1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010 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.
32 #include "libiberty.h"
36 #include "parameters.h"
40 #include "script-sections.h"
45 #include "compressed_output.h"
46 #include "reduced_debug_output.h"
48 #include "descriptors.h"
50 #include "incremental.h"
56 // Layout::Relaxation_debug_check methods.
58 // Check that sections and special data are in reset states.
59 // We do not save states for Output_sections and special Output_data.
60 // So we check that they have not assigned any addresses or offsets.
61 // clean_up_after_relaxation simply resets their addresses and offsets.
63 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
64 const Layout::Section_list
& sections
,
65 const Layout::Data_list
& special_outputs
)
67 for(Layout::Section_list::const_iterator p
= sections
.begin();
70 gold_assert((*p
)->address_and_file_offset_have_reset_values());
72 for(Layout::Data_list::const_iterator p
= special_outputs
.begin();
73 p
!= special_outputs
.end();
75 gold_assert((*p
)->address_and_file_offset_have_reset_values());
78 // Save information of SECTIONS for checking later.
81 Layout::Relaxation_debug_check::read_sections(
82 const Layout::Section_list
& sections
)
84 for(Layout::Section_list::const_iterator p
= sections
.begin();
88 Output_section
* os
= *p
;
90 info
.output_section
= os
;
91 info
.address
= os
->is_address_valid() ? os
->address() : 0;
92 info
.data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
93 info
.offset
= os
->is_offset_valid()? os
->offset() : -1 ;
94 this->section_infos_
.push_back(info
);
98 // Verify SECTIONS using previously recorded information.
101 Layout::Relaxation_debug_check::verify_sections(
102 const Layout::Section_list
& sections
)
105 for(Layout::Section_list::const_iterator p
= sections
.begin();
109 Output_section
* os
= *p
;
110 uint64_t address
= os
->is_address_valid() ? os
->address() : 0;
111 off_t data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
112 off_t offset
= os
->is_offset_valid()? os
->offset() : -1 ;
114 if (i
>= this->section_infos_
.size())
116 gold_fatal("Section_info of %s missing.\n", os
->name());
118 const Section_info
& info
= this->section_infos_
[i
];
119 if (os
!= info
.output_section
)
120 gold_fatal("Section order changed. Expecting %s but see %s\n",
121 info
.output_section
->name(), os
->name());
122 if (address
!= info
.address
123 || data_size
!= info
.data_size
124 || offset
!= info
.offset
)
125 gold_fatal("Section %s changed.\n", os
->name());
129 // Layout_task_runner methods.
131 // Lay out the sections. This is called after all the input objects
135 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
137 off_t file_size
= this->layout_
->finalize(this->input_objects_
,
142 // Now we know the final size of the output file and we know where
143 // each piece of information goes.
145 if (this->mapfile_
!= NULL
)
147 this->mapfile_
->print_discarded_sections(this->input_objects_
);
148 this->layout_
->print_to_mapfile(this->mapfile_
);
151 Output_file
* of
= new Output_file(parameters
->options().output_file_name());
152 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
153 of
->set_is_temporary();
156 // Queue up the final set of tasks.
157 gold::queue_final_tasks(this->options_
, this->input_objects_
,
158 this->symtab_
, this->layout_
, workqueue
, of
);
163 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
164 : number_of_input_files_(number_of_input_files
),
165 script_options_(script_options
),
173 unattached_section_list_(),
174 special_output_list_(),
175 section_headers_(NULL
),
177 relro_segment_(NULL
),
179 symtab_section_(NULL
),
180 symtab_xindex_(NULL
),
181 dynsym_section_(NULL
),
182 dynsym_xindex_(NULL
),
183 dynamic_section_(NULL
),
184 dynamic_symbol_(NULL
),
186 eh_frame_section_(NULL
),
187 eh_frame_data_(NULL
),
188 added_eh_frame_data_(false),
189 eh_frame_hdr_section_(NULL
),
190 build_id_note_(NULL
),
194 output_file_size_(-1),
195 have_added_input_section_(false),
196 sections_are_attached_(false),
197 input_requires_executable_stack_(false),
198 input_with_gnu_stack_note_(false),
199 input_without_gnu_stack_note_(false),
200 has_static_tls_(false),
201 any_postprocessing_sections_(false),
202 resized_signatures_(false),
203 have_stabstr_section_(false),
204 incremental_inputs_(NULL
),
205 record_output_section_data_from_script_(false),
206 script_output_section_data_list_(),
207 segment_states_(NULL
),
208 relaxation_debug_check_(NULL
)
210 // Make space for more than enough segments for a typical file.
211 // This is just for efficiency--it's OK if we wind up needing more.
212 this->segment_list_
.reserve(12);
214 // We expect two unattached Output_data objects: the file header and
215 // the segment headers.
216 this->special_output_list_
.reserve(2);
218 // Initialize structure needed for an incremental build.
219 if (parameters
->options().incremental())
220 this->incremental_inputs_
= new Incremental_inputs
;
222 // The section name pool is worth optimizing in all cases, because
223 // it is small, but there are often overlaps due to .rel sections.
224 this->namepool_
.set_optimize();
227 // Hash a key we use to look up an output section mapping.
230 Layout::Hash_key::operator()(const Layout::Key
& k
) const
232 return k
.first
+ k
.second
.first
+ k
.second
.second
;
235 // Returns whether the given section is in the list of
236 // debug-sections-used-by-some-version-of-gdb. Currently,
237 // we've checked versions of gdb up to and including 6.7.1.
239 static const char* gdb_sections
[] =
241 // ".debug_aranges", // not used by gdb as of 6.7.1
247 // ".debug_pubnames", // not used by gdb as of 6.7.1
252 static const char* lines_only_debug_sections
[] =
254 // ".debug_aranges", // not used by gdb as of 6.7.1
260 // ".debug_pubnames", // not used by gdb as of 6.7.1
266 is_gdb_debug_section(const char* str
)
268 // We can do this faster: binary search or a hashtable. But why bother?
269 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
270 if (strcmp(str
, gdb_sections
[i
]) == 0)
276 is_lines_only_debug_section(const char* str
)
278 // We can do this faster: binary search or a hashtable. But why bother?
280 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
282 if (strcmp(str
, lines_only_debug_sections
[i
]) == 0)
287 // Whether to include this section in the link.
289 template<int size
, bool big_endian
>
291 Layout::include_section(Sized_relobj
<size
, big_endian
>*, const char* name
,
292 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
294 if (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
)
297 switch (shdr
.get_sh_type())
299 case elfcpp::SHT_NULL
:
300 case elfcpp::SHT_SYMTAB
:
301 case elfcpp::SHT_DYNSYM
:
302 case elfcpp::SHT_HASH
:
303 case elfcpp::SHT_DYNAMIC
:
304 case elfcpp::SHT_SYMTAB_SHNDX
:
307 case elfcpp::SHT_STRTAB
:
308 // Discard the sections which have special meanings in the ELF
309 // ABI. Keep others (e.g., .stabstr). We could also do this by
310 // checking the sh_link fields of the appropriate sections.
311 return (strcmp(name
, ".dynstr") != 0
312 && strcmp(name
, ".strtab") != 0
313 && strcmp(name
, ".shstrtab") != 0);
315 case elfcpp::SHT_RELA
:
316 case elfcpp::SHT_REL
:
317 case elfcpp::SHT_GROUP
:
318 // If we are emitting relocations these should be handled
320 gold_assert(!parameters
->options().relocatable()
321 && !parameters
->options().emit_relocs());
324 case elfcpp::SHT_PROGBITS
:
325 if (parameters
->options().strip_debug()
326 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
328 if (is_debug_info_section(name
))
331 if (parameters
->options().strip_debug_non_line()
332 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
334 // Debugging sections can only be recognized by name.
335 if (is_prefix_of(".debug", name
)
336 && !is_lines_only_debug_section(name
))
339 if (parameters
->options().strip_debug_gdb()
340 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
342 // Debugging sections can only be recognized by name.
343 if (is_prefix_of(".debug", name
)
344 && !is_gdb_debug_section(name
))
347 if (parameters
->options().strip_lto_sections()
348 && !parameters
->options().relocatable()
349 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
351 // Ignore LTO sections containing intermediate code.
352 if (is_prefix_of(".gnu.lto_", name
))
355 // The GNU linker strips .gnu_debuglink sections, so we do too.
356 // This is a feature used to keep debugging information in
358 if (strcmp(name
, ".gnu_debuglink") == 0)
367 // Return an output section named NAME, or NULL if there is none.
370 Layout::find_output_section(const char* name
) const
372 for (Section_list::const_iterator p
= this->section_list_
.begin();
373 p
!= this->section_list_
.end();
375 if (strcmp((*p
)->name(), name
) == 0)
380 // Return an output segment of type TYPE, with segment flags SET set
381 // and segment flags CLEAR clear. Return NULL if there is none.
384 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
385 elfcpp::Elf_Word clear
) const
387 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
388 p
!= this->segment_list_
.end();
390 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
391 && ((*p
)->flags() & set
) == set
392 && ((*p
)->flags() & clear
) == 0)
397 // Return the output section to use for section NAME with type TYPE
398 // and section flags FLAGS. NAME must be canonicalized in the string
399 // pool, and NAME_KEY is the key. IS_INTERP is true if this is the
400 // .interp section. IS_DYNAMIC_LINKER_SECTION is true if this section
401 // is used by the dynamic linker. IS_RELRO is true for a relro
402 // section. IS_LAST_RELRO is true for the last relro section.
403 // IS_FIRST_NON_RELRO is true for the first non-relro section.
406 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
407 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
408 bool is_interp
, bool is_dynamic_linker_section
,
409 bool is_relro
, bool is_last_relro
,
410 bool is_first_non_relro
)
412 elfcpp::Elf_Xword lookup_flags
= flags
;
414 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
415 // read-write with read-only sections. Some other ELF linkers do
416 // not do this. FIXME: Perhaps there should be an option
418 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
420 const Key
key(name_key
, std::make_pair(type
, lookup_flags
));
421 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
422 std::pair
<Section_name_map::iterator
, bool> ins(
423 this->section_name_map_
.insert(v
));
426 return ins
.first
->second
;
429 // This is the first time we've seen this name/type/flags
430 // combination. For compatibility with the GNU linker, we
431 // combine sections with contents and zero flags with sections
432 // with non-zero flags. This is a workaround for cases where
433 // assembler code forgets to set section flags. FIXME: Perhaps
434 // there should be an option to control this.
435 Output_section
* os
= NULL
;
437 if (type
== elfcpp::SHT_PROGBITS
)
441 Output_section
* same_name
= this->find_output_section(name
);
442 if (same_name
!= NULL
443 && same_name
->type() == elfcpp::SHT_PROGBITS
444 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
447 else if ((flags
& elfcpp::SHF_TLS
) == 0)
449 elfcpp::Elf_Xword zero_flags
= 0;
450 const Key
zero_key(name_key
, std::make_pair(type
, zero_flags
));
451 Section_name_map::iterator p
=
452 this->section_name_map_
.find(zero_key
);
453 if (p
!= this->section_name_map_
.end())
459 os
= this->make_output_section(name
, type
, flags
, is_interp
,
460 is_dynamic_linker_section
, is_relro
,
461 is_last_relro
, is_first_non_relro
);
462 ins
.first
->second
= os
;
467 // Pick the output section to use for section NAME, in input file
468 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
469 // linker created section. IS_INPUT_SECTION is true if we are
470 // choosing an output section for an input section found in a input
471 // file. IS_INTERP is true if this is the .interp section.
472 // IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
473 // dynamic linker. IS_RELRO is true for a relro section.
474 // IS_LAST_RELRO is true for the last relro section.
475 // IS_FIRST_NON_RELRO is true for the first non-relro section. This
476 // will return NULL if the input section should be discarded.
479 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
480 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
481 bool is_input_section
, bool is_interp
,
482 bool is_dynamic_linker_section
, bool is_relro
,
483 bool is_last_relro
, bool is_first_non_relro
)
485 // We should not see any input sections after we have attached
486 // sections to segments.
487 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
489 // Some flags in the input section should not be automatically
490 // copied to the output section.
491 flags
&= ~ (elfcpp::SHF_INFO_LINK
492 | elfcpp::SHF_LINK_ORDER
495 | elfcpp::SHF_STRINGS
);
497 if (this->script_options_
->saw_sections_clause())
499 // We are using a SECTIONS clause, so the output section is
500 // chosen based only on the name.
502 Script_sections
* ss
= this->script_options_
->script_sections();
503 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
504 Output_section
** output_section_slot
;
505 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
);
508 // The SECTIONS clause says to discard this input section.
512 // If this is an orphan section--one not mentioned in the linker
513 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
514 // default processing below.
516 if (output_section_slot
!= NULL
)
518 if (*output_section_slot
!= NULL
)
520 (*output_section_slot
)->update_flags_for_input_section(flags
);
521 return *output_section_slot
;
524 // We don't put sections found in the linker script into
525 // SECTION_NAME_MAP_. That keeps us from getting confused
526 // if an orphan section is mapped to a section with the same
527 // name as one in the linker script.
529 name
= this->namepool_
.add(name
, false, NULL
);
532 this->make_output_section(name
, type
, flags
, is_interp
,
533 is_dynamic_linker_section
, is_relro
,
534 is_last_relro
, is_first_non_relro
);
535 os
->set_found_in_sections_clause();
536 *output_section_slot
= os
;
541 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
543 // Turn NAME from the name of the input section into the name of the
546 size_t len
= strlen(name
);
548 && !this->script_options_
->saw_sections_clause()
549 && !parameters
->options().relocatable())
550 name
= Layout::output_section_name(name
, &len
);
552 Stringpool::Key name_key
;
553 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
555 // Find or make the output section. The output section is selected
556 // based on the section name, type, and flags.
