1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008 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"
54 // Layout_task_runner methods.
56 // Lay out the sections. This is called after all the input objects
60 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
62 off_t file_size
= this->layout_
->finalize(this->input_objects_
,
67 // Now we know the final size of the output file and we know where
68 // each piece of information goes.
70 if (this->mapfile_
!= NULL
)
72 this->mapfile_
->print_discarded_sections(this->input_objects_
);
73 this->layout_
->print_to_mapfile(this->mapfile_
);
76 Output_file
* of
= new Output_file(parameters
->options().output_file_name());
77 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
78 of
->set_is_temporary();
81 // Queue up the final set of tasks.
82 gold::queue_final_tasks(this->options_
, this->input_objects_
,
83 this->symtab_
, this->layout_
, workqueue
, of
);
88 Layout::Layout(const General_options
& options
, Script_options
* script_options
)
90 script_options_(script_options
),
98 unattached_section_list_(),
99 sections_are_attached_(false),
100 special_output_list_(),
101 section_headers_(NULL
),
103 relro_segment_(NULL
),
104 symtab_section_(NULL
),
105 symtab_xindex_(NULL
),
106 dynsym_section_(NULL
),
107 dynsym_xindex_(NULL
),
108 dynamic_section_(NULL
),
110 eh_frame_section_(NULL
),
111 eh_frame_data_(NULL
),
112 added_eh_frame_data_(false),
113 eh_frame_hdr_section_(NULL
),
114 build_id_note_(NULL
),
118 output_file_size_(-1),
119 input_requires_executable_stack_(false),
120 input_with_gnu_stack_note_(false),
121 input_without_gnu_stack_note_(false),
122 has_static_tls_(false),
123 any_postprocessing_sections_(false)
125 // Make space for more than enough segments for a typical file.
126 // This is just for efficiency--it's OK if we wind up needing more.
127 this->segment_list_
.reserve(12);
129 // We expect two unattached Output_data objects: the file header and
130 // the segment headers.
131 this->special_output_list_
.reserve(2);
134 // Hash a key we use to look up an output section mapping.
137 Layout::Hash_key::operator()(const Layout::Key
& k
) const
139 return k
.first
+ k
.second
.first
+ k
.second
.second
;
142 // Return whether PREFIX is a prefix of STR.
145 is_prefix_of(const char* prefix
, const char* str
)
147 return strncmp(prefix
, str
, strlen(prefix
)) == 0;
150 // Returns whether the given section is in the list of
151 // debug-sections-used-by-some-version-of-gdb. Currently,
152 // we've checked versions of gdb up to and including 6.7.1.
154 static const char* gdb_sections
[] =
156 // ".debug_aranges", // not used by gdb as of 6.7.1
162 // ".debug_pubnames", // not used by gdb as of 6.7.1
167 static const char* lines_only_debug_sections
[] =
169 // ".debug_aranges", // not used by gdb as of 6.7.1
175 // ".debug_pubnames", // not used by gdb as of 6.7.1
181 is_gdb_debug_section(const char* str
)
183 // We can do this faster: binary search or a hashtable. But why bother?
184 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
185 if (strcmp(str
, gdb_sections
[i
]) == 0)
191 is_lines_only_debug_section(const char* str
)
193 // We can do this faster: binary search or a hashtable. But why bother?
195 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
197 if (strcmp(str
, lines_only_debug_sections
[i
]) == 0)
202 // Whether to include this section in the link.
204 template<int size
, bool big_endian
>
206 Layout::include_section(Sized_relobj
<size
, big_endian
>*, const char* name
,
207 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
209 switch (shdr
.get_sh_type())
211 case elfcpp::SHT_NULL
:
212 case elfcpp::SHT_SYMTAB
:
213 case elfcpp::SHT_DYNSYM
:
214 case elfcpp::SHT_HASH
:
215 case elfcpp::SHT_DYNAMIC
:
216 case elfcpp::SHT_SYMTAB_SHNDX
:
219 case elfcpp::SHT_STRTAB
:
220 // Discard the sections which have special meanings in the ELF
221 // ABI. Keep others (e.g., .stabstr). We could also do this by
222 // checking the sh_link fields of the appropriate sections.
223 return (strcmp(name
, ".dynstr") != 0
224 && strcmp(name
, ".strtab") != 0
225 && strcmp(name
, ".shstrtab") != 0);
227 case elfcpp::SHT_RELA
:
228 case elfcpp::SHT_REL
:
229 case elfcpp::SHT_GROUP
:
230 // If we are emitting relocations these should be handled
232 gold_assert(!parameters
->options().relocatable()
233 && !parameters
->options().emit_relocs());
236 case elfcpp::SHT_PROGBITS
:
237 if (parameters
->options().strip_debug()
238 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
240 if (is_debug_info_section(name
))
243 if (parameters
->options().strip_debug_non_line()
244 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
246 // Debugging sections can only be recognized by name.
247 if (is_prefix_of(".debug", name
)
248 && !is_lines_only_debug_section(name
))
251 if (parameters
->options().strip_debug_gdb()
252 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
254 // Debugging sections can only be recognized by name.
255 if (is_prefix_of(".debug", name
)
256 && !is_gdb_debug_section(name
))
266 // Return an output section named NAME, or NULL if there is none.
269 Layout::find_output_section(const char* name
) const
271 for (Section_list::const_iterator p
= this->section_list_
.begin();
272 p
!= this->section_list_
.end();
274 if (strcmp((*p
)->name(), name
) == 0)
279 // Return an output segment of type TYPE, with segment flags SET set
280 // and segment flags CLEAR clear. Return NULL if there is none.
283 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
284 elfcpp::Elf_Word clear
) const
286 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
287 p
!= this->segment_list_
.end();
289 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
290 && ((*p
)->flags() & set
) == set
291 && ((*p
)->flags() & clear
) == 0)
296 // Return the output section to use for section NAME with type TYPE
297 // and section flags FLAGS. NAME must be canonicalized in the string
298 // pool, and NAME_KEY is the key.
301 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
302 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
)
304 elfcpp::Elf_Xword lookup_flags
= flags
;
306 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
307 // read-write with read-only sections. Some other ELF linkers do
308 // not do this. FIXME: Perhaps there should be an option
310 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
312 const Key
key(name_key
, std::make_pair(type
, lookup_flags
));
313 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
314 std::pair
<Section_name_map::iterator
, bool> ins(
315 this->section_name_map_
.insert(v
));
318 return ins
.first
->second
;
321 // This is the first time we've seen this name/type/flags
322 // combination. For compatibility with the GNU linker, we
323 // combine sections with contents and zero flags with sections
324 // with non-zero flags. This is a workaround for cases where
325 // assembler code forgets to set section flags. FIXME: Perhaps
326 // there should be an option to control this.
327 Output_section
* os
= NULL
;
329 if (type
== elfcpp::SHT_PROGBITS
)
333 Output_section
* same_name
= this->find_output_section(name
);
334 if (same_name
!= NULL
335 && same_name
->type() == elfcpp::SHT_PROGBITS
336 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
339 else if ((flags
& elfcpp::SHF_TLS
) == 0)
341 elfcpp::Elf_Xword zero_flags
= 0;
342 const Key
zero_key(name_key
, std::make_pair(type
, zero_flags
));
343 Section_name_map::iterator p
=
344 this->section_name_map_
.find(zero_key
);
345 if (p
!= this->section_name_map_
.end())
351 os
= this->make_output_section(name
, type
, flags
);
352 ins
.first
->second
= os
;
357 // Pick the output section to use for section NAME, in input file
358 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
359 // linker created section. IS_INPUT_SECTION is true if we are
360 // choosing an output section for an input section found in a input
361 // file. This will return NULL if the input section should be
365 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
366 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
367 bool is_input_section
)
369 // We should not see any input sections after we have attached
370 // sections to segments.
371 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
373 // Some flags in the input section should not be automatically
374 // copied to the output section.
375 flags
&= ~ (elfcpp::SHF_INFO_LINK
376 | elfcpp::SHF_LINK_ORDER
379 | elfcpp::SHF_STRINGS
);
381 if (this->script_options_
->saw_sections_clause())
383 // We are using a SECTIONS clause, so the output section is
384 // chosen based only on the name.
386 Script_sections
* ss
= this->script_options_
->script_sections();
387 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
388 Output_section
** output_section_slot
;
389 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
);
392 // The SECTIONS clause says to discard this input section.
396 // If this is an orphan section--one not mentioned in the linker
397 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
398 // default processing below.
400 if (output_section_slot
!= NULL
)
402 if (*output_section_slot
!= NULL
)
403 return *output_section_slot
;
405 // We don't put sections found in the linker script into
406 // SECTION_NAME_MAP_. That keeps us from getting confused
407 // if an orphan section is mapped to a section with the same
408 // name as one in the linker script.
410 name
= this->namepool_
.add(name
, false, NULL
);
412 Output_section
* os
= this->make_output_section(name
, type
, flags
);
413 os
->set_found_in_sections_clause();
414 *output_section_slot
= os
;
419 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
421 // Turn NAME from the name of the input section into the name of the
424 size_t len
= strlen(name
);
425 if (is_input_section
&& !parameters
->options().relocatable())
426 name
= Layout::output_section_name(name
, &len
);
428 Stringpool::Key name_key
;
429 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
431 // Find or make the output section. The output section is selected
432 // based on the section name, type, and flags.
433 return this->get_output_section(name
, name_key
, type
, flags
);
436 // Return the output section to use for input section SHNDX, with name
437 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
438 // index of a relocation section which applies to this section, or 0
439 // if none, or -1U if more than one. RELOC_TYPE is the type of the
440 // relocation section if there is one. Set *OFF to the offset of this
441 // input section without the output section. Return NULL if the
442 // section should be discarded. Set *OFF to -1 if the section
443 // contents should not be written directly to the output file, but
444 // will instead receive special handling.
446 template<int size
, bool big_endian
>
448 Layout::layout(Sized_relobj
<size
, big_endian
>* object
, unsigned int shndx
,
449 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
450 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
454 if (!this->include_section(object
, name
, shdr
))
459 // In a relocatable link a grouped section must not be combined with
460 // any other sections.
461 if (parameters
->options().relocatable()
462 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
464 name
= this->namepool_
.add(name
, true, NULL
);
465 os
= this->make_output_section(name
, shdr
.get_sh_type(),
466 shdr
.get_sh_flags());
470 os
= this->choose_output_section(object
, name
, shdr
.get_sh_type(),
471 shdr
.get_sh_flags(), true);
476 // By default the GNU linker sorts input sections whose names match
477 // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
478 // are sorted by name. This is used to implement constructor
479 // priority ordering. We are compatible.
480 if (!this->script_options_
->saw_sections_clause()
481 && (is_prefix_of(".ctors.", name
)
482 || is_prefix_of(".dtors.", name
)
483 || is_prefix_of(".init_array.", name
)
484 || is_prefix_of(".fini_array.", name
)))
485 os
->set_must_sort_attached_input_sections();
487 // FIXME: Handle SHF_LINK_ORDER somewhere.
489 *off
= os
->add_input_section(object
, shndx
, name
, shdr
, reloc_shndx
,
490 this->script_options_
->saw_sections_clause());
495 // Handle a relocation section when doing a relocatable link.
