1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
7 // This file is part of gold.
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
35 #include "libiberty.h"
39 #include "parameters.h"
43 #include "script-sections.h"
48 #include "gdb-index.h"
49 #include "compressed_output.h"
50 #include "reduced_debug_output.h"
53 #include "descriptors.h"
55 #include "incremental.h"
63 // The total number of free lists used.
64 unsigned int Free_list::num_lists
= 0;
65 // The total number of free list nodes used.
66 unsigned int Free_list::num_nodes
= 0;
67 // The total number of calls to Free_list::remove.
68 unsigned int Free_list::num_removes
= 0;
69 // The total number of nodes visited during calls to Free_list::remove.
70 unsigned int Free_list::num_remove_visits
= 0;
71 // The total number of calls to Free_list::allocate.
72 unsigned int Free_list::num_allocates
= 0;
73 // The total number of nodes visited during calls to Free_list::allocate.
74 unsigned int Free_list::num_allocate_visits
= 0;
76 // Initialize the free list. Creates a single free list node that
77 // describes the entire region of length LEN. If EXTEND is true,
78 // allocate() is allowed to extend the region beyond its initial
82 Free_list::init(off_t len
, bool extend
)
84 this->list_
.push_front(Free_list_node(0, len
));
85 this->last_remove_
= this->list_
.begin();
86 this->extend_
= extend
;
88 ++Free_list::num_lists
;
89 ++Free_list::num_nodes
;
92 // Remove a chunk from the free list. Because we start with a single
93 // node that covers the entire section, and remove chunks from it one
94 // at a time, we do not need to coalesce chunks or handle cases that
95 // span more than one free node. We expect to remove chunks from the
96 // free list in order, and we expect to have only a few chunks of free
97 // space left (corresponding to files that have changed since the last
98 // incremental link), so a simple linear list should provide sufficient
102 Free_list::remove(off_t start
, off_t end
)
106 gold_assert(start
< end
);
108 ++Free_list::num_removes
;
110 Iterator p
= this->last_remove_
;
111 if (p
->start_
> start
)
112 p
= this->list_
.begin();
114 for (; p
!= this->list_
.end(); ++p
)
116 ++Free_list::num_remove_visits
;
117 // Find a node that wholly contains the indicated region.
118 if (p
->start_
<= start
&& p
->end_
>= end
)
120 // Case 1: the indicated region spans the whole node.
121 // Add some fuzz to avoid creating tiny free chunks.
122 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
123 p
= this->list_
.erase(p
);
124 // Case 2: remove a chunk from the start of the node.
125 else if (p
->start_
+ 3 >= start
)
127 // Case 3: remove a chunk from the end of the node.
128 else if (p
->end_
<= end
+ 3)
130 // Case 4: remove a chunk from the middle, and split
131 // the node into two.
134 Free_list_node
newnode(p
->start_
, start
);
136 this->list_
.insert(p
, newnode
);
137 ++Free_list::num_nodes
;
139 this->last_remove_
= p
;
144 // Did not find a node containing the given chunk. This could happen
145 // because a small chunk was already removed due to the fuzz.
146 gold_debug(DEBUG_INCREMENTAL
,
147 "Free_list::remove(%d,%d) not found",
148 static_cast<int>(start
), static_cast<int>(end
));
151 // Allocate a chunk of size LEN from the free list. Returns -1ULL
152 // if a sufficiently large chunk of free space is not found.
153 // We use a simple first-fit algorithm.
156 Free_list::allocate(off_t len
, uint64_t align
, off_t minoff
)
158 gold_debug(DEBUG_INCREMENTAL
,
159 "Free_list::allocate(%08lx, %d, %08lx)",
160 static_cast<long>(len
), static_cast<int>(align
),
161 static_cast<long>(minoff
));
163 return align_address(minoff
, align
);
165 ++Free_list::num_allocates
;
167 // We usually want to drop free chunks smaller than 4 bytes.
168 // If we need to guarantee a minimum hole size, though, we need
169 // to keep track of all free chunks.
170 const int fuzz
= this->min_hole_
> 0 ? 0 : 3;
172 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
174 ++Free_list::num_allocate_visits
;
175 off_t start
= p
->start_
> minoff
? p
->start_
: minoff
;
176 start
= align_address(start
, align
);
177 off_t end
= start
+ len
;
178 if (end
> p
->end_
&& p
->end_
== this->length_
&& this->extend_
)
183 if (end
== p
->end_
|| (end
<= p
->end_
- this->min_hole_
))
185 if (p
->start_
+ fuzz
>= start
&& p
->end_
<= end
+ fuzz
)
186 this->list_
.erase(p
);
187 else if (p
->start_
+ fuzz
>= start
)
189 else if (p
->end_
<= end
+ fuzz
)
193 Free_list_node
newnode(p
->start_
, start
);
195 this->list_
.insert(p
, newnode
);
196 ++Free_list::num_nodes
;
203 off_t start
= align_address(this->length_
, align
);
204 this->length_
= start
+ len
;
210 // Dump the free list (for debugging).
214 gold_info("Free list:\n start end length\n");
215 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
216 gold_info(" %08lx %08lx %08lx", static_cast<long>(p
->start_
),
217 static_cast<long>(p
->end_
),
218 static_cast<long>(p
->end_
- p
->start_
));
221 // Print the statistics for the free lists.
223 Free_list::print_stats()
225 fprintf(stderr
, _("%s: total free lists: %u\n"),
226 program_name
, Free_list::num_lists
);
227 fprintf(stderr
, _("%s: total free list nodes: %u\n"),
228 program_name
, Free_list::num_nodes
);
229 fprintf(stderr
, _("%s: calls to Free_list::remove: %u\n"),
230 program_name
, Free_list::num_removes
);
231 fprintf(stderr
, _("%s: nodes visited: %u\n"),
232 program_name
, Free_list::num_remove_visits
);
233 fprintf(stderr
, _("%s: calls to Free_list::allocate: %u\n"),
234 program_name
, Free_list::num_allocates
);
235 fprintf(stderr
, _("%s: nodes visited: %u\n"),
236 program_name
, Free_list::num_allocate_visits
);
239 // Layout::Relaxation_debug_check methods.
241 // Check that sections and special data are in reset states.
242 // We do not save states for Output_sections and special Output_data.
243 // So we check that they have not assigned any addresses or offsets.
244 // clean_up_after_relaxation simply resets their addresses and offsets.
246 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
247 const Layout::Section_list
& sections
,
248 const Layout::Data_list
& special_outputs
)
250 for(Layout::Section_list::const_iterator p
= sections
.begin();
253 gold_assert((*p
)->address_and_file_offset_have_reset_values());
255 for(Layout::Data_list::const_iterator p
= special_outputs
.begin();
256 p
!= special_outputs
.end();
258 gold_assert((*p
)->address_and_file_offset_have_reset_values());
261 // Save information of SECTIONS for checking later.
264 Layout::Relaxation_debug_check::read_sections(
265 const Layout::Section_list
& sections
)
267 for(Layout::Section_list::const_iterator p
= sections
.begin();
271 Output_section
* os
= *p
;
273 info
.output_section
= os
;
274 info
.address
= os
->is_address_valid() ? os
->address() : 0;
275 info
.data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
276 info
.offset
= os
->is_offset_valid()? os
->offset() : -1 ;
277 this->section_infos_
.push_back(info
);
281 // Verify SECTIONS using previously recorded information.
284 Layout::Relaxation_debug_check::verify_sections(
285 const Layout::Section_list
& sections
)
288 for(Layout::Section_list::const_iterator p
= sections
.begin();
292 Output_section
* os
= *p
;
293 uint64_t address
= os
->is_address_valid() ? os
->address() : 0;
294 off_t data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
295 off_t offset
= os
->is_offset_valid()? os
->offset() : -1 ;
297 if (i
>= this->section_infos_
.size())
299 gold_fatal("Section_info of %s missing.\n", os
->name());
301 const Section_info
& info
= this->section_infos_
[i
];
302 if (os
!= info
.output_section
)
303 gold_fatal("Section order changed. Expecting %s but see %s\n",
304 info
.output_section
->name(), os
->name());
305 if (address
!= info
.address
306 || data_size
!= info
.data_size
307 || offset
!= info
.offset
)
308 gold_fatal("Section %s changed.\n", os
->name());
312 // Layout_task_runner methods.
314 // Lay out the sections. This is called after all the input objects
318 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
320 // See if any of the input definitions violate the One Definition Rule.
321 // TODO: if this is too slow, do this as a task, rather than inline.
322 this->symtab_
->detect_odr_violations(task
, this->options_
.output_file_name());
324 Layout
* layout
= this->layout_
;
325 off_t file_size
= layout
->finalize(this->input_objects_
,
330 // Now we know the final size of the output file and we know where
331 // each piece of information goes.
333 if (this->mapfile_
!= NULL
)
335 this->mapfile_
->print_discarded_sections(this->input_objects_
);
336 layout
->print_to_mapfile(this->mapfile_
);
340 if (layout
->incremental_base() == NULL
)
342 of
= new Output_file(parameters
->options().output_file_name());
343 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
344 of
->set_is_temporary();
349 of
= layout
->incremental_base()->output_file();
351 // Apply the incremental relocations for symbols whose values
352 // have changed. We do this before we resize the file and start
353 // writing anything else to it, so that we can read the old
354 // incremental information from the file before (possibly)
356 if (parameters
->incremental_update())
357 layout
->incremental_base()->apply_incremental_relocs(this->symtab_
,
361 of
->resize(file_size
);
364 // Queue up the final set of tasks.