557 return this->get_output_section(name
, name_key
, type
, flags
, is_interp
,
558 is_dynamic_linker_section
, is_relro
,
559 is_last_relro
, is_first_non_relro
);
562 // Return the output section to use for input section SHNDX, with name
563 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
564 // index of a relocation section which applies to this section, or 0
565 // if none, or -1U if more than one. RELOC_TYPE is the type of the
566 // relocation section if there is one. Set *OFF to the offset of this
567 // input section without the output section. Return NULL if the
568 // section should be discarded. Set *OFF to -1 if the section
569 // contents should not be written directly to the output file, but
570 // will instead receive special handling.
572 template<int size
, bool big_endian
>
574 Layout::layout(Sized_relobj
<size
, big_endian
>* object
, unsigned int shndx
,
575 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
576 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
580 if (!this->include_section(object
, name
, shdr
))
585 // In a relocatable link a grouped section must not be combined with
586 // any other sections.
587 if (parameters
->options().relocatable()
588 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
590 name
= this->namepool_
.add(name
, true, NULL
);
591 os
= this->make_output_section(name
, shdr
.get_sh_type(),
592 shdr
.get_sh_flags(), false, false,
593 false, false, false);
597 os
= this->choose_output_section(object
, name
, shdr
.get_sh_type(),
598 shdr
.get_sh_flags(), true, false,
599 false, false, false, false);
604 // By default the GNU linker sorts input sections whose names match
605 // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
606 // are sorted by name. This is used to implement constructor
607 // priority ordering. We are compatible.
608 if (!this->script_options_
->saw_sections_clause()
609 && (is_prefix_of(".ctors.", name
)
610 || is_prefix_of(".dtors.", name
)
611 || is_prefix_of(".init_array.", name
)
612 || is_prefix_of(".fini_array.", name
)))
613 os
->set_must_sort_attached_input_sections();
615 // FIXME: Handle SHF_LINK_ORDER somewhere.
617 *off
= os
->add_input_section(object
, shndx
, name
, shdr
, reloc_shndx
,
618 this->script_options_
->saw_sections_clause());
619 this->have_added_input_section_
= true;
624 // Handle a relocation section when doing a relocatable link.
626 template<int size
, bool big_endian
>
628 Layout::layout_reloc(Sized_relobj
<size
, big_endian
>* object
,
630 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
631 Output_section
* data_section
,
632 Relocatable_relocs
* rr
)
634 gold_assert(parameters
->options().relocatable()
635 || parameters
->options().emit_relocs());
637 int sh_type
= shdr
.get_sh_type();
640 if (sh_type
== elfcpp::SHT_REL
)
642 else if (sh_type
== elfcpp::SHT_RELA
)
646 name
+= data_section
->name();
648 Output_section
* os
= this->choose_output_section(object
, name
.c_str(),
652 false, false, false);
654 os
->set_should_link_to_symtab();
655 os
->set_info_section(data_section
);
657 Output_section_data
* posd
;
658 if (sh_type
== elfcpp::SHT_REL
)
660 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
661 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
665 else if (sh_type
== elfcpp::SHT_RELA
)
667 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
668 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
675 os
->add_output_section_data(posd
);
676 rr
->set_output_data(posd
);
681 // Handle a group section when doing a relocatable link.
683 template<int size
, bool big_endian
>
685 Layout::layout_group(Symbol_table
* symtab
,
686 Sized_relobj
<size
, big_endian
>* object
,
688 const char* group_section_name
,
689 const char* signature
,
690 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
691 elfcpp::Elf_Word flags
,
692 std::vector
<unsigned int>* shndxes
)
694 gold_assert(parameters
->options().relocatable());
695 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
696 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
697 Output_section
* os
= this->make_output_section(group_section_name
,
703 // We need to find a symbol with the signature in the symbol table.
704 // If we don't find one now, we need to look again later.
705 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
707 os
->set_info_symndx(sym
);
710 // Reserve some space to minimize reallocations.
711 if (this->group_signatures_
.empty())
712 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
714 // We will wind up using a symbol whose name is the signature.
715 // So just put the signature in the symbol name pool to save it.
716 signature
= symtab
->canonicalize_name(signature
);
717 this->group_signatures_
.push_back(Group_signature(os
, signature
));
720 os
->set_should_link_to_symtab();
723 section_size_type entry_count
=
724 convert_to_section_size_type(shdr
.get_sh_size() / 4);
725 Output_section_data
* posd
=
726 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
728 os
->add_output_section_data(posd
);
731 // Special GNU handling of sections name .eh_frame. They will
732 // normally hold exception frame data as defined by the C++ ABI
733 // (http://codesourcery.com/cxx-abi/).
735 template<int size
, bool big_endian
>
737 Layout::layout_eh_frame(Sized_relobj
<size
, big_endian
>* object
,
738 const unsigned char* symbols
,
740 const unsigned char* symbol_names
,
741 off_t symbol_names_size
,
743 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
744 unsigned int reloc_shndx
, unsigned int reloc_type
,
747 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
);
748 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
750 const char* const name
= ".eh_frame";
751 Output_section
* os
= this->choose_output_section(object
,
753 elfcpp::SHT_PROGBITS
,
756 false, false, false);
760 if (this->eh_frame_section_
== NULL
)
762 this->eh_frame_section_
= os
;
763 this->eh_frame_data_
= new Eh_frame();
765 if (parameters
->options().eh_frame_hdr())
767 Output_section
* hdr_os
=
768 this->choose_output_section(NULL
,
770 elfcpp::SHT_PROGBITS
,
773 false, false, false);
777 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
778 this->eh_frame_data_
);
779 hdr_os
->add_output_section_data(hdr_posd
);
781 hdr_os
->set_after_input_sections();
783 if (!this->script_options_
->saw_phdrs_clause())
785 Output_segment
* hdr_oseg
;
786 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
788 hdr_oseg
->add_output_section(hdr_os
, elfcpp::PF_R
, false);
791 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
796 gold_assert(this->eh_frame_section_
== os
);
798 if (this->eh_frame_data_
->add_ehframe_input_section(object
,
807 os
->update_flags_for_input_section(shdr
.get_sh_flags());
809 // We found a .eh_frame section we are going to optimize, so now
810 // we can add the set of optimized sections to the output
811 // section. We need to postpone adding this until we've found a
812 // section we can optimize so that the .eh_frame section in
813 // crtbegin.o winds up at the start of the output section.
814 if (!this->added_eh_frame_data_
)
816 os
->add_output_section_data(this->eh_frame_data_
);
817 this->added_eh_frame_data_
= true;
823 // We couldn't handle this .eh_frame section for some reason.
824 // Add it as a normal section.
825 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
826 *off
= os
->add_input_section(object
, shndx
, name
, shdr
, reloc_shndx
,
827 saw_sections_clause
);
828 this->have_added_input_section_
= true;
834 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
835 // the output section.
838 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
839 elfcpp::Elf_Xword flags
,
840 Output_section_data
* posd
,
841 bool is_dynamic_linker_section
,
842 bool is_relro
, bool is_last_relro
,
843 bool is_first_non_relro
)
845 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
847 is_dynamic_linker_section
,
848 is_relro
, is_last_relro
,
851 os
->add_output_section_data(posd
);
855 // Map section flags to segment flags.
858 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
860 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
861 if ((flags
& elfcpp::SHF_WRITE
) != 0)
863 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
868 // Sometimes we compress sections. This is typically done for
869 // sections that are not part of normal program execution (such as
870 // .debug_* sections), and where the readers of these sections know
871 // how to deal with compressed sections. This routine doesn't say for
872 // certain whether we'll compress -- it depends on commandline options
873 // as well -- just whether this section is a candidate for compression.
874 // (The Output_compressed_section class decides whether to compress
875 // a given section, and picks the name of the compressed section.)
878 is_compressible_debug_section(const char* secname
)
880 return (strncmp(secname
, ".debug", sizeof(".debug") - 1) == 0);
883 // Make a new Output_section, and attach it to segments as
884 // appropriate. IS_INTERP is true if this is the .interp section.
885 // IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
886 // dynamic linker. IS_RELRO is true if this is a relro section.
887 // IS_LAST_RELRO is true if this is the last relro section.
888 // IS_FIRST_NON_RELRO is true if this is the first non relro section.
891 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
892 elfcpp::Elf_Xword flags
, bool is_interp
,
893 bool is_dynamic_linker_section
, bool is_relro
,
894 bool is_last_relro
, bool is_first_non_relro
)
897 if ((flags
& elfcpp::SHF_ALLOC
) == 0
898 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
899 && is_compressible_debug_section(name
))
900 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
902 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
903 && parameters
->options().strip_debug_non_line()
904 && strcmp(".debug_abbrev", name
) == 0)
906 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
908 if (this->debug_info_
)
909 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
911 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
912 && parameters
->options().strip_debug_non_line()
913 && strcmp(".debug_info", name
) == 0)
915 os
= this->debug_info_
= new Output_reduced_debug_info_section(
917 if (this->debug_abbrev_
)
918 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
922 // FIXME: const_cast is ugly.
923 Target
* target
= const_cast<Target
*>(¶meters
->target());
924 os
= target
->make_output_section(name
, type
, flags
);
929 if (is_dynamic_linker_section
)
930 os
->set_is_dynamic_linker_section();
934 os
->set_is_last_relro();
935 if (is_first_non_relro
)
936 os
->set_is_first_non_relro();
938 parameters
->target().new_output_section(os
);
940 this->section_list_
.push_back(os
);
942 // The GNU linker by default sorts some sections by priority, so we
943 // do the same. We need to know that this might happen before we
944 // attach any input sections.
945 if (!this->script_options_
->saw_sections_clause()
946 && (strcmp(name
, ".ctors") == 0
947 || strcmp(name
, ".dtors") == 0
948 || strcmp(name
, ".init_array") == 0
949 || strcmp(name
, ".fini_array") == 0))
950 os
->set_may_sort_attached_input_sections();
952 // With -z relro, we have to recognize the special sections by name.
953 // There is no other way.
954 if (!this->script_options_
->saw_sections_clause()
955 && parameters
->options().relro()
956 && type
== elfcpp::SHT_PROGBITS
957 && (flags
& elfcpp::SHF_ALLOC
) != 0
958 && (flags
& elfcpp::SHF_WRITE
) != 0)
960 if (strcmp(name
, ".data.rel.ro") == 0)
962 else if (strcmp(name
, ".data.rel.ro.local") == 0)
965 os
->set_is_relro_local();
969 // Check for .stab*str sections, as .stab* sections need to link to
971 if (type
== elfcpp::SHT_STRTAB
972 && !this->have_stabstr_section_
973 && strncmp(name
, ".stab", 5) == 0
974 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
975 this->have_stabstr_section_
= true;
977 // If we have already attached the sections to segments, then we
978 // need to attach this one now. This happens for sections created
979 // directly by the linker.
980 if (this->sections_are_attached_
)
981 this->attach_section_to_segment(os
);
986 // Attach output sections to segments. This is called after we have
987 // seen all the input sections.
990 Layout::attach_sections_to_segments()
992 for (Section_list::iterator p
= this->section_list_
.begin();
993 p
!= this->section_list_
.end();
995 this->attach_section_to_segment(*p
);
997 this->sections_are_attached_
= true;
1000 // Attach an output section to a segment.
1003 Layout::attach_section_to_segment(Output_section
* os
)
1005 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1006 this->unattached_section_list_
.push_back(os
);
1008 this->attach_allocated_section_to_segment(os
);
1011 // Attach an allocated output section to a segment.
1014 Layout::attach_allocated_section_to_segment(Output_section
* os
)
1016 elfcpp::Elf_Xword flags
= os
->flags();
1017 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1019 if (parameters
->options().relocatable())
1022 // If we have a SECTIONS clause, we can't handle the attachment to
1023 // segments until after we've seen all the sections.
1024 if (this->script_options_
->saw_sections_clause())
1027 gold_assert(!this->script_options_
->saw_phdrs_clause());
1029 // This output section goes into a PT_LOAD segment.
1031 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1033 // Check for --section-start.
1035 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1037 // In general the only thing we really care about for PT_LOAD
1038 // segments is whether or not they are writable, so that is how we
1039 // search for them. Large data sections also go into their own
1040 // PT_LOAD segment. People who need segments sorted on some other
1041 // basis will have to use a linker script.
1043 Segment_list::const_iterator p
;
1044 for (p
= this->segment_list_
.begin();
1045 p
!= this->segment_list_
.end();
1048 if ((*p
)->type() != elfcpp::PT_LOAD
)
1050 if (!parameters
->options().omagic()
1051 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1053 // If -Tbss was specified, we need to separate the data and BSS
1055 if (parameters
->options().user_set_Tbss())
1057 if ((os
->type() == elfcpp::SHT_NOBITS
)
1058 == (*p
)->has_any_data_sections())
1061 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1066 if ((*p
)->are_addresses_set())
1069 (*p
)->add_initial_output_data(os
);
1070 (*p
)->update_flags_for_output_section(seg_flags
);
1071 (*p
)->set_addresses(addr
, addr
);
1075 (*p
)->add_output_section(os
, seg_flags
, true);
1079 if (p
== this->segment_list_
.end())
1081 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1083 if (os
->is_large_data_section())
1084 oseg
->set_is_large_data_segment();
1085 oseg
->add_output_section(os
, seg_flags
, true);
1087 oseg
->set_addresses(addr
, addr
);
1090 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1092 if (os
->type() == elfcpp::SHT_NOTE
)
1094 // See if we already have an equivalent PT_NOTE segment.