497 template<int size
, bool big_endian
>
499 Layout::layout_reloc(Sized_relobj
<size
, big_endian
>* object
,
501 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
502 Output_section
* data_section
,
503 Relocatable_relocs
* rr
)
505 gold_assert(parameters
->options().relocatable()
506 || parameters
->options().emit_relocs());
508 int sh_type
= shdr
.get_sh_type();
511 if (sh_type
== elfcpp::SHT_REL
)
513 else if (sh_type
== elfcpp::SHT_RELA
)
517 name
+= data_section
->name();
519 Output_section
* os
= this->choose_output_section(object
, name
.c_str(),
524 os
->set_should_link_to_symtab();
525 os
->set_info_section(data_section
);
527 Output_section_data
* posd
;
528 if (sh_type
== elfcpp::SHT_REL
)
530 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
531 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
535 else if (sh_type
== elfcpp::SHT_RELA
)
537 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
538 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
545 os
->add_output_section_data(posd
);
546 rr
->set_output_data(posd
);
551 // Handle a group section when doing a relocatable link.
553 template<int size
, bool big_endian
>
555 Layout::layout_group(Symbol_table
* symtab
,
556 Sized_relobj
<size
, big_endian
>* object
,
558 const char* group_section_name
,
559 const char* signature
,
560 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
561 elfcpp::Elf_Word flags
,
562 std::vector
<unsigned int>* shndxes
)
564 gold_assert(parameters
->options().relocatable());
565 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
566 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
567 Output_section
* os
= this->make_output_section(group_section_name
,
569 shdr
.get_sh_flags());
571 // We need to find a symbol with the signature in the symbol table.
572 // If we don't find one now, we need to look again later.
573 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
575 os
->set_info_symndx(sym
);
578 // We will wind up using a symbol whose name is the signature.
579 // So just put the signature in the symbol name pool to save it.
580 signature
= symtab
->canonicalize_name(signature
);
581 this->group_signatures_
.push_back(Group_signature(os
, signature
));
584 os
->set_should_link_to_symtab();
587 section_size_type entry_count
=
588 convert_to_section_size_type(shdr
.get_sh_size() / 4);
589 Output_section_data
* posd
=
590 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
592 os
->add_output_section_data(posd
);
595 // Special GNU handling of sections name .eh_frame. They will
596 // normally hold exception frame data as defined by the C++ ABI
597 // (http://codesourcery.com/cxx-abi/).
599 template<int size
, bool big_endian
>
601 Layout::layout_eh_frame(Sized_relobj
<size
, big_endian
>* object
,
602 const unsigned char* symbols
,
604 const unsigned char* symbol_names
,
605 off_t symbol_names_size
,
607 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
608 unsigned int reloc_shndx
, unsigned int reloc_type
,
611 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
);
612 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
614 const char* const name
= ".eh_frame";
615 Output_section
* os
= this->choose_output_section(object
,
617 elfcpp::SHT_PROGBITS
,
623 if (this->eh_frame_section_
== NULL
)
625 this->eh_frame_section_
= os
;
626 this->eh_frame_data_
= new Eh_frame();
628 if (this->options_
.eh_frame_hdr())
630 Output_section
* hdr_os
=
631 this->choose_output_section(NULL
,
633 elfcpp::SHT_PROGBITS
,
639 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
640 this->eh_frame_data_
);
641 hdr_os
->add_output_section_data(hdr_posd
);
643 hdr_os
->set_after_input_sections();
645 if (!this->script_options_
->saw_phdrs_clause())
647 Output_segment
* hdr_oseg
;
648 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
650 hdr_oseg
->add_output_section(hdr_os
, elfcpp::PF_R
);
653 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
658 gold_assert(this->eh_frame_section_
== os
);
660 if (this->eh_frame_data_
->add_ehframe_input_section(object
,
669 os
->update_flags_for_input_section(shdr
.get_sh_flags());
671 // We found a .eh_frame section we are going to optimize, so now
672 // we can add the set of optimized sections to the output
673 // section. We need to postpone adding this until we've found a
674 // section we can optimize so that the .eh_frame section in
675 // crtbegin.o winds up at the start of the output section.
676 if (!this->added_eh_frame_data_
)
678 os
->add_output_section_data(this->eh_frame_data_
);
679 this->added_eh_frame_data_
= true;
685 // We couldn't handle this .eh_frame section for some reason.
686 // Add it as a normal section.
687 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
688 *off
= os
->add_input_section(object
, shndx
, name
, shdr
, reloc_shndx
,
689 saw_sections_clause
);
695 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
696 // the output section.
699 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
700 elfcpp::Elf_Xword flags
,
701 Output_section_data
* posd
)
703 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
706 os
->add_output_section_data(posd
);
710 // Map section flags to segment flags.
713 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
715 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
716 if ((flags
& elfcpp::SHF_WRITE
) != 0)
718 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
723 // Sometimes we compress sections. This is typically done for
724 // sections that are not part of normal program execution (such as
725 // .debug_* sections), and where the readers of these sections know
726 // how to deal with compressed sections. (To make it easier for them,
727 // we will rename the ouput section in such cases from .foo to
728 // .foo.zlib.nnnn, where nnnn is the uncompressed size.) This routine
729 // doesn't say for certain whether we'll compress -- it depends on
730 // commandline options as well -- just whether this section is a
731 // candidate for compression.
734 is_compressible_debug_section(const char* secname
)
736 return (strncmp(secname
, ".debug", sizeof(".debug") - 1) == 0);
739 // Make a new Output_section, and attach it to segments as
743 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
744 elfcpp::Elf_Xword flags
)
747 if ((flags
& elfcpp::SHF_ALLOC
) == 0
748 && strcmp(this->options_
.compress_debug_sections(), "none") != 0
749 && is_compressible_debug_section(name
))
750 os
= new Output_compressed_section(&this->options_
, name
, type
, flags
);
752 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
753 && this->options_
.strip_debug_non_line()
754 && strcmp(".debug_abbrev", name
) == 0)
756 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
758 if (this->debug_info_
)
759 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
761 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
762 && this->options_
.strip_debug_non_line()
763 && strcmp(".debug_info", name
) == 0)
765 os
= this->debug_info_
= new Output_reduced_debug_info_section(
767 if (this->debug_abbrev_
)
768 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
771 os
= new Output_section(name
, type
, flags
);
773 this->section_list_
.push_back(os
);
775 // The GNU linker by default sorts some sections by priority, so we
776 // do the same. We need to know that this might happen before we
777 // attach any input sections.
778 if (!this->script_options_
->saw_sections_clause()
779 && (strcmp(name
, ".ctors") == 0
780 || strcmp(name
, ".dtors") == 0
781 || strcmp(name
, ".init_array") == 0
782 || strcmp(name
, ".fini_array") == 0))
783 os
->set_may_sort_attached_input_sections();
785 // With -z relro, we have to recognize the special sections by name.
786 // There is no other way.
787 if (!this->script_options_
->saw_sections_clause()
788 && parameters
->options().relro()
789 && type
== elfcpp::SHT_PROGBITS
790 && (flags
& elfcpp::SHF_ALLOC
) != 0
791 && (flags
& elfcpp::SHF_WRITE
) != 0)
793 if (strcmp(name
, ".data.rel.ro") == 0)
795 else if (strcmp(name
, ".data.rel.ro.local") == 0)
798 os
->set_is_relro_local();
802 // If we have already attached the sections to segments, then we
803 // need to attach this one now. This happens for sections created
804 // directly by the linker.
805 if (this->sections_are_attached_
)
806 this->attach_section_to_segment(os
);
811 // Attach output sections to segments. This is called after we have
812 // seen all the input sections.
815 Layout::attach_sections_to_segments()
817 for (Section_list::iterator p
= this->section_list_
.begin();
818 p
!= this->section_list_
.end();
820 this->attach_section_to_segment(*p
);
822 this->sections_are_attached_
= true;
825 // Attach an output section to a segment.
828 Layout::attach_section_to_segment(Output_section
* os
)
830 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
831 this->unattached_section_list_
.push_back(os
);
833 this->attach_allocated_section_to_segment(os
);
836 // Attach an allocated output section to a segment.
839 Layout::attach_allocated_section_to_segment(Output_section
* os
)
841 elfcpp::Elf_Xword flags
= os
->flags();
842 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
844 if (parameters
->options().relocatable())
847 // If we have a SECTIONS clause, we can't handle the attachment to
848 // segments until after we've seen all the sections.
849 if (this->script_options_
->saw_sections_clause())
852 gold_assert(!this->script_options_
->saw_phdrs_clause());
854 // This output section goes into a PT_LOAD segment.
856 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
858 // In general the only thing we really care about for PT_LOAD
859 // segments is whether or not they are writable, so that is how we
860 // search for them. People who need segments sorted on some other
861 // basis will have to use a linker script.
863 Segment_list::const_iterator p
;
864 for (p
= this->segment_list_
.begin();
865 p
!= this->segment_list_
.end();
868 if ((*p
)->type() == elfcpp::PT_LOAD
869 && (parameters
->options().omagic()
870 || ((*p
)->flags() & elfcpp::PF_W
) == (seg_flags
& elfcpp::PF_W
)))
872 // If -Tbss was specified, we need to separate the data
874 if (this->options_
.user_set_Tbss())
876 if ((os
->type() == elfcpp::SHT_NOBITS
)
877 == (*p
)->has_any_data_sections())
881 (*p
)->add_output_section(os
, seg_flags
);
886 if (p
== this->segment_list_
.end())
888 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
890 oseg
->add_output_section(os
, seg_flags
);
893 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
895 if (os
->type() == elfcpp::SHT_NOTE
)
897 // See if we already have an equivalent PT_NOTE segment.
898 for (p
= this->segment_list_
.begin();
899 p
!= segment_list_
.end();
902 if ((*p
)->type() == elfcpp::PT_NOTE
903 && (((*p
)->flags() & elfcpp::PF_W
)
904 == (seg_flags
& elfcpp::PF_W
)))
906 (*p
)->add_output_section(os
, seg_flags
);
911 if (p
== this->segment_list_
.end())
913 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
915 oseg
->add_output_section(os
, seg_flags
);
919 // If we see a loadable SHF_TLS section, we create a PT_TLS
920 // segment. There can only be one such segment.
921 if ((flags
& elfcpp::SHF_TLS
) != 0)
923 if (this->tls_segment_
== NULL
)
924 this->tls_segment_
= this->make_output_segment(elfcpp::PT_TLS
,
926 this->tls_segment_
->add_output_section(os
, seg_flags
);
929 // If -z relro is in effect, and we see a relro section, we create a
930 // PT_GNU_RELRO segment. There can only be one such segment.
931 if (os
->is_relro() && parameters
->options().relro())
933 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
934 if (this->relro_segment_
== NULL
)
935 this->relro_segment_
= this->make_output_segment(elfcpp::PT_GNU_RELRO
,
937 this->relro_segment_
->add_output_section(os
, seg_flags
);
941 // Make an output section for a script.
944 Layout::make_output_section_for_script(const char* name
)
946 name
= this->namepool_
.add(name
, false, NULL
);
947 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
949 os
->set_found_in_sections_clause();
953 // Return the number of segments we expect to see.
