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 off_t file_size
= this->layout_
->finalize(this->input_objects_
,
306 // Now we know the final size of the output file and we know where
307 // each piece of information goes.
309 if (this->mapfile_
!= NULL
)
311 this->mapfile_
->print_discarded_sections(this->input_objects_
);
312 this->layout_
->print_to_mapfile(this->mapfile_
);
316 if (this->layout_
->incremental_base() == NULL
)
318 of
= new Output_file(parameters
->options().output_file_name());
319 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
320 of
->set_is_temporary();
325 of
= this->layout_
->incremental_base()->output_file();
326 of
->resize(file_size
);
329 // Queue up the final set of tasks.
330 gold::queue_final_tasks(this->options_
, this->input_objects_
,
331 this->symtab_
, this->layout_
, workqueue
, of
);
336 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
337 : number_of_input_files_(number_of_input_files
),
338 script_options_(script_options
),
346 unattached_section_list_(),
347 special_output_list_(),
348 section_headers_(NULL
),
350 relro_segment_(NULL
),
352 symtab_section_(NULL
),
353 symtab_xindex_(NULL
),
354 dynsym_section_(NULL
),
355 dynsym_xindex_(NULL
),
356 dynamic_section_(NULL
),
357 dynamic_symbol_(NULL
),
359 eh_frame_section_(NULL
),
360 eh_frame_data_(NULL
),
361 added_eh_frame_data_(false),
362 eh_frame_hdr_section_(NULL
),
363 build_id_note_(NULL
),
367 output_file_size_(-1),
368 have_added_input_section_(false),
369 sections_are_attached_(false),
370 input_requires_executable_stack_(false),
371 input_with_gnu_stack_note_(false),
372 input_without_gnu_stack_note_(false),
373 has_static_tls_(false),
374 any_postprocessing_sections_(false),
375 resized_signatures_(false),
376 have_stabstr_section_(false),
377 incremental_inputs_(NULL
),
378 record_output_section_data_from_script_(false),
379 script_output_section_data_list_(),
380 segment_states_(NULL
),
381 relaxation_debug_check_(NULL
),
382 incremental_base_(NULL
),
385 // Make space for more than enough segments for a typical file.
386 // This is just for efficiency--it's OK if we wind up needing more.
387 this->segment_list_
.reserve(12);
389 // We expect two unattached Output_data objects: the file header and
390 // the segment headers.
391 this->special_output_list_
.reserve(2);
393 // Initialize structure needed for an incremental build.
394 if (parameters
->incremental())
395 this->incremental_inputs_
= new Incremental_inputs
;
397 // The section name pool is worth optimizing in all cases, because
398 // it is small, but there are often overlaps due to .rel sections.
399 this->namepool_
.set_optimize();
402 // For incremental links, record the base file to be modified.
405 Layout::set_incremental_base(Incremental_binary
* base
)
407 this->incremental_base_
= base
;
408 this->free_list_
.init(base
->output_file()->filesize(), true);
411 // Hash a key we use to look up an output section mapping.
414 Layout::Hash_key::operator()(const Layout::Key
& k
) const
416 return k
.first
+ k
.second
.first
+ k
.second
.second
;
419 // Returns whether the given section is in the list of
420 // debug-sections-used-by-some-version-of-gdb. Currently,
421 // we've checked versions of gdb up to and including 6.7.1.
423 static const char* gdb_sections
[] =
425 // ".debug_aranges", // not used by gdb as of 6.7.1
432 // ".debug_pubnames", // not used by gdb as of 6.7.1
437 static const char* lines_only_debug_sections
[] =
439 // ".debug_aranges", // not used by gdb as of 6.7.1
446 // ".debug_pubnames", // not used by gdb as of 6.7.1
452 is_gdb_debug_section(const char* str
)
454 // We can do this faster: binary search or a hashtable. But why bother?
455 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
456 if (strcmp(str
, gdb_sections
[i
]) == 0)
462 is_lines_only_debug_section(const char* str
)
464 // We can do this faster: binary search or a hashtable. But why bother?
466 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
468 if (strcmp(str
, lines_only_debug_sections
[i
]) == 0)
473 // Sometimes we compress sections. This is typically done for
474 // sections that are not part of normal program execution (such as
475 // .debug_* sections), and where the readers of these sections know
476 // how to deal with compressed sections. This routine doesn't say for
477 // certain whether we'll compress -- it depends on commandline options
478 // as well -- just whether this section is a candidate for compression.
479 // (The Output_compressed_section class decides whether to compress
480 // a given section, and picks the name of the compressed section.)
483 is_compressible_debug_section(const char* secname
)
485 return (is_prefix_of(".debug", secname
));
488 // We may see compressed debug sections in input files. Return TRUE
489 // if this is the name of a compressed debug section.
492 is_compressed_debug_section(const char* secname
)
494 return (is_prefix_of(".zdebug", secname
));
497 // Whether to include this section in the link.
499 template<int size
, bool big_endian
>
501 Layout::include_section(Sized_relobj
<size
, big_endian
>*, const char* name
,
502 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
504 if (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
)
507 switch (shdr
.get_sh_type())
509 case elfcpp::SHT_NULL
:
510 case elfcpp::SHT_SYMTAB
:
511 case elfcpp::SHT_DYNSYM
:
512 case elfcpp::SHT_HASH
:
513 case elfcpp::SHT_DYNAMIC
:
514 case elfcpp::SHT_SYMTAB_SHNDX
:
517 case elfcpp::SHT_STRTAB
:
518 // Discard the sections which have special meanings in the ELF
519 // ABI. Keep others (e.g., .stabstr). We could also do this by
520 // checking the sh_link fields of the appropriate sections.
521 return (strcmp(name
, ".dynstr") != 0
522 && strcmp(name
, ".strtab") != 0
523 && strcmp(name
, ".shstrtab") != 0);
525 case elfcpp::SHT_RELA
:
526 case elfcpp::SHT_REL
:
527 case elfcpp::SHT_GROUP
:
528 // If we are emitting relocations these should be handled
530 gold_assert(!parameters
->options().relocatable()
531 && !parameters
->options().emit_relocs());
534 case elfcpp::SHT_PROGBITS
:
535 if (parameters
->options().strip_debug()
536 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
538 if (is_debug_info_section(name
))
541 if (parameters
->options().strip_debug_non_line()
542 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
544 // Debugging sections can only be recognized by name.
545 if (is_prefix_of(".debug", name
)
546 && !is_lines_only_debug_section(name
))
549 if (parameters
->options().strip_debug_gdb()
550 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
552 // Debugging sections can only be recognized by name.
553 if (is_prefix_of(".debug", name
)
554 && !is_gdb_debug_section(name
))
557 if (parameters
->options().strip_lto_sections()
558 && !parameters
->options().relocatable()
559 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
561 // Ignore LTO sections containing intermediate code.
562 if (is_prefix_of(".gnu.lto_", name
))
565 // The GNU linker strips .gnu_debuglink sections, so we do too.
566 // This is a feature used to keep debugging information in
568 if (strcmp(name
, ".gnu_debuglink") == 0)
577 // Return an output section named NAME, or NULL if there is none.
580 Layout::find_output_section(const char* name
) const
582 for (Section_list::const_iterator p
= this->section_list_
.begin();
583 p
!= this->section_list_
.end();
585 if (strcmp((*p
)->name(), name
) == 0)
590 // Return an output segment of type TYPE, with segment flags SET set
591 // and segment flags CLEAR clear. Return NULL if there is none.
594 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
595 elfcpp::Elf_Word clear
) const
597 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
598 p
!= this->segment_list_
.end();
600 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
601 && ((*p
)->flags() & set
) == set
602 && ((*p
)->flags() & clear
) == 0)
607 // Return the output section to use for section NAME with type TYPE
608 // and section flags FLAGS. NAME must be canonicalized in the string
609 // pool, and NAME_KEY is the key. IS_INTERP is true if this is the
610 // .interp section. IS_DYNAMIC_LINKER_SECTION is true if this section
611 // is used by the dynamic linker. IS_RELRO is true for a relro
612 // section. IS_LAST_RELRO is true for the last relro section.
613 // IS_FIRST_NON_RELRO is true for the first non-relro section.
616 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
617 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
618 Output_section_order order
, bool is_relro
)
620 elfcpp::Elf_Xword lookup_flags
= flags
;
622 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
623 // read-write with read-only sections. Some other ELF linkers do
624 // not do this. FIXME: Perhaps there should be an option
626 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
628 const Key
key(name_key
, std::make_pair(type
, lookup_flags
));
629 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
630 std::pair
<Section_name_map::iterator
, bool> ins(
631 this->section_name_map_
.insert(v
));
634 return ins
.first
->second
;
637 // This is the first time we've seen this name/type/flags
638 // combination. For compatibility with the GNU linker, we
639 // combine sections with contents and zero flags with sections
640 // with non-zero flags. This is a workaround for cases where
641 // assembler code forgets to set section flags. FIXME: Perhaps
642 // there should be an option to control this.
643 Output_section
* os
= NULL
;
645 if (type
== elfcpp::SHT_PROGBITS
)
649 Output_section
* same_name
= this->find_output_section(name
);
650 if (same_name
!= NULL
651 && same_name
->type() == elfcpp::SHT_PROGBITS
652 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
655 else if ((flags
& elfcpp::SHF_TLS
) == 0)
657 elfcpp::Elf_Xword zero_flags
= 0;
658 const Key
zero_key(name_key
, std::make_pair(type
, zero_flags
));
659 Section_name_map::iterator p
=
660 this->section_name_map_
.find(zero_key
);
661 if (p
!= this->section_name_map_
.end())
667 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
669 ins
.first
->second
= os
;
674 // Pick the output section to use for section NAME, in input file
675 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
676 // linker created section. IS_INPUT_SECTION is true if we are
677 // choosing an output section for an input section found in a input
678 // file. IS_INTERP is true if this is the .interp section.
679 // IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
680 // dynamic linker. IS_RELRO is true for a relro section.
681 // IS_LAST_RELRO is true for the last relro section.
682 // IS_FIRST_NON_RELRO is true for the first non-relro section. This
683 // will return NULL if the input section should be discarded.
686 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
687 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
688 bool is_input_section
, Output_section_order order
,
691 // We should not see any input sections after we have attached
692 // sections to segments.
693 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
695 // Some flags in the input section should not be automatically
696 // copied to the output section.
697 flags
&= ~ (elfcpp::SHF_INFO_LINK
700 | elfcpp::SHF_STRINGS
);
702 // We only clear the SHF_LINK_ORDER flag in for
703 // a non-relocatable link.
704 if (!parameters
->options().relocatable())
705 flags
&= ~elfcpp::SHF_LINK_ORDER
;
707 if (this->script_options_
->saw_sections_clause())
709 // We are using a SECTIONS clause, so the output section is
710 // chosen based only on the name.
712 Script_sections
* ss
= this->script_options_
->script_sections();
713 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
714 Output_section
** output_section_slot
;
715 Script_sections::Section_type script_section_type
;
716 const char* orig_name
= name
;
717 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
718 &script_section_type
);
721 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
722 "because it is not allowed by the "
723 "SECTIONS clause of the linker script"),
725 // The SECTIONS clause says to discard this input section.
729 // We can only handle script section types ST_NONE and ST_NOLOAD.
730 switch (script_section_type
)
732 case Script_sections::ST_NONE
:
734 case Script_sections::ST_NOLOAD
:
735 flags
&= elfcpp::SHF_ALLOC
;
741 // If this is an orphan section--one not mentioned in the linker
742 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
743 // default processing below.
745 if (output_section_slot
!= NULL
)
747 if (*output_section_slot
!= NULL
)
749 (*output_section_slot
)->update_flags_for_input_section(flags
);
750 return *output_section_slot
;
753 // We don't put sections found in the linker script into
754 // SECTION_NAME_MAP_. That keeps us from getting confused
755 // if an orphan section is mapped to a section with the same
756 // name as one in the linker script.
758 name
= this->namepool_
.add(name
, false, NULL
);
760 Output_section
* os
= this->make_output_section(name
, type
, flags
,
763 os
->set_found_in_sections_clause();
765 // Special handling for NOLOAD sections.
766 if (script_section_type
== Script_sections::ST_NOLOAD
)
770 // The constructor of Output_section sets addresses of non-ALLOC
771 // sections to 0 by default. We don't want that for NOLOAD
772 // sections even if they have no SHF_ALLOC flag.
773 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
774 && os
->is_address_valid())
776 gold_assert(os
->address() == 0
777 && !os
->is_offset_valid()
778 && !os
->is_data_size_valid());
779 os
->reset_address_and_file_offset();
783 *output_section_slot
= os
;
788 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
790 size_t len
= strlen(name
);
791 char* uncompressed_name
= NULL
;
793 // Compressed debug sections should be mapped to the corresponding
794 // uncompressed section.
795 if (is_compressed_debug_section(name
))
797 uncompressed_name
= new char[len
];
798 uncompressed_name
[0] = '.';
799 gold_assert(name
[0] == '.' && name
[1] == 'z');
800 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
801 uncompressed_name
[len
- 1] = '\0';
803 name
= uncompressed_name
;
806 // Turn NAME from the name of the input section into the name of the
809 && !this->script_options_
->saw_sections_clause()
810 && !parameters
->options().relocatable())
811 name
= Layout::output_section_name(name
, &len
);
813 Stringpool::Key name_key
;
814 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
816 if (uncompressed_name
!= NULL
)
817 delete[] uncompressed_name
;
819 // Find or make the output section. The output section is selected
820 // based on the section name, type, and flags.
821 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
824 // For incremental links, record the initial fixed layout of a section
825 // from the base file, and return a pointer to the Output_section.
827 template<int size
, bool big_endian
>
829 Layout::init_fixed_output_section(const char* name
,
830 elfcpp::Shdr
<size
, big_endian
>& shdr
)
832 unsigned int sh_type
= shdr
.get_sh_type();
834 // We preserve the layout of PROGBITS, NOBITS, and NOTE sections.
835 // All others will be created from scratch and reallocated.
836 if (sh_type
!= elfcpp::SHT_PROGBITS
837 && sh_type
!= elfcpp::SHT_NOBITS
838 && sh_type
!= elfcpp::SHT_NOTE
)
841 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
842 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
843 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
844 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
845 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
846 shdr
.get_sh_addralign();
848 // Make the output section.
849 Stringpool::Key name_key
;
850 name
= this->namepool_
.add(name
, true, &name_key
);
851 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
852 sh_flags
, ORDER_INVALID
, false);
853 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
854 if (sh_type
!= elfcpp::SHT_NOBITS
)
855 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
859 // Return the output section to use for input section SHNDX, with name
860 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
861 // index of a relocation section which applies to this section, or 0
862 // if none, or -1U if more than one. RELOC_TYPE is the type of the
863 // relocation section if there is one. Set *OFF to the offset of this
864 // input section without the output section. Return NULL if the
865 // section should be discarded. Set *OFF to -1 if the section
866 // contents should not be written directly to the output file, but
867 // will instead receive special handling.