1095 for (p
= this->segment_list_
.begin();
1096 p
!= segment_list_
.end();
1099 if ((*p
)->type() == elfcpp::PT_NOTE
1100 && (((*p
)->flags() & elfcpp::PF_W
)
1101 == (seg_flags
& elfcpp::PF_W
)))
1103 (*p
)->add_output_section(os
, seg_flags
, false);
1108 if (p
== this->segment_list_
.end())
1110 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1112 oseg
->add_output_section(os
, seg_flags
, false);
1116 // If we see a loadable SHF_TLS section, we create a PT_TLS
1117 // segment. There can only be one such segment.
1118 if ((flags
& elfcpp::SHF_TLS
) != 0)
1120 if (this->tls_segment_
== NULL
)
1121 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1122 this->tls_segment_
->add_output_section(os
, seg_flags
, false);
1125 // If -z relro is in effect, and we see a relro section, we create a
1126 // PT_GNU_RELRO segment. There can only be one such segment.
1127 if (os
->is_relro() && parameters
->options().relro())
1129 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1130 if (this->relro_segment_
== NULL
)
1131 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1132 this->relro_segment_
->add_output_section(os
, seg_flags
, false);
1136 // Make an output section for a script.
1139 Layout::make_output_section_for_script(const char* name
)
1141 name
= this->namepool_
.add(name
, false, NULL
);
1142 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1143 elfcpp::SHF_ALLOC
, false,
1144 false, false, false, false);
1145 os
->set_found_in_sections_clause();
1149 // Return the number of segments we expect to see.
1152 Layout::expected_segment_count() const
1154 size_t ret
= this->segment_list_
.size();
1156 // If we didn't see a SECTIONS clause in a linker script, we should
1157 // already have the complete list of segments. Otherwise we ask the
1158 // SECTIONS clause how many segments it expects, and add in the ones
1159 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1161 if (!this->script_options_
->saw_sections_clause())
1165 const Script_sections
* ss
= this->script_options_
->script_sections();
1166 return ret
+ ss
->expected_segment_count(this);
1170 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
1171 // is whether we saw a .note.GNU-stack section in the object file.
1172 // GNU_STACK_FLAGS is the section flags. The flags give the
1173 // protection required for stack memory. We record this in an
1174 // executable as a PT_GNU_STACK segment. If an object file does not
1175 // have a .note.GNU-stack segment, we must assume that it is an old
1176 // object. On some targets that will force an executable stack.
1179 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
)
1181 if (!seen_gnu_stack
)
1182 this->input_without_gnu_stack_note_
= true;
1185 this->input_with_gnu_stack_note_
= true;
1186 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
1187 this->input_requires_executable_stack_
= true;
1191 // Create automatic note sections.
1194 Layout::create_notes()
1196 this->create_gold_note();
1197 this->create_executable_stack_info();
1198 this->create_build_id();
1201 // Create the dynamic sections which are needed before we read the
1205 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
1207 if (parameters
->doing_static_link())
1210 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
1211 elfcpp::SHT_DYNAMIC
,
1213 | elfcpp::SHF_WRITE
),
1215 true, false, false);
1217 this->dynamic_symbol_
=
1218 symtab
->define_in_output_data("_DYNAMIC", NULL
, Symbol_table::PREDEFINED
,
1219 this->dynamic_section_
, 0, 0,
1220 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
1221 elfcpp::STV_HIDDEN
, 0, false, false);
1223 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
1225 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
1228 // For each output section whose name can be represented as C symbol,
1229 // define __start and __stop symbols for the section. This is a GNU
1233 Layout::define_section_symbols(Symbol_table
* symtab
)
1235 for (Section_list::const_iterator p
= this->section_list_
.begin();
1236 p
!= this->section_list_
.end();
1239 const char* const name
= (*p
)->name();
1240 if (is_cident(name
))
1242 const std::string
name_string(name
);
1243 const std::string
start_name(cident_section_start_prefix
1245 const std::string
stop_name(cident_section_stop_prefix
1248 symtab
->define_in_output_data(start_name
.c_str(),
1250 Symbol_table::PREDEFINED
,
1256 elfcpp::STV_DEFAULT
,
1258 false, // offset_is_from_end
1259 true); // only_if_ref
1261 symtab
->define_in_output_data(stop_name
.c_str(),
1263 Symbol_table::PREDEFINED
,
1269 elfcpp::STV_DEFAULT
,
1271 true, // offset_is_from_end
1272 true); // only_if_ref
1277 // Define symbols for group signatures.
1280 Layout::define_group_signatures(Symbol_table
* symtab
)
1282 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
1283 p
!= this->group_signatures_
.end();
1286 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
1288 p
->section
->set_info_symndx(sym
);
1291 // Force the name of the group section to the group
1292 // signature, and use the group's section symbol as the
1293 // signature symbol.
1294 if (strcmp(p
->section
->name(), p
->signature
) != 0)
1296 const char* name
= this->namepool_
.add(p
->signature
,
1298 p
->section
->set_name(name
);
1300 p
->section
->set_needs_symtab_index();
1301 p
->section
->set_info_section_symndx(p
->section
);
1305 this->group_signatures_
.clear();
1308 // Find the first read-only PT_LOAD segment, creating one if
1312 Layout::find_first_load_seg()
1314 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1315 p
!= this->segment_list_
.end();
1318 if ((*p
)->type() == elfcpp::PT_LOAD
1319 && ((*p
)->flags() & elfcpp::PF_R
) != 0
1320 && (parameters
->options().omagic()
1321 || ((*p
)->flags() & elfcpp::PF_W
) == 0))
1325 gold_assert(!this->script_options_
->saw_phdrs_clause());
1327 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
1332 // Save states of all current output segments. Store saved states
1333 // in SEGMENT_STATES.
1336 Layout::save_segments(Segment_states
* segment_states
)
1338 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1339 p
!= this->segment_list_
.end();
1342 Output_segment
* segment
= *p
;
1344 Output_segment
* copy
= new Output_segment(*segment
);
1345 (*segment_states
)[segment
] = copy
;
1349 // Restore states of output segments and delete any segment not found in
1353 Layout::restore_segments(const Segment_states
* segment_states
)
1355 // Go through the segment list and remove any segment added in the
1357 this->tls_segment_
= NULL
;
1358 this->relro_segment_
= NULL
;
1359 Segment_list::iterator list_iter
= this->segment_list_
.begin();
1360 while (list_iter
!= this->segment_list_
.end())
1362 Output_segment
* segment
= *list_iter
;
1363 Segment_states::const_iterator states_iter
=
1364 segment_states
->find(segment
);
1365 if (states_iter
!= segment_states
->end())
1367 const Output_segment
* copy
= states_iter
->second
;
1368 // Shallow copy to restore states.
1371 // Also fix up TLS and RELRO segment pointers as appropriate.
1372 if (segment
->type() == elfcpp::PT_TLS
)
1373 this->tls_segment_
= segment
;
1374 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
1375 this->relro_segment_
= segment
;
1381 list_iter
= this->segment_list_
.erase(list_iter
);
1382 // This is a segment created during section layout. It should be
1383 // safe to remove it since we should have removed all pointers to it.
1389 // Clean up after relaxation so that sections can be laid out again.
1392 Layout::clean_up_after_relaxation()
1394 // Restore the segments to point state just prior to the relaxation loop.
1395 Script_sections
* script_section
= this->script_options_
->script_sections();
1396 script_section
->release_segments();
1397 this->restore_segments(this->segment_states_
);
1399 // Reset section addresses and file offsets
1400 for (Section_list::iterator p
= this->section_list_
.begin();
1401 p
!= this->section_list_
.end();
1404 (*p
)->restore_states();
1406 // If an input section changes size because of relaxation,
1407 // we need to adjust the section offsets of all input sections.
1408 // after such a section.
1409 if ((*p
)->section_offsets_need_adjustment())
1410 (*p
)->adjust_section_offsets();
1412 (*p
)->reset_address_and_file_offset();
1415 // Reset special output object address and file offsets.
1416 for (Data_list::iterator p
= this->special_output_list_
.begin();
1417 p
!= this->special_output_list_
.end();
1419 (*p
)->reset_address_and_file_offset();
1421 // A linker script may have created some output section data objects.
1422 // They are useless now.
1423 for (Output_section_data_list::const_iterator p
=
1424 this->script_output_section_data_list_
.begin();
1425 p
!= this->script_output_section_data_list_
.end();
1428 this->script_output_section_data_list_
.clear();
1431 // Prepare for relaxation.
1434 Layout::prepare_for_relaxation()
1436 // Create an relaxation debug check if in debugging mode.
1437 if (is_debugging_enabled(DEBUG_RELAXATION
))
1438 this->relaxation_debug_check_
= new Relaxation_debug_check();
1440 // Save segment states.
1441 this->segment_states_
= new Segment_states();
1442 this->save_segments(this->segment_states_
);
1444 for(Section_list::const_iterator p
= this->section_list_
.begin();
1445 p
!= this->section_list_
.end();
1447 (*p
)->save_states();
1449 if (is_debugging_enabled(DEBUG_RELAXATION
))
1450 this->relaxation_debug_check_
->check_output_data_for_reset_values(
1451 this->section_list_
, this->special_output_list_
);
1453 // Also enable recording of output section data from scripts.
1454 this->record_output_section_data_from_script_
= true;
1457 // Relaxation loop body: If target has no relaxation, this runs only once
1458 // Otherwise, the target relaxation hook is called at the end of
1459 // each iteration. If the hook returns true, it means re-layout of
1460 // section is required.
1462 // The number of segments created by a linking script without a PHDRS
1463 // clause may be affected by section sizes and alignments. There is
1464 // a remote chance that relaxation causes different number of PT_LOAD
1465 // segments are created and sections are attached to different segments.
1466 // Therefore, we always throw away all segments created during section
1467 // layout. In order to be able to restart the section layout, we keep
1468 // a copy of the segment list right before the relaxation loop and use
1469 // that to restore the segments.
1471 // PASS is the current relaxation pass number.
1472 // SYMTAB is a symbol table.
1473 // PLOAD_SEG is the address of a pointer for the load segment.
1474 // PHDR_SEG is a pointer to the PHDR segment.
1475 // SEGMENT_HEADERS points to the output segment header.
1476 // FILE_HEADER points to the output file header.
1477 // PSHNDX is the address to store the output section index.
1480 Layout::relaxation_loop_body(
1483 Symbol_table
* symtab
,
1484 Output_segment
** pload_seg
,
1485 Output_segment
* phdr_seg
,
1486 Output_segment_headers
* segment_headers
,
1487 Output_file_header
* file_header
,
1488 unsigned int* pshndx
)
1490 // If this is not the first iteration, we need to clean up after
1491 // relaxation so that we can lay out the sections again.
1493 this->clean_up_after_relaxation();
1495 // If there is a SECTIONS clause, put all the input sections into
1496 // the required order.
1497 Output_segment
* load_seg
;
1498 if (this->script_options_
->saw_sections_clause())
1499 load_seg
= this->set_section_addresses_from_script(symtab
);
1500 else if (parameters
->options().relocatable())
1503 load_seg
= this->find_first_load_seg();
1505 if (parameters
->options().oformat_enum()
1506 != General_options::OBJECT_FORMAT_ELF
)
1509 // If the user set the address of the text segment, that may not be
1510 // compatible with putting the segment headers and file headers into
1512 if (parameters
->options().user_set_Ttext())
1515 gold_assert(phdr_seg
== NULL
1517 || this->script_options_
->saw_sections_clause());
1519 // If the address of the load segment we found has been set by
1520 // --section-start rather than by a script, then we don't want to
1521 // use it for the file and segment headers.
1522 if (load_seg
!= NULL
1523 && load_seg
->are_addresses_set()
1524 && !this->script_options_
->saw_sections_clause())
1527 // Lay out the segment headers.
1528 if (!parameters
->options().relocatable())
1530 gold_assert(segment_headers
!= NULL
);
1531 if (load_seg
!= NULL
)
1532 load_seg
->add_initial_output_data(segment_headers
);
1533 if (phdr_seg
!= NULL
)
1534 phdr_seg
->add_initial_output_data(segment_headers
);
1537 // Lay out the file header.
1538 if (load_seg
!= NULL
)
1539 load_seg
->add_initial_output_data(file_header
);
1541 if (this->script_options_
->saw_phdrs_clause()
1542 && !parameters
->options().relocatable())
1544 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1545 // clause in a linker script.
1546 Script_sections
* ss
= this->script_options_
->script_sections();
1547 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
1550 // We set the output section indexes in set_segment_offsets and
1551 // set_section_indexes.
1554 // Set the file offsets of all the segments, and all the sections
1557 if (!parameters
->options().relocatable())
1558 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
1560 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
1562 // Verify that the dummy relaxation does not change anything.
1563 if (is_debugging_enabled(DEBUG_RELAXATION
))
1566 this->relaxation_debug_check_
->read_sections(this->section_list_
);
1568 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
1571 *pload_seg
= load_seg
;
1575 // Finalize the layout. When this is called, we have created all the
1576 // output sections and all the output segments which are based on
1577 // input sections. We have several things to do, and we have to do
1578 // them in the right order, so that we get the right results correctly
1581 // 1) Finalize the list of output segments and create the segment
1584 // 2) Finalize the dynamic symbol table and associated sections.
1586 // 3) Determine the final file offset of all the output segments.
1588 // 4) Determine the final file offset of all the SHF_ALLOC output
1591 // 5) Create the symbol table sections and the section name table
1594 // 6) Finalize the symbol table: set symbol values to their final
1595 // value and make a final determination of which symbols are going
1596 // into the output symbol table.
1598 // 7) Create the section table header.