956 Layout::expected_segment_count() const
958 size_t ret
= this->segment_list_
.size();
960 // If we didn't see a SECTIONS clause in a linker script, we should
961 // already have the complete list of segments. Otherwise we ask the
962 // SECTIONS clause how many segments it expects, and add in the ones
963 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
965 if (!this->script_options_
->saw_sections_clause())
969 const Script_sections
* ss
= this->script_options_
->script_sections();
970 return ret
+ ss
->expected_segment_count(this);
974 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
975 // is whether we saw a .note.GNU-stack section in the object file.
976 // GNU_STACK_FLAGS is the section flags. The flags give the
977 // protection required for stack memory. We record this in an
978 // executable as a PT_GNU_STACK segment. If an object file does not
979 // have a .note.GNU-stack segment, we must assume that it is an old
980 // object. On some targets that will force an executable stack.
983 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
)
986 this->input_without_gnu_stack_note_
= true;
989 this->input_with_gnu_stack_note_
= true;
990 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
991 this->input_requires_executable_stack_
= true;
995 // Create the dynamic sections which are needed before we read the
999 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
1001 if (parameters
->doing_static_link())
1004 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
1005 elfcpp::SHT_DYNAMIC
,
1007 | elfcpp::SHF_WRITE
),
1009 this->dynamic_section_
->set_is_relro();
1011 symtab
->define_in_output_data("_DYNAMIC", NULL
, this->dynamic_section_
, 0, 0,
1012 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
1013 elfcpp::STV_HIDDEN
, 0, false, false);
1015 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
1017 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
1020 // For each output section whose name can be represented as C symbol,
1021 // define __start and __stop symbols for the section. This is a GNU
1025 Layout::define_section_symbols(Symbol_table
* symtab
)
1027 for (Section_list::const_iterator p
= this->section_list_
.begin();
1028 p
!= this->section_list_
.end();
1031 const char* const name
= (*p
)->name();
1032 if (name
[strspn(name
,
1034 "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
1035 "abcdefghijklmnopqrstuvwxyz"
1039 const std::string
name_string(name
);
1040 const std::string
start_name("__start_" + name_string
);
1041 const std::string
stop_name("__stop_" + name_string
);
1043 symtab
->define_in_output_data(start_name
.c_str(),
1050 elfcpp::STV_DEFAULT
,
1052 false, // offset_is_from_end
1053 true); // only_if_ref
1055 symtab
->define_in_output_data(stop_name
.c_str(),
1062 elfcpp::STV_DEFAULT
,
1064 true, // offset_is_from_end
1065 true); // only_if_ref
1070 // Define symbols for group signatures.
1073 Layout::define_group_signatures(Symbol_table
* symtab
)
1075 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
1076 p
!= this->group_signatures_
.end();
1079 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
1081 p
->section
->set_info_symndx(sym
);
1084 // Force the name of the group section to the group
1085 // signature, and use the group's section symbol as the
1086 // signature symbol.
1087 if (strcmp(p
->section
->name(), p
->signature
) != 0)
1089 const char* name
= this->namepool_
.add(p
->signature
,
1091 p
->section
->set_name(name
);
1093 p
->section
->set_needs_symtab_index();
1094 p
->section
->set_info_section_symndx(p
->section
);
1098 this->group_signatures_
.clear();
1101 // Find the first read-only PT_LOAD segment, creating one if
1105 Layout::find_first_load_seg()
1107 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
1108 p
!= this->segment_list_
.end();
1111 if ((*p
)->type() == elfcpp::PT_LOAD
1112 && ((*p
)->flags() & elfcpp::PF_R
) != 0
1113 && (parameters
->options().omagic()
1114 || ((*p
)->flags() & elfcpp::PF_W
) == 0))
1118 gold_assert(!this->script_options_
->saw_phdrs_clause());
1120 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
1125 // Finalize the layout. When this is called, we have created all the
1126 // output sections and all the output segments which are based on
1127 // input sections. We have several things to do, and we have to do
1128 // them in the right order, so that we get the right results correctly
1131 // 1) Finalize the list of output segments and create the segment
1134 // 2) Finalize the dynamic symbol table and associated sections.
1136 // 3) Determine the final file offset of all the output segments.
1138 // 4) Determine the final file offset of all the SHF_ALLOC output
1141 // 5) Create the symbol table sections and the section name table
1144 // 6) Finalize the symbol table: set symbol values to their final
1145 // value and make a final determination of which symbols are going
1146 // into the output symbol table.
1148 // 7) Create the section table header.
1150 // 8) Determine the final file offset of all the output sections which
1151 // are not SHF_ALLOC, including the section table header.
1153 // 9) Finalize the ELF file header.
1155 // This function returns the size of the output file.
1158 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
1159 Target
* target
, const Task
* task
)
1161 target
->finalize_sections(this);
1163 this->count_local_symbols(task
, input_objects
);
1165 this->create_gold_note();
1166 this->create_executable_stack_info(target
);
1167 this->create_build_id();
1169 Output_segment
* phdr_seg
= NULL
;
1170 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
1172 // There was a dynamic object in the link. We need to create
1173 // some information for the dynamic linker.
1175 // Create the PT_PHDR segment which will hold the program
1177 if (!this->script_options_
->saw_phdrs_clause())
1178 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
1180 // Create the dynamic symbol table, including the hash table.
1181 Output_section
* dynstr
;
1182 std::vector
<Symbol
*> dynamic_symbols
;
1183 unsigned int local_dynamic_count
;
1184 Versions
versions(*this->script_options()->version_script_info(),
1186 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
1187 &local_dynamic_count
, &dynamic_symbols
,
1190 // Create the .interp section to hold the name of the
1191 // interpreter, and put it in a PT_INTERP segment.
1192 if (!parameters
->options().shared())
1193 this->create_interp(target
);
1195 // Finish the .dynamic section to hold the dynamic data, and put
1196 // it in a PT_DYNAMIC segment.
1197 this->finish_dynamic_section(input_objects
, symtab
);
1199 // We should have added everything we need to the dynamic string
1201 this->dynpool_
.set_string_offsets();
1203 // Create the version sections. We can't do this until the
1204 // dynamic string table is complete.
1205 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
1206 dynamic_symbols
, dynstr
);
1209 // If there is a SECTIONS clause, put all the input sections into
1210 // the required order.
1211 Output_segment
* load_seg
;
1212 if (this->script_options_
->saw_sections_clause())
1213 load_seg
= this->set_section_addresses_from_script(symtab
);
1214 else if (parameters
->options().relocatable())
1217 load_seg
= this->find_first_load_seg();
1219 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
1222 gold_assert(phdr_seg
== NULL
|| load_seg
!= NULL
);
1224 // Lay out the segment headers.
1225 Output_segment_headers
* segment_headers
;
1226 if (parameters
->options().relocatable())
1227 segment_headers
= NULL
;
1230 segment_headers
= new Output_segment_headers(this->segment_list_
);
1231 if (load_seg
!= NULL
)
1232 load_seg
->add_initial_output_data(segment_headers
);
1233 if (phdr_seg
!= NULL
)
1234 phdr_seg
->add_initial_output_data(segment_headers
);
1237 // Lay out the file header.
1238 Output_file_header
* file_header
;
1239 file_header
= new Output_file_header(target
, symtab
, segment_headers
,
1240 this->options_
.entry());
1241 if (load_seg
!= NULL
)
1242 load_seg
->add_initial_output_data(file_header
);
1244 this->special_output_list_
.push_back(file_header
);
1245 if (segment_headers
!= NULL
)
1246 this->special_output_list_
.push_back(segment_headers
);
1248 if (this->script_options_
->saw_phdrs_clause()
1249 && !parameters
->options().relocatable())
1251 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1252 // clause in a linker script.
1253 Script_sections
* ss
= this->script_options_
->script_sections();
1254 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
1257 // We set the output section indexes in set_segment_offsets and
1258 // set_section_indexes.
1259 unsigned int shndx
= 1;
1261 // Set the file offsets of all the segments, and all the sections
1264 if (!parameters
->options().relocatable())
1265 off
= this->set_segment_offsets(target
, load_seg
, &shndx
);
1267 off
= this->set_relocatable_section_offsets(file_header
, &shndx
);
1269 // Set the file offsets of all the non-data sections we've seen so
1270 // far which don't have to wait for the input sections. We need
1271 // this in order to finalize local symbols in non-allocated
1273 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
1275 // Set the section indexes of all unallocated sections seen so far,
1276 // in case any of them are somehow referenced by a symbol.
1277 shndx
= this->set_section_indexes(shndx
);
1279 // Create the symbol table sections.
1280 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
1281 if (!parameters
->doing_static_link())
1282 this->assign_local_dynsym_offsets(input_objects
);
1284 // Process any symbol assignments from a linker script. This must
1285 // be called after the symbol table has been finalized.
1286 this->script_options_
->finalize_symbols(symtab
, this);
1288 // Create the .shstrtab section.
1289 Output_section
* shstrtab_section
= this->create_shstrtab();
1291 // Set the file offsets of the rest of the non-data sections which
1292 // don't have to wait for the input sections.
1293 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
1295 // Now that all sections have been created, set the section indexes
1296 // for any sections which haven't been done yet.
1297 shndx
= this->set_section_indexes(shndx
);
1299 // Create the section table header.
1300 this->create_shdrs(shstrtab_section
, &off
);
1302 // If there are no sections which require postprocessing, we can
1303 // handle the section names now, and avoid a resize later.
1304 if (!this->any_postprocessing_sections_
)
1305 off
= this->set_section_offsets(off
,
1306 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
1308 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
1310 // Now we know exactly where everything goes in the output file
1311 // (except for non-allocated sections which require postprocessing).
1312 Output_data::layout_complete();
1314 this->output_file_size_
= off
;
1319 // Create a note header following the format defined in the ELF ABI.
1320 // NAME is the name, NOTE_TYPE is the type, DESCSZ is the size of the
1321 // descriptor. ALLOCATE is true if the section should be allocated in
1322 // memory. This returns the new note section. It sets
1323 // *TRAILING_PADDING to the number of trailing zero bytes required.
1326 Layout::create_note(const char* name
, int note_type
, size_t descsz
,
1327 bool allocate
, size_t* trailing_padding
)
1329 // Authorities all agree that the values in a .note field should
1330 // be aligned on 4-byte boundaries for 32-bit binaries. However,
1331 // they differ on what the alignment is for 64-bit binaries.
1332 // The GABI says unambiguously they take 8-byte alignment:
1333 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
1334 // Other documentation says alignment should always be 4 bytes:
1335 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
1336 // GNU ld and GNU readelf both support the latter (at least as of
1337 // version 2.16.91), and glibc always generates the latter for
1338 // .note.ABI-tag (as of version 1.6), so that's the one we go with
1340 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
1341 const int size
= parameters
->target().get_size();
1343 const int size
= 32;
1346 // The contents of the .note section.
