file we used to generate the
4552 // ELF code. We simply walk through the segments, read them from
4553 // their file offset in IN, and write them to their load address in
4554 // the output file. FIXME: with a bit more work, we could support
4555 // S-records and/or Intel hex format here.
4558 Layout::write_binary(Output_file
* in
) const
4560 gold_assert(parameters
->options().oformat_enum()
4561 == General_options::OBJECT_FORMAT_BINARY
);
4563 // Get the size of the binary file.
4564 uint64_t max_load_address
= 0;
4565 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4566 p
!= this->segment_list_
.end();
4569 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4571 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
4572 if (max_paddr
> max_load_address
)
4573 max_load_address
= max_paddr
;
4577 Output_file
out(parameters
->options().output_file_name());
4578 out
.open(max_load_address
);
4580 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4581 p
!= this->segment_list_
.end();
4584 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4586 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
4588 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
4590 memcpy(vout
, vin
, (*p
)->filesz());
4591 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
4592 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
4599 // Print the output sections to the map file.
4602 Layout::print_to_mapfile(Mapfile
* mapfile
) const
4604 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4605 p
!= this->segment_list_
.end();
4607 (*p
)->print_sections_to_mapfile(mapfile
);
4610 // Print statistical information to stderr. This is used for --stats.
4613 Layout::print_stats() const
4615 this->namepool_
.print_stats("section name pool");
4616 this->sympool_
.print_stats("output symbol name pool");
4617 this->dynpool_
.print_stats("dynamic name pool");
4619 for (Section_list::const_iterator p
= this->section_list_
.begin();
4620 p
!= this->section_list_
.end();
4622 (*p
)->print_merge_stats();
4625 // Write_sections_task methods.
4627 // We can always run this task.
4630 Write_sections_task::is_runnable()
4635 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4639 Write_sections_task::locks(Task_locker
* tl
)
4641 tl
->add(this, this->output_sections_blocker_
);
4642 tl
->add(this, this->final_blocker_
);
4645 // Run the task--write out the data.
4648 Write_sections_task::run(Workqueue
*)
4650 this->layout_
->write_output_sections(this->of_
);
4653 // Write_data_task methods.
4655 // We can always run this task.
4658 Write_data_task::is_runnable()
4663 // We need to unlock FINAL_BLOCKER when finished.
4666 Write_data_task::locks(Task_locker
* tl
)
4668 tl
->add(this, this->final_blocker_
);
4671 // Run the task--write out the data.
4674 Write_data_task::run(Workqueue
*)
4676 this->layout_
->write_data(this->symtab_
, this->of_
);
4679 // Write_symbols_task methods.
4681 // We can always run this task.
4684 Write_symbols_task::is_runnable()
4689 // We need to unlock FINAL_BLOCKER when finished.
4692 Write_symbols_task::locks(Task_locker
* tl
)
4694 tl
->add(this, this->final_blocker_
);
4697 // Run the task--write out the symbols.
4700 Write_symbols_task::run(Workqueue
*)
4702 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
4703 this->layout_
->symtab_xindex(),
4704 this->layout_
->dynsym_xindex(), this->of_
);
4707 // Write_after_input_sections_task methods.
4709 // We can only run this task after the input sections have completed.
4712 Write_after_input_sections_task::is_runnable()
4714 if (this->input_sections_blocker_
->is_blocked())
4715 return this->input_sections_blocker_
;
4719 // We need to unlock FINAL_BLOCKER when finished.
4722 Write_after_input_sections_task::locks(Task_locker
* tl
)
4724 tl
->add(this, this->final_blocker_
);
4730 Write_after_input_sections_task::run(Workqueue
*)
4732 this->layout_
->write_sections_after_input_sections(this->of_
);
4735 // Close_task_runner methods.
4737 // Run the task--close the file.
4740 Close_task_runner::run(Workqueue
*, const Task
*)
4742 // If we need to compute a checksum for the BUILD if, we do so here.
4743 this->layout_
->write_build_id(this->of_
);
4745 // If we've been asked to create a binary file, we do so here.
4746 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
4747 this->layout_
->write_binary(this->of_
);
4752 // Instantiate the templates we need. We could use the configure
4753 // script to restrict this to only the ones for implemented targets.