869 template<int size
, bool big_endian
>
871 Layout::layout(Sized_relobj
<size
, big_endian
>* object
, unsigned int shndx
,
872 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
873 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
877 if (!this->include_section(object
, name
, shdr
))
882 // Sometimes .init_array*, .preinit_array* and .fini_array* do not have
883 // correct section types. Force them here.
884 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
885 if (sh_type
== elfcpp::SHT_PROGBITS
)
887 static const char init_array_prefix
[] = ".init_array";
888 static const char preinit_array_prefix
[] = ".preinit_array";
889 static const char fini_array_prefix
[] = ".fini_array";
890 static size_t init_array_prefix_size
= sizeof(init_array_prefix
) - 1;
891 static size_t preinit_array_prefix_size
=
892 sizeof(preinit_array_prefix
) - 1;
893 static size_t fini_array_prefix_size
= sizeof(fini_array_prefix
) - 1;
895 if (strncmp(name
, init_array_prefix
, init_array_prefix_size
) == 0)
896 sh_type
= elfcpp::SHT_INIT_ARRAY
;
897 else if (strncmp(name
, preinit_array_prefix
, preinit_array_prefix_size
)
899 sh_type
= elfcpp::SHT_PREINIT_ARRAY
;
900 else if (strncmp(name
, fini_array_prefix
, fini_array_prefix_size
) == 0)
901 sh_type
= elfcpp::SHT_FINI_ARRAY
;
904 // In a relocatable link a grouped section must not be combined with
905 // any other sections.
906 if (parameters
->options().relocatable()
907 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
909 name
= this->namepool_
.add(name
, true, NULL
);
910 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
911 ORDER_INVALID
, false);
915 os
= this->choose_output_section(object
, name
, sh_type
,
916 shdr
.get_sh_flags(), true,
917 ORDER_INVALID
, false);
922 // By default the GNU linker sorts input sections whose names match
923 // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
924 // are sorted by name. This is used to implement constructor
925 // priority ordering. We are compatible.
926 if (!this->script_options_
->saw_sections_clause()
927 && (is_prefix_of(".ctors.", name
)
928 || is_prefix_of(".dtors.", name
)
929 || is_prefix_of(".init_array.", name
)
930 || is_prefix_of(".fini_array.", name
)))
931 os
->set_must_sort_attached_input_sections();
933 // FIXME: Handle SHF_LINK_ORDER somewhere.
935 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
936 this->script_options_
->saw_sections_clause());
937 this->have_added_input_section_
= true;
942 // Handle a relocation section when doing a relocatable link.
944 template<int size
, bool big_endian
>
946 Layout::layout_reloc(Sized_relobj
<size
, big_endian
>* object
,
948 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
949 Output_section
* data_section
,
950 Relocatable_relocs
* rr
)
952 gold_assert(parameters
->options().relocatable()
953 || parameters
->options().emit_relocs());
955 int sh_type
= shdr
.get_sh_type();
958 if (sh_type
== elfcpp::SHT_REL
)
960 else if (sh_type
== elfcpp::SHT_RELA
)
964 name
+= data_section
->name();
966 // In a relocatable link relocs for a grouped section must not be
967 // combined with other reloc sections.
969 if (!parameters
->options().relocatable()
970 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
971 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
972 shdr
.get_sh_flags(), false,
973 ORDER_INVALID
, false);
976 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
977 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
978 ORDER_INVALID
, false);
981 os
->set_should_link_to_symtab();
982 os
->set_info_section(data_section
);
984 Output_section_data
* posd
;
985 if (sh_type
== elfcpp::SHT_REL
)
987 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
988 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
992 else if (sh_type
== elfcpp::SHT_RELA
)
994 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
995 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1002 os
->add_output_section_data(posd
);
1003 rr
->set_output_data(posd
);
1008 // Handle a group section when doing a relocatable link.
1010 template<int size
, bool big_endian
>
1012 Layout::layout_group(Symbol_table
* symtab
,
1013 Sized_relobj
<size
, big_endian
>* object
,
1015 const char* group_section_name
,
1016 const char* signature
,
1017 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1018 elfcpp::Elf_Word flags
,
1019 std::vector
<unsigned int>* shndxes
)
1021 gold_assert(parameters
->options().relocatable());
1022 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1023 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1024 Output_section
* os
= this->make_output_section(group_section_name
,
1026 shdr
.get_sh_flags(),
1027 ORDER_INVALID
, false);
1029 // We need to find a symbol with the signature in the symbol table.
1030 // If we don't find one now, we need to look again later.
1031 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1033 os
->set_info_symndx(sym
);
1036 // Reserve some space to minimize reallocations.
1037 if (this->group_signatures_
.empty())
1038 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1040 // We will wind up using a symbol whose name is the signature.
1041 // So just put the signature in the symbol name pool to save it.
1042 signature
= symtab
->canonicalize_name(signature
);
1043 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1046 os
->set_should_link_to_symtab();
1049 section_size_type entry_count
=
1050 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1051 Output_section_data
* posd
=
1052 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1054 os
->add_output_section_data(posd
);
1057 // Special GNU handling of sections name .eh_frame. They will
1058 // normally hold exception frame data as defined by the C++ ABI
1059 // (http://codesourcery.com/cxx-abi/).
1061 template<int size
, bool big_endian
>
1063 Layout::layout_eh_frame(Sized_relobj
<size
, big_endian
>* object
,
1064 const unsigned char* symbols
,
1066 const unsigned char* symbol_names
,
1067 off_t symbol_names_size
,
1069 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1070 unsigned int reloc_shndx
, unsigned int reloc_type
,
1073 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
);
1074 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1076 const char* const name
= ".eh_frame";
1077 Output_section
* os
= this->choose_output_section(object
, name
,
1078 elfcpp::SHT_PROGBITS
,
1079 elfcpp::SHF_ALLOC
, false,
1080 ORDER_EHFRAME
, false);
1084 if (this->eh_frame_section_
== NULL
)
1086 this->eh_frame_section_
= os
;
1087 this->eh_frame_data_
= new Eh_frame();
1089 // For incremental linking, we do not optimize .eh_frame sections
1090 // or create a .eh_frame_hdr section.
1091 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1093 Output_section
* hdr_os
=
1094 this->choose_output_section(NULL
, ".eh_frame_hdr",
1095 elfcpp::SHT_PROGBITS
,
1096 elfcpp::SHF_ALLOC
, false,
1097 ORDER_EHFRAME
, false);
1101 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1102 this->eh_frame_data_
);
1103 hdr_os
->add_output_section_data(hdr_posd
);
1105 hdr_os
->set_after_input_sections();
1107 if (!this->script_options_
->saw_phdrs_clause())
1109 Output_segment
* hdr_oseg
;
1110 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1112 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1116 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1121 gold_assert(this->eh_frame_section_
== os
);
1123 if (!parameters
->incremental()
1124 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1133 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1135 // A writable .eh_frame section is a RELRO section.
1136 if ((shdr
.get_sh_flags() & elfcpp::SHF_WRITE
) != 0)
1139 // We found a .eh_frame section we are going to optimize, so now
1140 // we can add the set of optimized sections to the output
1141 // section. We need to postpone adding this until we've found a
1142 // section we can optimize so that the .eh_frame section in
1143 // crtbegin.o winds up at the start of the output section.
1144 if (!this->added_eh_frame_data_
)
1146 os
->add_output_section_data(this->eh_frame_data_
);
1147 this->added_eh_frame_data_
= true;
1153 // We couldn't handle this .eh_frame section for some reason.
1154 // Add it as a normal section.
1155 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1156 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1157 saw_sections_clause
);
1158 this->have_added_input_section_
= true;
1164 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1165 // the output section.
1168 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1169 elfcpp::Elf_Xword flags
,
1170 Output_section_data
* posd
,
1171 Output_section_order order
, bool is_relro
)
1173 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1174 false, order
, is_relro
);
1176 os
->add_output_section_data(posd
);
1180 // Map section flags to segment flags.
1183 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1185 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1186 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1187 ret
|= elfcpp::PF_W
;
1188 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1189 ret
|= elfcpp::PF_X
;
1193 // Make a new Output_section, and attach it to segments as
1194 // appropriate. ORDER is the order in which this section should
1195 // appear in the output segment. IS_RELRO is true if this is a relro
1196 // (read-only after relocations) section.
1199 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1200 elfcpp::Elf_Xword flags
,
1201 Output_section_order order
, bool is_relro
)
1204 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1205 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1206 && is_compressible_debug_section(name
))
1207 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1209 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1210 && parameters
->options().strip_debug_non_line()
1211 && strcmp(".debug_abbrev", name
) == 0)
1213 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1215 if (this->debug_info_
)
1216 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1218 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1219 && parameters
->options().strip_debug_non_line()
1220 && strcmp(".debug_info", name
) == 0)
1222 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1224 if (this->debug_abbrev_
)
1225 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1229 // FIXME: const_cast is ugly.
1230 Target
* target
= const_cast<Target
*>(¶meters
->target());
1231 os
= target
->make_output_section(name
, type
, flags
);
1234 // With -z relro, we have to recognize the special sections by name.
1235 // There is no other way.
1236 bool is_relro_local
= false;
1237 if (!this->script_options_
->saw_sections_clause()
1238 && parameters
->options().relro()
1239 && type
== elfcpp::SHT_PROGBITS
1240 && (flags
& elfcpp::SHF_ALLOC
) != 0
1241 && (flags
& elfcpp::SHF_WRITE
) != 0)
1243 if (strcmp(name
, ".data.rel.ro") == 0)
1245 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1248 is_relro_local
= true;
1250 else if (type
== elfcpp::SHT_INIT_ARRAY
1251 || type
== elfcpp::SHT_FINI_ARRAY
1252 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1254 else if (strcmp(name
, ".ctors") == 0
1255 || strcmp(name
, ".dtors") == 0
1256 || strcmp(name
, ".jcr") == 0)
1263 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1264 order
= this->default_section_order(os
, is_relro_local
);
1266 os
->set_order(order
);
1268 parameters
->target().new_output_section(os
);
1270 this->section_list_
.push_back(os
);
1272 // The GNU linker by default sorts some sections by priority, so we
1273 // do the same. We need to know that this might happen before we
1274 // attach any input sections.
1275 if (!this->script_options_
->saw_sections_clause()
1276 && (strcmp(name
, ".ctors") == 0
1277 || strcmp(name
, ".dtors") == 0
1278 || strcmp(name
, ".init_array") == 0
1279 || strcmp(name
, ".fini_array") == 0))
1280 os
->set_may_sort_attached_input_sections();
1282 // Check for .stab*str sections, as .stab* sections need to link to
1284 if (type
== elfcpp::SHT_STRTAB
1285 && !this->have_stabstr_section_
1286 && strncmp(name
, ".stab", 5) == 0
1287 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1288 this->have_stabstr_section_
= true;
1290 // If we have already attached the sections to segments, then we
1291 // need to attach this one now. This happens for sections created
1292 // directly by the linker.
1293 if (this->sections_are_attached_
)
1294 this->attach_section_to_segment(os
);
1299 // Return the default order in which a section should be placed in an
1300 // output segment. This function captures a lot of the ideas in
1301 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1302 // linker created section is normally set when the section is created;
1303 // this function is used for input sections.
1305 Output_section_order
1306 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1308 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1309 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1310 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1311 bool is_bss
= false;
1316 case elfcpp::SHT_PROGBITS
:
1318 case elfcpp::SHT_NOBITS
:
1321 case elfcpp::SHT_RELA
:
1322 case elfcpp::SHT_REL
:
1324 return ORDER_DYNAMIC_RELOCS
;
1326 case elfcpp::SHT_HASH
:
1327 case elfcpp::SHT_DYNAMIC
:
1328 case elfcpp::SHT_SHLIB
:
1329 case elfcpp::SHT_DYNSYM
:
1330 case elfcpp::SHT_GNU_HASH
:
1331 case elfcpp::SHT_GNU_verdef
:
1332 case elfcpp::SHT_GNU_verneed
:
1333 case elfcpp::SHT_GNU_versym
:
1335 return ORDER_DYNAMIC_LINKER
;
1337 case elfcpp::SHT_NOTE
:
1338 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1341 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1342 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1344 if (!is_bss
&& !is_write
)
1348 if (strcmp(os
->name(), ".init") == 0)
1350 else if (strcmp(os
->name(), ".fini") == 0)
1353 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1357 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1359 if (os
->is_small_section())
1360 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1361 if (os
->is_large_section())
1362 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1364 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1367 // Attach output sections to segments. This is called after we have
1368 // seen all the input sections.
1371 Layout::attach_sections_to_segments()
1373 for (Section_list::iterator p
= this->section_list_
.begin();
1374 p
!= this->section_list_
.end();
1376 this->attach_section_to_segment(*p
);
1378 this->sections_are_attached_
= true;
1381 // Attach an output section to a segment.
1384 Layout::attach_section_to_segment(Output_section
* os
)
1386 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1387 this->unattached_section_list_
.push_back(os
);
1389 this->attach_allocated_section_to_segment(os
);
1392 // Attach an allocated output section to a segment.
1395 Layout::attach_allocated_section_to_segment(Output_section
* os
)
1397 elfcpp::Elf_Xword flags
= os
->flags();
1398 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1400 if (parameters
->options().relocatable())
1403 // If we have a SECTIONS clause, we can't handle the attachment to
1404 // segments until after we've seen all the sections.
1405 if (this->script_options_
->saw_sections_clause())
1408 gold_assert(!this->script_options_
->saw_phdrs_clause());
1410 // This output section goes into a PT_LOAD segment.
1412 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1414 // Check for --section-start.
1416 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1418 // In general the only thing we really care about for PT_LOAD
1419 // segments is whether or not they are writable or executable,
1420 // so that is how we search for them.
1421 // Large data sections also go into their own PT_LOAD segment.
1422 // People who need segments sorted on some other basis will
1423 // have to use a linker script.