1347 size_t namesz
= strlen(name
) + 1;
1348 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
1349 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
1351 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
1353 unsigned char* buffer
= new unsigned char[notehdrsz
];
1354 memset(buffer
, 0, notehdrsz
);
1356 bool is_big_endian
= parameters
->target().is_big_endian();
1362 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
1363 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
1364 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
1368 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
1369 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
1370 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
1373 else if (size
== 64)
1377 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
1378 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
1379 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
1383 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
1384 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
1385 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
1391 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
1393 const char* note_name
= this->namepool_
.add(".note", false, NULL
);
1394 elfcpp::Elf_Xword flags
= 0;
1396 flags
= elfcpp::SHF_ALLOC
;
1397 Output_section
* os
= this->make_output_section(note_name
,
1400 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
1403 os
->add_output_section_data(posd
);
1405 *trailing_padding
= aligned_descsz
- descsz
;
1410 // For an executable or shared library, create a note to record the
1411 // version of gold used to create the binary.
1414 Layout::create_gold_note()
1416 if (parameters
->options().relocatable())
1419 std::string desc
= std::string("gold ") + gold::get_version_string();
1421 size_t trailing_padding
;
1422 Output_section
*os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
1423 desc
.size(), false, &trailing_padding
);
1425 Output_section_data
* posd
= new Output_data_const(desc
, 4);
1426 os
->add_output_section_data(posd
);
1428 if (trailing_padding
> 0)
1430 posd
= new Output_data_zero_fill(trailing_padding
, 0);
1431 os
->add_output_section_data(posd
);
1435 // Record whether the stack should be executable. This can be set
1436 // from the command line using the -z execstack or -z noexecstack
1437 // options. Otherwise, if any input file has a .note.GNU-stack
1438 // section with the SHF_EXECINSTR flag set, the stack should be
1439 // executable. Otherwise, if at least one input file a
1440 // .note.GNU-stack section, and some input file has no .note.GNU-stack
1441 // section, we use the target default for whether the stack should be
1442 // executable. Otherwise, we don't generate a stack note. When
1443 // generating a object file, we create a .note.GNU-stack section with
1444 // the appropriate marking. When generating an executable or shared
1445 // library, we create a PT_GNU_STACK segment.
1448 Layout::create_executable_stack_info(const Target
* target
)
1450 bool is_stack_executable
;
1451 if (this->options_
.is_execstack_set())
1452 is_stack_executable
= this->options_
.is_stack_executable();
1453 else if (!this->input_with_gnu_stack_note_
)
1457 if (this->input_requires_executable_stack_
)
1458 is_stack_executable
= true;
1459 else if (this->input_without_gnu_stack_note_
)
1460 is_stack_executable
= target
->is_default_stack_executable();
1462 is_stack_executable
= false;
1465 if (parameters
->options().relocatable())
1467 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
1468 elfcpp::Elf_Xword flags
= 0;
1469 if (is_stack_executable
)
1470 flags
|= elfcpp::SHF_EXECINSTR
;
1471 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
);
1475 if (this->script_options_
->saw_phdrs_clause())
1477 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
1478 if (is_stack_executable
)
1479 flags
|= elfcpp::PF_X
;
1480 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
1484 // If --build-id was used, set up the build ID note.
1487 Layout::create_build_id()
1489 if (!parameters
->options().user_set_build_id())
1492 const char* style
= parameters
->options().build_id();
1493 if (strcmp(style
, "none") == 0)
1496 // Set DESCSZ to the size of the note descriptor. When possible,
1497 // set DESC to the note descriptor contents.
1500 if (strcmp(style
, "md5") == 0)
1502 else if (strcmp(style
, "sha1") == 0)
1504 else if (strcmp(style
, "uuid") == 0)
1506 const size_t uuidsz
= 128 / 8;
1508 char buffer
[uuidsz
];
1509 memset(buffer
, 0, uuidsz
);
1511 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
1513 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
1517 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
1518 release_descriptor(descriptor
, true);
1520 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
1521 else if (static_cast<size_t>(got
) != uuidsz
)
1522 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
1526 desc
.assign(buffer
, uuidsz
);
1529 else if (strncmp(style
, "0x", 2) == 0)
1532 const char* p
= style
+ 2;
1535 if (hex_p(p
[0]) && hex_p(p
[1]))
1537 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
1541 else if (*p
== '-' || *p
== ':')
1544 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
1547 descsz
= desc
.size();
1550 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
1553 size_t trailing_padding
;
1554 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
1555 descsz
, true, &trailing_padding
);
1559 // We know the value already, so we fill it in now.
1560 gold_assert(desc
.size() == descsz
);
1562 Output_section_data
* posd
= new Output_data_const(desc
, 4);
1563 os
->add_output_section_data(posd
);
1565 if (trailing_padding
!= 0)
1567 posd
= new Output_data_zero_fill(trailing_padding
, 0);
1568 os
->add_output_section_data(posd
);
1573 // We need to compute a checksum after we have completed the
1575 gold_assert(trailing_padding
== 0);
1576 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
1577 os
->add_output_section_data(this->build_id_note_
);
1578 os
->set_after_input_sections();
1582 // Return whether SEG1 should be before SEG2 in the output file. This
1583 // is based entirely on the segment type and flags. When this is
1584 // called the segment addresses has normally not yet been set.
1587 Layout::segment_precedes(const Output_segment
* seg1
,
1588 const Output_segment
* seg2
)
1590 elfcpp::Elf_Word type1
= seg1
->type();
1591 elfcpp::Elf_Word type2
= seg2
->type();
1593 // The single PT_PHDR segment is required to precede any loadable
1594 // segment. We simply make it always first.
1595 if (type1
== elfcpp::PT_PHDR
)
1597 gold_assert(type2
!= elfcpp::PT_PHDR
);
1600 if (type2
== elfcpp::PT_PHDR
)
1603 // The single PT_INTERP segment is required to precede any loadable
1604 // segment. We simply make it always second.
1605 if (type1
== elfcpp::PT_INTERP
)
1607 gold_assert(type2
!= elfcpp::PT_INTERP
);
1610 if (type2
== elfcpp::PT_INTERP
)
1613 // We then put PT_LOAD segments before any other segments.
1614 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
1616 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
1619 // We put the PT_TLS segment last except for the PT_GNU_RELRO
1620 // segment, because that is where the dynamic linker expects to find
1621 // it (this is just for efficiency; other positions would also work
1623 if (type1
== elfcpp::PT_TLS
1624 && type2
!= elfcpp::PT_TLS
1625 && type2
!= elfcpp::PT_GNU_RELRO
)
1627 if (type2
== elfcpp::PT_TLS
1628 && type1
!= elfcpp::PT_TLS
1629 && type1
!= elfcpp::PT_GNU_RELRO
)
1632 // We put the PT_GNU_RELRO segment last, because that is where the
1633 // dynamic linker expects to find it (as with PT_TLS, this is just
1635 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
1637 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
1640 const elfcpp::Elf_Word flags1
= seg1
->flags();
1641 const elfcpp::Elf_Word flags2
= seg2
->flags();
1643 // The order of non-PT_LOAD segments is unimportant. We simply sort
1644 // by the numeric segment type and flags values. There should not
1645 // be more than one segment with the same type and flags.
1646 if (type1
!= elfcpp::PT_LOAD
)
1649 return type1
< type2
;
1650 gold_assert(flags1
!= flags2
);
1651 return flags1
< flags2
;
1654 // If the addresses are set already, sort by load address.
1655 if (seg1
->are_addresses_set())
1657 if (!seg2
->are_addresses_set())
1660 unsigned int section_count1
= seg1
->output_section_count();
1661 unsigned int section_count2
= seg2
->output_section_count();
1662 if (section_count1
== 0 && section_count2
> 0)
1664 if (section_count1
> 0 && section_count2
== 0)
1667 uint64_t paddr1
= seg1
->first_section_load_address();
1668 uint64_t paddr2
= seg2
->first_section_load_address();
1669 if (paddr1
!= paddr2
)
1670 return paddr1
< paddr2
;
1672 else if (seg2
->are_addresses_set())
1675 // We sort PT_LOAD segments based on the flags. Readonly segments
1676 // come before writable segments. Then writable segments with data
1677 // come before writable segments without data. Then executable
1678 // segments come before non-executable segments. Then the unlikely
1679 // case of a non-readable segment comes before the normal case of a
1680 // readable segment. If there are multiple segments with the same
1681 // type and flags, we require that the address be set, and we sort
1682 // by virtual address and then physical address.
1683 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
1684 return (flags1
& elfcpp::PF_W
) == 0;
1685 if ((flags1
& elfcpp::PF_W
) != 0
1686 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
1687 return seg1
->has_any_data_sections();
1688 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
1689 return (flags1
& elfcpp::PF_X
) != 0;
1690 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
1691 return (flags1
& elfcpp::PF_R
) == 0;
1693 // We shouldn't get here--we shouldn't create segments which we
1694 // can't distinguish.
1698 // Set the file offsets of all the segments, and all the sections they
1699 // contain. They have all been created. LOAD_SEG must be be laid out
1700 // first. Return the offset of the data to follow.
1703 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
1704 unsigned int *pshndx
)
1706 // Sort them into the final order.
1707 std::sort(this->segment_list_
.begin(), this->segment_list_
.end(),
1708 Layout::Compare_segments());
1710 // Find the PT_LOAD segments, and set their addresses and offsets
1711 // and their section's addresses and offsets.
1713 if (this->options_
.user_set_Ttext())
1714 addr
= this->options_
.Ttext();
1715 else if (parameters
->options().shared())
1718 addr
= target
->default_text_segment_address();
1721 // If LOAD_SEG is NULL, then the file header and segment headers
1722 // will not be loadable. But they still need to be at offset 0 in
1723 // the file. Set their offsets now.
1724 if (load_seg
== NULL
)
1726 for (Data_list::iterator p
= this->special_output_list_
.begin();
1727 p
!= this->special_output_list_
.end();
1730 off
= align_address(off
, (*p
)->addralign());
1731 (*p
)->set_address_and_file_offset(0, off
);
1732 off
+= (*p
)->data_size();
1736 const bool check_sections
= parameters
->options().check_sections();
1737 Output_segment
* last_load_segment
= NULL
;
1739 bool was_readonly
= false;
1740 for (Segment_list::iterator p
= this->segment_list_
.begin();
1741 p
!= this->segment_list_
.end();
1744 if ((*p
)->type() == elfcpp::PT_LOAD
)
1746 if (load_seg
!= NULL
&& load_seg
!= *p
)
1750 bool are_addresses_set
= (*p
)->are_addresses_set();
1751 if (are_addresses_set
)
1753 // When it comes to setting file offsets, we care about
1754 // the physical address.
1755 addr
= (*p
)->paddr();
1757 else if (this->options_
.user_set_Tdata()
1758 && ((*p
)->flags() & elfcpp::PF_W
) != 0
1759 && (!this->options_
.user_set_Tbss()
1760 || (*p
)->has_any_data_sections()))
1762 addr
= this->options_
.Tdata();
1763 are_addresses_set
= true;
1765 else if (this->options_
.user_set_Tbss()
1766 && ((*p
)->flags() & elfcpp::PF_W
) != 0
1767 && !(*p
)->has_any_data_sections())
1769 addr
= this->options_
.Tbss();
1770 are_addresses_set
= true;
1773 uint64_t orig_addr
= addr
;
1774 uint64_t orig_off
= off
;
1776 uint64_t aligned_addr
= 0;
1777 uint64_t abi_pagesize
= target
->abi_pagesize();
1778 uint64_t common_pagesize
= target
->common_pagesize();
1780 if (!parameters
->options().nmagic()
1781 && !parameters
->options().omagic())
1782 (*p
)->set_minimum_p_align(common_pagesize
);
1784 if (are_addresses_set
)
1786 if (!parameters
->options().nmagic()
1787 && !parameters
->options().omagic())
1789 // Adjust the file offset to the same address modulo
1791 uint64_t unsigned_off
= off
;
1792 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
1793 | (addr
& (abi_pagesize
- 1)));
1794 if (aligned_off
< unsigned_off
)
1795 aligned_off
+= abi_pagesize
;
1801 // If the last segment was readonly, and this one is
1802 // not, then skip the address forward one page,
1803 // maintaining the same position within the page. This
1804 // lets us store both segments overlapping on a single
1805 // page in the file, but the loader will put them on
1806 // different pages in memory.