1600 // 8) Determine the final file offset of all the output sections which
1601 // are not SHF_ALLOC, including the section table header.
1603 // 9) Finalize the ELF file header.
1605 // This function returns the size of the output file.
1608 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
1609 Target
* target
, const Task
* task
)
1611 target
->finalize_sections(this, input_objects
, symtab
);
1613 this->count_local_symbols(task
, input_objects
);
1615 this->link_stabs_sections();
1617 Output_segment
* phdr_seg
= NULL
;
1618 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
1620 // There was a dynamic object in the link. We need to create
1621 // some information for the dynamic linker.
1623 // Create the PT_PHDR segment which will hold the program
1625 if (!this->script_options_
->saw_phdrs_clause())
1626 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
1628 // Create the dynamic symbol table, including the hash table.
1629 Output_section
* dynstr
;
1630 std::vector
<Symbol
*> dynamic_symbols
;
1631 unsigned int local_dynamic_count
;
1632 Versions
versions(*this->script_options()->version_script_info(),
1634 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
1635 &local_dynamic_count
, &dynamic_symbols
,
1638 // Create the .interp section to hold the name of the
1639 // interpreter, and put it in a PT_INTERP segment.
1640 if (!parameters
->options().shared())
1641 this->create_interp(target
);
1643 // Finish the .dynamic section to hold the dynamic data, and put
1644 // it in a PT_DYNAMIC segment.
1645 this->finish_dynamic_section(input_objects
, symtab
);
1647 // We should have added everything we need to the dynamic string
1649 this->dynpool_
.set_string_offsets();
1651 // Create the version sections. We can't do this until the
1652 // dynamic string table is complete.
1653 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
1654 dynamic_symbols
, dynstr
);
1656 // Set the size of the _DYNAMIC symbol. We can't do this until
1657 // after we call create_version_sections.
1658 this->set_dynamic_symbol_size(symtab
);
1661 if (this->incremental_inputs_
)
1663 this->incremental_inputs_
->finalize();
1664 this->create_incremental_info_sections();
1667 // Create segment headers.
1668 Output_segment_headers
* segment_headers
=
1669 (parameters
->options().relocatable()
1671 : new Output_segment_headers(this->segment_list_
));
1673 // Lay out the file header.
1674 Output_file_header
* file_header
1675 = new Output_file_header(target
, symtab
, segment_headers
,
1676 parameters
->options().entry());
1678 this->special_output_list_
.push_back(file_header
);
1679 if (segment_headers
!= NULL
)
1680 this->special_output_list_
.push_back(segment_headers
);
1682 // Find approriate places for orphan output sections if we are using
1684 if (this->script_options_
->saw_sections_clause())
1685 this->place_orphan_sections_in_script();
1687 Output_segment
* load_seg
;
1692 // Take a snapshot of the section layout as needed.
1693 if (target
->may_relax())
1694 this->prepare_for_relaxation();
1696 // Run the relaxation loop to lay out sections.
1699 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
1700 phdr_seg
, segment_headers
, file_header
,
1704 while (target
->may_relax()
1705 && target
->relax(pass
, input_objects
, symtab
, this));
1707 // Set the file offsets of all the non-data sections we've seen so
1708 // far which don't have to wait for the input sections. We need
1709 // this in order to finalize local symbols in non-allocated
1711 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
1713 // Set the section indexes of all unallocated sections seen so far,
1714 // in case any of them are somehow referenced by a symbol.
1715 shndx
= this->set_section_indexes(shndx
);
1717 // Create the symbol table sections.
1718 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
1719 if (!parameters
->doing_static_link())
1720 this->assign_local_dynsym_offsets(input_objects
);
1722 // Process any symbol assignments from a linker script. This must
1723 // be called after the symbol table has been finalized.
1724 this->script_options_
->finalize_symbols(symtab
, this);
1726 // Create the .shstrtab section.
1727 Output_section
* shstrtab_section
= this->create_shstrtab();
1729 // Set the file offsets of the rest of the non-data sections which
1730 // don't have to wait for the input sections.
1731 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
1733 // Now that all sections have been created, set the section indexes
1734 // for any sections which haven't been done yet.
1735 shndx
= this->set_section_indexes(shndx
);
1737 // Create the section table header.
1738 this->create_shdrs(shstrtab_section
, &off
);
1740 // If there are no sections which require postprocessing, we can
1741 // handle the section names now, and avoid a resize later.
1742 if (!this->any_postprocessing_sections_
)
1743 off
= this->set_section_offsets(off
,
1744 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
1746 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
1748 // Now we know exactly where everything goes in the output file
1749 // (except for non-allocated sections which require postprocessing).
1750 Output_data::layout_complete();
1752 this->output_file_size_
= off
;
1757 // Create a note header following the format defined in the ELF ABI.
1758 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
1759 // of the section to create, DESCSZ is the size of the descriptor.
1760 // ALLOCATE is true if the section should be allocated in memory.
1761 // This returns the new note section. It sets *TRAILING_PADDING to
1762 // the number of trailing zero bytes required.
1765 Layout::create_note(const char* name
, int note_type
,
1766 const char* section_name
, size_t descsz
,
1767 bool allocate
, size_t* trailing_padding
)
1769 // Authorities all agree that the values in a .note field should
1770 // be aligned on 4-byte boundaries for 32-bit binaries. However,
1771 // they differ on what the alignment is for 64-bit binaries.
1772 // The GABI says unambiguously they take 8-byte alignment:
1773 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
1774 // Other documentation says alignment should always be 4 bytes:
1775 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
1776 // GNU ld and GNU readelf both support the latter (at least as of
1777 // version 2.16.91), and glibc always generates the latter for
1778 // .note.ABI-tag (as of version 1.6), so that's the one we go with
1780 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
1781 const int size
= parameters
->target().get_size();
1783 const int size
= 32;
1786 // The contents of the .note section.
1787 size_t namesz
= strlen(name
) + 1;
1788 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
1789 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
1791 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
1793 unsigned char* buffer
= new unsigned char[notehdrsz
];
1794 memset(buffer
, 0, notehdrsz
);
1796 bool is_big_endian
= parameters
->target().is_big_endian();
1802 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
1803 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
1804 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
1808 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
1809 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
1810 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
1813 else if (size
== 64)
1817 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
1818 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
1819 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
1823 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
1824 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
1825 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
1831 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
1833 elfcpp::Elf_Xword flags
= 0;
1835 flags
= elfcpp::SHF_ALLOC
;
1836 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
1838 flags
, false, false,
1839 false, false, false, false);
1843 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
1846 os
->add_output_section_data(posd
);
1848 *trailing_padding
= aligned_descsz
- descsz
;
1853 // For an executable or shared library, create a note to record the
1854 // version of gold used to create the binary.
1857 Layout::create_gold_note()
1859 if (parameters
->options().relocatable())
1862 std::string desc
= std::string("gold ") + gold::get_version_string();
1864 size_t trailing_padding
;
1865 Output_section
*os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
1866 ".note.gnu.gold-version", desc
.size(),
1867 false, &trailing_padding
);
1871 Output_section_data
* posd
= new Output_data_const(desc
, 4);
1872 os
->add_output_section_data(posd
);
1874 if (trailing_padding
> 0)
1876 posd
= new Output_data_zero_fill(trailing_padding
, 0);
1877 os
->add_output_section_data(posd
);
1881 // Record whether the stack should be executable. This can be set
1882 // from the command line using the -z execstack or -z noexecstack
1883 // options. Otherwise, if any input file has a .note.GNU-stack
1884 // section with the SHF_EXECINSTR flag set, the stack should be
1885 // executable. Otherwise, if at least one input file a
1886 // .note.GNU-stack section, and some input file has no .note.GNU-stack
1887 // section, we use the target default for whether the stack should be
1888 // executable. Otherwise, we don't generate a stack note. When
1889 // generating a object file, we create a .note.GNU-stack section with
1890 // the appropriate marking. When generating an executable or shared
1891 // library, we create a PT_GNU_STACK segment.
1894 Layout::create_executable_stack_info()
1896 bool is_stack_executable
;
1897 if (parameters
->options().is_execstack_set())
1898 is_stack_executable
= parameters
->options().is_stack_executable();
1899 else if (!this->input_with_gnu_stack_note_
)
1903 if (this->input_requires_executable_stack_
)
1904 is_stack_executable
= true;
1905 else if (this->input_without_gnu_stack_note_
)
1906 is_stack_executable
=
1907 parameters
->target().is_default_stack_executable();
1909 is_stack_executable
= false;
1912 if (parameters
->options().relocatable())
1914 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
1915 elfcpp::Elf_Xword flags
= 0;
1916 if (is_stack_executable
)
1917 flags
|= elfcpp::SHF_EXECINSTR
;
1918 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
, false,
1919 false, false, false, false);
1923 if (this->script_options_
->saw_phdrs_clause())
1925 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
1926 if (is_stack_executable
)
1927 flags
|= elfcpp::PF_X
;
1928 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
1932 // If --build-id was used, set up the build ID note.
1935 Layout::create_build_id()
1937 if (!parameters
->options().user_set_build_id())
1940 const char* style
= parameters
->options().build_id();
1941 if (strcmp(style
, "none") == 0)
1944 // Set DESCSZ to the size of the note descriptor. When possible,
1945 // set DESC to the note descriptor contents.
1948 if (strcmp(style
, "md5") == 0)
1950 else if (strcmp(style
, "sha1") == 0)
1952 else if (strcmp(style
, "uuid") == 0)
1954 const size_t uuidsz
= 128 / 8;
1956 char buffer
[uuidsz
];
1957 memset(buffer
, 0, uuidsz
);
1959 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
1961 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
1965 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
1966 release_descriptor(descriptor
, true);
1968 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
1969 else if (static_cast<size_t>(got
) != uuidsz
)
1970 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
1974 desc
.assign(buffer
, uuidsz
);
1977 else if (strncmp(style
, "0x", 2) == 0)
1980 const char* p
= style
+ 2;
1983 if (hex_p(p
[0]) && hex_p(p
[1]))
1985 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
1989 else if (*p
== '-' || *p
== ':')
1992 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
1995 descsz
= desc
.size();
1998 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2001 size_t trailing_padding
;
2002 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2003 ".note.gnu.build-id", descsz
, true,
2010 // We know the value already, so we fill it in now.
2011 gold_assert(desc
.size() == descsz
);
2013 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2014 os
->add_output_section_data(posd
);
2016 if (trailing_padding
!= 0)
2018 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2019 os
->add_output_section_data(posd
);
2024 // We need to compute a checksum after we have completed the
2026 gold_assert(trailing_padding
== 0);
2027 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
2028 os
->add_output_section_data(this->build_id_note_
);
2032 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2033 // field of the former should point to the latter. I'm not sure who
2034 // started this, but the GNU linker does it, and some tools depend
2038 Layout::link_stabs_sections()
2040 if (!this->have_stabstr_section_
)
2043 for (Section_list::iterator p
= this->section_list_
.begin();
2044 p
!= this->section_list_
.end();
2047 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
2050 const char* name
= (*p
)->name();
2051 if (strncmp(name
, ".stab", 5) != 0)
2054 size_t len
= strlen(name
);
2055 if (strcmp(name
+ len
- 3, "str") != 0)
2058 std::string
stab_name(name
, len
- 3);
2059 Output_section
* stab_sec
;
2060 stab_sec
= this->find_output_section(stab_name
.c_str());
2061 if (stab_sec
!= NULL
)
2062 stab_sec
->set_link_section(*p
);
2066 // Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
2067 // for the next run of incremental linking to check what has changed.
2070 Layout::create_incremental_info_sections()
2072 gold_assert(this->incremental_inputs_
!= NULL
);
2074 // Add the .gnu_incremental_inputs section.
2075 const char *incremental_inputs_name
=
2076 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
2077 Output_section
* inputs_os
=
2078 this->make_output_section(incremental_inputs_name
,
2079 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
2080 false, false, false, false, false);
2081 Output_section_data
* posd
=
2082 this->incremental_inputs_
->create_incremental_inputs_section_data();
2083 inputs_os
->add_output_section_data(posd
);
2085 // Add the .gnu_incremental_strtab section.
2086 const char *incremental_strtab_name
=
2087 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
2088 Output_section
* strtab_os
= this->make_output_section(incremental_strtab_name
,
2091 false, false, false);
2092 Output_data_strtab
* strtab_data
=
2093 new Output_data_strtab(this->incremental_inputs_
->get_stringpool());
2094 strtab_os
->add_output_section_data(strtab_data
);
2096 inputs_os
->set_link_section(strtab_data
);
2099 // Return whether SEG1 should be before SEG2 in the output file. This
2100 // is based entirely on the segment type and flags. When this is
2101 // called the segment addresses has normally not yet been set.
2104 Layout::segment_precedes(const Output_segment
* seg1
,
2105 const Output_segment
* seg2
)
2107 elfcpp::Elf_Word type1
= seg1
->type();
2108 elfcpp::Elf_Word type2
= seg2
->type();
2110 // The single PT_PHDR segment is required to precede any loadable
2111 // segment. We simply make it always first.
2112 if (type1
== elfcpp::PT_PHDR
)
2114 gold_assert(type2
!= elfcpp::PT_PHDR
);
2117 if (type2
== elfcpp::PT_PHDR
)
2120 // The single PT_INTERP segment is required to precede any loadable
2121 // segment. We simply make it always second.
2122 if (type1
== elfcpp::PT_INTERP
)
2124 gold_assert(type2
!= elfcpp::PT_INTERP
);
2127 if (type2
== elfcpp::PT_INTERP
)
2130 // We then put PT_LOAD segments before any other segments.