1425 Segment_list::const_iterator p
;
1426 for (p
= this->segment_list_
.begin();
1427 p
!= this->segment_list_
.end();
1430 if ((*p
)->type() != elfcpp::PT_LOAD
)
1432 if (!parameters
->options().omagic()
1433 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1435 if (parameters
->options().rosegment()
1436 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1438 // If -Tbss was specified, we need to separate the data and BSS
1440 if (parameters
->options().user_set_Tbss())
1442 if ((os
->type() == elfcpp::SHT_NOBITS
)
1443 == (*p
)->has_any_data_sections())
1446 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1451 if ((*p
)->are_addresses_set())
1454 (*p
)->add_initial_output_data(os
);
1455 (*p
)->update_flags_for_output_section(seg_flags
);
1456 (*p
)->set_addresses(addr
, addr
);
1460 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1464 if (p
== this->segment_list_
.end())
1466 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1468 if (os
->is_large_data_section())
1469 oseg
->set_is_large_data_segment();
1470 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1472 oseg
->set_addresses(addr
, addr
);
1475 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1477 if (os
->type() == elfcpp::SHT_NOTE
)
1479 // See if we already have an equivalent PT_NOTE segment.
1480 for (p
= this->segment_list_
.begin();
1481 p
!= segment_list_
.end();
1484 if ((*p
)->type() == elfcpp::PT_NOTE
1485 && (((*p
)->flags() & elfcpp::PF_W
)
1486 == (seg_flags
& elfcpp::PF_W
)))
1488 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1493 if (p
== this->segment_list_
.end())
1495 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1497 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1501 // If we see a loadable SHF_TLS section, we create a PT_TLS
1502 // segment. There can only be one such segment.
1503 if ((flags
& elfcpp::SHF_TLS
) != 0)
1505 if (this->tls_segment_
== NULL
)
1506 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1507 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1510 // If -z relro is in effect, and we see a relro section, we create a
1511 // PT_GNU_RELRO segment. There can only be one such segment.
1512 if (os
->is_relro() && parameters
->options().relro())
1514 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1515 if (this->relro_segment_
== NULL
)
1516 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1517 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1521 // Make an output section for a script.
1524 Layout::make_output_section_for_script(
1526 Script_sections::Section_type section_type
)
1528 name
= this->namepool_
.add(name
, false, NULL
);
1529 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
1530 if (section_type
== Script_sections::ST_NOLOAD
)
1532 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1533 sh_flags
, ORDER_INVALID
,
1535 os
->set_found_in_sections_clause();
1536 if (section_type
== Script_sections::ST_NOLOAD
)
1537 os
->set_is_noload();
1541 // Return the number of segments we expect to see.
1544 Layout::expected_segment_count() const
1546 size_t ret
= this->segment_list_
.size();
1548 // If we didn't see a SECTIONS clause in a linker script, we should
1549 // already have the complete list of segments. Otherwise we ask the
1550 // SECTIONS clause how many segments it expects, and add in the ones
1551 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1553 if (!this->script_options_
->saw_sections_clause())
1557 const Script_sections
* ss
= this->script_options_
->script_sections();
1558 return ret
+ ss
->expected_segment_count(this);
1562 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
1563 // is whether we saw a .note.GNU-stack section in the object file.
1564 // GNU_STACK_FLAGS is the section flags. The flags give the
1565 // protection required for stack memory. We record this in an
1566 // executable as a PT_GNU_STACK segment. If an object file does not
1567 // have a .note.GNU-stack segment, we must assume that it is an old
1568 // object. On some targets that will force an executable stack.
1571 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
1574 if (!seen_gnu_stack
)
1576 this->input_without_gnu_stack_note_
= true;
1577 if (parameters
->options().warn_execstack()
1578 && parameters
->target().is_default_stack_executable())
1579 gold_warning(_("%s: missing .note.GNU-stack section"
1580 " implies executable stack"),
1581 obj
->name().c_str());
1585 this->input_with_gnu_stack_note_
= true;
1586 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
1588 this->input_requires_executable_stack_
= true;
1589 if (parameters
->options().warn_execstack()
1590 || parameters
->options().is_stack_executable())
1591 gold_warning(_("%s: requires executable stack"),
1592 obj
->name().c_str());
1597 // Create automatic note sections.
1600 Layout::create_notes()
1602 this->create_gold_note();
1603 this->create_executable_stack_info();
1604 this->create_build_id();
1607 // Create the dynamic sections which are needed before we read the
1611 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
1613 if (parameters
->doing_static_link())
1616 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
1617 elfcpp::SHT_DYNAMIC
,
1619 | elfcpp::SHF_WRITE
),
1623 this->dynamic_symbol_
=
1624 symtab
->define_in_output_data("_DYNAMIC", NULL
, Symbol_table::PREDEFINED
,
1625 this->dynamic_section_
, 0, 0,
1626 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
1627 elfcpp::STV_HIDDEN
, 0, false, false);
1629 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
1631 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
1634 // For each output section whose name can be represented as C symbol,
1635 // define __start and __stop symbols for the section. This is a GNU
1639 Layout::define_section_symbols(Symbol_table
* symtab
)
1641 for (Section_list::const_iterator p
= this->section_list_
.begin();
1642 p
!= this->section_list_
.end();
1645 const char* const name
= (*p
)->name();
1646 if (is_cident(name
))
1648 const std::string
name_string(name
);
1649 const std::string
start_name(cident_section_start_prefix
1651 const std::string
stop_name(cident_section_stop_prefix
1654 symtab
->define_in_output_data(start_name
.c_str(),
1656 Symbol_table::PREDEFINED
,
1662 elfcpp::STV_DEFAULT
,
1664 false, // offset_is_from_end
1665 true); // only_if_ref
1667 symtab
->define_in_output_data(stop_name
.c_str(),
1669 Symbol_table::PREDEFINED
,
1675 elfcpp::STV_DEFAULT
,
1677 true, // offset_is_from_end
1678 true); // only_if_ref
1683 // Define symbols for group signatures.
1686 Layout::define_group_signatures(Symbol_table
* symtab
)
1688 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
1689 p
!= this->group_signatures_
.end();
1692 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
1694 p
->section
->set_info_symndx(sym
);
1697 // Force the name of the group section to the group
1698 // signature, and use the group's section symbol as the
1699 // signature symbol.
1700 if (strcmp(p
->section
->name(), p
->signature
) != 0)
1702 const char* name
= this->namepool_
.add(p
->signature
,
1704 p
->section
->set_name(name
);
1706 p
->section
->set_needs_symtab_index();
1707 p
->section
->set_info_section_symndx(p
->section
);
1711 this->group_signatures_
.clear();
1714 // Find the first read-only PT_LOAD segment, creating one if
1718 Layout::find_first_load_seg()
1720 Output_segment
* best
= NULL
;
1721 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1722 p
!= this->segment_list_
.end();
1725 if ((*p
)->type() == elfcpp::PT_LOAD
1726 && ((*p
)->flags() & elfcpp::PF_R
) != 0
1727 && (parameters
->options().omagic()
1728 || ((*p
)->flags() & elfcpp::PF_W
) == 0))
1730 if (best
== NULL
|| this->segment_precedes(*p
, best
))
1737 gold_assert(!this->script_options_
->saw_phdrs_clause());
1739 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
1744 // Save states of all current output segments. Store saved states
1745 // in SEGMENT_STATES.
1748 Layout::save_segments(Segment_states
* segment_states
)
1750 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1751 p
!= this->segment_list_
.end();
1754 Output_segment
* segment
= *p
;
1756 Output_segment
* copy
= new Output_segment(*segment
);
1757 (*segment_states
)[segment
] = copy
;
1761 // Restore states of output segments and delete any segment not found in
1765 Layout::restore_segments(const Segment_states
* segment_states
)
1767 // Go through the segment list and remove any segment added in the
1769 this->tls_segment_
= NULL
;
1770 this->relro_segment_
= NULL
;
1771 Segment_list::iterator list_iter
= this->segment_list_
.begin();
1772 while (list_iter
!= this->segment_list_
.end())
1774 Output_segment
* segment
= *list_iter
;
1775 Segment_states::const_iterator states_iter
=
1776 segment_states
->find(segment
);
1777 if (states_iter
!= segment_states
->end())
1779 const Output_segment
* copy
= states_iter
->second
;
1780 // Shallow copy to restore states.
1783 // Also fix up TLS and RELRO segment pointers as appropriate.
1784 if (segment
->type() == elfcpp::PT_TLS
)
1785 this->tls_segment_
= segment
;
1786 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
1787 this->relro_segment_
= segment
;
1793 list_iter
= this->segment_list_
.erase(list_iter
);
1794 // This is a segment created during section layout. It should be
1795 // safe to remove it since we should have removed all pointers to it.
1801 // Clean up after relaxation so that sections can be laid out again.
1804 Layout::clean_up_after_relaxation()
1806 // Restore the segments to point state just prior to the relaxation loop.
1807 Script_sections
* script_section
= this->script_options_
->script_sections();
1808 script_section
->release_segments();
1809 this->restore_segments(this->segment_states_
);
1811 // Reset section addresses and file offsets
1812 for (Section_list::iterator p
= this->section_list_
.begin();
1813 p
!= this->section_list_
.end();
1816 (*p
)->restore_states();
1818 // If an input section changes size because of relaxation,
1819 // we need to adjust the section offsets of all input sections.
1820 // after such a section.
1821 if ((*p
)->section_offsets_need_adjustment())
1822 (*p
)->adjust_section_offsets();
1824 (*p
)->reset_address_and_file_offset();
1827 // Reset special output object address and file offsets.
1828 for (Data_list::iterator p
= this->special_output_list_
.begin();
1829 p
!= this->special_output_list_
.end();
1831 (*p
)->reset_address_and_file_offset();
1833 // A linker script may have created some output section data objects.
1834 // They are useless now.
1835 for (Output_section_data_list::const_iterator p
=
1836 this->script_output_section_data_list_
.begin();
1837 p
!= this->script_output_section_data_list_
.end();
1840 this->script_output_section_data_list_
.clear();
1843 // Prepare for relaxation.
1846 Layout::prepare_for_relaxation()
1848 // Create an relaxation debug check if in debugging mode.
1849 if (is_debugging_enabled(DEBUG_RELAXATION
))
1850 this->relaxation_debug_check_
= new Relaxation_debug_check();
1852 // Save segment states.
1853 this->segment_states_
= new Segment_states();
1854 this->save_segments(this->segment_states_
);
1856 for(Section_list::const_iterator p
= this->section_list_
.begin();
1857 p
!= this->section_list_
.end();
1859 (*p
)->save_states();
1861 if (is_debugging_enabled(DEBUG_RELAXATION
))
1862 this->relaxation_debug_check_
->check_output_data_for_reset_values(
1863 this->section_list_
, this->special_output_list_
);
1865 // Also enable recording of output section data from scripts.
1866 this->record_output_section_data_from_script_
= true;
1869 // Relaxation loop body: If target has no relaxation, this runs only once
1870 // Otherwise, the target relaxation hook is called at the end of
1871 // each iteration. If the hook returns true, it means re-layout of
1872 // section is required.
1874 // The number of segments created by a linking script without a PHDRS
1875 // clause may be affected by section sizes and alignments. There is
1876 // a remote chance that relaxation causes different number of PT_LOAD
1877 // segments are created and sections are attached to different segments.
1878 // Therefore, we always throw away all segments created during section
1879 // layout. In order to be able to restart the section layout, we keep
1880 // a copy of the segment list right before the relaxation loop and use
1881 // that to restore the segments.
1883 // PASS is the current relaxation pass number.
1884 // SYMTAB is a symbol table.
1885 // PLOAD_SEG is the address of a pointer for the load segment.
1886 // PHDR_SEG is a pointer to the PHDR segment.
1887 // SEGMENT_HEADERS points to the output segment header.
1888 // FILE_HEADER points to the output file header.
1889 // PSHNDX is the address to store the output section index.
1892 Layout::relaxation_loop_body(
1895 Symbol_table
* symtab
,
1896 Output_segment
** pload_seg
,
1897 Output_segment
* phdr_seg
,
1898 Output_segment_headers
* segment_headers
,
1899 Output_file_header
* file_header
,
1900 unsigned int* pshndx
)
1902 // If this is not the first iteration, we need to clean up after
1903 // relaxation so that we can lay out the sections again.
1905 this->clean_up_after_relaxation();
1907 // If there is a SECTIONS clause, put all the input sections into
1908 // the required order.
1909 Output_segment
* load_seg
;
1910 if (this->script_options_
->saw_sections_clause())
1911 load_seg
= this->set_section_addresses_from_script(symtab
);
1912 else if (parameters
->options().relocatable())
1915 load_seg
= this->find_first_load_seg();
1917 if (parameters
->options().oformat_enum()
1918 != General_options::OBJECT_FORMAT_ELF
)
1921 // If the user set the address of the text segment, that may not be
1922 // compatible with putting the segment headers and file headers into
1924 if (parameters
->options().user_set_Ttext())
1927 gold_assert(phdr_seg
== NULL
1929 || this->script_options_
->saw_sections_clause());
1931 // If the address of the load segment we found has been set by
1932 // --section-start rather than by a script, then adjust the VMA and
1933 // LMA downward if possible to include the file and section headers.
1934 uint64_t header_gap
= 0;
1935 if (load_seg
!= NULL
1936 && load_seg
->are_addresses_set()
1937 && !this->script_options_
->saw_sections_clause()
1938 && !parameters
->options().relocatable())
1940 file_header
->finalize_data_size();
1941 segment_headers
->finalize_data_size();
1942 size_t sizeof_headers
= (file_header
->data_size()
1943 + segment_headers
->data_size());
1944 const uint64_t abi_pagesize
= target
->abi_pagesize();
1945 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
1946 hdr_paddr
&= ~(abi_pagesize
- 1);
1947 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
1948 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
1952 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
1953 load_seg
->paddr() - subtract
);
1954 header_gap
= subtract
- sizeof_headers
;
1958 // Lay out the segment headers.
1959 if (!parameters
->options().relocatable())
1961 gold_assert(segment_headers
!= NULL
);
1962 if (header_gap
!= 0 && load_seg
!= NULL
)
1964 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
1965 load_seg
->add_initial_output_data(z
);
1967 if (load_seg
!= NULL
)
1968 load_seg
->add_initial_output_data(segment_headers
);
1969 if (phdr_seg
!= NULL
)
1970 phdr_seg
->add_initial_output_data(segment_headers
);
1973 // Lay out the file header.
1974 if (load_seg
!= NULL
)
1975 load_seg
->add_initial_output_data(file_header
);
1977 if (this->script_options_
->saw_phdrs_clause()
1978 && !parameters
->options().relocatable())
1980 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1981 // clause in a linker script.
1982 Script_sections
* ss
= this->script_options_
->script_sections();
1983 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
1986 // We set the output section indexes in set_segment_offsets and
1987 // set_section_indexes.
1990 // Set the file offsets of all the segments, and all the sections
1993 if (!parameters
->options().relocatable())
1994 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
1996 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
1998 // Verify that the dummy relaxation does not change anything.