1808 addr
= align_address(addr
, (*p
)->maximum_alignment());
1809 aligned_addr
= addr
;
1811 if (was_readonly
&& ((*p
)->flags() & elfcpp::PF_W
) != 0)
1813 if ((addr
& (abi_pagesize
- 1)) != 0)
1814 addr
= addr
+ abi_pagesize
;
1817 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
1820 unsigned int shndx_hold
= *pshndx
;
1821 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
1824 // Now that we know the size of this segment, we may be able
1825 // to save a page in memory, at the cost of wasting some
1826 // file space, by instead aligning to the start of a new
1827 // page. Here we use the real machine page size rather than
1828 // the ABI mandated page size.
1830 if (!are_addresses_set
&& aligned_addr
!= addr
)
1832 uint64_t first_off
= (common_pagesize
1834 & (common_pagesize
- 1)));
1835 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
1838 && ((aligned_addr
& ~ (common_pagesize
- 1))
1839 != (new_addr
& ~ (common_pagesize
- 1)))
1840 && first_off
+ last_off
<= common_pagesize
)
1842 *pshndx
= shndx_hold
;
1843 addr
= align_address(aligned_addr
, common_pagesize
);
1844 addr
= align_address(addr
, (*p
)->maximum_alignment());
1845 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
1846 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
1853 if (((*p
)->flags() & elfcpp::PF_W
) == 0)
1854 was_readonly
= true;
1856 // Implement --check-sections. We know that the segments
1857 // are sorted by LMA.
1858 if (check_sections
&& last_load_segment
!= NULL
)
1860 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
1861 if (last_load_segment
->paddr() + last_load_segment
->memsz()
1864 unsigned long long lb1
= last_load_segment
->paddr();
1865 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
1866 unsigned long long lb2
= (*p
)->paddr();
1867 unsigned long long le2
= lb2
+ (*p
)->memsz();
1868 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
1869 "[0x%llx -> 0x%llx]"),
1870 lb1
, le1
, lb2
, le2
);
1873 last_load_segment
= *p
;
1877 // Handle the non-PT_LOAD segments, setting their offsets from their
1878 // section's offsets.
1879 for (Segment_list::iterator p
= this->segment_list_
.begin();
1880 p
!= this->segment_list_
.end();
1883 if ((*p
)->type() != elfcpp::PT_LOAD
)
1887 // Set the TLS offsets for each section in the PT_TLS segment.
1888 if (this->tls_segment_
!= NULL
)
1889 this->tls_segment_
->set_tls_offsets();
1894 // Set the offsets of all the allocated sections when doing a
1895 // relocatable link. This does the same jobs as set_segment_offsets,
1896 // only for a relocatable link.
1899 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
1900 unsigned int *pshndx
)
1904 file_header
->set_address_and_file_offset(0, 0);
1905 off
+= file_header
->data_size();
1907 for (Section_list::iterator p
= this->section_list_
.begin();
1908 p
!= this->section_list_
.end();
1911 // We skip unallocated sections here, except that group sections
1912 // have to come first.
1913 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
1914 && (*p
)->type() != elfcpp::SHT_GROUP
)
1917 off
= align_address(off
, (*p
)->addralign());
1919 // The linker script might have set the address.
1920 if (!(*p
)->is_address_valid())
1921 (*p
)->set_address(0);
1922 (*p
)->set_file_offset(off
);
1923 (*p
)->finalize_data_size();
1924 off
+= (*p
)->data_size();
1926 (*p
)->set_out_shndx(*pshndx
);
1933 // Set the file offset of all the sections not associated with a
1937 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
1939 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
1940 p
!= this->unattached_section_list_
.end();
1943 // The symtab section is handled in create_symtab_sections.
1944 if (*p
== this->symtab_section_
)
1947 // If we've already set the data size, don't set it again.
1948 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
1951 if (pass
== BEFORE_INPUT_SECTIONS_PASS
1952 && (*p
)->requires_postprocessing())
1954 (*p
)->create_postprocessing_buffer();
1955 this->any_postprocessing_sections_
= true;
1958 if (pass
== BEFORE_INPUT_SECTIONS_PASS
1959 && (*p
)->after_input_sections())
1961 else if (pass
== POSTPROCESSING_SECTIONS_PASS
1962 && (!(*p
)->after_input_sections()
1963 || (*p
)->type() == elfcpp::SHT_STRTAB
))
1965 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
1966 && (!(*p
)->after_input_sections()
1967 || (*p
)->type() != elfcpp::SHT_STRTAB
))
1970 off
= align_address(off
, (*p
)->addralign());
1971 (*p
)->set_file_offset(off
);
1972 (*p
)->finalize_data_size();
1973 off
+= (*p
)->data_size();
1975 // At this point the name must be set.
1976 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
1977 this->namepool_
.add((*p
)->name(), false, NULL
);
1982 // Set the section indexes of all the sections not associated with a
1986 Layout::set_section_indexes(unsigned int shndx
)
1988 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
1989 p
!= this->unattached_section_list_
.end();
1992 if (!(*p
)->has_out_shndx())
1994 (*p
)->set_out_shndx(shndx
);
2001 // Set the section addresses according to the linker script. This is
2002 // only called when we see a SECTIONS clause. This returns the
2003 // program segment which should hold the file header and segment
2004 // headers, if any. It will return NULL if they should not be in a
2008 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
2010 Script_sections
* ss
= this->script_options_
->script_sections();
2011 gold_assert(ss
->saw_sections_clause());
2013 // Place each orphaned output section in the script.
2014 for (Section_list::iterator p
= this->section_list_
.begin();
2015 p
!= this->section_list_
.end();
2018 if (!(*p
)->found_in_sections_clause())
2019 ss
->place_orphan(*p
);
2022 return this->script_options_
->set_section_addresses(symtab
, this);
2025 // Count the local symbols in the regular symbol table and the dynamic
2026 // symbol table, and build the respective string pools.
2029 Layout::count_local_symbols(const Task
* task
,
2030 const Input_objects
* input_objects
)
2032 // First, figure out an upper bound on the number of symbols we'll
2033 // be inserting into each pool. This helps us create the pools with
2034 // the right size, to avoid unnecessary hashtable resizing.
2035 unsigned int symbol_count
= 0;
2036 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2037 p
!= input_objects
->relobj_end();
2039 symbol_count
+= (*p
)->local_symbol_count();
2041 // Go from "upper bound" to "estimate." We overcount for two
2042 // reasons: we double-count symbols that occur in more than one
2043 // object file, and we count symbols that are dropped from the
2044 // output. Add it all together and assume we overcount by 100%.
2047 // We assume all symbols will go into both the sympool and dynpool.
2048 this->sympool_
.reserve(symbol_count
);
2049 this->dynpool_
.reserve(symbol_count
);
2051 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2052 p
!= input_objects
->relobj_end();
2055 Task_lock_obj
<Object
> tlo(task
, *p
);
2056 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
2060 // Create the symbol table sections. Here we also set the final
2061 // values of the symbols. At this point all the loadable sections are
2062 // fully laid out. SHNUM is the number of sections so far.
2065 Layout::create_symtab_sections(const Input_objects
* input_objects
,
2066 Symbol_table
* symtab
,
2072 if (parameters
->target().get_size() == 32)
2074 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
2077 else if (parameters
->target().get_size() == 64)
2079 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
2086 off
= align_address(off
, align
);
2087 off_t startoff
= off
;
2089 // Save space for the dummy symbol at the start of the section. We
2090 // never bother to write this out--it will just be left as zero.
2092 unsigned int local_symbol_index
= 1;
2094 // Add STT_SECTION symbols for each Output section which needs one.
2095 for (Section_list::iterator p
= this->section_list_
.begin();
2096 p
!= this->section_list_
.end();
2099 if (!(*p
)->needs_symtab_index())
2100 (*p
)->set_symtab_index(-1U);
2103 (*p
)->set_symtab_index(local_symbol_index
);
2104 ++local_symbol_index
;
2109 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2110 p
!= input_objects
->relobj_end();
2113 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
2115 off
+= (index
- local_symbol_index
) * symsize
;
2116 local_symbol_index
= index
;
2119 unsigned int local_symcount
= local_symbol_index
;
2120 gold_assert(local_symcount
* symsize
== off
- startoff
);
2123 size_t dyn_global_index
;
2125 if (this->dynsym_section_
== NULL
)
2128 dyn_global_index
= 0;
2133 dyn_global_index
= this->dynsym_section_
->info();
2134 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
2135 dynoff
= this->dynsym_section_
->offset() + locsize
;
2136 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
2137 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
2138 == this->dynsym_section_
->data_size() - locsize
);
2141 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
2142 &this->sympool_
, &local_symcount
);
2144 if (!parameters
->options().strip_all())
2146 this->sympool_
.set_string_offsets();
2148 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
2149 Output_section
* osymtab
= this->make_output_section(symtab_name
,
2152 this->symtab_section_
= osymtab
;
2154 Output_section_data
* pos
= new Output_data_fixed_space(off
- startoff
,
2157 osymtab
->add_output_section_data(pos
);
2159 // We generate a .symtab_shndx section if we have more than
2160 // SHN_LORESERVE sections. Technically it is possible that we
2161 // don't need one, because it is possible that there are no
2162 // symbols in any of sections with indexes larger than
2163 // SHN_LORESERVE. That is probably unusual, though, and it is
2164 // easier to always create one than to compute section indexes
2165 // twice (once here, once when writing out the symbols).
2166 if (shnum
>= elfcpp::SHN_LORESERVE
)
2168 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
2170 Output_section
* osymtab_xindex
=
2171 this->make_output_section(symtab_xindex_name
,
2172 elfcpp::SHT_SYMTAB_SHNDX
, 0);
2174 size_t symcount
= (off
- startoff
) / symsize
;
2175 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
2177 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
2179 osymtab_xindex
->set_link_section(osymtab
);
2180 osymtab_xindex
->set_addralign(4);
2181 osymtab_xindex
->set_entsize(4);
2183 osymtab_xindex
->set_after_input_sections();
2185 // This tells the driver code to wait until the symbol table
2186 // has written out before writing out the postprocessing
2187 // sections, including the .symtab_shndx section.