365 gold::queue_final_tasks(this->options_
, this->input_objects_
,
366 this->symtab_
, layout
, workqueue
, of
);
371 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
372 : number_of_input_files_(number_of_input_files
),
373 script_options_(script_options
),
381 unattached_section_list_(),
382 special_output_list_(),
383 section_headers_(NULL
),
385 relro_segment_(NULL
),
386 interp_segment_(NULL
),
388 symtab_section_(NULL
),
389 symtab_xindex_(NULL
),
390 dynsym_section_(NULL
),
391 dynsym_xindex_(NULL
),
392 dynamic_section_(NULL
),
393 dynamic_symbol_(NULL
),
395 eh_frame_section_(NULL
),
396 eh_frame_data_(NULL
),
397 added_eh_frame_data_(false),
398 eh_frame_hdr_section_(NULL
),
399 gdb_index_data_(NULL
),
400 build_id_note_(NULL
),
404 output_file_size_(-1),
405 have_added_input_section_(false),
406 sections_are_attached_(false),
407 input_requires_executable_stack_(false),
408 input_with_gnu_stack_note_(false),
409 input_without_gnu_stack_note_(false),
410 has_static_tls_(false),
411 any_postprocessing_sections_(false),
412 resized_signatures_(false),
413 have_stabstr_section_(false),
414 section_ordering_specified_(false),
415 unique_segment_for_sections_specified_(false),
416 incremental_inputs_(NULL
),
417 record_output_section_data_from_script_(false),
418 script_output_section_data_list_(),
419 segment_states_(NULL
),
420 relaxation_debug_check_(NULL
),
421 section_order_map_(),
422 section_segment_map_(),
423 input_section_position_(),
424 input_section_glob_(),
425 incremental_base_(NULL
),
428 // Make space for more than enough segments for a typical file.
429 // This is just for efficiency--it's OK if we wind up needing more.
430 this->segment_list_
.reserve(12);
432 // We expect two unattached Output_data objects: the file header and
433 // the segment headers.
434 this->special_output_list_
.reserve(2);
436 // Initialize structure needed for an incremental build.
437 if (parameters
->incremental())
438 this->incremental_inputs_
= new Incremental_inputs
;
440 // The section name pool is worth optimizing in all cases, because
441 // it is small, but there are often overlaps due to .rel sections.
442 this->namepool_
.set_optimize();
445 // For incremental links, record the base file to be modified.
448 Layout::set_incremental_base(Incremental_binary
* base
)
450 this->incremental_base_
= base
;
451 this->free_list_
.init(base
->output_file()->filesize(), true);
454 // Hash a key we use to look up an output section mapping.
457 Layout::Hash_key::operator()(const Layout::Key
& k
) const
459 return k
.first
+ k
.second
.first
+ k
.second
.second
;
462 // These are the debug sections that are actually used by gdb.
463 // Currently, we've checked versions of gdb up to and including 7.4.
464 // We only check the part of the name that follows ".debug_" or
467 static const char* gdb_sections
[] =
470 "addr", // Fission extension
471 // "aranges", // not used by gdb as of 7.4
479 // "pubnames", // not used by gdb as of 7.4
480 // "pubtypes", // not used by gdb as of 7.4
485 // This is the minimum set of sections needed for line numbers.
487 static const char* lines_only_debug_sections
[] =
490 // "addr", // Fission extension
491 // "aranges", // not used by gdb as of 7.4
499 // "pubnames", // not used by gdb as of 7.4
500 // "pubtypes", // not used by gdb as of 7.4
505 // These sections are the DWARF fast-lookup tables, and are not needed
506 // when building a .gdb_index section.
508 static const char* gdb_fast_lookup_sections
[] =
515 // Returns whether the given debug section is in the list of
516 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
517 // portion of the name following ".debug_" or ".zdebug_".
520 is_gdb_debug_section(const char* suffix
)
522 // We can do this faster: binary search or a hashtable. But why bother?
523 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
524 if (strcmp(suffix
, gdb_sections
[i
]) == 0)
529 // Returns whether the given section is needed for lines-only debugging.
532 is_lines_only_debug_section(const char* suffix
)
534 // We can do this faster: binary search or a hashtable. But why bother?
536 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
538 if (strcmp(suffix
, lines_only_debug_sections
[i
]) == 0)
543 // Returns whether the given section is a fast-lookup section that
544 // will not be needed when building a .gdb_index section.
547 is_gdb_fast_lookup_section(const char* suffix
)
549 // We can do this faster: binary search or a hashtable. But why bother?
551 i
< sizeof(gdb_fast_lookup_sections
)/sizeof(*gdb_fast_lookup_sections
);
553 if (strcmp(suffix
, gdb_fast_lookup_sections
[i
]) == 0)
558 // Sometimes we compress sections. This is typically done for
559 // sections that are not part of normal program execution (such as
560 // .debug_* sections), and where the readers of these sections know
561 // how to deal with compressed sections. This routine doesn't say for
562 // certain whether we'll compress -- it depends on commandline options
563 // as well -- just whether this section is a candidate for compression.
564 // (The Output_compressed_section class decides whether to compress
565 // a given section, and picks the name of the compressed section.)
568 is_compressible_debug_section(const char* secname
)
570 return (is_prefix_of(".debug", secname
));
573 // We may see compressed debug sections in input files. Return TRUE
574 // if this is the name of a compressed debug section.
577 is_compressed_debug_section(const char* secname
)
579 return (is_prefix_of(".zdebug", secname
));
582 // Whether to include this section in the link.
584 template<int size
, bool big_endian
>
586 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
587 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
589 if (!parameters
->options().relocatable()
590 && (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
))
593 switch (shdr
.get_sh_type())
595 case elfcpp::SHT_NULL
:
596 case elfcpp::SHT_SYMTAB
:
597 case elfcpp::SHT_DYNSYM
:
598 case elfcpp::SHT_HASH
:
599 case elfcpp::SHT_DYNAMIC
:
600 case elfcpp::SHT_SYMTAB_SHNDX
:
603 case elfcpp::SHT_STRTAB
:
604 // Discard the sections which have special meanings in the ELF
605 // ABI. Keep others (e.g., .stabstr). We could also do this by
606 // checking the sh_link fields of the appropriate sections.
607 return (strcmp(name
, ".dynstr") != 0
608 && strcmp(name
, ".strtab") != 0
609 && strcmp(name
, ".shstrtab") != 0);
611 case elfcpp::SHT_RELA
:
612 case elfcpp::SHT_REL
:
613 case elfcpp::SHT_GROUP
:
614 // If we are emitting relocations these should be handled
616 gold_assert(!parameters
->options().relocatable());
619 case elfcpp::SHT_PROGBITS
:
620 if (parameters
->options().strip_debug()
621 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
623 if (is_debug_info_section(name
))
626 if (parameters
->options().strip_debug_non_line()
627 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
629 // Debugging sections can only be recognized by name.
630 if (is_prefix_of(".debug_", name
)
631 && !is_lines_only_debug_section(name
+ 7))
633 if (is_prefix_of(".zdebug_", name
)
634 && !is_lines_only_debug_section(name
+ 8))
637 if (parameters
->options().strip_debug_gdb()
638 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
640 // Debugging sections can only be recognized by name.
641 if (is_prefix_of(".debug_", name
)
642 && !is_gdb_debug_section(name
+ 7))
644 if (is_prefix_of(".zdebug_", name
)
645 && !is_gdb_debug_section(name
+ 8))
648 if (parameters
->options().gdb_index()
649 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
651 // When building .gdb_index, we can strip .debug_pubnames,
652 // .debug_pubtypes, and .debug_aranges sections.
653 if (is_prefix_of(".debug_", name
)
654 && is_gdb_fast_lookup_section(name
+ 7))
656 if (is_prefix_of(".zdebug_", name
)
657 && is_gdb_fast_lookup_section(name
+ 8))
660 if (parameters
->options().strip_lto_sections()
661 && !parameters
->options().relocatable()
662 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
664 // Ignore LTO sections containing intermediate code.
665 if (is_prefix_of(".gnu.lto_", name
))
668 // The GNU linker strips .gnu_debuglink sections, so we do too.
669 // This is a feature used to keep debugging information in
671 if (strcmp(name
, ".gnu_debuglink") == 0)
680 // Return an output section named NAME, or NULL if there is none.
683 Layout::find_output_section(const char* name
) const
685 for (Section_list::const_iterator p
= this->section_list_
.begin();
686 p
!= this->section_list_
.end();
688 if (strcmp((*p
)->name(), name
) == 0)
693 // Return an output segment of type TYPE, with segment flags SET set
694 // and segment flags CLEAR clear. Return NULL if there is none.
697 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
698 elfcpp::Elf_Word clear
) const
700 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
701 p
!= this->segment_list_
.end();
703 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
704 && ((*p
)->flags() & set
) == set
705 && ((*p
)->flags() & clear
) == 0)
710 // When we put a .ctors or .dtors section with more than one word into
711 // a .init_array or .fini_array section, we need to reverse the words
712 // in the .ctors/.dtors section. This is because .init_array executes
713 // constructors front to back, where .ctors executes them back to
714 // front, and vice-versa for .fini_array/.dtors. Although we do want
715 // to remap .ctors/.dtors into .init_array/.fini_array because it can
716 // be more efficient, we don't want to change the order in which
717 // constructors/destructors are run. This set just keeps track of
718 // these sections which need to be reversed. It is only changed by
719 // Layout::layout. It should be a private member of Layout, but that
720 // would require layout.h to #include object.h to get the definition
722 static Unordered_set
<Section_id
, Section_id_hash
> ctors_sections_in_init_array
;
724 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
725 // .init_array/.fini_array section.
728 Layout::is_ctors_in_init_array(Relobj
* relobj
, unsigned int shndx
) const
730 return (ctors_sections_in_init_array
.find(Section_id(relobj
, shndx
))
731 != ctors_sections_in_init_array
.end());
734 // Return the output section to use for section NAME with type TYPE
735 // and section flags FLAGS. NAME must be canonicalized in the string
736 // pool, and NAME_KEY is the key. ORDER is where this should appear
737 // in the output sections. IS_RELRO is true for a relro section.
740 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
741 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
742 Output_section_order order
, bool is_relro
)
744 elfcpp::Elf_Word lookup_type
= type
;
746 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
747 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
748 // .init_array, .fini_array, and .preinit_array sections by name
749 // whatever their type in the input file. We do this because the
750 // types are not always right in the input files.