2131 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
2133 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
2136 // We put the PT_TLS segment last except for the PT_GNU_RELRO
2137 // segment, because that is where the dynamic linker expects to find
2138 // it (this is just for efficiency; other positions would also work
2140 if (type1
== elfcpp::PT_TLS
2141 && type2
!= elfcpp::PT_TLS
2142 && type2
!= elfcpp::PT_GNU_RELRO
)
2144 if (type2
== elfcpp::PT_TLS
2145 && type1
!= elfcpp::PT_TLS
2146 && type1
!= elfcpp::PT_GNU_RELRO
)
2149 // We put the PT_GNU_RELRO segment last, because that is where the
2150 // dynamic linker expects to find it (as with PT_TLS, this is just
2152 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
2154 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
2157 const elfcpp::Elf_Word flags1
= seg1
->flags();
2158 const elfcpp::Elf_Word flags2
= seg2
->flags();
2160 // The order of non-PT_LOAD segments is unimportant. We simply sort
2161 // by the numeric segment type and flags values. There should not
2162 // be more than one segment with the same type and flags.
2163 if (type1
!= elfcpp::PT_LOAD
)
2166 return type1
< type2
;
2167 gold_assert(flags1
!= flags2
);
2168 return flags1
< flags2
;
2171 // If the addresses are set already, sort by load address.
2172 if (seg1
->are_addresses_set())
2174 if (!seg2
->are_addresses_set())
2177 unsigned int section_count1
= seg1
->output_section_count();
2178 unsigned int section_count2
= seg2
->output_section_count();
2179 if (section_count1
== 0 && section_count2
> 0)
2181 if (section_count1
> 0 && section_count2
== 0)
2184 uint64_t paddr1
= seg1
->first_section_load_address();
2185 uint64_t paddr2
= seg2
->first_section_load_address();
2186 if (paddr1
!= paddr2
)
2187 return paddr1
< paddr2
;
2189 else if (seg2
->are_addresses_set())
2192 // A segment which holds large data comes after a segment which does
2193 // not hold large data.
2194 if (seg1
->is_large_data_segment())
2196 if (!seg2
->is_large_data_segment())
2199 else if (seg2
->is_large_data_segment())
2202 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
2203 // segments come before writable segments. Then writable segments
2204 // with data come before writable segments without data. Then
2205 // executable segments come before non-executable segments. Then
2206 // the unlikely case of a non-readable segment comes before the
2207 // normal case of a readable segment. If there are multiple
2208 // segments with the same type and flags, we require that the
2209 // address be set, and we sort by virtual address and then physical
2211 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
2212 return (flags1
& elfcpp::PF_W
) == 0;
2213 if ((flags1
& elfcpp::PF_W
) != 0
2214 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
2215 return seg1
->has_any_data_sections();
2216 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
2217 return (flags1
& elfcpp::PF_X
) != 0;
2218 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
2219 return (flags1
& elfcpp::PF_R
) == 0;
2221 // We shouldn't get here--we shouldn't create segments which we
2222 // can't distinguish.
2226 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2229 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
2231 uint64_t unsigned_off
= off
;
2232 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
2233 | (addr
& (abi_pagesize
- 1)));
2234 if (aligned_off
< unsigned_off
)
2235 aligned_off
+= abi_pagesize
;
2239 // Set the file offsets of all the segments, and all the sections they
2240 // contain. They have all been created. LOAD_SEG must be be laid out
2241 // first. Return the offset of the data to follow.
2244 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
2245 unsigned int *pshndx
)
2247 // Sort them into the final order.
2248 std::sort(this->segment_list_
.begin(), this->segment_list_
.end(),
2249 Layout::Compare_segments());
2251 // Find the PT_LOAD segments, and set their addresses and offsets
2252 // and their section's addresses and offsets.
2254 if (parameters
->options().user_set_Ttext())
2255 addr
= parameters
->options().Ttext();
2256 else if (parameters
->options().output_is_position_independent())
2259 addr
= target
->default_text_segment_address();
2262 // If LOAD_SEG is NULL, then the file header and segment headers
2263 // will not be loadable. But they still need to be at offset 0 in
2264 // the file. Set their offsets now.
2265 if (load_seg
== NULL
)
2267 for (Data_list::iterator p
= this->special_output_list_
.begin();
2268 p
!= this->special_output_list_
.end();
2271 off
= align_address(off
, (*p
)->addralign());
2272 (*p
)->set_address_and_file_offset(0, off
);
2273 off
+= (*p
)->data_size();
2277 unsigned int increase_relro
= this->increase_relro_
;
2278 if (this->script_options_
->saw_sections_clause())
2281 const bool check_sections
= parameters
->options().check_sections();
2282 Output_segment
* last_load_segment
= NULL
;
2284 bool was_readonly
= false;
2285 for (Segment_list::iterator p
= this->segment_list_
.begin();
2286 p
!= this->segment_list_
.end();
2289 if ((*p
)->type() == elfcpp::PT_LOAD
)
2291 if (load_seg
!= NULL
&& load_seg
!= *p
)
2295 bool are_addresses_set
= (*p
)->are_addresses_set();
2296 if (are_addresses_set
)
2298 // When it comes to setting file offsets, we care about
2299 // the physical address.
2300 addr
= (*p
)->paddr();
2302 else if (parameters
->options().user_set_Tdata()
2303 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2304 && (!parameters
->options().user_set_Tbss()
2305 || (*p
)->has_any_data_sections()))
2307 addr
= parameters
->options().Tdata();
2308 are_addresses_set
= true;
2310 else if (parameters
->options().user_set_Tbss()
2311 && ((*p
)->flags() & elfcpp::PF_W
) != 0
2312 && !(*p
)->has_any_data_sections())
2314 addr
= parameters
->options().Tbss();
2315 are_addresses_set
= true;
2318 uint64_t orig_addr
= addr
;
2319 uint64_t orig_off
= off
;
2321 uint64_t aligned_addr
= 0;
2322 uint64_t abi_pagesize
= target
->abi_pagesize();
2323 uint64_t common_pagesize
= target
->common_pagesize();
2325 if (!parameters
->options().nmagic()
2326 && !parameters
->options().omagic())
2327 (*p
)->set_minimum_p_align(common_pagesize
);
2329 if (!are_addresses_set
)
2331 // If the last segment was readonly, and this one is
2332 // not, then skip the address forward one page,
2333 // maintaining the same position within the page. This
2334 // lets us store both segments overlapping on a single
2335 // page in the file, but the loader will put them on
2336 // different pages in memory.
2338 addr
= align_address(addr
, (*p
)->maximum_alignment());
2339 aligned_addr
= addr
;
2341 if (was_readonly
&& ((*p
)->flags() & elfcpp::PF_W
) != 0)
2343 if ((addr
& (abi_pagesize
- 1)) != 0)
2344 addr
= addr
+ abi_pagesize
;
2347 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2350 if (!parameters
->options().nmagic()
2351 && !parameters
->options().omagic())
2352 off
= align_file_offset(off
, addr
, abi_pagesize
);
2353 else if (load_seg
== NULL
)
2355 // This is -N or -n with a section script which prevents
2356 // us from using a load segment. We need to ensure that
2357 // the file offset is aligned to the alignment of the
2358 // segment. This is because the linker script
2359 // implicitly assumed a zero offset. If we don't align
2360 // here, then the alignment of the sections in the
2361 // linker script may not match the alignment of the
2362 // sections in the set_section_addresses call below,
2363 // causing an error about dot moving backward.
2364 off
= align_address(off
, (*p
)->maximum_alignment());
2367 unsigned int shndx_hold
= *pshndx
;
2368 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
2372 // Now that we know the size of this segment, we may be able
2373 // to save a page in memory, at the cost of wasting some
2374 // file space, by instead aligning to the start of a new
2375 // page. Here we use the real machine page size rather than
2376 // the ABI mandated page size.
2378 if (!are_addresses_set
&& aligned_addr
!= addr
)
2380 uint64_t first_off
= (common_pagesize
2382 & (common_pagesize
- 1)));
2383 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
2386 && ((aligned_addr
& ~ (common_pagesize
- 1))
2387 != (new_addr
& ~ (common_pagesize
- 1)))
2388 && first_off
+ last_off
<= common_pagesize
)
2390 *pshndx
= shndx_hold
;
2391 addr
= align_address(aligned_addr
, common_pagesize
);
2392 addr
= align_address(addr
, (*p
)->maximum_alignment());
2393 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
2394 off
= align_file_offset(off
, addr
, abi_pagesize
);
2395 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
2403 if (((*p
)->flags() & elfcpp::PF_W
) == 0)
2404 was_readonly
= true;
2406 // Implement --check-sections. We know that the segments
2407 // are sorted by LMA.
2408 if (check_sections
&& last_load_segment
!= NULL
)
2410 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
2411 if (last_load_segment
->paddr() + last_load_segment
->memsz()
2414 unsigned long long lb1
= last_load_segment
->paddr();
2415 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
2416 unsigned long long lb2
= (*p
)->paddr();
2417 unsigned long long le2
= lb2
+ (*p
)->memsz();
2418 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
2419 "[0x%llx -> 0x%llx]"),
2420 lb1
, le1
, lb2
, le2
);
2423 last_load_segment
= *p
;
2427 // Handle the non-PT_LOAD segments, setting their offsets from their
2428 // section's offsets.
2429 for (Segment_list::iterator p
= this->segment_list_
.begin();
2430 p
!= this->segment_list_
.end();
2433 if ((*p
)->type() != elfcpp::PT_LOAD
)
2434 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
2439 // Set the TLS offsets for each section in the PT_TLS segment.
2440 if (this->tls_segment_
!= NULL
)
2441 this->tls_segment_
->set_tls_offsets();
2446 // Set the offsets of all the allocated sections when doing a
2447 // relocatable link. This does the same jobs as set_segment_offsets,
2448 // only for a relocatable link.
2451 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
2452 unsigned int *pshndx
)
2456 file_header
->set_address_and_file_offset(0, 0);
2457 off
+= file_header
->data_size();
2459 for (Section_list::iterator p
= this->section_list_
.begin();
2460 p
!= this->section_list_
.end();
2463 // We skip unallocated sections here, except that group sections
2464 // have to come first.
2465 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
2466 && (*p
)->type() != elfcpp::SHT_GROUP
)
2469 off
= align_address(off
, (*p
)->addralign());
2471 // The linker script might have set the address.
2472 if (!(*p
)->is_address_valid())
2473 (*p
)->set_address(0);
2474 (*p
)->set_file_offset(off
);
2475 (*p
)->finalize_data_size();
2476 off
+= (*p
)->data_size();
2478 (*p
)->set_out_shndx(*pshndx
);
2485 // Set the file offset of all the sections not associated with a
2489 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
2491 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
2492 p
!= this->unattached_section_list_
.end();
2495 // The symtab section is handled in create_symtab_sections.
2496 if (*p
== this->symtab_section_
)
2499 // If we've already set the data size, don't set it again.
2500 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
2503 if (pass
== BEFORE_INPUT_SECTIONS_PASS
2504 && (*p
)->requires_postprocessing())
2506 (*p
)->create_postprocessing_buffer();
2507 this->any_postprocessing_sections_
= true;
2510 if (pass
== BEFORE_INPUT_SECTIONS_PASS
2511 && (*p
)->after_input_sections())
2513 else if (pass
== POSTPROCESSING_SECTIONS_PASS
2514 && (!(*p
)->after_input_sections()
2515 || (*p
)->type() == elfcpp::SHT_STRTAB
))
2517 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
2518 && (!(*p
)->after_input_sections()
2519 || (*p
)->type() != elfcpp::SHT_STRTAB
))
2522 off
= align_address(off
, (*p
)->addralign());
2523 (*p
)->set_file_offset(off
);
2524 (*p
)->finalize_data_size();
2525 off
+= (*p
)->data_size();
2527 // At this point the name must be set.
2528 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
2529 this->namepool_
.add((*p
)->name(), false, NULL
);
2534 // Set the section indexes of all the sections not associated with a
2538 Layout::set_section_indexes(unsigned int shndx
)
2540 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
2541 p
!= this->unattached_section_list_
.end();
2544 if (!(*p
)->has_out_shndx())
2546 (*p
)->set_out_shndx(shndx
);
2553 // Set the section addresses according to the linker script. This is
2554 // only called when we see a SECTIONS clause. This returns the
2555 // program segment which should hold the file header and segment
2556 // headers, if any. It will return NULL if they should not be in a
2560 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
2562 Script_sections
* ss
= this->script_options_
->script_sections();
2563 gold_assert(ss
->saw_sections_clause());
2564 return this->script_options_
->set_section_addresses(symtab
, this);
2567 // Place the orphan sections in the linker script.
2570 Layout::place_orphan_sections_in_script()
2572 Script_sections
* ss
= this->script_options_
->script_sections();
2573 gold_assert(ss
->saw_sections_clause());
2575 // Place each orphaned output section in the script.
2576 for (Section_list::iterator p
= this->section_list_
.begin();
2577 p
!= this->section_list_
.end();
2580 if (!(*p
)->found_in_sections_clause())
2581 ss
->place_orphan(*p
);
2585 // Count the local symbols in the regular symbol table and the dynamic
2586 // symbol table, and build the respective string pools.
2589 Layout::count_local_symbols(const Task
* task
,
2590 const Input_objects
* input_objects
)
2592 // First, figure out an upper bound on the number of symbols we'll
2593 // be inserting into each pool. This helps us create the pools with
2594 // the right size, to avoid unnecessary hashtable resizing.