1999 if (is_debugging_enabled(DEBUG_RELAXATION
))
2002 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2004 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2007 *pload_seg
= load_seg
;
2011 // Search the list of patterns and find the postion of the given section
2012 // name in the output section. If the section name matches a glob
2013 // pattern and a non-glob name, then the non-glob position takes
2014 // precedence. Return 0 if no match is found.
2017 Layout::find_section_order_index(const std::string
& section_name
)
2019 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2020 map_it
= this->input_section_position_
.find(section_name
);
2021 if (map_it
!= this->input_section_position_
.end())
2022 return map_it
->second
;
2024 // Absolute match failed. Linear search the glob patterns.
2025 std::vector
<std::string
>::iterator it
;
2026 for (it
= this->input_section_glob_
.begin();
2027 it
!= this->input_section_glob_
.end();
2030 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2032 map_it
= this->input_section_position_
.find(*it
);
2033 gold_assert(map_it
!= this->input_section_position_
.end());
2034 return map_it
->second
;
2040 // Read the sequence of input sections from the file specified with
2041 // --section-ordering-file.
2044 Layout::read_layout_from_file()
2046 const char* filename
= parameters
->options().section_ordering_file();
2052 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2053 filename
, strerror(errno
));
2055 std::getline(in
, line
); // this chops off the trailing \n, if any
2056 unsigned int position
= 1;
2060 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2061 line
.resize(line
.length() - 1);
2062 // Ignore comments, beginning with '#'
2065 std::getline(in
, line
);
2068 this->input_section_position_
[line
] = position
;
2069 // Store all glob patterns in a vector.
2070 if (is_wildcard_string(line
.c_str()))
2071 this->input_section_glob_
.push_back(line
);
2073 std::getline(in
, line
);
2077 // Finalize the layout. When this is called, we have created all the
2078 // output sections and all the output segments which are based on
2079 // input sections. We have several things to do, and we have to do
2080 // them in the right order, so that we get the right results correctly
2083 // 1) Finalize the list of output segments and create the segment
2086 // 2) Finalize the dynamic symbol table and associated sections.
2088 // 3) Determine the final file offset of all the output segments.
2090 // 4) Determine the final file offset of all the SHF_ALLOC output
2093 // 5) Create the symbol table sections and the section name table
2096 // 6) Finalize the symbol table: set symbol values to their final
2097 // value and make a final determination of which symbols are going
2098 // into the output symbol table.
2100 // 7) Create the section table header.
2102 // 8) Determine the final file offset of all the output sections which
2103 // are not SHF_ALLOC, including the section table header.
2105 // 9) Finalize the ELF file header.
2107 // This function returns the size of the output file.
2110 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2111 Target
* target
, const Task
* task
)
2113 target
->finalize_sections(this, input_objects
, symtab
);
2115 this->count_local_symbols(task
, input_objects
);
2117 this->link_stabs_sections();
2119 Output_segment
* phdr_seg
= NULL
;
2120 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2122 // There was a dynamic object in the link. We need to create
2123 // some information for the dynamic linker.
2125 // Create the PT_PHDR segment which will hold the program
2127 if (!this->script_options_
->saw_phdrs_clause())
2128 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2130 // Create the dynamic symbol table, including the hash table.
2131 Output_section
* dynstr
;
2132 std::vector
<Symbol
*> dynamic_symbols
;
2133 unsigned int local_dynamic_count
;
2134 Versions
versions(*this->script_options()->version_script_info(),
2136 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2137 &local_dynamic_count
, &dynamic_symbols
,
2140 // Create the .interp section to hold the name of the
2141 // interpreter, and put it in a PT_INTERP segment.
2142 if (!parameters
->options().shared())
2143 this->create_interp(target
);
2145 // Finish the .dynamic section to hold the dynamic data, and put
2146 // it in a PT_DYNAMIC segment.
2147 this->finish_dynamic_section(input_objects
, symtab
);
2149 // We should have added everything we need to the dynamic string
2151 this->dynpool_
.set_string_offsets();
2153 // Create the version sections. We can't do this until the
2154 // dynamic string table is complete.
2155 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2156 dynamic_symbols
, dynstr
);
2158 // Set the size of the _DYNAMIC symbol. We can't do this until
2159 // after we call create_version_sections.
2160 this->set_dynamic_symbol_size(symtab
);
2163 // Create segment headers.
2164 Output_segment_headers
* segment_headers
=
2165 (parameters
->options().relocatable()
2167 : new Output_segment_headers(this->segment_list_
));
2169 // Lay out the file header.
2170 Output_file_header
* file_header
2171 = new Output_file_header(target
, symtab
, segment_headers
,
2172 parameters
->options().entry());
2174 this->special_output_list_
.push_back(file_header
);
2175 if (segment_headers
!= NULL
)
2176 this->special_output_list_
.push_back(segment_headers
);
2178 // Find approriate places for orphan output sections if we are using
2180 if (this->script_options_
->saw_sections_clause())
2181 this->place_orphan_sections_in_script();
2183 Output_segment
* load_seg
;
2188 // Take a snapshot of the section layout as needed.
2189 if (target
->may_relax())
2190 this->prepare_for_relaxation();
2192 // Run the relaxation loop to lay out sections.
2195 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2196 phdr_seg
, segment_headers
, file_header
,
2200 while (target
->may_relax()
2201 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2203 // Set the file offsets of all the non-data sections we've seen so
2204 // far which don't have to wait for the input sections. We need
2205 // this in order to finalize local symbols in non-allocated
2207 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2209 // Set the section indexes of all unallocated sections seen so far,
2210 // in case any of them are somehow referenced by a symbol.
2211 shndx
= this->set_section_indexes(shndx
);
2213 // Create the symbol table sections.
2214 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2215 if (!parameters
->doing_static_link())
2216 this->assign_local_dynsym_offsets(input_objects
);
2218 // Process any symbol assignments from a linker script. This must
2219 // be called after the symbol table has been finalized.
2220 this->script_options_
->finalize_symbols(symtab
, this);
2222 // Create the incremental inputs sections.
2223 if (this->incremental_inputs_
)
2225 this->incremental_inputs_
->finalize();
2226 this->create_incremental_info_sections(symtab
);
2229 // Create the .shstrtab section.
2230 Output_section
* shstrtab_section
= this->create_shstrtab();
2232 // Set the file offsets of the rest of the non-data sections which
2233 // don't have to wait for the input sections.
2234 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2236 // Now that all sections have been created, set the section indexes
2237 // for any sections which haven't been done yet.
2238 shndx
= this->set_section_indexes(shndx
);
2240 // Create the section table header.
2241 this->create_shdrs(shstrtab_section
, &off
);
2243 // If there are no sections which require postprocessing, we can
2244 // handle the section names now, and avoid a resize later.
2245 if (!this->any_postprocessing_sections_
)
2247 off
= this->set_section_offsets(off
,
2248 POSTPROCESSING_SECTIONS_PASS
);
2250 this->set_section_offsets(off
,
2251 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2254 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2256 // Now we know exactly where everything goes in the output file
2257 // (except for non-allocated sections which require postprocessing).
2258 Output_data::layout_complete();
2260 this->output_file_size_
= off
;
2265 // Create a note header following the format defined in the ELF ABI.
2266 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2267 // of the section to create, DESCSZ is the size of the descriptor.
2268 // ALLOCATE is true if the section should be allocated in memory.
2269 // This returns the new note section. It sets *TRAILING_PADDING to
2270 // the number of trailing zero bytes required.
2273 Layout::create_note(const char* name
, int note_type
,
2274 const char* section_name
, size_t descsz
,
2275 bool allocate
, size_t* trailing_padding
)
2277 // Authorities all agree that the values in a .note field should
2278 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2279 // they differ on what the alignment is for 64-bit binaries.
2280 // The GABI says unambiguously they take 8-byte alignment:
2281 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2282 // Other documentation says alignment should always be 4 bytes:
2283 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2284 // GNU ld and GNU readelf both support the latter (at least as of
2285 // version 2.16.91), and glibc always generates the latter for
2286 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2288 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2289 const int size
= parameters
->target().get_size();
2291 const int size
= 32;
2294 // The contents of the .note section.
2295 size_t namesz
= strlen(name
) + 1;
2296 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2297 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2299 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2301 unsigned char* buffer
= new unsigned char[notehdrsz
];
2302 memset(buffer
, 0, notehdrsz
);
2304 bool is_big_endian
= parameters
->target().is_big_endian();
2310 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2311 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2312 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2316 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2317 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2318 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2321 else if (size
== 64)
2325 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2326 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2327 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2331 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2332 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2333 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2339 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2341 elfcpp::Elf_Xword flags
= 0;
2342 Output_section_order order
= ORDER_INVALID
;
2345 flags
= elfcpp::SHF_ALLOC
;
2346 order
= ORDER_RO_NOTE
;
2348 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2350 flags
, false, order
, false);
2354 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2357 os
->add_output_section_data(posd
);
2359 *trailing_padding
= aligned_descsz
- descsz
;
2364 // For an executable or shared library, create a note to record the
2365 // version of gold used to create the binary.
2368 Layout::create_gold_note()
2370 if (parameters
->options().relocatable()
2371 || parameters
->incremental_update())
2374 std::string desc
= std::string("gold ") + gold::get_version_string();
2376 size_t trailing_padding
;
2377 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2378 ".note.gnu.gold-version", desc
.size(),
2379 false, &trailing_padding
);
2383 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2384 os
->add_output_section_data(posd
);
2386 if (trailing_padding
> 0)
2388 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2389 os
->add_output_section_data(posd
);
2393 // Record whether the stack should be executable. This can be set
2394 // from the command line using the -z execstack or -z noexecstack
2395 // options. Otherwise, if any input file has a .note.GNU-stack
2396 // section with the SHF_EXECINSTR flag set, the stack should be
2397 // executable. Otherwise, if at least one input file a
2398 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2399 // section, we use the target default for whether the stack should be
2400 // executable. Otherwise, we don't generate a stack note. When
2401 // generating a object file, we create a .note.GNU-stack section with
2402 // the appropriate marking. When generating an executable or shared
2403 // library, we create a PT_GNU_STACK segment.
2406 Layout::create_executable_stack_info()
2408 bool is_stack_executable
;
2409 if (parameters
->options().is_execstack_set())
2410 is_stack_executable
= parameters
->options().is_stack_executable();
2411 else if (!this->input_with_gnu_stack_note_
)
2415 if (this->input_requires_executable_stack_
)
2416 is_stack_executable
= true;
2417 else if (this->input_without_gnu_stack_note_
)
2418 is_stack_executable
=
2419 parameters
->target().is_default_stack_executable();
2421 is_stack_executable
= false;
2424 if (parameters
->options().relocatable())
2426 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2427 elfcpp::Elf_Xword flags
= 0;
2428 if (is_stack_executable
)
2429 flags
|= elfcpp::SHF_EXECINSTR
;
2430 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2431 ORDER_INVALID
, false);
2435 if (this->script_options_
->saw_phdrs_clause())
2437 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2438 if (is_stack_executable
)
2439 flags
|= elfcpp::PF_X
;
2440 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2444 // If --build-id was used, set up the build ID note.
2447 Layout::create_build_id()
2449 if (!parameters
->options().user_set_build_id())
2452 const char* style
= parameters
->options().build_id();
2453 if (strcmp(style
, "none") == 0)
2456 // Set DESCSZ to the size of the note descriptor. When possible,
2457 // set DESC to the note descriptor contents.
2460 if (strcmp(style
, "md5") == 0)
2462 else if (strcmp(style
, "sha1") == 0)
2464 else if (strcmp(style
, "uuid") == 0)
2466 const size_t uuidsz
= 128 / 8;
2468 char buffer
[uuidsz
];
2469 memset(buffer
, 0, uuidsz
);
2471 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2473 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2477 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2478 release_descriptor(descriptor
, true);
2480 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
2481 else if (static_cast<size_t>(got
) != uuidsz
)
2482 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2486 desc
.assign(buffer
, uuidsz
);
2489 else if (strncmp(style
, "0x", 2) == 0)
2492 const char* p
= style
+ 2;
2495 if (hex_p(p
[0]) && hex_p(p
[1]))
2497 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
2501 else if (*p
== '-' || *p
== ':')
2504 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2507 descsz
= desc
.size();
2510 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2513 size_t trailing_padding
;
2514 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2515 ".note.gnu.build-id", descsz
, true,
2522 // We know the value already, so we fill it in now.
2523 gold_assert(desc
.size() == descsz
);
2525 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2526 os
->add_output_section_data(posd
);
2528 if (trailing_padding
!= 0)
2530 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2531 os
->add_output_section_data(posd
);
2536 // We need to compute a checksum after we have completed the
2538 gold_assert(trailing_padding
== 0);
2539 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
2540 os
->add_output_section_data(this->build_id_note_
);
2544 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2545 // field of the former should point to the latter. I'm not sure who
2546 // started this, but the GNU linker does it, and some tools depend
2550 Layout::link_stabs_sections()
2552 if (!this->have_stabstr_section_
)
2555 for (Section_list::iterator p
= this->section_list_
.begin();
2556 p
!= this->section_list_
.end();
2559 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
2562 const char* name
= (*p
)->name();
2563 if (strncmp(name
, ".stab", 5) != 0)
2566 size_t len
= strlen(name
);
2567 if (strcmp(name
+ len
- 3, "str") != 0)
2570 std::string
stab_name(name
, len
- 3);
2571 Output_section
* stab_sec
;
2572 stab_sec
= this->find_output_section(stab_name
.c_str());
2573 if (stab_sec
!= NULL
)
2574 stab_sec
->set_link_section(*p
);
2578 // Create .gnu_incremental_inputs and related sections needed
2579 // for the next run of incremental linking to check what has changed.
2582 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
2584 Incremental_inputs
* incr
= this->incremental_inputs_
;
2586 gold_assert(incr
!= NULL
);
2588 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2589 incr
->create_data_sections(symtab
);
2591 // Add the .gnu_incremental_inputs section.
2592 const char* incremental_inputs_name
=
2593 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
2594 Output_section
* incremental_inputs_os
=
2595 this->make_output_section(incremental_inputs_name
,
2596 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
2597 ORDER_INVALID
, false);
2598 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
2600 // Add the .gnu_incremental_symtab section.
2601 const char* incremental_symtab_name
=
2602 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
2603 Output_section
* incremental_symtab_os
=
2604 this->make_output_section(incremental_symtab_name
,
2605 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
2606 ORDER_INVALID
, false);
2607 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
2608 incremental_symtab_os
->set_entsize(4);
2610 // Add the .gnu_incremental_relocs section.