751 if (lookup_type
== elfcpp::SHT_INIT_ARRAY
752 || lookup_type
== elfcpp::SHT_FINI_ARRAY
753 || lookup_type
== elfcpp::SHT_PREINIT_ARRAY
)
754 lookup_type
= elfcpp::SHT_PROGBITS
;
756 elfcpp::Elf_Xword lookup_flags
= flags
;
758 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
759 // read-write with read-only sections. Some other ELF linkers do
760 // not do this. FIXME: Perhaps there should be an option
762 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
764 const Key
key(name_key
, std::make_pair(lookup_type
, lookup_flags
));
765 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
766 std::pair
<Section_name_map::iterator
, bool> ins(
767 this->section_name_map_
.insert(v
));
770 return ins
.first
->second
;
773 // This is the first time we've seen this name/type/flags
774 // combination. For compatibility with the GNU linker, we
775 // combine sections with contents and zero flags with sections
776 // with non-zero flags. This is a workaround for cases where
777 // assembler code forgets to set section flags. FIXME: Perhaps
778 // there should be an option to control this.
779 Output_section
* os
= NULL
;
781 if (lookup_type
== elfcpp::SHT_PROGBITS
)
785 Output_section
* same_name
= this->find_output_section(name
);
786 if (same_name
!= NULL
787 && (same_name
->type() == elfcpp::SHT_PROGBITS
788 || same_name
->type() == elfcpp::SHT_INIT_ARRAY
789 || same_name
->type() == elfcpp::SHT_FINI_ARRAY
790 || same_name
->type() == elfcpp::SHT_PREINIT_ARRAY
)
791 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
794 else if ((flags
& elfcpp::SHF_TLS
) == 0)
796 elfcpp::Elf_Xword zero_flags
= 0;
797 const Key
zero_key(name_key
, std::make_pair(lookup_type
,
799 Section_name_map::iterator p
=
800 this->section_name_map_
.find(zero_key
);
801 if (p
!= this->section_name_map_
.end())
807 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
809 ins
.first
->second
= os
;
814 // Returns TRUE iff NAME (an input section from RELOBJ) will
815 // be mapped to an output section that should be KEPT.
818 Layout::keep_input_section(const Relobj
* relobj
, const char* name
)
820 if (! this->script_options_
->saw_sections_clause())
823 Script_sections
* ss
= this->script_options_
->script_sections();
824 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
825 Output_section
** output_section_slot
;
826 Script_sections::Section_type script_section_type
;
829 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
830 &script_section_type
, &keep
);
831 return name
!= NULL
&& keep
;
834 // Clear the input section flags that should not be copied to the
838 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags
)
840 // Some flags in the input section should not be automatically
841 // copied to the output section.
842 input_section_flags
&= ~ (elfcpp::SHF_INFO_LINK
845 | elfcpp::SHF_STRINGS
);
847 // We only clear the SHF_LINK_ORDER flag in for
848 // a non-relocatable link.
849 if (!parameters
->options().relocatable())
850 input_section_flags
&= ~elfcpp::SHF_LINK_ORDER
;
852 return input_section_flags
;
855 // Pick the output section to use for section NAME, in input file
856 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
857 // linker created section. IS_INPUT_SECTION is true if we are
858 // choosing an output section for an input section found in a input
859 // file. ORDER is where this section should appear in the output
860 // sections. IS_RELRO is true for a relro section. This will return
861 // NULL if the input section should be discarded.
864 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
865 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
866 bool is_input_section
, Output_section_order order
,
869 // We should not see any input sections after we have attached
870 // sections to segments.
871 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
873 flags
= this->get_output_section_flags(flags
);
875 if (this->script_options_
->saw_sections_clause())
877 // We are using a SECTIONS clause, so the output section is
878 // chosen based only on the name.
880 Script_sections
* ss
= this->script_options_
->script_sections();
881 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
882 Output_section
** output_section_slot
;
883 Script_sections::Section_type script_section_type
;
884 const char* orig_name
= name
;
886 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
887 &script_section_type
, &keep
);
891 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
892 "because it is not allowed by the "
893 "SECTIONS clause of the linker script"),
895 // The SECTIONS clause says to discard this input section.
899 // We can only handle script section types ST_NONE and ST_NOLOAD.
900 switch (script_section_type
)
902 case Script_sections::ST_NONE
:
904 case Script_sections::ST_NOLOAD
:
905 flags
&= elfcpp::SHF_ALLOC
;
911 // If this is an orphan section--one not mentioned in the linker
912 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
913 // default processing below.
915 if (output_section_slot
!= NULL
)
917 if (*output_section_slot
!= NULL
)
919 (*output_section_slot
)->update_flags_for_input_section(flags
);
920 return *output_section_slot
;
923 // We don't put sections found in the linker script into
924 // SECTION_NAME_MAP_. That keeps us from getting confused
925 // if an orphan section is mapped to a section with the same
926 // name as one in the linker script.
928 name
= this->namepool_
.add(name
, false, NULL
);
930 Output_section
* os
= this->make_output_section(name
, type
, flags
,
933 os
->set_found_in_sections_clause();
935 // Special handling for NOLOAD sections.
936 if (script_section_type
== Script_sections::ST_NOLOAD
)
940 // The constructor of Output_section sets addresses of non-ALLOC
941 // sections to 0 by default. We don't want that for NOLOAD
942 // sections even if they have no SHF_ALLOC flag.
943 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
944 && os
->is_address_valid())
946 gold_assert(os
->address() == 0
947 && !os
->is_offset_valid()
948 && !os
->is_data_size_valid());
949 os
->reset_address_and_file_offset();
953 *output_section_slot
= os
;
958 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
960 size_t len
= strlen(name
);
961 char* uncompressed_name
= NULL
;
963 // Compressed debug sections should be mapped to the corresponding
964 // uncompressed section.
965 if (is_compressed_debug_section(name
))
967 uncompressed_name
= new char[len
];
968 uncompressed_name
[0] = '.';
969 gold_assert(name
[0] == '.' && name
[1] == 'z');
970 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
971 uncompressed_name
[len
- 1] = '\0';
973 name
= uncompressed_name
;
976 // Turn NAME from the name of the input section into the name of the
979 && !this->script_options_
->saw_sections_clause()
980 && !parameters
->options().relocatable())
982 const char *orig_name
= name
;
983 name
= parameters
->target().output_section_name(relobj
, name
, &len
);
985 name
= Layout::output_section_name(relobj
, orig_name
, &len
);
988 Stringpool::Key name_key
;
989 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
991 if (uncompressed_name
!= NULL
)
992 delete[] uncompressed_name
;
994 // Find or make the output section. The output section is selected
995 // based on the section name, type, and flags.
996 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
999 // For incremental links, record the initial fixed layout of a section
1000 // from the base file, and return a pointer to the Output_section.
1002 template<int size
, bool big_endian
>
1004 Layout::init_fixed_output_section(const char* name
,
1005 elfcpp::Shdr
<size
, big_endian
>& shdr
)
1007 unsigned int sh_type
= shdr
.get_sh_type();
1009 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1010 // PRE_INIT_ARRAY, and NOTE sections.
1011 // All others will be created from scratch and reallocated.
1012 if (!can_incremental_update(sh_type
))
1015 // If we're generating a .gdb_index section, we need to regenerate
1017 if (parameters
->options().gdb_index()
1018 && sh_type
== elfcpp::SHT_PROGBITS
1019 && strcmp(name
, ".gdb_index") == 0)
1022 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
1023 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
1024 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
1025 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
1026 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
1027 shdr
.get_sh_addralign();
1029 // Make the output section.
1030 Stringpool::Key name_key
;
1031 name
= this->namepool_
.add(name
, true, &name_key
);
1032 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
1033 sh_flags
, ORDER_INVALID
, false);
1034 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
1035 if (sh_type
!= elfcpp::SHT_NOBITS
)
1036 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
1040 // Return the index by which an input section should be ordered. This
1041 // is used to sort some .text sections, for compatibility with GNU ld.
1044 Layout::special_ordering_of_input_section(const char* name
)
1046 // The GNU linker has some special handling for some sections that
1047 // wind up in the .text section. Sections that start with these
1048 // prefixes must appear first, and must appear in the order listed
1050 static const char* const text_section_sort
[] =
1059 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1061 if (is_prefix_of(text_section_sort
[i
], name
))
1067 // Return the output section to use for input section SHNDX, with name
1068 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1069 // index of a relocation section which applies to this section, or 0
1070 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1071 // relocation section if there is one. Set *OFF to the offset of this
1072 // input section without the output section. Return NULL if the
1073 // section should be discarded. Set *OFF to -1 if the section
1074 // contents should not be written directly to the output file, but
1075 // will instead receive special handling.
1077 template<int size
, bool big_endian
>
1079 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1080 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1081 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
1085 if (!this->include_section(object
, name
, shdr
))
1088 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
1090 // In a relocatable link a grouped section must not be combined with
1091 // any other sections.
1093 if (parameters
->options().relocatable()
1094 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1096 name
= this->namepool_
.add(name
, true, NULL
);
1097 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
1098 ORDER_INVALID
, false);
1102 // Plugins can choose to place one or more subsets of sections in
1103 // unique segments and this is done by mapping these section subsets
1104 // to unique output sections. Check if this section needs to be
1105 // remapped to a unique output section.
1106 Section_segment_map::iterator it
1107 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1108 if (it
== this->section_segment_map_
.end())
1110 os
= this->choose_output_section(object
, name
, sh_type
,
1111 shdr
.get_sh_flags(), true,
1112 ORDER_INVALID
, false);
1116 // We know the name of the output section, directly call
1117 // get_output_section here by-passing choose_output_section.
1118 elfcpp::Elf_Xword flags
1119 = this->get_output_section_flags(shdr
.get_sh_flags());
1121 const char* os_name
= it
->second
->name
;
1122 Stringpool::Key name_key
;
1123 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1124 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1125 ORDER_INVALID
, false);
1126 if (!os
->is_unique_segment())
1128 os
->set_is_unique_segment();
1129 os
->set_extra_segment_flags(it
->second
->flags
);
1130 os
->set_segment_alignment(it
->second
->align
);
1137 // By default the GNU linker sorts input sections whose names match
1138 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1139 // sections are sorted by name. This is used to implement
1140 // constructor priority ordering. We are compatible. When we put
1141 // .ctor sections in .init_array and .dtor sections in .fini_array,
1142 // we must also sort plain .ctor and .dtor sections.