2595 unsigned int symbol_count
= 0;
2596 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2597 p
!= input_objects
->relobj_end();
2599 symbol_count
+= (*p
)->local_symbol_count();
2601 // Go from "upper bound" to "estimate." We overcount for two
2602 // reasons: we double-count symbols that occur in more than one
2603 // object file, and we count symbols that are dropped from the
2604 // output. Add it all together and assume we overcount by 100%.
2607 // We assume all symbols will go into both the sympool and dynpool.
2608 this->sympool_
.reserve(symbol_count
);
2609 this->dynpool_
.reserve(symbol_count
);
2611 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2612 p
!= input_objects
->relobj_end();
2615 Task_lock_obj
<Object
> tlo(task
, *p
);
2616 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
2620 // Create the symbol table sections. Here we also set the final
2621 // values of the symbols. At this point all the loadable sections are
2622 // fully laid out. SHNUM is the number of sections so far.
2625 Layout::create_symtab_sections(const Input_objects
* input_objects
,
2626 Symbol_table
* symtab
,
2632 if (parameters
->target().get_size() == 32)
2634 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
2637 else if (parameters
->target().get_size() == 64)
2639 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
2646 off
= align_address(off
, align
);
2647 off_t startoff
= off
;
2649 // Save space for the dummy symbol at the start of the section. We
2650 // never bother to write this out--it will just be left as zero.
2652 unsigned int local_symbol_index
= 1;
2654 // Add STT_SECTION symbols for each Output section which needs one.
2655 for (Section_list::iterator p
= this->section_list_
.begin();
2656 p
!= this->section_list_
.end();
2659 if (!(*p
)->needs_symtab_index())
2660 (*p
)->set_symtab_index(-1U);
2663 (*p
)->set_symtab_index(local_symbol_index
);
2664 ++local_symbol_index
;
2669 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2670 p
!= input_objects
->relobj_end();
2673 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
2675 off
+= (index
- local_symbol_index
) * symsize
;
2676 local_symbol_index
= index
;
2679 unsigned int local_symcount
= local_symbol_index
;
2680 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
- startoff
);
2683 size_t dyn_global_index
;
2685 if (this->dynsym_section_
== NULL
)
2688 dyn_global_index
= 0;
2693 dyn_global_index
= this->dynsym_section_
->info();
2694 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
2695 dynoff
= this->dynsym_section_
->offset() + locsize
;
2696 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
2697 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
2698 == this->dynsym_section_
->data_size() - locsize
);
2701 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
2702 &this->sympool_
, &local_symcount
);
2704 if (!parameters
->options().strip_all())
2706 this->sympool_
.set_string_offsets();
2708 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
2709 Output_section
* osymtab
= this->make_output_section(symtab_name
,
2712 false, false, false);
2713 this->symtab_section_
= osymtab
;
2715 Output_section_data
* pos
= new Output_data_fixed_space(off
- startoff
,
2718 osymtab
->add_output_section_data(pos
);
2720 // We generate a .symtab_shndx section if we have more than
2721 // SHN_LORESERVE sections. Technically it is possible that we
2722 // don't need one, because it is possible that there are no
2723 // symbols in any of sections with indexes larger than
2724 // SHN_LORESERVE. That is probably unusual, though, and it is
2725 // easier to always create one than to compute section indexes
2726 // twice (once here, once when writing out the symbols).
2727 if (shnum
>= elfcpp::SHN_LORESERVE
)
2729 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
2731 Output_section
* osymtab_xindex
=
2732 this->make_output_section(symtab_xindex_name
,
2733 elfcpp::SHT_SYMTAB_SHNDX
, 0, false,
2734 false, false, false, false);
2736 size_t symcount
= (off
- startoff
) / symsize
;
2737 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
2739 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
2741 osymtab_xindex
->set_link_section(osymtab
);
2742 osymtab_xindex
->set_addralign(4);
2743 osymtab_xindex
->set_entsize(4);
2745 osymtab_xindex
->set_after_input_sections();
2747 // This tells the driver code to wait until the symbol table
2748 // has written out before writing out the postprocessing
2749 // sections, including the .symtab_shndx section.
2750 this->any_postprocessing_sections_
= true;
2753 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
2754 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
2757 false, false, false);
2759 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
2760 ostrtab
->add_output_section_data(pstr
);
2762 osymtab
->set_file_offset(startoff
);
2763 osymtab
->finalize_data_size();
2764 osymtab
->set_link_section(ostrtab
);
2765 osymtab
->set_info(local_symcount
);
2766 osymtab
->set_entsize(symsize
);
2772 // Create the .shstrtab section, which holds the names of the
2773 // sections. At the time this is called, we have created all the
2774 // output sections except .shstrtab itself.
2777 Layout::create_shstrtab()
2779 // FIXME: We don't need to create a .shstrtab section if we are
2780 // stripping everything.
2782 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
2784 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
2785 false, false, false, false,
2788 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
2790 // We can't write out this section until we've set all the
2791 // section names, and we don't set the names of compressed
2792 // output sections until relocations are complete. FIXME: With
2793 // the current names we use, this is unnecessary.
2794 os
->set_after_input_sections();
2797 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
2798 os
->add_output_section_data(posd
);
2803 // Create the section headers. SIZE is 32 or 64. OFF is the file
2807 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
2809 Output_section_headers
* oshdrs
;
2810 oshdrs
= new Output_section_headers(this,
2811 &this->segment_list_
,
2812 &this->section_list_
,
2813 &this->unattached_section_list_
,
2816 off_t off
= align_address(*poff
, oshdrs
->addralign());
2817 oshdrs
->set_address_and_file_offset(0, off
);
2818 off
+= oshdrs
->data_size();
2820 this->section_headers_
= oshdrs
;
2823 // Count the allocated sections.
2826 Layout::allocated_output_section_count() const
2828 size_t section_count
= 0;
2829 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2830 p
!= this->segment_list_
.end();
2832 section_count
+= (*p
)->output_section_count();
2833 return section_count
;
2836 // Create the dynamic symbol table.
2839 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
2840 Symbol_table
* symtab
,
2841 Output_section
**pdynstr
,
2842 unsigned int* plocal_dynamic_count
,
2843 std::vector
<Symbol
*>* pdynamic_symbols
,
2844 Versions
* pversions
)
2846 // Count all the symbols in the dynamic symbol table, and set the
2847 // dynamic symbol indexes.
2849 // Skip symbol 0, which is always all zeroes.
2850 unsigned int index
= 1;
2852 // Add STT_SECTION symbols for each Output section which needs one.
2853 for (Section_list::iterator p
= this->section_list_
.begin();
2854 p
!= this->section_list_
.end();
2857 if (!(*p
)->needs_dynsym_index())
2858 (*p
)->set_dynsym_index(-1U);
2861 (*p
)->set_dynsym_index(index
);
2866 // Count the local symbols that need to go in the dynamic symbol table,
2867 // and set the dynamic symbol indexes.
2868 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2869 p
!= input_objects
->relobj_end();
2872 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
2876 unsigned int local_symcount
= index
;
2877 *plocal_dynamic_count
= local_symcount
;
2879 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
2880 &this->dynpool_
, pversions
);
2884 const int size
= parameters
->target().get_size();
2887 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
2890 else if (size
== 64)
2892 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
2898 // Create the dynamic symbol table section.
2900 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
2904 false, false, false);
2906 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
2909 dynsym
->add_output_section_data(odata
);
2911 dynsym
->set_info(local_symcount
);
2912 dynsym
->set_entsize(symsize
);
2913 dynsym
->set_addralign(align
);
2915 this->dynsym_section_
= dynsym
;
2917 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
2918 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
2919 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
2921 // If there are more than SHN_LORESERVE allocated sections, we
2922 // create a .dynsym_shndx section. It is possible that we don't
2923 // need one, because it is possible that there are no dynamic
2924 // symbols in any of the sections with indexes larger than
2925 // SHN_LORESERVE. This is probably unusual, though, and at this
2926 // time we don't know the actual section indexes so it is
2927 // inconvenient to check.
2928 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
2930 Output_section
* dynsym_xindex
=
2931 this->choose_output_section(NULL
, ".dynsym_shndx",
2932 elfcpp::SHT_SYMTAB_SHNDX
,
2934 false, false, true, false, false, false);
2936 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
2938 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
2940 dynsym_xindex
->set_link_section(dynsym
);
2941 dynsym_xindex
->set_addralign(4);
2942 dynsym_xindex
->set_entsize(4);
2944 dynsym_xindex
->set_after_input_sections();
2946 // This tells the driver code to wait until the symbol table has
2947 // written out before writing out the postprocessing sections,
2948 // including the .dynsym_shndx section.
2949 this->any_postprocessing_sections_
= true;
2952 // Create the dynamic string table section.
2954 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
2958 false, false, false);
2960 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
2961 dynstr
->add_output_section_data(strdata
);
2963 dynsym
->set_link_section(dynstr
);
2964 this->dynamic_section_
->set_link_section(dynstr
);
2966 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
2967 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
2971 // Create the hash tables.
2973 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
2974 || strcmp(parameters
->options().hash_style(), "both") == 0)
2976 unsigned char* phash
;
2977 unsigned int hashlen
;
2978 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
2981 Output_section
* hashsec
= this->choose_output_section(NULL
, ".hash",
2988 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
2992 hashsec
->add_output_section_data(hashdata
);
2994 hashsec
->set_link_section(dynsym
);
2995 hashsec
->set_entsize(4);
2997 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
3000 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
3001 || strcmp(parameters
->options().hash_style(), "both") == 0)
3003 unsigned char* phash
;
3004 unsigned int hashlen
;
3005 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
3008 Output_section
* hashsec
= this->choose_output_section(NULL
, ".gnu.hash",
3009 elfcpp::SHT_GNU_HASH
,
3015 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
3019 hashsec
->add_output_section_data(hashdata
);
3021 hashsec
->set_link_section(dynsym
);
3023 // For a 64-bit target, the entries in .gnu.hash do not have a
3024 // uniform size, so we only set the entry size for a 32-bit
3026 if (parameters
->target().get_size() == 32)
3027 hashsec
->set_entsize(4);
3029 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
3033 // Assign offsets to each local portion of the dynamic symbol table.
3036 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
3038 Output_section
* dynsym
= this->dynsym_section_
;
3039 gold_assert(dynsym
!= NULL
);
3041 off_t off
= dynsym
->offset();
3043 // Skip the dummy symbol at the start of the section.
3044 off
+= dynsym
->entsize();
3046 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3047 p
!= input_objects
->relobj_end();
3050 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
3051 off
+= count
* dynsym
->entsize();
3055 // Create the version sections.
3058 Layout::create_version_sections(const Versions
* versions
,
3059 const Symbol_table
* symtab
,
3060 unsigned int local_symcount
,
3061 const std::vector
<Symbol
*>& dynamic_symbols
,
3062 const Output_section
* dynstr
)
3064 if (!versions
->any_defs() && !versions
->any_needs())
3067 switch (parameters
->size_and_endianness())
3069 #ifdef HAVE_TARGET_32_LITTLE
3070 case Parameters::TARGET_32_LITTLE
:
3071 this->sized_create_version_sections
<32, false>(versions
, symtab
,
3073 dynamic_symbols
, dynstr
);
3076 #ifdef HAVE_TARGET_32_BIG
3077 case Parameters::TARGET_32_BIG
:
3078 this->sized_create_version_sections
<32, true>(versions
, symtab
,
3080 dynamic_symbols
, dynstr
);
3083 #ifdef HAVE_TARGET_64_LITTLE
3084 case Parameters::TARGET_64_LITTLE
:
3085 this->sized_create_version_sections
<64, false>(versions
, symtab
,
3087 dynamic_symbols
, dynstr
);
3090 #ifdef HAVE_TARGET_64_BIG
3091 case Parameters::TARGET_64_BIG
:
3092 this->sized_create_version_sections
<64, true>(versions
, symtab
,
3094 dynamic_symbols
, dynstr
);
3102 // Create the version sections, sized version.
3104 template<int size
, bool big_endian
>
3106 Layout::sized_create_version_sections(
3107 const Versions
* versions
,
3108 const Symbol_table
* symtab
,
3109 unsigned int local_symcount
,
3110 const std::vector
<Symbol
*>& dynamic_symbols
,
3111 const Output_section
* dynstr
)
3113 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
3114 elfcpp::SHT_GNU_versym
,
3117 false, false, false);
3119 unsigned char* vbuf
;
3121 versions
->symbol_section_contents
<size
, big_endian
>(symtab
, &this->dynpool_
,
3126 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
3129 vsec
->add_output_section_data(vdata
);
3130 vsec
->set_entsize(2);
3131 vsec
->set_link_section(this->dynsym_section_
);
3133 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3134 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
3136 if (versions
->any_defs())
3138 Output_section
* vdsec
;
3139 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
3140 elfcpp::SHT_GNU_verdef
,
3142 false, false, true, false, false,
3145 unsigned char* vdbuf
;
3146 unsigned int vdsize
;
3147 unsigned int vdentries
;
3148 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
, &vdbuf
,
3149 &vdsize
, &vdentries
);
3151 Output_section_data
* vddata
=
3152 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
3154 vdsec
->add_output_section_data(vddata
);
3155 vdsec
->set_link_section(dynstr
);
3156 vdsec
->set_info(vdentries
);
3158 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
3159 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
3162 if (versions
->any_needs())
3164 Output_section
* vnsec
;
3165 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
3166 elfcpp::SHT_GNU_verneed
,
3168 false, false, true, false, false,
3171 unsigned char* vnbuf
;
3172 unsigned int vnsize
;
3173 unsigned int vnentries
;
3174 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
3178 Output_section_data
* vndata
=
3179 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
3181 vnsec
->add_output_section_data(vndata
);
3182 vnsec
->set_link_section(dynstr
);
3183 vnsec
->set_info(vnentries
);
3185 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
3186 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
3190 // Create the .interp section and PT_INTERP segment.