2611 const char* incremental_relocs_name
=
2612 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
2613 Output_section
* incremental_relocs_os
=
2614 this->make_output_section(incremental_relocs_name
,
2615 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
2616 ORDER_INVALID
, false);
2617 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
2618 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
2620 // Add the .gnu_incremental_got_plt section.
2621 const char* incremental_got_plt_name
=
2622 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
2623 Output_section
* incremental_got_plt_os
=
2624 this->make_output_section(incremental_got_plt_name
,
2625 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
2626 ORDER_INVALID
, false);
2627 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
2629 // Add the .gnu_incremental_strtab section.
2630 const char* incremental_strtab_name
=
2631 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
2632 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
2633 elfcpp::SHT_STRTAB
, 0,
2634 ORDER_INVALID
, false);
2635 Output_data_strtab
* strtab_data
=
2636 new Output_data_strtab(incr
->get_stringpool());
2637 incremental_strtab_os
->add_output_section_data(strtab_data
);
2639 incremental_inputs_os
->set_after_input_sections();
2640 incremental_symtab_os
->set_after_input_sections();
2641 incremental_relocs_os
->set_after_input_sections();
2642 incremental_got_plt_os
->set_after_input_sections();
2644 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
2645 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
2646 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
2647 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
2650 // Return whether SEG1 should be before SEG2 in the output file. This
2651 // is based entirely on the segment type and flags. When this is
2652 // called the segment addresses has normally not yet been set.
2655 Layout::segment_precedes(const Output_segment
* seg1
,
2656 const Output_segment
* seg2
)
2658 elfcpp::Elf_Word type1
= seg1
->type();
2659 elfcpp::Elf_Word type2
= seg2
->type();
2661 // The single PT_PHDR segment is required to precede any loadable
2662 // segment. We simply make it always first.
2663 if (type1
== elfcpp::PT_PHDR
)
2665 gold_assert(type2
!= elfcpp::PT_PHDR
);
2668 if (type2
== elfcpp::PT_PHDR
)
2671 // The single PT_INTERP segment is required to precede any loadable
2672 // segment. We simply make it always second.
2673 if (type1
== elfcpp::PT_INTERP
)
2675 gold_assert(type2
!= elfcpp::PT_INTERP
);
2678 if (type2
== elfcpp::PT_INTERP
)
2681 // We then put PT_LOAD segments before any other segments.
2682 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
2684 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
2687 // We put the PT_TLS segment last except for the PT_GNU_RELRO
2688 // segment, because that is where the dynamic linker expects to find
2689 // it (this is just for efficiency; other positions would also work
2691 if (type1
== elfcpp::PT_TLS
2692 && type2
!= elfcpp::PT_TLS
2693 && type2
!= elfcpp::PT_GNU_RELRO
)
2695 if (type2
== elfcpp::PT_TLS
2696 && type1
!= elfcpp::PT_TLS
2697 && type1
!= elfcpp::PT_GNU_RELRO
)
2700 // We put the PT_GNU_RELRO segment last, because that is where the
2701 // dynamic linker expects to find it (as with PT_TLS, this is just
2703 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
2705 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
2708 const elfcpp::Elf_Word flags1
= seg1
->flags();
2709 const elfcpp::Elf_Word flags2
= seg2
->flags();
2711 // The order of non-PT_LOAD segments is unimportant. We simply sort
2712 // by the numeric segment type and flags values. There should not
2713 // be more than one segment with the same type and flags.
2714 if (type1
!= elfcpp::PT_LOAD
)
2717 return type1
< type2
;
2718 gold_assert(flags1
!= flags2
);
2719 return flags1
< flags2
;
2722 // If the addresses are set already, sort by load address.
2723 if (seg1
->are_addresses_set())
2725 if (!seg2
->are_addresses_set())
2728 unsigned int section_count1
= seg1
->output_section_count();
2729 unsigned int section_count2
= seg2
->output_section_count();
2730 if (section_count1
== 0 && section_count2
> 0)
2732 if (section_count1
> 0 && section_count2
== 0)
2735 uint64_t paddr1
= (seg1
->are_addresses_set()
2737 : seg1
->first_section_load_address());
2738 uint64_t paddr2
= (seg2
->are_addresses_set()
2740 : seg2
->first_section_load_address());
2742 if (paddr1
!= paddr2
)
2743 return paddr1
< paddr2
;
2745 else if (seg2
->are_addresses_set())
2748 // A segment which holds large data comes after a segment which does
2749 // not hold large data.
2750 if (seg1
->is_large_data_segment())
2752 if (!seg2
->is_large_data_segment())
2755 else if (seg2
->is_large_data_segment())
2758 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
2759 // segments come before writable segments. Then writable segments
2760 // with data come before writable segments without data. Then
2761 // executable segments come before non-executable segments. Then
2762 // the unlikely case of a non-readable segment comes before the
2763 // normal case of a readable segment. If there are multiple
2764 // segments with the same type and flags, we require that the
2765 // address be set, and we sort by virtual address and then physical
2767 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
2768 return (flags1
& elfcpp::PF_W
) == 0;
2769 if ((flags1
& elfcpp::PF_W
) != 0
2770 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
2771 return seg1
->has_any_data_sections();
2772 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
2773 return (flags1
& elfcpp::PF_X
) != 0;
2774 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
2775 return (flags1
& elfcpp::PF_R
) == 0;
2777 // We shouldn't get here--we shouldn't create segments which we
2778 // can't distinguish.
2782 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2785 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
2787 uint64_t unsigned_off
= off
;
2788 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
2789 | (addr
& (abi_pagesize
- 1)));
2790 if (aligned_off
< unsigned_off
)
2791 aligned_off
+= abi_pagesize
;
2795 // Set the file offsets of all the segments, and all the sections they
2796 // contain. They have all been created. LOAD_SEG must be be laid out
2797 // first. Return the offset of the data to follow.
2800 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
2801 unsigned int* pshndx
)
2803 // Sort them into the final order.
2804 std::sort(this->segment_list_
.begin(), this->segment_list_
.end(),
2805 Layout::Compare_segments());
2807 // Find the PT_LOAD segments, and set their addresses and offsets
2808 // and their section's addresses and offsets.
2810 if (parameters
->options().user_set_Ttext())
2811 addr
= parameters
->options().Ttext();
2812 else if (parameters
->options().output_is_position_independent())
2815 addr
= target
->default_text_segment_address();
2818 // If LOAD_SEG is NULL, then the file header and segment headers
2819 // will not be loadable. But they still need to be at offset 0 in
2820 // the file. Set their offsets now.
2821 if (load_seg
== NULL
)
2823 for (Data_list::iterator p
= this->special_output_list_
.begin();
2824 p
!= this->special_output_list_
.end();
2827 off
= align_address(off
, (*p
)->addralign());
2828 (*p
)->set_address_and_file_offset(0, off
);
2829 off
+= (*p
)->data_size();
2833 unsigned int increase_relro
= this->increase_relro_
;
2834 if (this->script_options_
->saw_sections_clause())
2837 const bool check_sections
= parameters
->options().check_sections();
2838 Output_segment
* last_load_segment
= NULL
;
2840 for (Segment_list::iterator p
= this->segment_list_
.begin();
2841 p
!= this->segment_list_
.end();
2844 if ((*p
)->type() == elfcpp::PT_LOAD
)
2846 if (load_seg
!= NULL
&& load_seg
!= *p
)
2850 bool are_addresses_set
= (*p
)->are_addresses_set();
2851 if (are_addresses_set
)
2853 // When it comes to setting file offsets, we care about
2854 // the physical address.
2855 addr
= (*p
)->paddr();
2857 else if (parameters
->options().user_set_Tdata()
2858 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2859 && (!parameters
->options().user_set_Tbss()
2860 || (*p
)->has_any_data_sections()))
2862 addr
= parameters
->options().Tdata();
2863 are_addresses_set
= true;
2865 else if (parameters
->options().user_set_Tbss()
2866 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2867 && !(*p
)->has_any_data_sections())
2869 addr
= parameters
->options().Tbss();
2870 are_addresses_set
= true;
2873 uint64_t orig_addr
= addr
;
2874 uint64_t orig_off
= off
;
2876 uint64_t aligned_addr
= 0;
2877 uint64_t abi_pagesize
= target
->abi_pagesize();
2878 uint64_t common_pagesize
= target
->common_pagesize();
2880 if (!parameters
->options().nmagic()
2881 && !parameters
->options().omagic())
2882 (*p
)->set_minimum_p_align(common_pagesize
);
2884 if (!are_addresses_set
)
2886 // Skip the address forward one page, maintaining the same
2887 // position within the page. This lets us store both segments
2888 // overlapping on a single page in the file, but the loader will
2889 // put them on different pages in memory. We will revisit this
2890 // decision once we know the size of the segment.
2892 addr
= align_address(addr
, (*p
)->maximum_alignment());
2893 aligned_addr
= addr
;
2895 if ((addr
& (abi_pagesize
- 1)) != 0)
2896 addr
= addr
+ abi_pagesize
;
2898 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2901 if (!parameters
->options().nmagic()
2902 && !parameters
->options().omagic())
2903 off
= align_file_offset(off
, addr
, abi_pagesize
);
2904 else if (load_seg
== NULL
)
2906 // This is -N or -n with a section script which prevents
2907 // us from using a load segment. We need to ensure that
2908 // the file offset is aligned to the alignment of the
2909 // segment. This is because the linker script
2910 // implicitly assumed a zero offset. If we don't align
2911 // here, then the alignment of the sections in the
2912 // linker script may not match the alignment of the
2913 // sections in the set_section_addresses call below,
2914 // causing an error about dot moving backward.
2915 off
= align_address(off
, (*p
)->maximum_alignment());
2918 unsigned int shndx_hold
= *pshndx
;
2919 bool has_relro
= false;
2920 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
2925 // Now that we know the size of this segment, we may be able
2926 // to save a page in memory, at the cost of wasting some
2927 // file space, by instead aligning to the start of a new
2928 // page. Here we use the real machine page size rather than
2929 // the ABI mandated page size. If the segment has been
2930 // aligned so that the relro data ends at a page boundary,
2931 // we do not try to realign it.
2933 if (!are_addresses_set
2935 && aligned_addr
!= addr
2936 && !parameters
->incremental_update())
2938 uint64_t first_off
= (common_pagesize
2940 & (common_pagesize
- 1)));
2941 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
2944 && ((aligned_addr
& ~ (common_pagesize
- 1))
2945 != (new_addr
& ~ (common_pagesize
- 1)))
2946 && first_off
+ last_off
<= common_pagesize
)
2948 *pshndx
= shndx_hold
;
2949 addr
= align_address(aligned_addr
, common_pagesize
);
2950 addr
= align_address(addr
, (*p
)->maximum_alignment());
2951 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2952 off
= align_file_offset(off
, addr
, abi_pagesize
);
2954 increase_relro
= this->increase_relro_
;
2955 if (this->script_options_
->saw_sections_clause())
2959 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
2968 // Implement --check-sections. We know that the segments
2969 // are sorted by LMA.
2970 if (check_sections
&& last_load_segment
!= NULL
)
2972 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
2973 if (last_load_segment
->paddr() + last_load_segment
->memsz()
2976 unsigned long long lb1
= last_load_segment
->paddr();
2977 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
2978 unsigned long long lb2
= (*p
)->paddr();
2979 unsigned long long le2
= lb2
+ (*p
)->memsz();
2980 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
2981 "[0x%llx -> 0x%llx]"),
2982 lb1
, le1
, lb2
, le2
);
2985 last_load_segment
= *p
;
2989 // Handle the non-PT_LOAD segments, setting their offsets from their
2990 // section's offsets.
2991 for (Segment_list::iterator p
= this->segment_list_
.begin();
2992 p
!= this->segment_list_
.end();
2995 if ((*p
)->type() != elfcpp::PT_LOAD
)
2996 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3001 // Set the TLS offsets for each section in the PT_TLS segment.
3002 if (this->tls_segment_
!= NULL
)
3003 this->tls_segment_
->set_tls_offsets();
3008 // Set the offsets of all the allocated sections when doing a
3009 // relocatable link. This does the same jobs as set_segment_offsets,
3010 // only for a relocatable link.
3013 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3014 unsigned int* pshndx
)
3018 file_header
->set_address_and_file_offset(0, 0);
3019 off
+= file_header
->data_size();
3021 for (Section_list::iterator p
= this->section_list_
.begin();
3022 p
!= this->section_list_
.end();
3025 // We skip unallocated sections here, except that group sections
3026 // have to come first.
3027 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3028 && (*p
)->type() != elfcpp::SHT_GROUP
)
3031 off
= align_address(off
, (*p
)->addralign());
3033 // The linker script might have set the address.
3034 if (!(*p
)->is_address_valid())
3035 (*p
)->set_address(0);
3036 (*p
)->set_file_offset(off
);
3037 (*p
)->finalize_data_size();
3038 off
+= (*p
)->data_size();
3040 (*p
)->set_out_shndx(*pshndx
);
3047 // Set the file offset of all the sections not associated with a
3051 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3053 off_t startoff
= off
;
3056 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3057 p
!= this->unattached_section_list_
.end();
3060 // The symtab section is handled in create_symtab_sections.
3061 if (*p
== this->symtab_section_
)
3064 // If we've already set the data size, don't set it again.
3065 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3068 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3069 && (*p
)->requires_postprocessing())
3071 (*p
)->create_postprocessing_buffer();
3072 this->any_postprocessing_sections_
= true;
3075 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3076 && (*p
)->after_input_sections())
3078 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3079 && (!(*p
)->after_input_sections()
3080 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3082 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3083 && (!(*p
)->after_input_sections()
3084 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3087 if (!parameters
->incremental_update())
3089 off
= align_address(off
, (*p
)->addralign());
3090 (*p
)->set_file_offset(off
);
3091 (*p
)->finalize_data_size();
3095 // Incremental update: allocate file space from free list.
3096 (*p
)->pre_finalize_data_size();
3097 off_t current_size
= (*p
)->current_data_size();
3098 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3101 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3102 this->free_list_
.dump();
3103 gold_assert((*p
)->output_section() != NULL
);
3104 gold_fatal(_("out of patch space for section %s; "
3105 "relink with --incremental-full"),
3106 (*p
)->output_section()->name());
3108 (*p
)->set_file_offset(off
);
3109 (*p
)->finalize_data_size();
3110 if ((*p
)->data_size() > current_size
)
3112 gold_assert((*p
)->output_section() != NULL
);
3113 gold_fatal(_("%s: section changed size; "
3114 "relink with --incremental-full"),
3115 (*p
)->output_section()->name());
3117 gold_debug(DEBUG_INCREMENTAL
,
3118 "set_section_offsets: %08lx %08lx %s",
3119 static_cast<long>(off
),
3120 static_cast<long>((*p
)->data_size()),
3121 ((*p
)->output_section() != NULL
3122 ? (*p
)->output_section()->name() : "(special)"));
3125 off
+= (*p
)->data_size();
3129 // At this point the name must be set.