1143 if (!this->script_options_
->saw_sections_clause()
1144 && !parameters
->options().relocatable()
1145 && (is_prefix_of(".ctors.", name
)
1146 || is_prefix_of(".dtors.", name
)
1147 || is_prefix_of(".init_array.", name
)
1148 || is_prefix_of(".fini_array.", name
)
1149 || (parameters
->options().ctors_in_init_array()
1150 && (strcmp(name
, ".ctors") == 0
1151 || strcmp(name
, ".dtors") == 0))))
1152 os
->set_must_sort_attached_input_sections();
1154 // By default the GNU linker sorts some special text sections ahead
1155 // of others. We are compatible.
1156 if (parameters
->options().text_reorder()
1157 && !this->script_options_
->saw_sections_clause()
1158 && !this->is_section_ordering_specified()
1159 && !parameters
->options().relocatable()
1160 && Layout::special_ordering_of_input_section(name
) >= 0)
1161 os
->set_must_sort_attached_input_sections();
1163 // If this is a .ctors or .ctors.* section being mapped to a
1164 // .init_array section, or a .dtors or .dtors.* section being mapped
1165 // to a .fini_array section, we will need to reverse the words if
1166 // there is more than one. Record this section for later. See
1167 // ctors_sections_in_init_array above.
1168 if (!this->script_options_
->saw_sections_clause()
1169 && !parameters
->options().relocatable()
1170 && shdr
.get_sh_size() > size
/ 8
1171 && (((strcmp(name
, ".ctors") == 0
1172 || is_prefix_of(".ctors.", name
))
1173 && strcmp(os
->name(), ".init_array") == 0)
1174 || ((strcmp(name
, ".dtors") == 0
1175 || is_prefix_of(".dtors.", name
))
1176 && strcmp(os
->name(), ".fini_array") == 0)))
1177 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1179 // FIXME: Handle SHF_LINK_ORDER somewhere.
1181 elfcpp::Elf_Xword orig_flags
= os
->flags();
1183 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1184 this->script_options_
->saw_sections_clause());
1186 // If the flags changed, we may have to change the order.
1187 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1189 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1190 elfcpp::Elf_Xword new_flags
=
1191 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1192 if (orig_flags
!= new_flags
)
1193 os
->set_order(this->default_section_order(os
, false));
1196 this->have_added_input_section_
= true;
1201 // Maps section SECN to SEGMENT s.
1203 Layout::insert_section_segment_map(Const_section_id secn
,
1204 Unique_segment_info
*s
)
1206 gold_assert(this->unique_segment_for_sections_specified_
);
1207 this->section_segment_map_
[secn
] = s
;
1210 // Handle a relocation section when doing a relocatable link.
1212 template<int size
, bool big_endian
>
1214 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
1216 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1217 Output_section
* data_section
,
1218 Relocatable_relocs
* rr
)
1220 gold_assert(parameters
->options().relocatable()
1221 || parameters
->options().emit_relocs());
1223 int sh_type
= shdr
.get_sh_type();
1226 if (sh_type
== elfcpp::SHT_REL
)
1228 else if (sh_type
== elfcpp::SHT_RELA
)
1232 name
+= data_section
->name();
1234 // In a relocatable link relocs for a grouped section must not be
1235 // combined with other reloc sections.
1237 if (!parameters
->options().relocatable()
1238 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
1239 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
1240 shdr
.get_sh_flags(), false,
1241 ORDER_INVALID
, false);
1244 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1245 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1246 ORDER_INVALID
, false);
1249 os
->set_should_link_to_symtab();
1250 os
->set_info_section(data_section
);
1252 Output_section_data
* posd
;
1253 if (sh_type
== elfcpp::SHT_REL
)
1255 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1256 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1260 else if (sh_type
== elfcpp::SHT_RELA
)
1262 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1263 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1270 os
->add_output_section_data(posd
);
1271 rr
->set_output_data(posd
);
1276 // Handle a group section when doing a relocatable link.
1278 template<int size
, bool big_endian
>
1280 Layout::layout_group(Symbol_table
* symtab
,
1281 Sized_relobj_file
<size
, big_endian
>* object
,
1283 const char* group_section_name
,
1284 const char* signature
,
1285 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1286 elfcpp::Elf_Word flags
,
1287 std::vector
<unsigned int>* shndxes
)
1289 gold_assert(parameters
->options().relocatable());
1290 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1291 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1292 Output_section
* os
= this->make_output_section(group_section_name
,
1294 shdr
.get_sh_flags(),
1295 ORDER_INVALID
, false);
1297 // We need to find a symbol with the signature in the symbol table.
1298 // If we don't find one now, we need to look again later.
1299 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1301 os
->set_info_symndx(sym
);
1304 // Reserve some space to minimize reallocations.
1305 if (this->group_signatures_
.empty())
1306 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1308 // We will wind up using a symbol whose name is the signature.
1309 // So just put the signature in the symbol name pool to save it.
1310 signature
= symtab
->canonicalize_name(signature
);
1311 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1314 os
->set_should_link_to_symtab();
1317 section_size_type entry_count
=
1318 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1319 Output_section_data
* posd
=
1320 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1322 os
->add_output_section_data(posd
);
1325 // Special GNU handling of sections name .eh_frame. They will
1326 // normally hold exception frame data as defined by the C++ ABI
1327 // (http://codesourcery.com/cxx-abi/).
1329 template<int size
, bool big_endian
>
1331 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1332 const unsigned char* symbols
,
1334 const unsigned char* symbol_names
,
1335 off_t symbol_names_size
,
1337 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1338 unsigned int reloc_shndx
, unsigned int reloc_type
,
1341 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1342 || shdr
.get_sh_type() == elfcpp::SHT_X86_64_UNWIND
);
1343 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1345 Output_section
* os
= this->make_eh_frame_section(object
);
1349 gold_assert(this->eh_frame_section_
== os
);
1351 elfcpp::Elf_Xword orig_flags
= os
->flags();
1353 if (!parameters
->incremental()
1354 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1363 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1365 // A writable .eh_frame section is a RELRO section.
1366 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1367 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1370 os
->set_order(ORDER_RELRO
);
1373 // We found a .eh_frame section we are going to optimize, so now
1374 // we can add the set of optimized sections to the output
1375 // section. We need to postpone adding this until we've found a
1376 // section we can optimize so that the .eh_frame section in
1377 // crtbegin.o winds up at the start of the output section.
1378 if (!this->added_eh_frame_data_
)
1380 os
->add_output_section_data(this->eh_frame_data_
);
1381 this->added_eh_frame_data_
= true;
1387 // We couldn't handle this .eh_frame section for some reason.
1388 // Add it as a normal section.
1389 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1390 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1391 reloc_shndx
, saw_sections_clause
);
1392 this->have_added_input_section_
= true;
1394 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1395 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1396 os
->set_order(this->default_section_order(os
, false));
1402 // Create and return the magic .eh_frame section. Create
1403 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1404 // input .eh_frame section; it may be NULL.
1407 Layout::make_eh_frame_section(const Relobj
* object
)
1409 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1411 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1412 elfcpp::SHT_PROGBITS
,
1413 elfcpp::SHF_ALLOC
, false,
1414 ORDER_EHFRAME
, false);
1418 if (this->eh_frame_section_
== NULL
)
1420 this->eh_frame_section_
= os
;
1421 this->eh_frame_data_
= new Eh_frame();
1423 // For incremental linking, we do not optimize .eh_frame sections
1424 // or create a .eh_frame_hdr section.
1425 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1427 Output_section
* hdr_os
=
1428 this->choose_output_section(NULL
, ".eh_frame_hdr",
1429 elfcpp::SHT_PROGBITS
,
1430 elfcpp::SHF_ALLOC
, false,
1431 ORDER_EHFRAME
, false);
1435 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1436 this->eh_frame_data_
);
1437 hdr_os
->add_output_section_data(hdr_posd
);
1439 hdr_os
->set_after_input_sections();
1441 if (!this->script_options_
->saw_phdrs_clause())
1443 Output_segment
* hdr_oseg
;
1444 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1446 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1450 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1458 // Add an exception frame for a PLT. This is called from target code.
1461 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1462 size_t cie_length
, const unsigned char* fde_data
,
1465 if (parameters
->incremental())
1467 // FIXME: Maybe this could work some day....
1470 Output_section
* os
= this->make_eh_frame_section(NULL
);
1473 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1474 fde_data
, fde_length
);
1475 if (!this->added_eh_frame_data_
)
1477 os
->add_output_section_data(this->eh_frame_data_
);
1478 this->added_eh_frame_data_
= true;
1482 // Scan a .debug_info or .debug_types section, and add summary
1483 // information to the .gdb_index section.
1485 template<int size
, bool big_endian
>
1487 Layout::add_to_gdb_index(bool is_type_unit
,
1488 Sized_relobj
<size
, big_endian
>* object
,
1489 const unsigned char* symbols
,
1492 unsigned int reloc_shndx
,
1493 unsigned int reloc_type
)
1495 if (this->gdb_index_data_
== NULL
)
1497 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1498 elfcpp::SHT_PROGBITS
, 0,
1499 false, ORDER_INVALID
,
1504 this->gdb_index_data_
= new Gdb_index(os
);
1505 os
->add_output_section_data(this->gdb_index_data_
);
1506 os
->set_after_input_sections();
1509 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1510 symbols_size
, shndx
, reloc_shndx
,
1514 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1515 // the output section.
1518 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1519 elfcpp::Elf_Xword flags
,
1520 Output_section_data
* posd
,
1521 Output_section_order order
, bool is_relro
)
1523 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1524 false, order
, is_relro
);
1526 os
->add_output_section_data(posd
);
1530 // Map section flags to segment flags.