3193 Layout::create_interp(const Target
* target
)
3195 const char* interp
= parameters
->options().dynamic_linker();
3198 interp
= target
->dynamic_linker();
3199 gold_assert(interp
!= NULL
);
3202 size_t len
= strlen(interp
) + 1;
3204 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
3206 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
3207 elfcpp::SHT_PROGBITS
,
3210 false, false, false);
3211 osec
->add_output_section_data(odata
);
3213 if (!this->script_options_
->saw_phdrs_clause())
3215 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_INTERP
,
3217 oseg
->add_output_section(osec
, elfcpp::PF_R
, false);
3221 // Add dynamic tags for the PLT and the dynamic relocs. This is
3222 // called by the target-specific code. This does nothing if not doing
3225 // USE_REL is true for REL relocs rather than RELA relocs.
3227 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3229 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3230 // and we also set DT_PLTREL. We use PLT_REL's output section, since
3231 // some targets have multiple reloc sections in PLT_REL.
3233 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3234 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3236 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3240 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
3241 const Output_data
* plt_rel
,
3242 const Output_data_reloc_generic
* dyn_rel
,
3243 bool add_debug
, bool dynrel_includes_plt
)
3245 Output_data_dynamic
* odyn
= this->dynamic_data_
;
3249 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
3250 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
3252 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
3254 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
3255 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
3256 odyn
->add_constant(elfcpp::DT_PLTREL
,
3257 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
3260 if (dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
3262 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
3264 if (plt_rel
!= NULL
&& dynrel_includes_plt
)
3265 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3268 odyn
->add_section_size(use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
,
3270 const int size
= parameters
->target().get_size();
3275 rel_tag
= elfcpp::DT_RELENT
;
3277 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
3278 else if (size
== 64)
3279 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
3285 rel_tag
= elfcpp::DT_RELAENT
;
3287 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
3288 else if (size
== 64)
3289 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
3293 odyn
->add_constant(rel_tag
, rel_size
);
3295 if (parameters
->options().combreloc())
3297 size_t c
= dyn_rel
->relative_reloc_count();
3299 odyn
->add_constant((use_rel
3300 ? elfcpp::DT_RELCOUNT
3301 : elfcpp::DT_RELACOUNT
),
3306 if (add_debug
&& !parameters
->options().shared())
3308 // The value of the DT_DEBUG tag is filled in by the dynamic
3309 // linker at run time, and used by the debugger.
3310 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
3314 // Finish the .dynamic section and PT_DYNAMIC segment.
3317 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
3318 const Symbol_table
* symtab
)
3320 if (!this->script_options_
->saw_phdrs_clause())
3322 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
3325 oseg
->add_output_section(this->dynamic_section_
,
3326 elfcpp::PF_R
| elfcpp::PF_W
,
3330 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3332 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
3333 p
!= input_objects
->dynobj_end();
3336 if (!(*p
)->is_needed()
3337 && (*p
)->input_file()->options().as_needed())
3339 // This dynamic object was linked with --as-needed, but it
3344 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
3347 if (parameters
->options().shared())
3349 const char* soname
= parameters
->options().soname();
3351 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
3354 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
3355 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
3356 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
3358 sym
= symtab
->lookup(parameters
->options().fini());
3359 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
3360 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
3362 // Look for .init_array, .preinit_array and .fini_array by checking
3364 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
3365 p
!= this->section_list_
.end();
3367 switch((*p
)->type())
3369 case elfcpp::SHT_FINI_ARRAY
:
3370 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
3371 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
3373 case elfcpp::SHT_INIT_ARRAY
:
3374 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
3375 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
3377 case elfcpp::SHT_PREINIT_ARRAY
:
3378 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
3379 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
3385 // Add a DT_RPATH entry if needed.
3386 const General_options::Dir_list
& rpath(parameters
->options().rpath());
3389 std::string rpath_val
;
3390 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
3394 if (rpath_val
.empty())
3395 rpath_val
= p
->name();
3398 // Eliminate duplicates.
3399 General_options::Dir_list::const_iterator q
;
3400 for (q
= rpath
.begin(); q
!= p
; ++q
)
3401 if (q
->name() == p
->name())
3406 rpath_val
+= p
->name();
3411 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
3412 if (parameters
->options().enable_new_dtags())
3413 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
3416 // Look for text segments that have dynamic relocations.
3417 bool have_textrel
= false;
3418 if (!this->script_options_
->saw_sections_clause())
3420 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3421 p
!= this->segment_list_
.end();
3424 if (((*p
)->flags() & elfcpp::PF_W
) == 0
3425 && (*p
)->dynamic_reloc_count() > 0)
3427 have_textrel
= true;
3434 // We don't know the section -> segment mapping, so we are
3435 // conservative and just look for readonly sections with
3436 // relocations. If those sections wind up in writable segments,
3437 // then we have created an unnecessary DT_TEXTREL entry.
3438 for (Section_list::const_iterator p
= this->section_list_
.begin();
3439 p
!= this->section_list_
.end();
3442 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
3443 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
3444 && ((*p
)->dynamic_reloc_count() > 0))
3446 have_textrel
= true;
3452 // Add a DT_FLAGS entry. We add it even if no flags are set so that
3453 // post-link tools can easily modify these flags if desired.
3454 unsigned int flags
= 0;
3457 // Add a DT_TEXTREL for compatibility with older loaders.
3458 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
3459 flags
|= elfcpp::DF_TEXTREL
;
3461 if (parameters
->options().text())
3462 gold_error(_("read-only segment has dynamic relocations"));
3463 else if (parameters
->options().warn_shared_textrel()
3464 && parameters
->options().shared())
3465 gold_warning(_("shared library text segment is not shareable"));
3467 if (parameters
->options().shared() && this->has_static_tls())
3468 flags
|= elfcpp::DF_STATIC_TLS
;
3469 if (parameters
->options().origin())
3470 flags
|= elfcpp::DF_ORIGIN
;
3471 if (parameters
->options().Bsymbolic())
3473 flags
|= elfcpp::DF_SYMBOLIC
;
3474 // Add DT_SYMBOLIC for compatibility with older loaders.
3475 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
3477 if (parameters
->options().now())
3478 flags
|= elfcpp::DF_BIND_NOW
;
3479 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
3482 if (parameters
->options().initfirst())
3483 flags
|= elfcpp::DF_1_INITFIRST
;
3484 if (parameters
->options().interpose())
3485 flags
|= elfcpp::DF_1_INTERPOSE
;
3486 if (parameters
->options().loadfltr())
3487 flags
|= elfcpp::DF_1_LOADFLTR
;
3488 if (parameters
->options().nodefaultlib())
3489 flags
|= elfcpp::DF_1_NODEFLIB
;
3490 if (parameters
->options().nodelete())
3491 flags
|= elfcpp::DF_1_NODELETE
;
3492 if (parameters
->options().nodlopen())
3493 flags
|= elfcpp::DF_1_NOOPEN
;
3494 if (parameters
->options().nodump())
3495 flags
|= elfcpp::DF_1_NODUMP
;
3496 if (!parameters
->options().shared())
3497 flags
&= ~(elfcpp::DF_1_INITFIRST
3498 | elfcpp::DF_1_NODELETE
3499 | elfcpp::DF_1_NOOPEN
);
3500 if (parameters
->options().origin())
3501 flags
|= elfcpp::DF_1_ORIGIN
;
3502 if (parameters
->options().now())
3503 flags
|= elfcpp::DF_1_NOW
;
3505 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
3508 // Set the size of the _DYNAMIC symbol table to be the size of the
3512 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
3514 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
3515 odyn
->finalize_data_size();
3516 off_t data_size
= odyn
->data_size();
3517 const int size
= parameters
->target().get_size();
3519 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
3520 else if (size
== 64)
3521 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
3526 // The mapping of input section name prefixes to output section names.
3527 // In some cases one prefix is itself a prefix of another prefix; in
3528 // such a case the longer prefix must come first. These prefixes are
3529 // based on the GNU linker default ELF linker script.
3531 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
3532 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
3534 MAPPING_INIT(".text.", ".text"),
3535 MAPPING_INIT(".ctors.", ".ctors"),
3536 MAPPING_INIT(".dtors.", ".dtors"),
3537 MAPPING_INIT(".rodata.", ".rodata"),
3538 MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
3539 MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
3540 MAPPING_INIT(".data.", ".data"),
3541 MAPPING_INIT(".bss.", ".bss"),
3542 MAPPING_INIT(".tdata.", ".tdata"),
3543 MAPPING_INIT(".tbss.", ".tbss"),
3544 MAPPING_INIT(".init_array.", ".init_array"),
3545 MAPPING_INIT(".fini_array.", ".fini_array"),
3546 MAPPING_INIT(".sdata.", ".sdata"),
3547 MAPPING_INIT(".sbss.", ".sbss"),
3548 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
3549 // differently depending on whether it is creating a shared library.
3550 MAPPING_INIT(".sdata2.", ".sdata"),
3551 MAPPING_INIT(".sbss2.", ".sbss"),
3552 MAPPING_INIT(".lrodata.", ".lrodata"),
3553 MAPPING_INIT(".ldata.", ".ldata"),
3554 MAPPING_INIT(".lbss.", ".lbss"),
3555 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
3556 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
3557 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
3558 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
3559 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
3560 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
3561 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
3562 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
3563 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
3564 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
3565 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
3566 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
3567 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
3568 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
3569 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
3570 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
3571 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
3572 MAPPING_INIT(".ARM.extab.", ".ARM.extab"),
3573 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
3574 MAPPING_INIT(".ARM.exidx.", ".ARM.exidx"),
3575 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
3579 const int Layout::section_name_mapping_count
=
3580 (sizeof(Layout::section_name_mapping
)
3581 / sizeof(Layout::section_name_mapping
[0]));
3583 // Choose the output section name to use given an input section name.
3584 // Set *PLEN to the length of the name. *PLEN is initialized to the
3588 Layout::output_section_name(const char* name
, size_t* plen
)
3590 // gcc 4.3 generates the following sorts of section names when it
3591 // needs a section name specific to a function:
3597 // .data.rel.local.FN
3599 // .data.rel.ro.local.FN
3606 // The GNU linker maps all of those to the part before the .FN,
3607 // except that .data.rel.local.FN is mapped to .data, and
3608 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
3609 // beginning with .data.rel.ro.local are grouped together.
3611 // For an anonymous namespace, the string FN can contain a '.'.
3613 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
3614 // GNU linker maps to .rodata.
3616 // The .data.rel.ro sections are used with -z relro. The sections
3617 // are recognized by name. We use the same names that the GNU
3618 // linker does for these sections.
3620 // It is hard to handle this in a principled way, so we don't even
3621 // try. We use a table of mappings. If the input section name is
3622 // not found in the table, we simply use it as the output section
3625 const Section_name_mapping
* psnm
= section_name_mapping
;
3626 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
3628 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
3630 *plen
= psnm
->tolen
;
3638 // Check if a comdat group or .gnu.linkonce section with the given
3639 // NAME is selected for the link. If there is already a section,
3640 // *KEPT_SECTION is set to point to the existing section and the
3641 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
3642 // IS_GROUP_NAME are recorded for this NAME in the layout object,
3643 // *KEPT_SECTION is set to the internal copy and the function returns
3647 Layout::find_or_add_kept_section(const std::string
& name
,
3652 Kept_section
** kept_section
)
3654 // It's normal to see a couple of entries here, for the x86 thunk
3655 // sections. If we see more than a few, we're linking a C++
3656 // program, and we resize to get more space to minimize rehashing.
3657 if (this->signatures_
.size() > 4
3658 && !this->resized_signatures_
)
3660 reserve_unordered_map(&this->signatures_
,
3661 this->number_of_input_files_
* 64);
3662 this->resized_signatures_
= true;
3665 Kept_section candidate
;
3666 std::pair
<Signatures::iterator
, bool> ins
=
3667 this->signatures_
.insert(std::make_pair(name
, candidate
));
3669 if (kept_section
!= NULL
)
3670 *kept_section
= &ins
.first
->second
;
3673 // This is the first time we've seen this signature.
3674 ins
.first
->second
.set_object(object
);
3675 ins
.first
->second
.set_shndx(shndx
);
3677 ins
.first
->second
.set_is_comdat();
3679 ins
.first
->second
.set_is_group_name();
3683 // We have already seen this signature.
3685 if (ins
.first
->second
.is_group_name())
3687 // We've already seen a real section group with this signature.
3688 // If the kept group is from a plugin object, and we're in the
3689 // replacement phase, accept the new one as a replacement.
3690 if (ins
.first
->second
.object() == NULL
3691 && parameters
->options().plugins()->in_replacement_phase())
3693 ins
.first
->second
.set_object(object
);
3694 ins
.first
->second
.set_shndx(shndx
);
3699 else if (is_group_name
)
3701 // This is a real section group, and we've already seen a
3702 // linkonce section with this signature. Record that we've seen
3703 // a section group, and don't include this section group.
3704 ins
.first
->second
.set_is_group_name();
3709 // We've already seen a linkonce section and this is a linkonce
3710 // section. These don't block each other--this may be the same
3711 // symbol name with different section types.
3716 // Store the allocated sections into the section list.
3719 Layout::get_allocated_sections(Section_list
* section_list
) const
3721 for (Section_list::const_iterator p
= this->section_list_
.begin();
3722 p
!= this->section_list_
.end();
3724 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
3725 section_list
->push_back(*p
);
3728 // Create an output segment.