3130 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3131 this->namepool_
.add((*p
)->name(), false, NULL
);
3136 // Set the section indexes of all the sections not associated with a
3140 Layout::set_section_indexes(unsigned int shndx
)
3142 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3143 p
!= this->unattached_section_list_
.end();
3146 if (!(*p
)->has_out_shndx())
3148 (*p
)->set_out_shndx(shndx
);
3155 // Set the section addresses according to the linker script. This is
3156 // only called when we see a SECTIONS clause. This returns the
3157 // program segment which should hold the file header and segment
3158 // headers, if any. It will return NULL if they should not be in a
3162 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3164 Script_sections
* ss
= this->script_options_
->script_sections();
3165 gold_assert(ss
->saw_sections_clause());
3166 return this->script_options_
->set_section_addresses(symtab
, this);
3169 // Place the orphan sections in the linker script.
3172 Layout::place_orphan_sections_in_script()
3174 Script_sections
* ss
= this->script_options_
->script_sections();
3175 gold_assert(ss
->saw_sections_clause());
3177 // Place each orphaned output section in the script.
3178 for (Section_list::iterator p
= this->section_list_
.begin();
3179 p
!= this->section_list_
.end();
3182 if (!(*p
)->found_in_sections_clause())
3183 ss
->place_orphan(*p
);
3187 // Count the local symbols in the regular symbol table and the dynamic
3188 // symbol table, and build the respective string pools.
3191 Layout::count_local_symbols(const Task
* task
,
3192 const Input_objects
* input_objects
)
3194 // First, figure out an upper bound on the number of symbols we'll
3195 // be inserting into each pool. This helps us create the pools with
3196 // the right size, to avoid unnecessary hashtable resizing.
3197 unsigned int symbol_count
= 0;
3198 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3199 p
!= input_objects
->relobj_end();
3201 symbol_count
+= (*p
)->local_symbol_count();
3203 // Go from "upper bound" to "estimate." We overcount for two
3204 // reasons: we double-count symbols that occur in more than one
3205 // object file, and we count symbols that are dropped from the
3206 // output. Add it all together and assume we overcount by 100%.
3209 // We assume all symbols will go into both the sympool and dynpool.
3210 this->sympool_
.reserve(symbol_count
);
3211 this->dynpool_
.reserve(symbol_count
);
3213 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3214 p
!= input_objects
->relobj_end();
3217 Task_lock_obj
<Object
> tlo(task
, *p
);
3218 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3222 // Create the symbol table sections. Here we also set the final
3223 // values of the symbols. At this point all the loadable sections are
3224 // fully laid out. SHNUM is the number of sections so far.
3227 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3228 Symbol_table
* symtab
,
3234 if (parameters
->target().get_size() == 32)
3236 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3239 else if (parameters
->target().get_size() == 64)
3241 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3247 // Compute file offsets relative to the start of the symtab section.
3250 // Save space for the dummy symbol at the start of the section. We
3251 // never bother to write this out--it will just be left as zero.
3253 unsigned int local_symbol_index
= 1;
3255 // Add STT_SECTION symbols for each Output section which needs one.
3256 for (Section_list::iterator p
= this->section_list_
.begin();
3257 p
!= this->section_list_
.end();
3260 if (!(*p
)->needs_symtab_index())
3261 (*p
)->set_symtab_index(-1U);
3264 (*p
)->set_symtab_index(local_symbol_index
);
3265 ++local_symbol_index
;
3270 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3271 p
!= input_objects
->relobj_end();
3274 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3276 off
+= (index
- local_symbol_index
) * symsize
;
3277 local_symbol_index
= index
;
3280 unsigned int local_symcount
= local_symbol_index
;
3281 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3284 size_t dyn_global_index
;
3286 if (this->dynsym_section_
== NULL
)
3289 dyn_global_index
= 0;
3294 dyn_global_index
= this->dynsym_section_
->info();
3295 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3296 dynoff
= this->dynsym_section_
->offset() + locsize
;
3297 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3298 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3299 == this->dynsym_section_
->data_size() - locsize
);
3302 off_t global_off
= off
;
3303 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3304 &this->sympool_
, &local_symcount
);
3306 if (!parameters
->options().strip_all())
3308 this->sympool_
.set_string_offsets();
3310 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3311 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3315 this->symtab_section_
= osymtab
;
3317 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3319 osymtab
->add_output_section_data(pos
);
3321 // We generate a .symtab_shndx section if we have more than
3322 // SHN_LORESERVE sections. Technically it is possible that we
3323 // don't need one, because it is possible that there are no
3324 // symbols in any of sections with indexes larger than
3325 // SHN_LORESERVE. That is probably unusual, though, and it is
3326 // easier to always create one than to compute section indexes
3327 // twice (once here, once when writing out the symbols).
3328 if (shnum
>= elfcpp::SHN_LORESERVE
)
3330 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3332 Output_section
* osymtab_xindex
=
3333 this->make_output_section(symtab_xindex_name
,
3334 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3335 ORDER_INVALID
, false);
3337 size_t symcount
= off
/ symsize
;
3338 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3340 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3342 osymtab_xindex
->set_link_section(osymtab
);
3343 osymtab_xindex
->set_addralign(4);
3344 osymtab_xindex
->set_entsize(4);
3346 osymtab_xindex
->set_after_input_sections();
3348 // This tells the driver code to wait until the symbol table
3349 // has written out before writing out the postprocessing
3350 // sections, including the .symtab_shndx section.
3351 this->any_postprocessing_sections_
= true;
3354 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3355 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3360 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3361 ostrtab
->add_output_section_data(pstr
);
3364 if (!parameters
->incremental_update())
3365 symtab_off
= align_address(*poff
, align
);
3368 symtab_off
= this->allocate(off
, align
, *poff
);
3370 gold_fatal(_("out of patch space for symbol table; "
3371 "relink with --incremental-full"));
3372 gold_debug(DEBUG_INCREMENTAL
,
3373 "create_symtab_sections: %08lx %08lx .symtab",
3374 static_cast<long>(symtab_off
),
3375 static_cast<long>(off
));
3378 symtab
->set_file_offset(symtab_off
+ global_off
);
3379 osymtab
->set_file_offset(symtab_off
);
3380 osymtab
->finalize_data_size();
3381 osymtab
->set_link_section(ostrtab
);
3382 osymtab
->set_info(local_symcount
);
3383 osymtab
->set_entsize(symsize
);
3385 if (symtab_off
+ off
> *poff
)
3386 *poff
= symtab_off
+ off
;
3390 // Create the .shstrtab section, which holds the names of the
3391 // sections. At the time this is called, we have created all the
3392 // output sections except .shstrtab itself.
3395 Layout::create_shstrtab()
3397 // FIXME: We don't need to create a .shstrtab section if we are
3398 // stripping everything.
3400 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
3402 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
3403 ORDER_INVALID
, false);
3405 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
3407 // We can't write out this section until we've set all the
3408 // section names, and we don't set the names of compressed
3409 // output sections until relocations are complete. FIXME: With
3410 // the current names we use, this is unnecessary.
3411 os
->set_after_input_sections();
3414 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
3415 os
->add_output_section_data(posd
);
3420 // Create the section headers. SIZE is 32 or 64. OFF is the file
3424 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
3426 Output_section_headers
* oshdrs
;
3427 oshdrs
= new Output_section_headers(this,
3428 &this->segment_list_
,
3429 &this->section_list_
,
3430 &this->unattached_section_list_
,
3434 if (!parameters
->incremental_update())
3435 off
= align_address(*poff
, oshdrs
->addralign());
3438 oshdrs
->pre_finalize_data_size();
3439 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
3441 gold_fatal(_("out of patch space for section header table; "
3442 "relink with --incremental-full"));
3443 gold_debug(DEBUG_INCREMENTAL
,
3444 "create_shdrs: %08lx %08lx (section header table)",
3445 static_cast<long>(off
),
3446 static_cast<long>(off
+ oshdrs
->data_size()));
3448 oshdrs
->set_address_and_file_offset(0, off
);
3449 off
+= oshdrs
->data_size();
3452 this->section_headers_
= oshdrs
;
3455 // Count the allocated sections.
3458 Layout::allocated_output_section_count() const
3460 size_t section_count
= 0;
3461 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3462 p
!= this->segment_list_
.end();
3464 section_count
+= (*p
)->output_section_count();
3465 return section_count
;
3468 // Create the dynamic symbol table.
3471 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
3472 Symbol_table
* symtab
,
3473 Output_section
** pdynstr
,
3474 unsigned int* plocal_dynamic_count
,
3475 std::vector
<Symbol
*>* pdynamic_symbols
,
3476 Versions
* pversions
)
3478 // Count all the symbols in the dynamic symbol table, and set the
3479 // dynamic symbol indexes.
3481 // Skip symbol 0, which is always all zeroes.
3482 unsigned int index
= 1;
3484 // Add STT_SECTION symbols for each Output section which needs one.
3485 for (Section_list::iterator p
= this->section_list_
.begin();
3486 p
!= this->section_list_
.end();
3489 if (!(*p
)->needs_dynsym_index())
3490 (*p
)->set_dynsym_index(-1U);
3493 (*p
)->set_dynsym_index(index
);
3498 // Count the local symbols that need to go in the dynamic symbol table,
3499 // and set the dynamic symbol indexes.
3500 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3501 p
!= input_objects
->relobj_end();
3504 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
3508 unsigned int local_symcount
= index
;
3509 *plocal_dynamic_count
= local_symcount
;
3511 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
3512 &this->dynpool_
, pversions
);
3516 const int size
= parameters
->target().get_size();
3519 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3522 else if (size
== 64)
3524 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3530 // Create the dynamic symbol table section.
3532 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
3536 ORDER_DYNAMIC_LINKER
,
3539 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
3542 dynsym
->add_output_section_data(odata
);
3544 dynsym
->set_info(local_symcount
);
3545 dynsym
->set_entsize(symsize
);
3546 dynsym
->set_addralign(align
);
3548 this->dynsym_section_
= dynsym
;
3550 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3551 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
3552 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
3554 // If there are more than SHN_LORESERVE allocated sections, we
3555 // create a .dynsym_shndx section. It is possible that we don't
3556 // need one, because it is possible that there are no dynamic
3557 // symbols in any of the sections with indexes larger than
3558 // SHN_LORESERVE. This is probably unusual, though, and at this
3559 // time we don't know the actual section indexes so it is
3560 // inconvenient to check.
3561 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
3563 Output_section
* dynsym_xindex
=
3564 this->choose_output_section(NULL
, ".dynsym_shndx",
3565 elfcpp::SHT_SYMTAB_SHNDX
,
3567 false, ORDER_DYNAMIC_LINKER
, false);
3569 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
3571 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
3573 dynsym_xindex
->set_link_section(dynsym
);
3574 dynsym_xindex
->set_addralign(4);
3575 dynsym_xindex
->set_entsize(4);
3577 dynsym_xindex
->set_after_input_sections();
3579 // This tells the driver code to wait until the symbol table has
3580 // written out before writing out the postprocessing sections,
3581 // including the .dynsym_shndx section.
3582 this->any_postprocessing_sections_
= true;
3585 // Create the dynamic string table section.
3587 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
3591 ORDER_DYNAMIC_LINKER
,
3594 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
3595 dynstr
->add_output_section_data(strdata
);
3597 dynsym
->set_link_section(dynstr
);
3598 this->dynamic_section_
->set_link_section(dynstr
);
3600 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
3601 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
3605 // Create the hash tables.
3607 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
3608 || strcmp(parameters
->options().hash_style(), "both") == 0)
3610 unsigned char* phash
;
3611 unsigned int hashlen
;
3612 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
3615 Output_section
* hashsec
=
3616 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
3617 elfcpp::SHF_ALLOC
, false,
3618 ORDER_DYNAMIC_LINKER
, false);
3620 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3624 hashsec
->add_output_section_data(hashdata
);
3626 hashsec
->set_link_section(dynsym
);
3627 hashsec
->set_entsize(4);
3629 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
3632 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
3633 || strcmp(parameters
->options().hash_style(), "both") == 0)
3635 unsigned char* phash
;
3636 unsigned int hashlen
;
3637 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
3640 Output_section
* hashsec
=
3641 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_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
);
3653 // For a 64-bit target, the entries in .gnu.hash do not have a
3654 // uniform size, so we only set the entry size for a 32-bit
3656 if (parameters
->target().get_size() == 32)
3657 hashsec
->set_entsize(4);
3659 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
3663 // Assign offsets to each local portion of the dynamic symbol table.
3666 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
3668 Output_section
* dynsym
= this->dynsym_section_
;
3669 gold_assert(dynsym
!= NULL
);
3671 off_t off
= dynsym
->offset();
3673 // Skip the dummy symbol at the start of the section.
3674 off
+= dynsym
->entsize();
3676 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3677 p
!= input_objects
->relobj_end();
3680 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
3681 off
+= count
* dynsym
->entsize();
3685 // Create the version sections.
3688 Layout::create_version_sections(const Versions
* versions
,
3689 const Symbol_table
* symtab
,
3690 unsigned int local_symcount
,
3691 const std::vector
<Symbol
*>& dynamic_symbols
,
3692 const Output_section
* dynstr
)
3694 if (!versions
->any_defs() && !versions
->any_needs())
3697 switch (parameters
->size_and_endianness())
3699 #ifdef HAVE_TARGET_32_LITTLE
3700 case Parameters::TARGET_32_LITTLE
:
3701 this->sized_create_version_sections
<32, false>(versions
, symtab
,
3703 dynamic_symbols
, dynstr
);
3706 #ifdef HAVE_TARGET_32_BIG
3707 case Parameters::TARGET_32_BIG
:
3708 this->sized_create_version_sections
<32, true>(versions
, symtab
,
3710 dynamic_symbols
, dynstr
);
3713 #ifdef HAVE_TARGET_64_LITTLE
3714 case Parameters::TARGET_64_LITTLE
:
3715 this->sized_create_version_sections
<64, false>(versions
, symtab
,
3717 dynamic_symbols
, dynstr
);
3720 #ifdef HAVE_TARGET_64_BIG
3721 case Parameters::TARGET_64_BIG
:
3722 this->sized_create_version_sections
<64, true>(versions
, symtab
,
3724 dynamic_symbols
, dynstr
);
3732 // Create the version sections, sized version.