1533 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1535 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1536 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1537 ret
|= elfcpp::PF_W
;
1538 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1539 ret
|= elfcpp::PF_X
;
1543 // Make a new Output_section, and attach it to segments as
1544 // appropriate. ORDER is the order in which this section should
1545 // appear in the output segment. IS_RELRO is true if this is a relro
1546 // (read-only after relocations) section.
1549 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1550 elfcpp::Elf_Xword flags
,
1551 Output_section_order order
, bool is_relro
)
1554 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1555 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1556 && is_compressible_debug_section(name
))
1557 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1559 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1560 && parameters
->options().strip_debug_non_line()
1561 && strcmp(".debug_abbrev", name
) == 0)
1563 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1565 if (this->debug_info_
)
1566 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1568 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1569 && parameters
->options().strip_debug_non_line()
1570 && strcmp(".debug_info", name
) == 0)
1572 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1574 if (this->debug_abbrev_
)
1575 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1579 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1580 // not have correct section types. Force them here.
1581 if (type
== elfcpp::SHT_PROGBITS
)
1583 if (is_prefix_of(".init_array", name
))
1584 type
= elfcpp::SHT_INIT_ARRAY
;
1585 else if (is_prefix_of(".preinit_array", name
))
1586 type
= elfcpp::SHT_PREINIT_ARRAY
;
1587 else if (is_prefix_of(".fini_array", name
))
1588 type
= elfcpp::SHT_FINI_ARRAY
;
1591 // FIXME: const_cast is ugly.
1592 Target
* target
= const_cast<Target
*>(¶meters
->target());
1593 os
= target
->make_output_section(name
, type
, flags
);
1596 // With -z relro, we have to recognize the special sections by name.
1597 // There is no other way.
1598 bool is_relro_local
= false;
1599 if (!this->script_options_
->saw_sections_clause()
1600 && parameters
->options().relro()
1601 && (flags
& elfcpp::SHF_ALLOC
) != 0
1602 && (flags
& elfcpp::SHF_WRITE
) != 0)
1604 if (type
== elfcpp::SHT_PROGBITS
)
1606 if ((flags
& elfcpp::SHF_TLS
) != 0)
1608 else if (strcmp(name
, ".data.rel.ro") == 0)
1610 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1613 is_relro_local
= true;
1615 else if (strcmp(name
, ".ctors") == 0
1616 || strcmp(name
, ".dtors") == 0
1617 || strcmp(name
, ".jcr") == 0)
1620 else if (type
== elfcpp::SHT_INIT_ARRAY
1621 || type
== elfcpp::SHT_FINI_ARRAY
1622 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1629 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1630 order
= this->default_section_order(os
, is_relro_local
);
1632 os
->set_order(order
);
1634 parameters
->target().new_output_section(os
);
1636 this->section_list_
.push_back(os
);
1638 // The GNU linker by default sorts some sections by priority, so we
1639 // do the same. We need to know that this might happen before we
1640 // attach any input sections.
1641 if (!this->script_options_
->saw_sections_clause()
1642 && !parameters
->options().relocatable()
1643 && (strcmp(name
, ".init_array") == 0
1644 || strcmp(name
, ".fini_array") == 0
1645 || (!parameters
->options().ctors_in_init_array()
1646 && (strcmp(name
, ".ctors") == 0
1647 || strcmp(name
, ".dtors") == 0))))
1648 os
->set_may_sort_attached_input_sections();
1650 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1651 // sections before other .text sections. We are compatible. We
1652 // need to know that this might happen before we attach any input
1654 if (parameters
->options().text_reorder()
1655 && !this->script_options_
->saw_sections_clause()
1656 && !this->is_section_ordering_specified()
1657 && !parameters
->options().relocatable()
1658 && strcmp(name
, ".text") == 0)
1659 os
->set_may_sort_attached_input_sections();
1661 // Check for .stab*str sections, as .stab* sections need to link to
1663 if (type
== elfcpp::SHT_STRTAB
1664 && !this->have_stabstr_section_
1665 && strncmp(name
, ".stab", 5) == 0
1666 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1667 this->have_stabstr_section_
= true;
1669 // During a full incremental link, we add patch space to most
1670 // PROGBITS and NOBITS sections. Flag those that may be
1671 // arbitrarily padded.
1672 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1673 && order
!= ORDER_INTERP
1674 && order
!= ORDER_INIT
1675 && order
!= ORDER_PLT
1676 && order
!= ORDER_FINI
1677 && order
!= ORDER_RELRO_LAST
1678 && order
!= ORDER_NON_RELRO_FIRST
1679 && strcmp(name
, ".eh_frame") != 0
1680 && strcmp(name
, ".ctors") != 0
1681 && strcmp(name
, ".dtors") != 0
1682 && strcmp(name
, ".jcr") != 0)
1684 os
->set_is_patch_space_allowed();
1686 // Certain sections require "holes" to be filled with
1687 // specific fill patterns. These fill patterns may have
1688 // a minimum size, so we must prevent allocations from the
1689 // free list that leave a hole smaller than the minimum.
1690 if (strcmp(name
, ".debug_info") == 0)
1691 os
->set_free_space_fill(new Output_fill_debug_info(false));
1692 else if (strcmp(name
, ".debug_types") == 0)
1693 os
->set_free_space_fill(new Output_fill_debug_info(true));
1694 else if (strcmp(name
, ".debug_line") == 0)
1695 os
->set_free_space_fill(new Output_fill_debug_line());
1698 // If we have already attached the sections to segments, then we
1699 // need to attach this one now. This happens for sections created
1700 // directly by the linker.
1701 if (this->sections_are_attached_
)
1702 this->attach_section_to_segment(¶meters
->target(), os
);
1707 // Return the default order in which a section should be placed in an
1708 // output segment. This function captures a lot of the ideas in
1709 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1710 // linker created section is normally set when the section is created;
1711 // this function is used for input sections.
1713 Output_section_order
1714 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1716 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1717 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1718 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1719 bool is_bss
= false;
1724 case elfcpp::SHT_PROGBITS
:
1726 case elfcpp::SHT_NOBITS
:
1729 case elfcpp::SHT_RELA
:
1730 case elfcpp::SHT_REL
:
1732 return ORDER_DYNAMIC_RELOCS
;
1734 case elfcpp::SHT_HASH
:
1735 case elfcpp::SHT_DYNAMIC
:
1736 case elfcpp::SHT_SHLIB
:
1737 case elfcpp::SHT_DYNSYM
:
1738 case elfcpp::SHT_GNU_HASH
:
1739 case elfcpp::SHT_GNU_verdef
:
1740 case elfcpp::SHT_GNU_verneed
:
1741 case elfcpp::SHT_GNU_versym
:
1743 return ORDER_DYNAMIC_LINKER
;
1745 case elfcpp::SHT_NOTE
:
1746 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1749 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1750 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1752 if (!is_bss
&& !is_write
)
1756 if (strcmp(os
->name(), ".init") == 0)
1758 else if (strcmp(os
->name(), ".fini") == 0)
1761 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1765 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1767 if (os
->is_small_section())
1768 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1769 if (os
->is_large_section())
1770 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1772 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1775 // Attach output sections to segments. This is called after we have
1776 // seen all the input sections.
1779 Layout::attach_sections_to_segments(const Target
* target
)
1781 for (Section_list::iterator p
= this->section_list_
.begin();
1782 p
!= this->section_list_
.end();
1784 this->attach_section_to_segment(target
, *p
);
1786 this->sections_are_attached_
= true;
1789 // Attach an output section to a segment.
1792 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1794 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1795 this->unattached_section_list_
.push_back(os
);
1797 this->attach_allocated_section_to_segment(target
, os
);
1800 // Attach an allocated output section to a segment.
1803 Layout::attach_allocated_section_to_segment(const Target
* target
,
1806 elfcpp::Elf_Xword flags
= os
->flags();
1807 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1809 if (parameters
->options().relocatable())
1812 // If we have a SECTIONS clause, we can't handle the attachment to
1813 // segments until after we've seen all the sections.
1814 if (this->script_options_
->saw_sections_clause())
1817 gold_assert(!this->script_options_
->saw_phdrs_clause());
1819 // This output section goes into a PT_LOAD segment.
1821 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1823 // If this output section's segment has extra flags that need to be set,
1824 // coming from a linker plugin, do that.
1825 seg_flags
|= os
->extra_segment_flags();
1827 // Check for --section-start.
1829 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1831 // In general the only thing we really care about for PT_LOAD
1832 // segments is whether or not they are writable or executable,
1833 // so that is how we search for them.
1834 // Large data sections also go into their own PT_LOAD segment.
1835 // People who need segments sorted on some other basis will
1836 // have to use a linker script.
1838 Segment_list::const_iterator p
;
1839 if (!os
->is_unique_segment())
1841 for (p
= this->segment_list_
.begin();
1842 p
!= this->segment_list_
.end();
1845 if ((*p
)->type() != elfcpp::PT_LOAD
)
1847 if ((*p
)->is_unique_segment())
1849 if (!parameters
->options().omagic()
1850 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1852 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
1853 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1855 // If -Tbss was specified, we need to separate the data and BSS
1857 if (parameters
->options().user_set_Tbss())
1859 if ((os
->type() == elfcpp::SHT_NOBITS
)
1860 == (*p
)->has_any_data_sections())
1863 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1868 if ((*p
)->are_addresses_set())
1871 (*p
)->add_initial_output_data(os
);
1872 (*p
)->update_flags_for_output_section(seg_flags
);
1873 (*p
)->set_addresses(addr
, addr
);
1877 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1882 if (p
== this->segment_list_
.end()
1883 || os
->is_unique_segment())
1885 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1887 if (os
->is_large_data_section())
1888 oseg
->set_is_large_data_segment();
1889 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1891 oseg
->set_addresses(addr
, addr
);
1892 // Check if segment should be marked unique. For segments marked
1893 // unique by linker plugins, set the new alignment if specified.
1894 if (os
->is_unique_segment())
1896 oseg
->set_is_unique_segment();
1897 if (os
->segment_alignment() != 0)
1898 oseg
->set_minimum_p_align(os
->segment_alignment());
1902 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1904 if (os
->type() == elfcpp::SHT_NOTE
)
1906 // See if we already have an equivalent PT_NOTE segment.