3731 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
3733 gold_assert(!parameters
->options().relocatable());
3734 Output_segment
* oseg
= new Output_segment(type
, flags
);
3735 this->segment_list_
.push_back(oseg
);
3737 if (type
== elfcpp::PT_TLS
)
3738 this->tls_segment_
= oseg
;
3739 else if (type
== elfcpp::PT_GNU_RELRO
)
3740 this->relro_segment_
= oseg
;
3745 // Write out the Output_sections. Most won't have anything to write,
3746 // since most of the data will come from input sections which are
3747 // handled elsewhere. But some Output_sections do have Output_data.
3750 Layout::write_output_sections(Output_file
* of
) const
3752 for (Section_list::const_iterator p
= this->section_list_
.begin();
3753 p
!= this->section_list_
.end();
3756 if (!(*p
)->after_input_sections())
3761 // Write out data not associated with a section or the symbol table.
3764 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
3766 if (!parameters
->options().strip_all())
3768 const Output_section
* symtab_section
= this->symtab_section_
;
3769 for (Section_list::const_iterator p
= this->section_list_
.begin();
3770 p
!= this->section_list_
.end();
3773 if ((*p
)->needs_symtab_index())
3775 gold_assert(symtab_section
!= NULL
);
3776 unsigned int index
= (*p
)->symtab_index();
3777 gold_assert(index
> 0 && index
!= -1U);
3778 off_t off
= (symtab_section
->offset()
3779 + index
* symtab_section
->entsize());
3780 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
3785 const Output_section
* dynsym_section
= this->dynsym_section_
;
3786 for (Section_list::const_iterator p
= this->section_list_
.begin();
3787 p
!= this->section_list_
.end();
3790 if ((*p
)->needs_dynsym_index())
3792 gold_assert(dynsym_section
!= NULL
);
3793 unsigned int index
= (*p
)->dynsym_index();
3794 gold_assert(index
> 0 && index
!= -1U);
3795 off_t off
= (dynsym_section
->offset()
3796 + index
* dynsym_section
->entsize());
3797 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
3801 // Write out the Output_data which are not in an Output_section.
3802 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
3803 p
!= this->special_output_list_
.end();
3808 // Write out the Output_sections which can only be written after the
3809 // input sections are complete.
3812 Layout::write_sections_after_input_sections(Output_file
* of
)
3814 // Determine the final section offsets, and thus the final output
3815 // file size. Note we finalize the .shstrab last, to allow the
3816 // after_input_section sections to modify their section-names before
3818 if (this->any_postprocessing_sections_
)
3820 off_t off
= this->output_file_size_
;
3821 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
3823 // Now that we've finalized the names, we can finalize the shstrab.
3825 this->set_section_offsets(off
,
3826 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
3828 if (off
> this->output_file_size_
)
3831 this->output_file_size_
= off
;
3835 for (Section_list::const_iterator p
= this->section_list_
.begin();
3836 p
!= this->section_list_
.end();
3839 if ((*p
)->after_input_sections())
3843 this->section_headers_
->write(of
);
3846 // If the build ID requires computing a checksum, do so here, and
3847 // write it out. We compute a checksum over the entire file because
3848 // that is simplest.
3851 Layout::write_build_id(Output_file
* of
) const
3853 if (this->build_id_note_
== NULL
)
3856 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
3858 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
3859 this->build_id_note_
->data_size());
3861 const char* style
= parameters
->options().build_id();
3862 if (strcmp(style
, "sha1") == 0)
3865 sha1_init_ctx(&ctx
);
3866 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
3867 sha1_finish_ctx(&ctx
, ov
);
3869 else if (strcmp(style
, "md5") == 0)
3873 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
3874 md5_finish_ctx(&ctx
, ov
);
3879 of
->write_output_view(this->build_id_note_
->offset(),
3880 this->build_id_note_
->data_size(),
3883 of
->free_input_view(0, this->output_file_size_
, iv
);
3886 // Write out a binary file. This is called after the link is
3887 // complete. IN is the temporary output file we used to generate the
3888 // ELF code. We simply walk through the segments, read them from
3889 // their file offset in IN, and write them to their load address in
3890 // the output file. FIXME: with a bit more work, we could support
3891 // S-records and/or Intel hex format here.
3894 Layout::write_binary(Output_file
* in
) const
3896 gold_assert(parameters
->options().oformat_enum()
3897 == General_options::OBJECT_FORMAT_BINARY
);
3899 // Get the size of the binary file.
3900 uint64_t max_load_address
= 0;
3901 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3902 p
!= this->segment_list_
.end();
3905 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
3907 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
3908 if (max_paddr
> max_load_address
)
3909 max_load_address
= max_paddr
;
3913 Output_file
out(parameters
->options().output_file_name());
3914 out
.open(max_load_address
);
3916 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3917 p
!= this->segment_list_
.end();
3920 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
3922 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
3924 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
3926 memcpy(vout
, vin
, (*p
)->filesz());
3927 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
3928 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
3935 // Print the output sections to the map file.
3938 Layout::print_to_mapfile(Mapfile
* mapfile
) const
3940 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3941 p
!= this->segment_list_
.end();
3943 (*p
)->print_sections_to_mapfile(mapfile
);
3946 // Print statistical information to stderr. This is used for --stats.
3949 Layout::print_stats() const
3951 this->namepool_
.print_stats("section name pool");
3952 this->sympool_
.print_stats("output symbol name pool");
3953 this->dynpool_
.print_stats("dynamic name pool");
3955 for (Section_list::const_iterator p
= this->section_list_
.begin();
3956 p
!= this->section_list_
.end();
3958 (*p
)->print_merge_stats();
3961 // Write_sections_task methods.
3963 // We can always run this task.
3966 Write_sections_task::is_runnable()
3971 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
3975 Write_sections_task::locks(Task_locker
* tl
)
3977 tl
->add(this, this->output_sections_blocker_
);
3978 tl
->add(this, this->final_blocker_
);
3981 // Run the task--write out the data.
3984 Write_sections_task::run(Workqueue
*)
3986 this->layout_
->write_output_sections(this->of_
);
3989 // Write_data_task methods.
3991 // We can always run this task.
3994 Write_data_task::is_runnable()
3999 // We need to unlock FINAL_BLOCKER when finished.
4002 Write_data_task::locks(Task_locker
* tl
)
4004 tl
->add(this, this->final_blocker_
);
4007 // Run the task--write out the data.
4010 Write_data_task::run(Workqueue
*)
4012 this->layout_
->write_data(this->symtab_
, this->of_
);
4015 // Write_symbols_task methods.
4017 // We can always run this task.
4020 Write_symbols_task::is_runnable()
4025 // We need to unlock FINAL_BLOCKER when finished.
4028 Write_symbols_task::locks(Task_locker
* tl
)
4030 tl
->add(this, this->final_blocker_
);
4033 // Run the task--write out the symbols.
4036 Write_symbols_task::run(Workqueue
*)
4038 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
4039 this->layout_
->symtab_xindex(),
4040 this->layout_
->dynsym_xindex(), this->of_
);
4043 // Write_after_input_sections_task methods.
4045 // We can only run this task after the input sections have completed.
4048 Write_after_input_sections_task::is_runnable()
4050 if (this->input_sections_blocker_
->is_blocked())
4051 return this->input_sections_blocker_
;
4055 // We need to unlock FINAL_BLOCKER when finished.
4058 Write_after_input_sections_task::locks(Task_locker
* tl
)
4060 tl
->add(this, this->final_blocker_
);
4066 Write_after_input_sections_task::run(Workqueue
*)
4068 this->layout_
->write_sections_after_input_sections(this->of_
);
4071 // Close_task_runner methods.
4073 // Run the task--close the file.
4076 Close_task_runner::run(Workqueue
*, const Task
*)
4078 // If we need to compute a checksum for the BUILD if, we do so here.
4079 this->layout_
->write_build_id(this->of_
);
4081 // If we've been asked to create a binary file, we do so here.
4082 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
4083 this->layout_
->write_binary(this->of_
);
4088 // Instantiate the templates we need. We could use the configure
4089 // script to restrict this to only the ones for implemented targets.
4091 #ifdef HAVE_TARGET_32_LITTLE
4094 Layout::layout
<32, false>(Sized_relobj
<32, false>* object
, unsigned int shndx
,
4096 const elfcpp::Shdr
<32, false>& shdr
,
4097 unsigned int, unsigned int, off_t
*);
4100 #ifdef HAVE_TARGET_32_BIG
4103 Layout::layout
<32, true>(Sized_relobj
<32, true>* object
, unsigned int shndx
,
4105 const elfcpp::Shdr
<32, true>& shdr
,
4106 unsigned int, unsigned int, off_t
*);
4109 #ifdef HAVE_TARGET_64_LITTLE
4112 Layout::layout
<64, false>(Sized_relobj
<64, false>* object
, unsigned int shndx
,
4114 const elfcpp::Shdr
<64, false>& shdr
,
4115 unsigned int, unsigned int, off_t
*);
4118 #ifdef HAVE_TARGET_64_BIG
4121 Layout::layout
<64, true>(Sized_relobj
<64, true>* object
, unsigned int shndx
,
4123 const elfcpp::Shdr
<64, true>& shdr
,
4124 unsigned int, unsigned int, off_t
*);
4127 #ifdef HAVE_TARGET_32_LITTLE
4130 Layout::layout_reloc
<32, false>(Sized_relobj
<32, false>* object
,
4131 unsigned int reloc_shndx
,
4132 const elfcpp::Shdr
<32, false>& shdr
,
4133 Output_section
* data_section
,
4134 Relocatable_relocs
* rr
);
4137 #ifdef HAVE_TARGET_32_BIG
4140 Layout::layout_reloc
<32, true>(Sized_relobj
<32, true>* object
,
4141 unsigned int reloc_shndx
,
4142 const elfcpp::Shdr
<32, true>& shdr
,
4143 Output_section
* data_section
,
4144 Relocatable_relocs
* rr
);
4147 #ifdef HAVE_TARGET_64_LITTLE
4150 Layout::layout_reloc
<64, false>(Sized_relobj
<64, false>* object
,
4151 unsigned int reloc_shndx
,
4152 const elfcpp::Shdr
<64, false>& shdr
,
4153 Output_section
* data_section
,
4154 Relocatable_relocs
* rr
);
4157 #ifdef HAVE_TARGET_64_BIG
4160 Layout::layout_reloc
<64, true>(Sized_relobj
<64, true>* object
,
4161 unsigned int reloc_shndx
,
4162 const elfcpp::Shdr
<64, true>& shdr
,
4163 Output_section
* data_section
,
4164 Relocatable_relocs
* rr
);
4167 #ifdef HAVE_TARGET_32_LITTLE
4170 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
4171 Sized_relobj
<32, false>* object
,
4173 const char* group_section_name
,
4174 const char* signature
,
4175 const elfcpp::Shdr
<32, false>& shdr
,
4176 elfcpp::Elf_Word flags
,
4177 std::vector
<unsigned int>* shndxes
);
4180 #ifdef HAVE_TARGET_32_BIG
4183 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
4184 Sized_relobj
<32, true>* object
,
4186 const char* group_section_name
,
4187 const char* signature
,
4188 const elfcpp::Shdr
<32, true>& shdr
,
4189 elfcpp::Elf_Word flags
,
4190 std::vector
<unsigned int>* shndxes
);
4193 #ifdef HAVE_TARGET_64_LITTLE
4196 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
4197 Sized_relobj
<64, false>* object
,
4199 const char* group_section_name
,
4200 const char* signature
,
4201 const elfcpp::Shdr
<64, false>& shdr
,
4202 elfcpp::Elf_Word flags
,
4203 std::vector
<unsigned int>* shndxes
);
4206 #ifdef HAVE_TARGET_64_BIG
4209 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
4210 Sized_relobj
<64, true>* object
,
4212 const char* group_section_name
,
4213 const char* signature
,
4214 const elfcpp::Shdr
<64, true>& shdr
,
4215 elfcpp::Elf_Word flags
,
4216 std::vector
<unsigned int>* shndxes
);
4219 #ifdef HAVE_TARGET_32_LITTLE
4222 Layout::layout_eh_frame
<32, false>(Sized_relobj
<32, false>* object
,
4223 const unsigned char* symbols
,
4225 const unsigned char* symbol_names
,
4226 off_t symbol_names_size
,
4228 const elfcpp::Shdr
<32, false>& shdr
,
4229 unsigned int reloc_shndx
,
4230 unsigned int reloc_type
,
4234 #ifdef HAVE_TARGET_32_BIG
4237 Layout::layout_eh_frame
<32, true>(Sized_relobj
<32, true>* object
,
4238 const unsigned char* symbols
,
4240 const unsigned char* symbol_names
,
4241 off_t symbol_names_size
,
4243 const elfcpp::Shdr
<32, true>& shdr
,
4244 unsigned int reloc_shndx
,
4245 unsigned int reloc_type
,
4249 #ifdef HAVE_TARGET_64_LITTLE
4252 Layout::layout_eh_frame
<64, false>(Sized_relobj
<64, false>* object
,
4253 const unsigned char* symbols
,
4255 const unsigned char* symbol_names
,
4256 off_t symbol_names_size
,
4258 const elfcpp::Shdr
<64, false>& shdr
,
4259 unsigned int reloc_shndx
,
4260 unsigned int reloc_type
,
4264 #ifdef HAVE_TARGET_64_BIG
4267 Layout::layout_eh_frame
<64, true>(Sized_relobj
<64, true>* object
,
4268 const unsigned char* symbols
,
4270 const unsigned char* symbol_names
,
4271 off_t symbol_names_size
,
4273 const elfcpp::Shdr
<64, true>& shdr
,
4274 unsigned int reloc_shndx
,
4275 unsigned int reloc_type
,
4279 } // End namespace gold.