2188 this->any_postprocessing_sections_
= true;
2191 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
2192 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
2196 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
2197 ostrtab
->add_output_section_data(pstr
);
2199 osymtab
->set_file_offset(startoff
);
2200 osymtab
->finalize_data_size();
2201 osymtab
->set_link_section(ostrtab
);
2202 osymtab
->set_info(local_symcount
);
2203 osymtab
->set_entsize(symsize
);
2209 // Create the .shstrtab section, which holds the names of the
2210 // sections. At the time this is called, we have created all the
2211 // output sections except .shstrtab itself.
2214 Layout::create_shstrtab()
2216 // FIXME: We don't need to create a .shstrtab section if we are
2217 // stripping everything.
2219 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
2221 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0);
2223 // We can't write out this section until we've set all the section
2224 // names, and we don't set the names of compressed output sections
2225 // until relocations are complete.
2226 os
->set_after_input_sections();
2228 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
2229 os
->add_output_section_data(posd
);
2234 // Create the section headers. SIZE is 32 or 64. OFF is the file
2238 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
2240 Output_section_headers
* oshdrs
;
2241 oshdrs
= new Output_section_headers(this,
2242 &this->segment_list_
,
2243 &this->section_list_
,
2244 &this->unattached_section_list_
,
2247 off_t off
= align_address(*poff
, oshdrs
->addralign());
2248 oshdrs
->set_address_and_file_offset(0, off
);
2249 off
+= oshdrs
->data_size();
2251 this->section_headers_
= oshdrs
;
2254 // Count the allocated sections.
2257 Layout::allocated_output_section_count() const
2259 size_t section_count
= 0;
2260 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2261 p
!= this->segment_list_
.end();
2263 section_count
+= (*p
)->output_section_count();
2264 return section_count
;
2267 // Create the dynamic symbol table.
2270 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
2271 Symbol_table
* symtab
,
2272 Output_section
**pdynstr
,
2273 unsigned int* plocal_dynamic_count
,
2274 std::vector
<Symbol
*>* pdynamic_symbols
,
2275 Versions
* pversions
)
2277 // Count all the symbols in the dynamic symbol table, and set the
2278 // dynamic symbol indexes.
2280 // Skip symbol 0, which is always all zeroes.
2281 unsigned int index
= 1;
2283 // Add STT_SECTION symbols for each Output section which needs one.
2284 for (Section_list::iterator p
= this->section_list_
.begin();
2285 p
!= this->section_list_
.end();
2288 if (!(*p
)->needs_dynsym_index())
2289 (*p
)->set_dynsym_index(-1U);
2292 (*p
)->set_dynsym_index(index
);
2297 // Count the local symbols that need to go in the dynamic symbol table,
2298 // and set the dynamic symbol indexes.
2299 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2300 p
!= input_objects
->relobj_end();
2303 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
2307 unsigned int local_symcount
= index
;
2308 *plocal_dynamic_count
= local_symcount
;
2310 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
2311 &this->dynpool_
, pversions
);
2315 const int size
= parameters
->target().get_size();
2318 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
2321 else if (size
== 64)
2323 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
2329 // Create the dynamic symbol table section.
2331 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
2336 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
2339 dynsym
->add_output_section_data(odata
);
2341 dynsym
->set_info(local_symcount
);
2342 dynsym
->set_entsize(symsize
);
2343 dynsym
->set_addralign(align
);
2345 this->dynsym_section_
= dynsym
;
2347 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
2348 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
2349 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
2351 // If there are more than SHN_LORESERVE allocated sections, we
2352 // create a .dynsym_shndx section. It is possible that we don't
2353 // need one, because it is possible that there are no dynamic
2354 // symbols in any of the sections with indexes larger than
2355 // SHN_LORESERVE. This is probably unusual, though, and at this
2356 // time we don't know the actual section indexes so it is
2357 // inconvenient to check.
2358 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
2360 Output_section
* dynsym_xindex
=
2361 this->choose_output_section(NULL
, ".dynsym_shndx",
2362 elfcpp::SHT_SYMTAB_SHNDX
,
2366 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
2368 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
2370 dynsym_xindex
->set_link_section(dynsym
);
2371 dynsym_xindex
->set_addralign(4);
2372 dynsym_xindex
->set_entsize(4);
2374 dynsym_xindex
->set_after_input_sections();
2376 // This tells the driver code to wait until the symbol table has
2377 // written out before writing out the postprocessing sections,
2378 // including the .dynsym_shndx section.
2379 this->any_postprocessing_sections_
= true;
2382 // Create the dynamic string table section.
2384 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
2389 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
2390 dynstr
->add_output_section_data(strdata
);
2392 dynsym
->set_link_section(dynstr
);
2393 this->dynamic_section_
->set_link_section(dynstr
);
2395 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
2396 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
2400 // Create the hash tables.
2402 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
2403 || strcmp(parameters
->options().hash_style(), "both") == 0)
2405 unsigned char* phash
;
2406 unsigned int hashlen
;
2407 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
2410 Output_section
* hashsec
= this->choose_output_section(NULL
, ".hash",
2415 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
2419 hashsec
->add_output_section_data(hashdata
);
2421 hashsec
->set_link_section(dynsym
);
2422 hashsec
->set_entsize(4);
2424 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
2427 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
2428 || strcmp(parameters
->options().hash_style(), "both") == 0)
2430 unsigned char* phash
;
2431 unsigned int hashlen
;
2432 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
2435 Output_section
* hashsec
= this->choose_output_section(NULL
, ".gnu.hash",
2436 elfcpp::SHT_GNU_HASH
,
2440 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
2444 hashsec
->add_output_section_data(hashdata
);
2446 hashsec
->set_link_section(dynsym
);
2447 hashsec
->set_entsize(4);
2449 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
2453 // Assign offsets to each local portion of the dynamic symbol table.
2456 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
2458 Output_section
* dynsym
= this->dynsym_section_
;
2459 gold_assert(dynsym
!= NULL
);
2461 off_t off
= dynsym
->offset();
2463 // Skip the dummy symbol at the start of the section.
2464 off
+= dynsym
->entsize();
2466 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
2467 p
!= input_objects
->relobj_end();
2470 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
2471 off
+= count
* dynsym
->entsize();
2475 // Create the version sections.
2478 Layout::create_version_sections(const Versions
* versions
,
2479 const Symbol_table
* symtab
,
2480 unsigned int local_symcount
,
2481 const std::vector
<Symbol
*>& dynamic_symbols
,
2482 const Output_section
* dynstr
)
2484 if (!versions
->any_defs() && !versions
->any_needs())
2487 switch (parameters
->size_and_endianness())
2489 #ifdef HAVE_TARGET_32_LITTLE
2490 case Parameters::TARGET_32_LITTLE
:
2491 this->sized_create_version_sections
<32, false>(versions
, symtab
,
2493 dynamic_symbols
, dynstr
);
2496 #ifdef HAVE_TARGET_32_BIG
2497 case Parameters::TARGET_32_BIG
:
2498 this->sized_create_version_sections
<32, true>(versions
, symtab
,
2500 dynamic_symbols
, dynstr
);
2503 #ifdef HAVE_TARGET_64_LITTLE
2504 case Parameters::TARGET_64_LITTLE
:
2505 this->sized_create_version_sections
<64, false>(versions
, symtab
,
2507 dynamic_symbols
, dynstr
);
2510 #ifdef HAVE_TARGET_64_BIG
2511 case Parameters::TARGET_64_BIG
:
2512 this->sized_create_version_sections
<64, true>(versions
, symtab
,
2514 dynamic_symbols
, dynstr
);
2522 // Create the version sections, sized version.
2524 template<int size
, bool big_endian
>
2526 Layout::sized_create_version_sections(
2527 const Versions
* versions
,
2528 const Symbol_table
* symtab
,
2529 unsigned int local_symcount
,
2530 const std::vector
<Symbol
*>& dynamic_symbols
,
2531 const Output_section
* dynstr
)
2533 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
2534 elfcpp::SHT_GNU_versym
,
2538 unsigned char* vbuf
;
2540 versions
->symbol_section_contents
<size
, big_endian
>(symtab
, &this->dynpool_
,
2545 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
2548 vsec
->add_output_section_data(vdata
);
2549 vsec
->set_entsize(2);
2550 vsec
->set_link_section(this->dynsym_section_
);
2552 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
2553 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
2555 if (versions
->any_defs())
2557 Output_section
* vdsec
;
2558 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
2559 elfcpp::SHT_GNU_verdef
,
2563 unsigned char* vdbuf
;
2564 unsigned int vdsize
;
2565 unsigned int vdentries
;
2566 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
, &vdbuf
,
2567 &vdsize
, &vdentries
);
2569 Output_section_data
* vddata
=
2570 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
2572 vdsec
->add_output_section_data(vddata
);
2573 vdsec
->set_link_section(dynstr
);
2574 vdsec
->set_info(vdentries
);
2576 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
2577 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
2580 if (versions
->any_needs())
2582 Output_section
* vnsec
;
2583 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
2584 elfcpp::SHT_GNU_verneed
,
2588 unsigned char* vnbuf
;
2589 unsigned int vnsize
;
2590 unsigned int vnentries
;
2591 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
2595 Output_section_data
* vndata
=
2596 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
2598 vnsec
->add_output_section_data(vndata
);
2599 vnsec
->set_link_section(dynstr
);
2600 vnsec
->set_info(vnentries
);
2602 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
2603 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
2607 // Create the .interp section and PT_INTERP segment.
2610 Layout::create_interp(const Target
* target
)
2612 const char* interp
= this->options_
.dynamic_linker();
2615 interp
= target
->dynamic_linker();
2616 gold_assert(interp
!= NULL
);
2619 size_t len
= strlen(interp
) + 1;
2621 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
2623 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
2624 elfcpp::SHT_PROGBITS
,
2627 osec
->add_output_section_data(odata
);
2629 if (!this->script_options_
->saw_phdrs_clause())
2631 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_INTERP
,
2633 oseg
->add_output_section(osec
, elfcpp::PF_R
);
2637 // Finish the .dynamic section and PT_DYNAMIC segment.
2640 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
2641 const Symbol_table
* symtab
)
2643 if (!this->script_options_
->saw_phdrs_clause())
2645 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
2648 oseg
->add_output_section(this->dynamic_section_
,
2649 elfcpp::PF_R
| elfcpp::PF_W
);
2652 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
2654 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
2655 p
!= input_objects
->dynobj_end();
2658 // FIXME: Handle --as-needed.
2659 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
2662 if (parameters
->options().shared())
2664 const char* soname
= this->options_
.soname();
2666 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
2669 // FIXME: Support --init and --fini.
2670 Symbol
* sym
= symtab
->lookup("_init");
2671 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
2672 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
2674 sym
= symtab
->lookup("_fini");
2675 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
2676 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
2678 // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.
2680 // Add a DT_RPATH entry if needed.
2681 const General_options::Dir_list
& rpath(this->options_
.rpath());
2684 std::string rpath_val
;
2685 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
2689 if (rpath_val
.empty())
2690 rpath_val
= p
->name();
2693 // Eliminate duplicates.
2694 General_options::Dir_list::const_iterator q
;
2695 for (q
= rpath
.begin(); q
!= p
; ++q
)
2696 if (q
->name() == p
->name())
2701 rpath_val
+= p
->name();
2706 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
2707 if (parameters
->options().enable_new_dtags())
2708 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
2711 // Look for text segments that have dynamic relocations.