1907 for (p
= this->segment_list_
.begin();
1908 p
!= segment_list_
.end();
1911 if ((*p
)->type() == elfcpp::PT_NOTE
1912 && (((*p
)->flags() & elfcpp::PF_W
)
1913 == (seg_flags
& elfcpp::PF_W
)))
1915 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1920 if (p
== this->segment_list_
.end())
1922 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1924 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1928 // If we see a loadable SHF_TLS section, we create a PT_TLS
1929 // segment. There can only be one such segment.
1930 if ((flags
& elfcpp::SHF_TLS
) != 0)
1932 if (this->tls_segment_
== NULL
)
1933 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1934 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1937 // If -z relro is in effect, and we see a relro section, we create a
1938 // PT_GNU_RELRO segment. There can only be one such segment.
1939 if (os
->is_relro() && parameters
->options().relro())
1941 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1942 if (this->relro_segment_
== NULL
)
1943 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1944 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1947 // If we see a section named .interp, put it into a PT_INTERP
1948 // segment. This seems broken to me, but this is what GNU ld does,
1949 // and glibc expects it.
1950 if (strcmp(os
->name(), ".interp") == 0
1951 && !this->script_options_
->saw_phdrs_clause())
1953 if (this->interp_segment_
== NULL
)
1954 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
1956 gold_warning(_("multiple '.interp' sections in input files "
1957 "may cause confusing PT_INTERP segment"));
1958 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1962 // Make an output section for a script.
1965 Layout::make_output_section_for_script(
1967 Script_sections::Section_type section_type
)
1969 name
= this->namepool_
.add(name
, false, NULL
);
1970 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
1971 if (section_type
== Script_sections::ST_NOLOAD
)
1973 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1974 sh_flags
, ORDER_INVALID
,
1976 os
->set_found_in_sections_clause();
1977 if (section_type
== Script_sections::ST_NOLOAD
)
1978 os
->set_is_noload();
1982 // Return the number of segments we expect to see.
1985 Layout::expected_segment_count() const
1987 size_t ret
= this->segment_list_
.size();
1989 // If we didn't see a SECTIONS clause in a linker script, we should
1990 // already have the complete list of segments. Otherwise we ask the
1991 // SECTIONS clause how many segments it expects, and add in the ones
1992 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1994 if (!this->script_options_
->saw_sections_clause())
1998 const Script_sections
* ss
= this->script_options_
->script_sections();
1999 return ret
+ ss
->expected_segment_count(this);
2003 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2004 // is whether we saw a .note.GNU-stack section in the object file.
2005 // GNU_STACK_FLAGS is the section flags. The flags give the
2006 // protection required for stack memory. We record this in an
2007 // executable as a PT_GNU_STACK segment. If an object file does not
2008 // have a .note.GNU-stack segment, we must assume that it is an old
2009 // object. On some targets that will force an executable stack.
2012 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2015 if (!seen_gnu_stack
)
2017 this->input_without_gnu_stack_note_
= true;
2018 if (parameters
->options().warn_execstack()
2019 && parameters
->target().is_default_stack_executable())
2020 gold_warning(_("%s: missing .note.GNU-stack section"
2021 " implies executable stack"),
2022 obj
->name().c_str());
2026 this->input_with_gnu_stack_note_
= true;
2027 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2029 this->input_requires_executable_stack_
= true;
2030 if (parameters
->options().warn_execstack()
2031 || parameters
->options().is_stack_executable())
2032 gold_warning(_("%s: requires executable stack"),
2033 obj
->name().c_str());
2038 // Create automatic note sections.
2041 Layout::create_notes()
2043 this->create_gold_note();
2044 this->create_executable_stack_info();
2045 this->create_build_id();
2048 // Create the dynamic sections which are needed before we read the
2052 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2054 if (parameters
->doing_static_link())
2057 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2058 elfcpp::SHT_DYNAMIC
,
2060 | elfcpp::SHF_WRITE
),
2064 // A linker script may discard .dynamic, so check for NULL.
2065 if (this->dynamic_section_
!= NULL
)
2067 this->dynamic_symbol_
=
2068 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2069 Symbol_table::PREDEFINED
,
2070 this->dynamic_section_
, 0, 0,
2071 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2072 elfcpp::STV_HIDDEN
, 0, false, false);
2074 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2076 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2080 // For each output section whose name can be represented as C symbol,
2081 // define __start and __stop symbols for the section. This is a GNU
2085 Layout::define_section_symbols(Symbol_table
* symtab
)
2087 for (Section_list::const_iterator p
= this->section_list_
.begin();
2088 p
!= this->section_list_
.end();
2091 const char* const name
= (*p
)->name();
2092 if (is_cident(name
))
2094 const std::string
name_string(name
);
2095 const std::string
start_name(cident_section_start_prefix
2097 const std::string
stop_name(cident_section_stop_prefix
2100 symtab
->define_in_output_data(start_name
.c_str(),
2102 Symbol_table::PREDEFINED
,
2108 elfcpp::STV_DEFAULT
,
2110 false, // offset_is_from_end
2111 true); // only_if_ref
2113 symtab
->define_in_output_data(stop_name
.c_str(),
2115 Symbol_table::PREDEFINED
,
2121 elfcpp::STV_DEFAULT
,
2123 true, // offset_is_from_end
2124 true); // only_if_ref
2129 // Define symbols for group signatures.
2132 Layout::define_group_signatures(Symbol_table
* symtab
)
2134 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2135 p
!= this->group_signatures_
.end();
2138 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2140 p
->section
->set_info_symndx(sym
);
2143 // Force the name of the group section to the group
2144 // signature, and use the group's section symbol as the
2145 // signature symbol.
2146 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2148 const char* name
= this->namepool_
.add(p
->signature
,
2150 p
->section
->set_name(name
);
2152 p
->section
->set_needs_symtab_index();
2153 p
->section
->set_info_section_symndx(p
->section
);
2157 this->group_signatures_
.clear();
2160 // Find the first read-only PT_LOAD segment, creating one if
2164 Layout::find_first_load_seg(const Target
* target
)
2166 Output_segment
* best
= NULL
;
2167 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2168 p
!= this->segment_list_
.end();
2171 if ((*p
)->type() == elfcpp::PT_LOAD
2172 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2173 && (parameters
->options().omagic()
2174 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2175 && (!target
->isolate_execinstr()
2176 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2178 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2185 gold_assert(!this->script_options_
->saw_phdrs_clause());
2187 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2192 // Save states of all current output segments. Store saved states
2193 // in SEGMENT_STATES.
2196 Layout::save_segments(Segment_states
* segment_states
)
2198 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2199 p
!= this->segment_list_
.end();
2202 Output_segment
* segment
= *p
;
2204 Output_segment
* copy
= new Output_segment(*segment
);
2205 (*segment_states
)[segment
] = copy
;
2209 // Restore states of output segments and delete any segment not found in
2213 Layout::restore_segments(const Segment_states
* segment_states
)
2215 // Go through the segment list and remove any segment added in the
2217 this->tls_segment_
= NULL
;
2218 this->relro_segment_
= NULL
;
2219 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2220 while (list_iter
!= this->segment_list_
.end())
2222 Output_segment
* segment
= *list_iter
;
2223 Segment_states::const_iterator states_iter
=
2224 segment_states
->find(segment
);
2225 if (states_iter
!= segment_states
->end())
2227 const Output_segment
* copy
= states_iter
->second
;
2228 // Shallow copy to restore states.
2231 // Also fix up TLS and RELRO segment pointers as appropriate.
2232 if (segment
->type() == elfcpp::PT_TLS
)
2233 this->tls_segment_
= segment
;
2234 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2235 this->relro_segment_
= segment
;
2241 list_iter
= this->segment_list_
.erase(list_iter
);
2242 // This is a segment created during section layout. It should be
2243 // safe to remove it since we should have removed all pointers to it.
2249 // Clean up after relaxation so that sections can be laid out again.
2252 Layout::clean_up_after_relaxation()
2254 // Restore the segments to point state just prior to the relaxation loop.
2255 Script_sections
* script_section
= this->script_options_
->script_sections();
2256 script_section
->release_segments();
2257 this->restore_segments(this->segment_states_
);
2259 // Reset section addresses and file offsets
2260 for (Section_list::iterator p
= this->section_list_
.begin();
2261 p
!= this->section_list_
.end();
2264 (*p
)->restore_states();
2266 // If an input section changes size because of relaxation,
2267 // we need to adjust the section offsets of all input sections.
2268 // after such a section.
2269 if ((*p
)->section_offsets_need_adjustment())
2270 (*p
)->adjust_section_offsets();
2272 (*p
)->reset_address_and_file_offset();
2275 // Reset special output object address and file offsets.
2276 for (Data_list::iterator p
= this->special_output_list_
.begin();
2277 p
!= this->special_output_list_
.end();
2279 (*p
)->reset_address_and_file_offset();
2281 // A linker script may have created some output section data objects.
2282 // They are useless now.
2283 for (Output_section_data_list::const_iterator p
=
2284 this->script_output_section_data_list_
.begin();
2285 p
!= this->script_output_section_data_list_
.end();
2288 this->script_output_section_data_list_
.clear();
2291 // Prepare for relaxation.
2294 Layout::prepare_for_relaxation()
2296 // Create an relaxation debug check if in debugging mode.
2297 if (is_debugging_enabled(DEBUG_RELAXATION
))
2298 this->relaxation_debug_check_
= new Relaxation_debug_check();
2300 // Save segment states.
2301 this->segment_states_
= new Segment_states();
2302 this->save_segments(this->segment_states_
);
2304 for(Section_list::const_iterator p
= this->section_list_
.begin();
2305 p
!= this->section_list_
.end();
2307 (*p
)->save_states();
2309 if (is_debugging_enabled(DEBUG_RELAXATION
))
2310 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2311 this->section_list_
, this->special_output_list_
);
2313 // Also enable recording of output section data from scripts.