3734 template<int size
, bool big_endian
>
3736 Layout::sized_create_version_sections(
3737 const Versions
* versions
,
3738 const Symbol_table
* symtab
,
3739 unsigned int local_symcount
,
3740 const std::vector
<Symbol
*>& dynamic_symbols
,
3741 const Output_section
* dynstr
)
3743 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
3744 elfcpp::SHT_GNU_versym
,
3747 ORDER_DYNAMIC_LINKER
,
3750 unsigned char* vbuf
;
3752 versions
->symbol_section_contents
<size
, big_endian
>(symtab
, &this->dynpool_
,
3757 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
3760 vsec
->add_output_section_data(vdata
);
3761 vsec
->set_entsize(2);
3762 vsec
->set_link_section(this->dynsym_section_
);
3764 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3765 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
3767 if (versions
->any_defs())
3769 Output_section
* vdsec
;
3770 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
3771 elfcpp::SHT_GNU_verdef
,
3773 false, ORDER_DYNAMIC_LINKER
, false);
3775 unsigned char* vdbuf
;
3776 unsigned int vdsize
;
3777 unsigned int vdentries
;
3778 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
, &vdbuf
,
3779 &vdsize
, &vdentries
);
3781 Output_section_data
* vddata
=
3782 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
3784 vdsec
->add_output_section_data(vddata
);
3785 vdsec
->set_link_section(dynstr
);
3786 vdsec
->set_info(vdentries
);
3788 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
3789 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
3792 if (versions
->any_needs())
3794 Output_section
* vnsec
;
3795 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
3796 elfcpp::SHT_GNU_verneed
,
3798 false, ORDER_DYNAMIC_LINKER
, false);
3800 unsigned char* vnbuf
;
3801 unsigned int vnsize
;
3802 unsigned int vnentries
;
3803 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
3807 Output_section_data
* vndata
=
3808 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
3810 vnsec
->add_output_section_data(vndata
);
3811 vnsec
->set_link_section(dynstr
);
3812 vnsec
->set_info(vnentries
);
3814 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
3815 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
3819 // Create the .interp section and PT_INTERP segment.
3822 Layout::create_interp(const Target
* target
)
3824 const char* interp
= parameters
->options().dynamic_linker();
3827 interp
= target
->dynamic_linker();
3828 gold_assert(interp
!= NULL
);
3831 size_t len
= strlen(interp
) + 1;
3833 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
3835 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
3836 elfcpp::SHT_PROGBITS
,
3838 false, ORDER_INTERP
,
3840 osec
->add_output_section_data(odata
);
3842 if (!this->script_options_
->saw_phdrs_clause())
3844 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_INTERP
,
3846 oseg
->add_output_section_to_nonload(osec
, elfcpp::PF_R
);
3850 // Add dynamic tags for the PLT and the dynamic relocs. This is
3851 // called by the target-specific code. This does nothing if not doing
3854 // USE_REL is true for REL relocs rather than RELA relocs.
3856 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3858 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3859 // and we also set DT_PLTREL. We use PLT_REL's output section, since
3860 // some targets have multiple reloc sections in PLT_REL.
3862 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3863 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3865 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3869 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
3870 const Output_data
* plt_rel
,
3871 const Output_data_reloc_generic
* dyn_rel
,
3872 bool add_debug
, bool dynrel_includes_plt
)
3874 Output_data_dynamic
* odyn
= this->dynamic_data_
;
3878 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
3879 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
3881 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
3883 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
3884 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
3885 odyn
->add_constant(elfcpp::DT_PLTREL
,
3886 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
3889 if (dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
3891 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
3893 if (plt_rel
!= NULL
&& dynrel_includes_plt
)
3894 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3897 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3899 const int size
= parameters
->target().get_size();
3904 rel_tag
= elfcpp::DT_RELENT
;
3906 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
3907 else if (size
== 64)
3908 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
3914 rel_tag
= elfcpp::DT_RELAENT
;
3916 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
3917 else if (size
== 64)
3918 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
3922 odyn
->add_constant(rel_tag
, rel_size
);
3924 if (parameters
->options().combreloc())
3926 size_t c
= dyn_rel
->relative_reloc_count();
3928 odyn
->add_constant((use_rel
3929 ? elfcpp::DT_RELCOUNT
3930 : elfcpp::DT_RELACOUNT
),
3935 if (add_debug
&& !parameters
->options().shared())
3937 // The value of the DT_DEBUG tag is filled in by the dynamic
3938 // linker at run time, and used by the debugger.
3939 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
3943 // Finish the .dynamic section and PT_DYNAMIC segment.
3946 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
3947 const Symbol_table
* symtab
)
3949 if (!this->script_options_
->saw_phdrs_clause())
3951 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
3954 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
3955 elfcpp::PF_R
| elfcpp::PF_W
);
3958 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3960 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
3961 p
!= input_objects
->dynobj_end();
3964 if (!(*p
)->is_needed()
3965 && !(*p
)->is_incremental()
3966 && (*p
)->input_file()->options().as_needed())
3968 // This dynamic object was linked with --as-needed, but it
3973 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
3976 if (parameters
->options().shared())
3978 const char* soname
= parameters
->options().soname();
3980 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
3983 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
3984 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
3985 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
3987 sym
= symtab
->lookup(parameters
->options().fini());
3988 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
3989 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
3991 // Look for .init_array, .preinit_array and .fini_array by checking
3993 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
3994 p
!= this->section_list_
.end();
3996 switch((*p
)->type())
3998 case elfcpp::SHT_FINI_ARRAY
:
3999 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4000 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4002 case elfcpp::SHT_INIT_ARRAY
:
4003 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4004 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4006 case elfcpp::SHT_PREINIT_ARRAY
:
4007 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4008 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4014 // Add a DT_RPATH entry if needed.
4015 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4018 std::string rpath_val
;
4019 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4023 if (rpath_val
.empty())
4024 rpath_val
= p
->name();
4027 // Eliminate duplicates.
4028 General_options::Dir_list::const_iterator q
;
4029 for (q
= rpath
.begin(); q
!= p
; ++q
)
4030 if (q
->name() == p
->name())
4035 rpath_val
+= p
->name();
4040 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4041 if (parameters
->options().enable_new_dtags())
4042 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4045 // Look for text segments that have dynamic relocations.
4046 bool have_textrel
= false;
4047 if (!this->script_options_
->saw_sections_clause())
4049 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4050 p
!= this->segment_list_
.end();
4053 if (((*p
)->flags() & elfcpp::PF_W
) == 0
4054 && (*p
)->has_dynamic_reloc())
4056 have_textrel
= true;
4063 // We don't know the section -> segment mapping, so we are
4064 // conservative and just look for readonly sections with
4065 // relocations. If those sections wind up in writable segments,
4066 // then we have created an unnecessary DT_TEXTREL entry.
4067 for (Section_list::const_iterator p
= this->section_list_
.begin();
4068 p
!= this->section_list_
.end();
4071 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4072 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4073 && ((*p
)->has_dynamic_reloc()))
4075 have_textrel
= true;
4081 // Add a DT_FLAGS entry. We add it even if no flags are set so that
4082 // post-link tools can easily modify these flags if desired.
4083 unsigned int flags
= 0;
4086 // Add a DT_TEXTREL for compatibility with older loaders.
4087 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4088 flags
|= elfcpp::DF_TEXTREL
;
4090 if (parameters
->options().text())
4091 gold_error(_("read-only segment has dynamic relocations"));
4092 else if (parameters
->options().warn_shared_textrel()
4093 && parameters
->options().shared())
4094 gold_warning(_("shared library text segment is not shareable"));
4096 if (parameters
->options().shared() && this->has_static_tls())
4097 flags
|= elfcpp::DF_STATIC_TLS
;
4098 if (parameters
->options().origin())
4099 flags
|= elfcpp::DF_ORIGIN
;
4100 if (parameters
->options().Bsymbolic())
4102 flags
|= elfcpp::DF_SYMBOLIC
;
4103 // Add DT_SYMBOLIC for compatibility with older loaders.
4104 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4106 if (parameters
->options().now())
4107 flags
|= elfcpp::DF_BIND_NOW
;
4108 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4111 if (parameters
->options().initfirst())
4112 flags
|= elfcpp::DF_1_INITFIRST
;
4113 if (parameters
->options().interpose())
4114 flags
|= elfcpp::DF_1_INTERPOSE
;
4115 if (parameters
->options().loadfltr())
4116 flags
|= elfcpp::DF_1_LOADFLTR
;
4117 if (parameters
->options().nodefaultlib())
4118 flags
|= elfcpp::DF_1_NODEFLIB
;
4119 if (parameters
->options().nodelete())
4120 flags
|= elfcpp::DF_1_NODELETE
;
4121 if (parameters
->options().nodlopen())
4122 flags
|= elfcpp::DF_1_NOOPEN
;
4123 if (parameters
->options().nodump())
4124 flags
|= elfcpp::DF_1_NODUMP
;
4125 if (!parameters
->options().shared())
4126 flags
&= ~(elfcpp::DF_1_INITFIRST
4127 | elfcpp::DF_1_NODELETE
4128 | elfcpp::DF_1_NOOPEN
);
4129 if (parameters
->options().origin())
4130 flags
|= elfcpp::DF_1_ORIGIN
;
4131 if (parameters
->options().now())
4132 flags
|= elfcpp::DF_1_NOW
;
4134 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4137 // Set the size of the _DYNAMIC symbol table to be the size of the
4141 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4143 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4144 odyn
->finalize_data_size();
4145 off_t data_size
= odyn
->data_size();
4146 const int size
= parameters
->target().get_size();
4148 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4149 else if (size
== 64)
4150 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4155 // The mapping of input section name prefixes to output section names.
4156 // In some cases one prefix is itself a prefix of another prefix; in
4157 // such a case the longer prefix must come first. These prefixes are
4158 // based on the GNU linker default ELF linker script.
4160 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4161 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4163 MAPPING_INIT(".text.", ".text"),
4164 MAPPING_INIT(".ctors.", ".ctors"),
4165 MAPPING_INIT(".dtors.", ".dtors"),
4166 MAPPING_INIT(".rodata.", ".rodata"),
4167 MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
4168 MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
4169 MAPPING_INIT(".data.", ".data"),
4170 MAPPING_INIT(".bss.", ".bss"),
4171 MAPPING_INIT(".tdata.", ".tdata"),
4172 MAPPING_INIT(".tbss.", ".tbss"),
4173 MAPPING_INIT(".init_array.", ".init_array"),
4174 MAPPING_INIT(".fini_array.", ".fini_array"),
4175 MAPPING_INIT(".sdata.", ".sdata"),
4176 MAPPING_INIT(".sbss.", ".sbss"),
4177 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4178 // differently depending on whether it is creating a shared library.
4179 MAPPING_INIT(".sdata2.", ".sdata"),
4180 MAPPING_INIT(".sbss2.", ".sbss"),
4181 MAPPING_INIT(".lrodata.", ".lrodata"),
4182 MAPPING_INIT(".ldata.", ".ldata"),
4183 MAPPING_INIT(".lbss.", ".lbss"),
4184 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4185 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4186 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4187 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4188 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4189 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4190 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4191 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4192 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4193 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4194 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4195 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4196 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4197 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4198 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4199 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4200 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4201 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4202 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4203 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4204 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4208 const int Layout::section_name_mapping_count
=
4209 (sizeof(Layout::section_name_mapping
)
4210 / sizeof(Layout::section_name_mapping
[0]));
4212 // Choose the output section name to use given an input section name.
4213 // Set *PLEN to the length of the name. *PLEN is initialized to the
4217 Layout::output_section_name(const char* name
, size_t* plen
)
4219 // gcc 4.3 generates the following sorts of section names when it
4220 // needs a section name specific to a function:
4226 // .data.rel.local.FN
4228 // .data.rel.ro.local.FN
4235 // The GNU linker maps all of those to the part before the .FN,
4236 // except that .data.rel.local.FN is mapped to .data, and
4237 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4238 // beginning with .data.rel.ro.local are grouped together.
4240 // For an anonymous namespace, the string FN can contain a '.'.
4242 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4243 // GNU linker maps to .rodata.
4245 // The .data.rel.ro sections are used with -z relro. The sections
4246 // are recognized by name. We use the same names that the GNU
4247 // linker does for these sections.
4249 // It is hard to handle this in a principled way, so we don't even
4250 // try. We use a table of mappings. If the input section name is
4251 // not found in the table, we simply use it as the output section
4254 const Section_name_mapping
* psnm
= section_name_mapping
;
4255 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4257 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4259 *plen
= psnm
->tolen
;
4267 // Check if a comdat group or .gnu.linkonce section with the given
4268 // NAME is selected for the link. If there is already a section,
4269 // *KEPT_SECTION is set to point to the existing section and the
4270 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4271 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4272 // *KEPT_SECTION is set to the internal copy and the function returns
4276 Layout::find_or_add_kept_section(const std::string
& name
,
4281 Kept_section
** kept_section
)
4283 // It's normal to see a couple of entries here, for the x86 thunk
4284 // sections. If we see more than a few, we're linking a C++
4285 // program, and we resize to get more space to minimize rehashing.
4286 if (this->signatures_
.size() > 4
4287 && !this->resized_signatures_
)
4289 reserve_unordered_map(&this->signatures_
,
4290 this->number_of_input_files_
* 64);
4291 this->resized_signatures_
= true;
4294 Kept_section candidate
;
4295 std::pair
<Signatures::iterator
, bool> ins
=
4296 this->signatures_
.insert(std::make_pair(name
, candidate
));
4298 if (kept_section
!= NULL
)
4299 *kept_section
= &ins
.first
->second
;
4302 // This is the first time we've seen this signature.
4303 ins
.first
->second
.set_object(object
);
4304 ins
.first
->second
.set_shndx(shndx
);
4306 ins
.first
->second
.set_is_comdat();
4308 ins
.first
->second
.set_is_group_name();
4312 // We have already seen this signature.
4314 if (ins
.first
->second
.is_group_name())
4316 // We've already seen a real section group with this signature.
4317 // If the kept group is from a plugin object, and we're in the
4318 // replacement phase, accept the new one as a replacement.
4319 if (ins
.first
->second
.object() == NULL
4320 && parameters
->options().plugins()->in_replacement_phase())
4322 ins
.first
->second
.set_object(object
);
4323 ins
.first
->second
.set_shndx(shndx
);
4328 else if (is_group_name
)
4330 // This is a real section group, and we've already seen a
4331 // linkonce section with this signature. Record that we've seen
4332 // a section group, and don't include this section group.
4333 ins
.first
->second
.set_is_group_name();
4338 // We've already seen a linkonce section and this is a linkonce
4339 // section. These don't block each other--this may be the same
4340 // symbol name with different section types.
4345 // Store the allocated sections into the section list.