2712 bool have_textrel
= false;
2713 if (!this->script_options_
->saw_sections_clause())
2715 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2716 p
!= this->segment_list_
.end();
2719 if (((*p
)->flags() & elfcpp::PF_W
) == 0
2720 && (*p
)->dynamic_reloc_count() > 0)
2722 have_textrel
= true;
2729 // We don't know the section -> segment mapping, so we are
2730 // conservative and just look for readonly sections with
2731 // relocations. If those sections wind up in writable segments,
2732 // then we have created an unnecessary DT_TEXTREL entry.
2733 for (Section_list::const_iterator p
= this->section_list_
.begin();
2734 p
!= this->section_list_
.end();
2737 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
2738 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
2739 && ((*p
)->dynamic_reloc_count() > 0))
2741 have_textrel
= true;
2747 // Add a DT_FLAGS entry. We add it even if no flags are set so that
2748 // post-link tools can easily modify these flags if desired.
2749 unsigned int flags
= 0;
2752 // Add a DT_TEXTREL for compatibility with older loaders.
2753 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
2754 flags
|= elfcpp::DF_TEXTREL
;
2756 if (parameters
->options().shared() && this->has_static_tls())
2757 flags
|= elfcpp::DF_STATIC_TLS
;
2758 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
2761 if (parameters
->options().initfirst())
2762 flags
|= elfcpp::DF_1_INITFIRST
;
2763 if (parameters
->options().interpose())
2764 flags
|= elfcpp::DF_1_INTERPOSE
;
2765 if (parameters
->options().loadfltr())
2766 flags
|= elfcpp::DF_1_LOADFLTR
;
2767 if (parameters
->options().nodefaultlib())
2768 flags
|= elfcpp::DF_1_NODEFLIB
;
2769 if (parameters
->options().nodelete())
2770 flags
|= elfcpp::DF_1_NODELETE
;
2771 if (parameters
->options().nodlopen())
2772 flags
|= elfcpp::DF_1_NOOPEN
;
2773 if (parameters
->options().nodump())
2774 flags
|= elfcpp::DF_1_NODUMP
;
2775 if (!parameters
->options().shared())
2776 flags
&= ~(elfcpp::DF_1_INITFIRST
2777 | elfcpp::DF_1_NODELETE
2778 | elfcpp::DF_1_NOOPEN
);
2780 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
2783 // The mapping of .gnu.linkonce section names to real section names.
2785 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
2786 const Layout::Linkonce_mapping
Layout::linkonce_mapping
[] =
2788 MAPPING_INIT("d.rel.ro.local", ".data.rel.ro.local"), // Before "d.rel.ro".
2789 MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Before "d".
2790 MAPPING_INIT("t", ".text"),
2791 MAPPING_INIT("r", ".rodata"),
2792 MAPPING_INIT("d", ".data"),
2793 MAPPING_INIT("b", ".bss"),
2794 MAPPING_INIT("s", ".sdata"),
2795 MAPPING_INIT("sb", ".sbss"),
2796 MAPPING_INIT("s2", ".sdata2"),
2797 MAPPING_INIT("sb2", ".sbss2"),
2798 MAPPING_INIT("wi", ".debug_info"),
2799 MAPPING_INIT("td", ".tdata"),
2800 MAPPING_INIT("tb", ".tbss"),
2801 MAPPING_INIT("lr", ".lrodata"),
2802 MAPPING_INIT("l", ".ldata"),
2803 MAPPING_INIT("lb", ".lbss"),
2807 const int Layout::linkonce_mapping_count
=
2808 sizeof(Layout::linkonce_mapping
) / sizeof(Layout::linkonce_mapping
[0]);
2810 // Return the name of the output section to use for a .gnu.linkonce
2811 // section. This is based on the default ELF linker script of the old
2812 // GNU linker. For example, we map a name like ".gnu.linkonce.t.foo"
2813 // to ".text". Set *PLEN to the length of the name. *PLEN is
2814 // initialized to the length of NAME.
2817 Layout::linkonce_output_name(const char* name
, size_t *plen
)
2819 const char* s
= name
+ sizeof(".gnu.linkonce") - 1;
2823 const Linkonce_mapping
* plm
= linkonce_mapping
;
2824 for (int i
= 0; i
< linkonce_mapping_count
; ++i
, ++plm
)
2826 if (strncmp(s
, plm
->from
, plm
->fromlen
) == 0 && s
[plm
->fromlen
] == '.')
2835 // Choose the output section name to use given an input section name.
2836 // Set *PLEN to the length of the name. *PLEN is initialized to the
2840 Layout::output_section_name(const char* name
, size_t* plen
)
2842 if (Layout::is_linkonce(name
))
2844 // .gnu.linkonce sections are laid out as though they were named
2845 // for the sections are placed into.
2846 return Layout::linkonce_output_name(name
, plen
);
2849 // gcc 4.3 generates the following sorts of section names when it
2850 // needs a section name specific to a function:
2856 // .data.rel.local.FN
2858 // .data.rel.ro.local.FN
2865 // The GNU linker maps all of those to the part before the .FN,
2866 // except that .data.rel.local.FN is mapped to .data, and
2867 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
2868 // beginning with .data.rel.ro.local are grouped together.
2870 // For an anonymous namespace, the string FN can contain a '.'.
2872 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
2873 // GNU linker maps to .rodata.
2875 // The .data.rel.ro sections enable a security feature triggered by
2876 // the -z relro option. Section which need to be relocated at
2877 // program startup time but which may be readonly after startup are
2878 // grouped into .data.rel.ro. They are then put into a PT_GNU_RELRO
2879 // segment. The dynamic linker will make that segment writable,
2880 // perform relocations, and then make it read-only. FIXME: We do
2881 // not yet implement this optimization.
2883 // It is hard to handle this in a principled way.
2885 // These are the rules we follow:
2887 // If the section name has no initial '.', or no dot other than an
2888 // initial '.', we use the name unchanged (i.e., "mysection" and
2889 // ".text" are unchanged).
2891 // If the name starts with ".data.rel.ro.local" we use
2892 // ".data.rel.ro.local".
2894 // If the name starts with ".data.rel.ro" we use ".data.rel.ro".
2896 // Otherwise, we drop the second '.' and everything that comes after
2897 // it (i.e., ".text.XXX" becomes ".text").
2899 const char* s
= name
;
2903 const char* sdot
= strchr(s
, '.');
2907 const char* const data_rel_ro_local
= ".data.rel.ro.local";
2908 if (strncmp(name
, data_rel_ro_local
, strlen(data_rel_ro_local
)) == 0)
2910 *plen
= strlen(data_rel_ro_local
);
2911 return data_rel_ro_local
;
2914 const char* const data_rel_ro
= ".data.rel.ro";
2915 if (strncmp(name
, data_rel_ro
, strlen(data_rel_ro
)) == 0)
2917 *plen
= strlen(data_rel_ro
);
2921 *plen
= sdot
- name
;
2925 // Record the signature of a comdat section, and return whether to
2926 // include it in the link. If GROUP is true, this is a regular
2927 // section group. If GROUP is false, this is a group signature
2928 // derived from the name of a linkonce section. We want linkonce
2929 // signatures and group signatures to block each other, but we don't
2930 // want a linkonce signature to block another linkonce signature.
2933 Layout::add_comdat(Relobj
* object
, unsigned int shndx
,
2934 const std::string
& signature
, bool group
)
2936 Kept_section
kept(object
, shndx
, group
);
2937 std::pair
<Signatures::iterator
, bool> ins(
2938 this->signatures_
.insert(std::make_pair(signature
, kept
)));
2942 // This is the first time we've seen this signature.
2946 if (ins
.first
->second
.group_
)
2948 // We've already seen a real section group with this signature.
2953 // This is a real section group, and we've already seen a
2954 // linkonce section with this signature. Record that we've seen
2955 // a section group, and don't include this section group.
2956 ins
.first
->second
.group_
= true;
2961 // We've already seen a linkonce section and this is a linkonce
2962 // section. These don't block each other--this may be the same
2963 // symbol name with different section types.
2968 // Find the given comdat signature, and return the object and section
2969 // index of the kept group.
2971 Layout::find_kept_object(const std::string
& signature
,
2972 unsigned int* pshndx
) const
2974 Signatures::const_iterator p
= this->signatures_
.find(signature
);
2975 if (p
== this->signatures_
.end())
2978 *pshndx
= p
->second
.shndx_
;
2979 return p
->second
.object_
;
2982 // Store the allocated sections into the section list.
2985 Layout::get_allocated_sections(Section_list
* section_list
) const
2987 for (Section_list::const_iterator p
= this->section_list_
.begin();
2988 p
!= this->section_list_
.end();
2990 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
2991 section_list
->push_back(*p
);
2994 // Create an output segment.
2997 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
2999 gold_assert(!parameters
->options().relocatable());
3000 Output_segment
* oseg
= new Output_segment(type
, flags
);
3001 this->segment_list_
.push_back(oseg
);
3005 // Write out the Output_sections. Most won't have anything to write,
3006 // since most of the data will come from input sections which are
3007 // handled elsewhere. But some Output_sections do have Output_data.
3010 Layout::write_output_sections(Output_file
* of
) const
3012 for (Section_list::const_iterator p
= this->section_list_
.begin();
3013 p
!= this->section_list_
.end();
3016 if (!(*p
)->after_input_sections())
3021 // Write out data not associated with a section or the symbol table.
3024 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
3026 if (!parameters
->options().strip_all())
3028 const Output_section
* symtab_section
= this->symtab_section_
;
3029 for (Section_list::const_iterator p
= this->section_list_
.begin();
3030 p
!= this->section_list_
.end();
3033 if ((*p
)->needs_symtab_index())
3035 gold_assert(symtab_section
!= NULL
);
3036 unsigned int index
= (*p
)->symtab_index();
3037 gold_assert(index
> 0 && index
!= -1U);
3038 off_t off
= (symtab_section
->offset()
3039 + index
* symtab_section
->entsize());
3040 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
3045 const Output_section
* dynsym_section
= this->dynsym_section_
;
3046 for (Section_list::const_iterator p
= this->section_list_
.begin();
3047 p
!= this->section_list_
.end();
3050 if ((*p
)->needs_dynsym_index())
3052 gold_assert(dynsym_section
!= NULL
);
3053 unsigned int index
= (*p
)->dynsym_index();
3054 gold_assert(index
> 0 && index
!= -1U);
3055 off_t off
= (dynsym_section
->offset()
3056 + index
* dynsym_section
->entsize());
3057 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
3061 // Write out the Output_data which are not in an Output_section.
3062 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
3063 p
!= this->special_output_list_
.end();
3068 // Write out the Output_sections which can only be written after the
3069 // input sections are complete.
3072 Layout::write_sections_after_input_sections(Output_file
* of
)
3074 // Determine the final section offsets, and thus the final output
3075 // file size. Note we finalize the .shstrab last, to allow the
3076 // after_input_section sections to modify their section-names before
3078 if (this->any_postprocessing_sections_
)
3080 off_t off
= this->output_file_size_
;
3081 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
3083 // Now that we've finalized the names, we can finalize the shstrab.