2314 this->record_output_section_data_from_script_
= true;
2317 // Relaxation loop body: If target has no relaxation, this runs only once
2318 // Otherwise, the target relaxation hook is called at the end of
2319 // each iteration. If the hook returns true, it means re-layout of
2320 // section is required.
2322 // The number of segments created by a linking script without a PHDRS
2323 // clause may be affected by section sizes and alignments. There is
2324 // a remote chance that relaxation causes different number of PT_LOAD
2325 // segments are created and sections are attached to different segments.
2326 // Therefore, we always throw away all segments created during section
2327 // layout. In order to be able to restart the section layout, we keep
2328 // a copy of the segment list right before the relaxation loop and use
2329 // that to restore the segments.
2331 // PASS is the current relaxation pass number.
2332 // SYMTAB is a symbol table.
2333 // PLOAD_SEG is the address of a pointer for the load segment.
2334 // PHDR_SEG is a pointer to the PHDR segment.
2335 // SEGMENT_HEADERS points to the output segment header.
2336 // FILE_HEADER points to the output file header.
2337 // PSHNDX is the address to store the output section index.
2340 Layout::relaxation_loop_body(
2343 Symbol_table
* symtab
,
2344 Output_segment
** pload_seg
,
2345 Output_segment
* phdr_seg
,
2346 Output_segment_headers
* segment_headers
,
2347 Output_file_header
* file_header
,
2348 unsigned int* pshndx
)
2350 // If this is not the first iteration, we need to clean up after
2351 // relaxation so that we can lay out the sections again.
2353 this->clean_up_after_relaxation();
2355 // If there is a SECTIONS clause, put all the input sections into
2356 // the required order.
2357 Output_segment
* load_seg
;
2358 if (this->script_options_
->saw_sections_clause())
2359 load_seg
= this->set_section_addresses_from_script(symtab
);
2360 else if (parameters
->options().relocatable())
2363 load_seg
= this->find_first_load_seg(target
);
2365 if (parameters
->options().oformat_enum()
2366 != General_options::OBJECT_FORMAT_ELF
)
2369 // If the user set the address of the text segment, that may not be
2370 // compatible with putting the segment headers and file headers into
2372 if (parameters
->options().user_set_Ttext()
2373 && parameters
->options().Ttext() % target
->abi_pagesize() != 0)
2379 gold_assert(phdr_seg
== NULL
2381 || this->script_options_
->saw_sections_clause());
2383 // If the address of the load segment we found has been set by
2384 // --section-start rather than by a script, then adjust the VMA and
2385 // LMA downward if possible to include the file and section headers.
2386 uint64_t header_gap
= 0;
2387 if (load_seg
!= NULL
2388 && load_seg
->are_addresses_set()
2389 && !this->script_options_
->saw_sections_clause()
2390 && !parameters
->options().relocatable())
2392 file_header
->finalize_data_size();
2393 segment_headers
->finalize_data_size();
2394 size_t sizeof_headers
= (file_header
->data_size()
2395 + segment_headers
->data_size());
2396 const uint64_t abi_pagesize
= target
->abi_pagesize();
2397 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2398 hdr_paddr
&= ~(abi_pagesize
- 1);
2399 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2400 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2404 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2405 load_seg
->paddr() - subtract
);
2406 header_gap
= subtract
- sizeof_headers
;
2410 // Lay out the segment headers.
2411 if (!parameters
->options().relocatable())
2413 gold_assert(segment_headers
!= NULL
);
2414 if (header_gap
!= 0 && load_seg
!= NULL
)
2416 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2417 load_seg
->add_initial_output_data(z
);
2419 if (load_seg
!= NULL
)
2420 load_seg
->add_initial_output_data(segment_headers
);
2421 if (phdr_seg
!= NULL
)
2422 phdr_seg
->add_initial_output_data(segment_headers
);
2425 // Lay out the file header.
2426 if (load_seg
!= NULL
)
2427 load_seg
->add_initial_output_data(file_header
);
2429 if (this->script_options_
->saw_phdrs_clause()
2430 && !parameters
->options().relocatable())
2432 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2433 // clause in a linker script.
2434 Script_sections
* ss
= this->script_options_
->script_sections();
2435 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2438 // We set the output section indexes in set_segment_offsets and
2439 // set_section_indexes.
2442 // Set the file offsets of all the segments, and all the sections
2445 if (!parameters
->options().relocatable())
2446 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2448 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2450 // Verify that the dummy relaxation does not change anything.
2451 if (is_debugging_enabled(DEBUG_RELAXATION
))
2454 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2456 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2459 *pload_seg
= load_seg
;
2463 // Search the list of patterns and find the postion of the given section
2464 // name in the output section. If the section name matches a glob
2465 // pattern and a non-glob name, then the non-glob position takes
2466 // precedence. Return 0 if no match is found.
2469 Layout::find_section_order_index(const std::string
& section_name
)
2471 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2472 map_it
= this->input_section_position_
.find(section_name
);
2473 if (map_it
!= this->input_section_position_
.end())
2474 return map_it
->second
;
2476 // Absolute match failed. Linear search the glob patterns.
2477 std::vector
<std::string
>::iterator it
;
2478 for (it
= this->input_section_glob_
.begin();
2479 it
!= this->input_section_glob_
.end();
2482 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2484 map_it
= this->input_section_position_
.find(*it
);
2485 gold_assert(map_it
!= this->input_section_position_
.end());
2486 return map_it
->second
;
2492 // Read the sequence of input sections from the file specified with
2493 // option --section-ordering-file.
2496 Layout::read_layout_from_file()
2498 const char* filename
= parameters
->options().section_ordering_file();
2504 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2505 filename
, strerror(errno
));
2507 std::getline(in
, line
); // this chops off the trailing \n, if any
2508 unsigned int position
= 1;
2509 this->set_section_ordering_specified();
2513 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2514 line
.resize(line
.length() - 1);
2515 // Ignore comments, beginning with '#'
2518 std::getline(in
, line
);
2521 this->input_section_position_
[line
] = position
;
2522 // Store all glob patterns in a vector.
2523 if (is_wildcard_string(line
.c_str()))
2524 this->input_section_glob_
.push_back(line
);
2526 std::getline(in
, line
);
2530 // Finalize the layout. When this is called, we have created all the
2531 // output sections and all the output segments which are based on
2532 // input sections. We have several things to do, and we have to do
2533 // them in the right order, so that we get the right results correctly
2536 // 1) Finalize the list of output segments and create the segment
2539 // 2) Finalize the dynamic symbol table and associated sections.
2541 // 3) Determine the final file offset of all the output segments.
2543 // 4) Determine the final file offset of all the SHF_ALLOC output
2546 // 5) Create the symbol table sections and the section name table
2549 // 6) Finalize the symbol table: set symbol values to their final
2550 // value and make a final determination of which symbols are going
2551 // into the output symbol table.
2553 // 7) Create the section table header.
2555 // 8) Determine the final file offset of all the output sections which
2556 // are not SHF_ALLOC, including the section table header.
2558 // 9) Finalize the ELF file header.
2560 // This function returns the size of the output file.
2563 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2564 Target
* target
, const Task
* task
)
2566 target
->finalize_sections(this, input_objects
, symtab
);
2568 this->count_local_symbols(task
, input_objects
);
2570 this->link_stabs_sections();
2572 Output_segment
* phdr_seg
= NULL
;
2573 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2575 // There was a dynamic object in the link. We need to create
2576 // some information for the dynamic linker.
2578 // Create the PT_PHDR segment which will hold the program
2580 if (!this->script_options_
->saw_phdrs_clause())
2581 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2583 // Create the dynamic symbol table, including the hash table.
2584 Output_section
* dynstr
;
2585 std::vector
<Symbol
*> dynamic_symbols
;
2586 unsigned int local_dynamic_count
;
2587 Versions
versions(*this->script_options()->version_script_info(),
2589 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2590 &local_dynamic_count
, &dynamic_symbols
,
2593 // Create the .interp section to hold the name of the
2594 // interpreter, and put it in a PT_INTERP segment. Don't do it
2595 // if we saw a .interp section in an input file.
2596 if ((!parameters
->options().shared()
2597 || parameters
->options().dynamic_linker() != NULL
)
2598 && this->interp_segment_
== NULL
)
2599 this->create_interp(target
);
2601 // Finish the .dynamic section to hold the dynamic data, and put
2602 // it in a PT_DYNAMIC segment.
2603 this->finish_dynamic_section(input_objects
, symtab
);
2605 // We should have added everything we need to the dynamic string
2607 this->dynpool_
.set_string_offsets();
2609 // Create the version sections. We can't do this until the
2610 // dynamic string table is complete.
2611 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2612 dynamic_symbols
, dynstr
);
2614 // Set the size of the _DYNAMIC symbol. We can't do this until
2615 // after we call create_version_sections.
2616 this->set_dynamic_symbol_size(symtab
);
2619 // Create segment headers.
2620 Output_segment_headers
* segment_headers
=
2621 (parameters
->options().relocatable()
2623 : new Output_segment_headers(this->segment_list_
));
2625 // Lay out the file header.
2626 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
2629 this->special_output_list_
.push_back(file_header
);
2630 if (segment_headers
!= NULL
)
2631 this->special_output_list_
.push_back(segment_headers
);
2633 // Find approriate places for orphan output sections if we are using
2635 if (this->script_options_
->saw_sections_clause())
2636 this->place_orphan_sections_in_script();
2638 Output_segment
* load_seg
;
2643 // Take a snapshot of the section layout as needed.
2644 if (target
->may_relax())
2645 this->prepare_for_relaxation();
2647 // Run the relaxation loop to lay out sections.
2650 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2651 phdr_seg
, segment_headers
, file_header
,
2655 while (target
->may_relax()
2656 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2658 // If there is a load segment that contains the file and program headers,
2659 // provide a symbol __ehdr_start pointing there.
2660 // A program can use this to examine itself robustly.