4348 Layout::get_allocated_sections(Section_list
* section_list
) const
4350 for (Section_list::const_iterator p
= this->section_list_
.begin();
4351 p
!= this->section_list_
.end();
4353 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
4354 section_list
->push_back(*p
);
4357 // Create an output segment.
4360 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
4362 gold_assert(!parameters
->options().relocatable());
4363 Output_segment
* oseg
= new Output_segment(type
, flags
);
4364 this->segment_list_
.push_back(oseg
);
4366 if (type
== elfcpp::PT_TLS
)
4367 this->tls_segment_
= oseg
;
4368 else if (type
== elfcpp::PT_GNU_RELRO
)
4369 this->relro_segment_
= oseg
;
4374 // Write out the Output_sections. Most won't have anything to write,
4375 // since most of the data will come from input sections which are
4376 // handled elsewhere. But some Output_sections do have Output_data.
4379 Layout::write_output_sections(Output_file
* of
) const
4381 for (Section_list::const_iterator p
= this->section_list_
.begin();
4382 p
!= this->section_list_
.end();
4385 if (!(*p
)->after_input_sections())
4390 // Write out data not associated with a section or the symbol table.
4393 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
4395 if (!parameters
->options().strip_all())
4397 const Output_section
* symtab_section
= this->symtab_section_
;
4398 for (Section_list::const_iterator p
= this->section_list_
.begin();
4399 p
!= this->section_list_
.end();
4402 if ((*p
)->needs_symtab_index())
4404 gold_assert(symtab_section
!= NULL
);
4405 unsigned int index
= (*p
)->symtab_index();
4406 gold_assert(index
> 0 && index
!= -1U);
4407 off_t off
= (symtab_section
->offset()
4408 + index
* symtab_section
->entsize());
4409 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
4414 const Output_section
* dynsym_section
= this->dynsym_section_
;
4415 for (Section_list::const_iterator p
= this->section_list_
.begin();
4416 p
!= this->section_list_
.end();
4419 if ((*p
)->needs_dynsym_index())
4421 gold_assert(dynsym_section
!= NULL
);
4422 unsigned int index
= (*p
)->dynsym_index();
4423 gold_assert(index
> 0 && index
!= -1U);
4424 off_t off
= (dynsym_section
->offset()
4425 + index
* dynsym_section
->entsize());
4426 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
4430 // Write out the Output_data which are not in an Output_section.
4431 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
4432 p
!= this->special_output_list_
.end();
4437 // Write out the Output_sections which can only be written after the
4438 // input sections are complete.
4441 Layout::write_sections_after_input_sections(Output_file
* of
)
4443 // Determine the final section offsets, and thus the final output
4444 // file size. Note we finalize the .shstrab last, to allow the
4445 // after_input_section sections to modify their section-names before
4447 if (this->any_postprocessing_sections_
)
4449 off_t off
= this->output_file_size_
;
4450 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
4452 // Now that we've finalized the names, we can finalize the shstrab.
4454 this->set_section_offsets(off
,
4455 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
4457 if (off
> this->output_file_size_
)
4460 this->output_file_size_
= off
;
4464 for (Section_list::const_iterator p
= this->section_list_
.begin();
4465 p
!= this->section_list_
.end();
4468 if ((*p
)->after_input_sections())
4472 this->section_headers_
->write(of
);
4475 // If the build ID requires computing a checksum, do so here, and
4476 // write it out. We compute a checksum over the entire file because
4477 // that is simplest.
4480 Layout::write_build_id(Output_file
* of
) const
4482 if (this->build_id_note_
== NULL
)
4485 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
4487 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
4488 this->build_id_note_
->data_size());
4490 const char* style
= parameters
->options().build_id();
4491 if (strcmp(style
, "sha1") == 0)
4494 sha1_init_ctx(&ctx
);
4495 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
4496 sha1_finish_ctx(&ctx
, ov
);
4498 else if (strcmp(style
, "md5") == 0)
4502 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
4503 md5_finish_ctx(&ctx
, ov
);
4508 of
->write_output_view(this->build_id_note_
->offset(),
4509 this->build_id_note_
->data_size(),
4512 of
->free_input_view(0, this->output_file_size_
, iv
);
4515 // Write out a binary file. This is called after the link is
4516 // complete. IN is the temporary output file we used to generate the
4517 // ELF code. We simply walk through the segments, read them from
4518 // their file offset in IN, and write them to their load address in
4519 // the output file. FIXME: with a bit more work, we could support
4520 // S-records and/or Intel hex format here.
4523 Layout::write_binary(Output_file
* in
) const
4525 gold_assert(parameters
->options().oformat_enum()
4526 == General_options::OBJECT_FORMAT_BINARY
);
4528 // Get the size of the binary file.
4529 uint64_t max_load_address
= 0;
4530 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4531 p
!= this->segment_list_
.end();
4534 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4536 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
4537 if (max_paddr
> max_load_address
)
4538 max_load_address
= max_paddr
;
4542 Output_file
out(parameters
->options().output_file_name());
4543 out
.open(max_load_address
);
4545 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4546 p
!= this->segment_list_
.end();
4549 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
4551 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
4553 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
4555 memcpy(vout
, vin
, (*p
)->filesz());
4556 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
4557 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
4564 // Print the output sections to the map file.
4567 Layout::print_to_mapfile(Mapfile
* mapfile
) const
4569 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4570 p
!= this->segment_list_
.end();
4572 (*p
)->print_sections_to_mapfile(mapfile
);
4575 // Print statistical information to stderr. This is used for --stats.
4578 Layout::print_stats() const
4580 this->namepool_
.print_stats("section name pool");
4581 this->sympool_
.print_stats("output symbol name pool");
4582 this->dynpool_
.print_stats("dynamic name pool");
4584 for (Section_list::const_iterator p
= this->section_list_
.begin();
4585 p
!= this->section_list_
.end();
4587 (*p
)->print_merge_stats();
4590 // Write_sections_task methods.
4592 // We can always run this task.
4595 Write_sections_task::is_runnable()
4600 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4604 Write_sections_task::locks(Task_locker
* tl
)
4606 tl
->add(this, this->output_sections_blocker_
);
4607 tl
->add(this, this->final_blocker_
);
4610 // Run the task--write out the data.
4613 Write_sections_task::run(Workqueue
*)
4615 this->layout_
->write_output_sections(this->of_
);
4618 // Write_data_task methods.
4620 // We can always run this task.
4623 Write_data_task::is_runnable()
4628 // We need to unlock FINAL_BLOCKER when finished.
4631 Write_data_task::locks(Task_locker
* tl
)
4633 tl
->add(this, this->final_blocker_
);
4636 // Run the task--write out the data.
4639 Write_data_task::run(Workqueue
*)
4641 this->layout_
->write_data(this->symtab_
, this->of_
);
4644 // Write_symbols_task methods.
4646 // We can always run this task.
4649 Write_symbols_task::is_runnable()
4654 // We need to unlock FINAL_BLOCKER when finished.
4657 Write_symbols_task::locks(Task_locker
* tl
)
4659 tl
->add(this, this->final_blocker_
);
4662 // Run the task--write out the symbols.
4665 Write_symbols_task::run(Workqueue
*)
4667 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
4668 this->layout_
->symtab_xindex(),
4669 this->layout_
->dynsym_xindex(), this->of_
);
4672 // Write_after_input_sections_task methods.
4674 // We can only run this task after the input sections have completed.
4677 Write_after_input_sections_task::is_runnable()
4679 if (this->input_sections_blocker_
->is_blocked())
4680 return this->input_sections_blocker_
;
4684 // We need to unlock FINAL_BLOCKER when finished.
4687 Write_after_input_sections_task::locks(Task_locker
* tl
)
4689 tl
->add(this, this->final_blocker_
);
4695 Write_after_input_sections_task::run(Workqueue
*)
4697 this->layout_
->write_sections_after_input_sections(this->of_
);
4700 // Close_task_runner methods.
4702 // Run the task--close the file.
4705 Close_task_runner::run(Workqueue
*, const Task
*)
4707 // If we need to compute a checksum for the BUILD if, we do so here.
4708 this->layout_
->write_build_id(this->of_
);
4710 // If we've been asked to create a binary file, we do so here.
4711 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
4712 this->layout_
->write_binary(this->of_
);
4717 // Instantiate the templates we need. We could use the configure
4718 // script to restrict this to only the ones for implemented targets.
4720 #ifdef HAVE_TARGET_32_LITTLE
4723 Layout::init_fixed_output_section
<32, false>(
4725 elfcpp::Shdr
<32, false>& shdr
);
4728 #ifdef HAVE_TARGET_32_BIG
4731 Layout::init_fixed_output_section
<32, true>(
4733 elfcpp::Shdr
<32, true>& shdr
);
4736 #ifdef HAVE_TARGET_64_LITTLE
4739 Layout::init_fixed_output_section
<64, false>(
4741 elfcpp::Shdr
<64, false>& shdr
);
4744 #ifdef HAVE_TARGET_64_BIG
4747 Layout::init_fixed_output_section
<64, true>(
4749 elfcpp::Shdr
<64, true>& shdr
);
4752 #ifdef HAVE_TARGET_32_LITTLE
4755 Layout::layout
<32, false>(Sized_relobj
<32, false>* object
, unsigned int shndx
,
4757 const elfcpp::Shdr
<32, false>& shdr
,
4758 unsigned int, unsigned int, off_t
*);
4761 #ifdef HAVE_TARGET_32_BIG
4764 Layout::layout
<32, true>(Sized_relobj
<32, true>* object
, unsigned int shndx
,
4766 const elfcpp::Shdr
<32, true>& shdr
,
4767 unsigned int, unsigned int, off_t
*);
4770 #ifdef HAVE_TARGET_64_LITTLE
4773 Layout::layout
<64, false>(Sized_relobj
<64, false>* object
, unsigned int shndx
,
4775 const elfcpp::Shdr
<64, false>& shdr
,
4776 unsigned int, unsigned int, off_t
*);
4779 #ifdef HAVE_TARGET_64_BIG
4782 Layout::layout
<64, true>(Sized_relobj
<64, true>* object
, unsigned int shndx
,
4784 const elfcpp::Shdr
<64, true>& shdr
,
4785 unsigned int, unsigned int, off_t
*);
4788 #ifdef HAVE_TARGET_32_LITTLE
4791 Layout::layout_reloc
<32, false>(Sized_relobj
<32, false>* object
,
4792 unsigned int reloc_shndx
,
4793 const elfcpp::Shdr
<32, false>& shdr
,
4794 Output_section
* data_section
,
4795 Relocatable_relocs
* rr
);
4798 #ifdef HAVE_TARGET_32_BIG
4801 Layout::layout_reloc
<32, true>(Sized_relobj
<32, true>* object
,
4802 unsigned int reloc_shndx
,
4803 const elfcpp::Shdr
<32, true>& shdr
,
4804 Output_section
* data_section
,
4805 Relocatable_relocs
* rr
);
4808 #ifdef HAVE_TARGET_64_LITTLE
4811 Layout::layout_reloc
<64, false>(Sized_relobj
<64, false>* object
,
4812 unsigned int reloc_shndx
,
4813 const elfcpp::Shdr
<64, false>& shdr
,
4814 Output_section
* data_section
,
4815 Relocatable_relocs
* rr
);
4818 #ifdef HAVE_TARGET_64_BIG
4821 Layout::layout_reloc
<64, true>(Sized_relobj
<64, true>* object
,
4822 unsigned int reloc_shndx
,
4823 const elfcpp::Shdr
<64, true>& shdr
,
4824 Output_section
* data_section
,
4825 Relocatable_relocs
* rr
);
4828 #ifdef HAVE_TARGET_32_LITTLE
4831 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
4832 Sized_relobj
<32, false>* object
,
4834 const char* group_section_name
,
4835 const char* signature
,
4836 const elfcpp::Shdr
<32, false>& shdr
,
4837 elfcpp::Elf_Word flags
,
4838 std::vector
<unsigned int>* shndxes
);
4841 #ifdef HAVE_TARGET_32_BIG
4844 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
4845 Sized_relobj
<32, true>* object
,
4847 const char* group_section_name
,
4848 const char* signature
,
4849 const elfcpp::Shdr
<32, true>& shdr
,
4850 elfcpp::Elf_Word flags
,
4851 std::vector
<unsigned int>* shndxes
);
4854 #ifdef HAVE_TARGET_64_LITTLE
4857 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
4858 Sized_relobj
<64, false>* object
,
4860 const char* group_section_name
,
4861 const char* signature
,
4862 const elfcpp::Shdr
<64, false>& shdr
,
4863 elfcpp::Elf_Word flags
,
4864 std::vector
<unsigned int>* shndxes
);
4867 #ifdef HAVE_TARGET_64_BIG
4870 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
4871 Sized_relobj
<64, true>* object
,
4873 const char* group_section_name
,
4874 const char* signature
,
4875 const elfcpp::Shdr
<64, true>& shdr
,
4876 elfcpp::Elf_Word flags
,
4877 std::vector
<unsigned int>* shndxes
);
4880 #ifdef HAVE_TARGET_32_LITTLE
4883 Layout::layout_eh_frame
<32, false>(Sized_relobj
<32, false>* object
,
4884 const unsigned char* symbols
,
4886 const unsigned char* symbol_names
,
4887 off_t symbol_names_size
,
4889 const elfcpp::Shdr
<32, false>& shdr
,
4890 unsigned int reloc_shndx
,
4891 unsigned int reloc_type
,
4895 #ifdef HAVE_TARGET_32_BIG
4898 Layout::layout_eh_frame
<32, true>(Sized_relobj
<32, true>* object
,
4899 const unsigned char* symbols
,
4901 const unsigned char* symbol_names
,
4902 off_t symbol_names_size
,
4904 const elfcpp::Shdr
<32, true>& shdr
,
4905 unsigned int reloc_shndx
,
4906 unsigned int reloc_type
,
4910 #ifdef HAVE_TARGET_64_LITTLE
4913 Layout::layout_eh_frame
<64, false>(Sized_relobj
<64, false>* object
,
4914 const unsigned char* symbols
,
4916 const unsigned char* symbol_names
,
4917 off_t symbol_names_size
,
4919 const elfcpp::Shdr
<64, false>& shdr
,
4920 unsigned int reloc_shndx
,
4921 unsigned int reloc_type
,
4925 #ifdef HAVE_TARGET_64_BIG
4928 Layout::layout_eh_frame
<64, true>(Sized_relobj
<64, true>* object
,
4929 const unsigned char* symbols
,
4931 const unsigned char* symbol_names
,
4932 off_t symbol_names_size
,
4934 const elfcpp::Shdr
<64, true>& shdr
,
4935 unsigned int reloc_shndx
,
4936 unsigned int reloc_type
,
4940 } // End namespace gold.