3085 this->set_section_offsets(off
,
3086 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
3088 if (off
> this->output_file_size_
)
3091 this->output_file_size_
= off
;
3095 for (Section_list::const_iterator p
= this->section_list_
.begin();
3096 p
!= this->section_list_
.end();
3099 if ((*p
)->after_input_sections())
3103 this->section_headers_
->write(of
);
3106 // If the build ID requires computing a checksum, do so here, and
3107 // write it out. We compute a checksum over the entire file because
3108 // that is simplest.
3111 Layout::write_build_id(Output_file
* of
) const
3113 if (this->build_id_note_
== NULL
)
3116 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
3118 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
3119 this->build_id_note_
->data_size());
3121 const char* style
= parameters
->options().build_id();
3122 if (strcmp(style
, "sha1") == 0)
3125 sha1_init_ctx(&ctx
);
3126 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
3127 sha1_finish_ctx(&ctx
, ov
);
3129 else if (strcmp(style
, "md5") == 0)
3133 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
3134 md5_finish_ctx(&ctx
, ov
);
3139 of
->write_output_view(this->build_id_note_
->offset(),
3140 this->build_id_note_
->data_size(),
3143 of
->free_input_view(0, this->output_file_size_
, iv
);
3146 // Write out a binary file. This is called after the link is
3147 // complete. IN is the temporary output file we used to generate the
3148 // ELF code. We simply walk through the segments, read them from
3149 // their file offset in IN, and write them to their load address in
3150 // the output file. FIXME: with a bit more work, we could support
3151 // S-records and/or Intel hex format here.
3154 Layout::write_binary(Output_file
* in
) const
3156 gold_assert(this->options_
.oformat_enum()
3157 == General_options::OBJECT_FORMAT_BINARY
);
3159 // Get the size of the binary file.
3160 uint64_t max_load_address
= 0;
3161 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3162 p
!= this->segment_list_
.end();
3165 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
3167 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
3168 if (max_paddr
> max_load_address
)
3169 max_load_address
= max_paddr
;
3173 Output_file
out(parameters
->options().output_file_name());
3174 out
.open(max_load_address
);
3176 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3177 p
!= this->segment_list_
.end();
3180 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
3182 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
3184 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
3186 memcpy(vout
, vin
, (*p
)->filesz());
3187 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
3188 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
3195 // Print the output sections to the map file.
3198 Layout::print_to_mapfile(Mapfile
* mapfile
) const
3200 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
3201 p
!= this->segment_list_
.end();
3203 (*p
)->print_sections_to_mapfile(mapfile
);
3206 // Print statistical information to stderr. This is used for --stats.
3209 Layout::print_stats() const
3211 this->namepool_
.print_stats("section name pool");
3212 this->sympool_
.print_stats("output symbol name pool");
3213 this->dynpool_
.print_stats("dynamic name pool");
3215 for (Section_list::const_iterator p
= this->section_list_
.begin();
3216 p
!= this->section_list_
.end();
3218 (*p
)->print_merge_stats();
3221 // Write_sections_task methods.
3223 // We can always run this task.
3226 Write_sections_task::is_runnable()
3231 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
3235 Write_sections_task::locks(Task_locker
* tl
)
3237 tl
->add(this, this->output_sections_blocker_
);
3238 tl
->add(this, this->final_blocker_
);
3241 // Run the task--write out the data.
3244 Write_sections_task::run(Workqueue
*)
3246 this->layout_
->write_output_sections(this->of_
);
3249 // Write_data_task methods.
3251 // We can always run this task.
3254 Write_data_task::is_runnable()
3259 // We need to unlock FINAL_BLOCKER when finished.
3262 Write_data_task::locks(Task_locker
* tl
)
3264 tl
->add(this, this->final_blocker_
);
3267 // Run the task--write out the data.
3270 Write_data_task::run(Workqueue
*)
3272 this->layout_
->write_data(this->symtab_
, this->of_
);
3275 // Write_symbols_task methods.
3277 // We can always run this task.
3280 Write_symbols_task::is_runnable()
3285 // We need to unlock FINAL_BLOCKER when finished.
3288 Write_symbols_task::locks(Task_locker
* tl
)
3290 tl
->add(this, this->final_blocker_
);
3293 // Run the task--write out the symbols.
3296 Write_symbols_task::run(Workqueue
*)
3298 this->symtab_
->write_globals(this->input_objects_
, this->sympool_
,
3299 this->dynpool_
, this->layout_
->symtab_xindex(),
3300 this->layout_
->dynsym_xindex(), this->of_
);
3303 // Write_after_input_sections_task methods.
3305 // We can only run this task after the input sections have completed.
3308 Write_after_input_sections_task::is_runnable()
3310 if (this->input_sections_blocker_
->is_blocked())
3311 return this->input_sections_blocker_
;
3315 // We need to unlock FINAL_BLOCKER when finished.
3318 Write_after_input_sections_task::locks(Task_locker
* tl
)
3320 tl
->add(this, this->final_blocker_
);
3326 Write_after_input_sections_task::run(Workqueue
*)
3328 this->layout_
->write_sections_after_input_sections(this->of_
);
3331 // Close_task_runner methods.
3333 // Run the task--close the file.
3336 Close_task_runner::run(Workqueue
*, const Task
*)
3338 // If we need to compute a checksum for the BUILD if, we do so here.
3339 this->layout_
->write_build_id(this->of_
);
3341 // If we've been asked to create a binary file, we do so here.
3342 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
3343 this->layout_
->write_binary(this->of_
);
3348 // Instantiate the templates we need. We could use the configure
3349 // script to restrict this to only the ones for implemented targets.
3351 #ifdef HAVE_TARGET_32_LITTLE
3354 Layout::layout
<32, false>(Sized_relobj
<32, false>* object
, unsigned int shndx
,
3356 const elfcpp::Shdr
<32, false>& shdr
,
3357 unsigned int, unsigned int, off_t
*);
3360 #ifdef HAVE_TARGET_32_BIG
3363 Layout::layout
<32, true>(Sized_relobj
<32, true>* object
, unsigned int shndx
,
3365 const elfcpp::Shdr
<32, true>& shdr
,
3366 unsigned int, unsigned int, off_t
*);
3369 #ifdef HAVE_TARGET_64_LITTLE
3372 Layout::layout
<64, false>(Sized_relobj
<64, false>* object
, unsigned int shndx
,
3374 const elfcpp::Shdr
<64, false>& shdr
,
3375 unsigned int, unsigned int, off_t
*);
3378 #ifdef HAVE_TARGET_64_BIG
3381 Layout::layout
<64, true>(Sized_relobj
<64, true>* object
, unsigned int shndx
,
3383 const elfcpp::Shdr
<64, true>& shdr
,
3384 unsigned int, unsigned int, off_t
*);
3387 #ifdef HAVE_TARGET_32_LITTLE
3390 Layout::layout_reloc
<32, false>(Sized_relobj
<32, false>* object
,
3391 unsigned int reloc_shndx
,
3392 const elfcpp::Shdr
<32, false>& shdr
,
3393 Output_section
* data_section
,
3394 Relocatable_relocs
* rr
);
3397 #ifdef HAVE_TARGET_32_BIG
3400 Layout::layout_reloc
<32, true>(Sized_relobj
<32, true>* object
,
3401 unsigned int reloc_shndx
,
3402 const elfcpp::Shdr
<32, true>& shdr
,
3403 Output_section
* data_section
,
3404 Relocatable_relocs
* rr
);
3407 #ifdef HAVE_TARGET_64_LITTLE
3410 Layout::layout_reloc
<64, false>(Sized_relobj
<64, false>* object
,
3411 unsigned int reloc_shndx
,
3412 const elfcpp::Shdr
<64, false>& shdr
,
3413 Output_section
* data_section
,
3414 Relocatable_relocs
* rr
);
3417 #ifdef HAVE_TARGET_64_BIG
3420 Layout::layout_reloc
<64, true>(Sized_relobj
<64, true>* object
,
3421 unsigned int reloc_shndx
,
3422 const elfcpp::Shdr
<64, true>& shdr
,
3423 Output_section
* data_section
,
3424 Relocatable_relocs
* rr
);
3427 #ifdef HAVE_TARGET_32_LITTLE
3430 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
3431 Sized_relobj
<32, false>* object
,
3433 const char* group_section_name
,
3434 const char* signature
,
3435 const elfcpp::Shdr
<32, false>& shdr
,
3436 elfcpp::Elf_Word flags
,
3437 std::vector
<unsigned int>* shndxes
);
3440 #ifdef HAVE_TARGET_32_BIG
3443 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
3444 Sized_relobj
<32, true>* object
,
3446 const char* group_section_name
,
3447 const char* signature
,
3448 const elfcpp::Shdr
<32, true>& shdr
,
3449 elfcpp::Elf_Word flags
,
3450 std::vector
<unsigned int>* shndxes
);
3453 #ifdef HAVE_TARGET_64_LITTLE
3456 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
3457 Sized_relobj
<64, false>* object
,
3459 const char* group_section_name
,
3460 const char* signature
,
3461 const elfcpp::Shdr
<64, false>& shdr
,
3462 elfcpp::Elf_Word flags
,
3463 std::vector
<unsigned int>* shndxes
);
3466 #ifdef HAVE_TARGET_64_BIG
3469 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
3470 Sized_relobj
<64, true>* object
,
3472 const char* group_section_name
,
3473 const char* signature
,
3474 const elfcpp::Shdr
<64, true>& shdr
,
3475 elfcpp::Elf_Word flags
,
3476 std::vector
<unsigned int>* shndxes
);
3479 #ifdef HAVE_TARGET_32_LITTLE
3482 Layout::layout_eh_frame
<32, false>(Sized_relobj
<32, false>* object
,
3483 const unsigned char* symbols
,
3485 const unsigned char* symbol_names
,
3486 off_t symbol_names_size
,
3488 const elfcpp::Shdr
<32, false>& shdr
,
3489 unsigned int reloc_shndx
,
3490 unsigned int reloc_type
,
3494 #ifdef HAVE_TARGET_32_BIG
3497 Layout::layout_eh_frame
<32, true>(Sized_relobj
<32, true>* object
,
3498 const unsigned char* symbols
,
3500 const unsigned char* symbol_names
,
3501 off_t symbol_names_size
,
3503 const elfcpp::Shdr
<32, true>& shdr
,
3504 unsigned int reloc_shndx
,
3505 unsigned int reloc_type
,
3509 #ifdef HAVE_TARGET_64_LITTLE
3512 Layout::layout_eh_frame
<64, false>(Sized_relobj
<64, false>* object
,
3513 const unsigned char* symbols
,
3515 const unsigned char* symbol_names
,
3516 off_t symbol_names_size
,
3518 const elfcpp::Shdr
<64, false>& shdr
,
3519 unsigned int reloc_shndx
,
3520 unsigned int reloc_type
,
3524 #ifdef HAVE_TARGET_64_BIG
3527 Layout::layout_eh_frame
<64, true>(Sized_relobj
<64, true>* object
,
3528 const unsigned char* symbols
,
3530 const unsigned char* symbol_names
,
3531 off_t symbol_names_size
,
3533 const elfcpp::Shdr
<64, true>& shdr
,
3534 unsigned int reloc_shndx
,
3535 unsigned int reloc_type
,
3539 } // End namespace gold.