4755 #ifdef HAVE_TARGET_32_LITTLE
4758 Layout::init_fixed_output_section
<32, false>(
4760 elfcpp::Shdr
<32, false>& shdr
);
4763 #ifdef HAVE_TARGET_32_BIG
4766 Layout::init_fixed_output_section
<32, true>(
4768 elfcpp::Shdr
<32, true>& shdr
);
4771 #ifdef HAVE_TARGET_64_LITTLE
4774 Layout::init_fixed_output_section
<64, false>(
4776 elfcpp::Shdr
<64, false>& shdr
);
4779 #ifdef HAVE_TARGET_64_BIG
4782 Layout::init_fixed_output_section
<64, true>(
4784 elfcpp::Shdr
<64, true>& shdr
);
4787 #ifdef HAVE_TARGET_32_LITTLE
4790 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
4793 const elfcpp::Shdr
<32, false>& shdr
,
4794 unsigned int, unsigned int, off_t
*);
4797 #ifdef HAVE_TARGET_32_BIG
4800 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
4803 const elfcpp::Shdr
<32, true>& shdr
,
4804 unsigned int, unsigned int, off_t
*);
4807 #ifdef HAVE_TARGET_64_LITTLE
4810 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
4813 const elfcpp::Shdr
<64, false>& shdr
,
4814 unsigned int, unsigned int, off_t
*);
4817 #ifdef HAVE_TARGET_64_BIG
4820 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
4823 const elfcpp::Shdr
<64, true>& shdr
,
4824 unsigned int, unsigned int, off_t
*);
4827 #ifdef HAVE_TARGET_32_LITTLE
4830 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
4831 unsigned int reloc_shndx
,
4832 const elfcpp::Shdr
<32, false>& shdr
,
4833 Output_section
* data_section
,
4834 Relocatable_relocs
* rr
);
4837 #ifdef HAVE_TARGET_32_BIG
4840 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
4841 unsigned int reloc_shndx
,
4842 const elfcpp::Shdr
<32, true>& shdr
,
4843 Output_section
* data_section
,
4844 Relocatable_relocs
* rr
);
4847 #ifdef HAVE_TARGET_64_LITTLE
4850 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
4851 unsigned int reloc_shndx
,
4852 const elfcpp::Shdr
<64, false>& shdr
,
4853 Output_section
* data_section
,
4854 Relocatable_relocs
* rr
);
4857 #ifdef HAVE_TARGET_64_BIG
4860 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
4861 unsigned int reloc_shndx
,
4862 const elfcpp::Shdr
<64, true>& shdr
,
4863 Output_section
* data_section
,
4864 Relocatable_relocs
* rr
);
4867 #ifdef HAVE_TARGET_32_LITTLE
4870 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
4871 Sized_relobj_file
<32, false>* object
,
4873 const char* group_section_name
,
4874 const char* signature
,
4875 const elfcpp::Shdr
<32, false>& shdr
,
4876 elfcpp::Elf_Word flags
,
4877 std::vector
<unsigned int>* shndxes
);
4880 #ifdef HAVE_TARGET_32_BIG
4883 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
4884 Sized_relobj_file
<32, true>* object
,
4886 const char* group_section_name
,
4887 const char* signature
,
4888 const elfcpp::Shdr
<32, true>& shdr
,
4889 elfcpp::Elf_Word flags
,
4890 std::vector
<unsigned int>* shndxes
);
4893 #ifdef HAVE_TARGET_64_LITTLE
4896 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
4897 Sized_relobj_file
<64, false>* object
,
4899 const char* group_section_name
,
4900 const char* signature
,
4901 const elfcpp::Shdr
<64, false>& shdr
,
4902 elfcpp::Elf_Word flags
,
4903 std::vector
<unsigned int>* shndxes
);
4906 #ifdef HAVE_TARGET_64_BIG
4909 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
4910 Sized_relobj_file
<64, true>* object
,
4912 const char* group_section_name
,
4913 const char* signature
,
4914 const elfcpp::Shdr
<64, true>& shdr
,
4915 elfcpp::Elf_Word flags
,
4916 std::vector
<unsigned int>* shndxes
);
4919 #ifdef HAVE_TARGET_32_LITTLE
4922 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
4923 const unsigned char* symbols
,
4925 const unsigned char* symbol_names
,
4926 off_t symbol_names_size
,
4928 const elfcpp::Shdr
<32, false>& shdr
,
4929 unsigned int reloc_shndx
,
4930 unsigned int reloc_type
,
4934 #ifdef HAVE_TARGET_32_BIG
4937 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
4938 const unsigned char* symbols
,
4940 const unsigned char* symbol_names
,
4941 off_t symbol_names_size
,
4943 const elfcpp::Shdr
<32, true>& shdr
,
4944 unsigned int reloc_shndx
,
4945 unsigned int reloc_type
,
4949 #ifdef HAVE_TARGET_64_LITTLE
4952 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
4953 const unsigned char* symbols
,
4955 const unsigned char* symbol_names
,
4956 off_t symbol_names_size
,
4958 const elfcpp::Shdr
<64, false>& shdr
,
4959 unsigned int reloc_shndx
,
4960 unsigned int reloc_type
,
4964 #ifdef HAVE_TARGET_64_BIG
4967 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
4968 const unsigned char* symbols
,
4970 const unsigned char* symbol_names
,
4971 off_t symbol_names_size
,
4973 const elfcpp::Shdr
<64, true>& shdr
,
4974 unsigned int reloc_shndx
,
4975 unsigned int reloc_type
,
4979 } // End namespace gold.