2661 if (load_seg
!= NULL
)
2662 symtab
->define_in_output_segment("__ehdr_start", NULL
,
2663 Symbol_table::PREDEFINED
, load_seg
, 0, 0,
2664 elfcpp::STT_NOTYPE
, elfcpp::STB_GLOBAL
,
2665 elfcpp::STV_DEFAULT
, 0,
2666 Symbol::SEGMENT_START
, true);
2668 // Set the file offsets of all the non-data sections we've seen so
2669 // far which don't have to wait for the input sections. We need
2670 // this in order to finalize local symbols in non-allocated
2672 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2674 // Set the section indexes of all unallocated sections seen so far,
2675 // in case any of them are somehow referenced by a symbol.
2676 shndx
= this->set_section_indexes(shndx
);
2678 // Create the symbol table sections.
2679 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2680 if (!parameters
->doing_static_link())
2681 this->assign_local_dynsym_offsets(input_objects
);
2683 // Process any symbol assignments from a linker script. This must
2684 // be called after the symbol table has been finalized.
2685 this->script_options_
->finalize_symbols(symtab
, this);
2687 // Create the incremental inputs sections.
2688 if (this->incremental_inputs_
)
2690 this->incremental_inputs_
->finalize();
2691 this->create_incremental_info_sections(symtab
);
2694 // Create the .shstrtab section.
2695 Output_section
* shstrtab_section
= this->create_shstrtab();
2697 // Set the file offsets of the rest of the non-data sections which
2698 // don't have to wait for the input sections.
2699 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2701 // Now that all sections have been created, set the section indexes
2702 // for any sections which haven't been done yet.
2703 shndx
= this->set_section_indexes(shndx
);
2705 // Create the section table header.
2706 this->create_shdrs(shstrtab_section
, &off
);
2708 // If there are no sections which require postprocessing, we can
2709 // handle the section names now, and avoid a resize later.
2710 if (!this->any_postprocessing_sections_
)
2712 off
= this->set_section_offsets(off
,
2713 POSTPROCESSING_SECTIONS_PASS
);
2715 this->set_section_offsets(off
,
2716 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2719 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2721 // Now we know exactly where everything goes in the output file
2722 // (except for non-allocated sections which require postprocessing).
2723 Output_data::layout_complete();
2725 this->output_file_size_
= off
;
2730 // Create a note header following the format defined in the ELF ABI.
2731 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2732 // of the section to create, DESCSZ is the size of the descriptor.
2733 // ALLOCATE is true if the section should be allocated in memory.
2734 // This returns the new note section. It sets *TRAILING_PADDING to
2735 // the number of trailing zero bytes required.
2738 Layout::create_note(const char* name
, int note_type
,
2739 const char* section_name
, size_t descsz
,
2740 bool allocate
, size_t* trailing_padding
)
2742 // Authorities all agree that the values in a .note field should
2743 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2744 // they differ on what the alignment is for 64-bit binaries.
2745 // The GABI says unambiguously they take 8-byte alignment:
2746 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2747 // Other documentation says alignment should always be 4 bytes:
2748 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2749 // GNU ld and GNU readelf both support the latter (at least as of
2750 // version 2.16.91), and glibc always generates the latter for
2751 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2753 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2754 const int size
= parameters
->target().get_size();
2756 const int size
= 32;
2759 // The contents of the .note section.
2760 size_t namesz
= strlen(name
) + 1;
2761 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2762 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2764 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2766 unsigned char* buffer
= new unsigned char[notehdrsz
];
2767 memset(buffer
, 0, notehdrsz
);
2769 bool is_big_endian
= parameters
->target().is_big_endian();
2775 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2776 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2777 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2781 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2782 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2783 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2786 else if (size
== 64)
2790 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2791 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2792 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2796 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2797 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2798 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2804 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2806 elfcpp::Elf_Xword flags
= 0;
2807 Output_section_order order
= ORDER_INVALID
;
2810 flags
= elfcpp::SHF_ALLOC
;
2811 order
= ORDER_RO_NOTE
;
2813 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2815 flags
, false, order
, false);
2819 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2822 os
->add_output_section_data(posd
);
2824 *trailing_padding
= aligned_descsz
- descsz
;
2829 // For an executable or shared library, create a note to record the
2830 // version of gold used to create the binary.
2833 Layout::create_gold_note()
2835 if (parameters
->options().relocatable()
2836 || parameters
->incremental_update())
2839 std::string desc
= std::string("gold ") + gold::get_version_string();
2841 size_t trailing_padding
;
2842 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2843 ".note.gnu.gold-version", desc
.size(),
2844 false, &trailing_padding
);
2848 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2849 os
->add_output_section_data(posd
);
2851 if (trailing_padding
> 0)
2853 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2854 os
->add_output_section_data(posd
);
2858 // Record whether the stack should be executable. This can be set
2859 // from the command line using the -z execstack or -z noexecstack
2860 // options. Otherwise, if any input file has a .note.GNU-stack
2861 // section with the SHF_EXECINSTR flag set, the stack should be
2862 // executable. Otherwise, if at least one input file a
2863 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2864 // section, we use the target default for whether the stack should be
2865 // executable. Otherwise, we don't generate a stack note. When
2866 // generating a object file, we create a .note.GNU-stack section with
2867 // the appropriate marking. When generating an executable or shared
2868 // library, we create a PT_GNU_STACK segment.
2871 Layout::create_executable_stack_info()
2873 bool is_stack_executable
;
2874 if (parameters
->options().is_execstack_set())
2875 is_stack_executable
= parameters
->options().is_stack_executable();
2876 else if (!this->input_with_gnu_stack_note_
)
2880 if (this->input_requires_executable_stack_
)
2881 is_stack_executable
= true;
2882 else if (this->input_without_gnu_stack_note_
)
2883 is_stack_executable
=
2884 parameters
->target().is_default_stack_executable();
2886 is_stack_executable
= false;
2889 if (parameters
->options().relocatable())
2891 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2892 elfcpp::Elf_Xword flags
= 0;
2893 if (is_stack_executable
)
2894 flags
|= elfcpp::SHF_EXECINSTR
;
2895 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2896 ORDER_INVALID
, false);
2900 if (this->script_options_
->saw_phdrs_clause())
2902 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2903 if (is_stack_executable
)
2904 flags
|= elfcpp::PF_X
;
2905 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2909 // If --build-id was used, set up the build ID note.
2912 Layout::create_build_id()
2914 if (!parameters
->options().user_set_build_id())
2917 const char* style
= parameters
->options().build_id();
2918 if (strcmp(style
, "none") == 0)
2921 // Set DESCSZ to the size of the note descriptor. When possible,
2922 // set DESC to the note descriptor contents.
2925 if (strcmp(style
, "md5") == 0)
2927 else if (strcmp(style
, "sha1") == 0)
2929 else if (strcmp(style
, "uuid") == 0)
2931 const size_t uuidsz
= 128 / 8;
2933 char buffer
[uuidsz
];
2934 memset(buffer
, 0, uuidsz
);
2936 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2938 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2942 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2943 release_descriptor(descriptor
, true);
2945 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
2946 else if (static_cast<size_t>(got
) != uuidsz
)
2947 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2951 desc
.assign(buffer
, uuidsz
);
2954 else if (strncmp(style
, "0x", 2) == 0)
2957 const char* p
= style
+ 2;
2960 if (hex_p(p
[0]) && hex_p(p
[1]))
2962 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
2966 else if (*p
== '-' || *p
== ':')
2969 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2972 descsz
= desc
.size();
2975 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2978 size_t trailing_padding
;
2979 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2980 ".note.gnu.build-id", descsz
, true,
2987 // We know the value already, so we fill it in now.
2988 gold_assert(desc
.size() == descsz
);
2990 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2991 os
->add_output_section_data(posd
);
2993 if (trailing_padding
!= 0)
2995 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2996 os
->add_output_section_data(posd
);
3001 // We need to compute a checksum after we have completed the
3003 gold_assert(trailing_padding
== 0);
3004 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3005 os
->add_output_section_data(this->build_id_note_
);
3009 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3010 // field of the former should point to the latter. I'm not sure who
3011 // started this, but the GNU linker does it, and some tools depend
3015 Layout::link_stabs_sections()
3017 if (!this->have_stabstr_section_
)
3020 for (Section_list::iterator p
= this->section_list_
.begin();
3021 p
!= this->section_list_
.end();
3024 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3027 const char* name
= (*p
)->name();
3028 if (strncmp(name
, ".stab", 5) != 0)
3031 size_t len
= strlen(name
);
3032 if (strcmp(name
+ len
- 3, "str") != 0)
3035 std::string
stab_name(name
, len
- 3);
3036 Output_section
* stab_sec
;
3037 stab_sec
= this->find_output_section(stab_name
.c_str());
3038 if (stab_sec
!= NULL
)
3039 stab_sec
->set_link_section(*p
);
3043 // Create .gnu_incremental_inputs and related sections needed
3044 // for the next run of incremental linking to check what has changed.
3047 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3049 Incremental_inputs
* incr
= this->incremental_inputs_
;
3051 gold_assert(incr
!= NULL
);
3053 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3054 incr
->create_data_sections(symtab
);
3056 // Add the .gnu_incremental_inputs section.
3057 const char* incremental_inputs_name
=
3058 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3059 Output_section
* incremental_inputs_os
=
3060 this->make_output_section(incremental_inputs_name
,
3061 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3062 ORDER_INVALID
, false);
3063 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3065 // Add the .gnu_incremental_symtab section.
3066 const char* incremental_symtab_name
=
3067 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3068 Output_section
* incremental_symtab_os
=
3069 this->make_output_section(incremental_symtab_name
,
3070 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3071 ORDER_INVALID
, false);
3072 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3073 incremental_symtab_os
->set_entsize(4);
3075 // Add the .gnu_incremental_relocs section.
3076 const char* incremental_relocs_name
=
3077 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3078 Output_section
* incremental_relocs_os
=
3079 this->make_output_section(incremental_relocs_name
,
3080 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3081 ORDER_INVALID
, false);
3082 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3083 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3085 // Add the .gnu_incremental_got_plt section.
3086 const char* incremental_got_plt_name
=
3087 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3088 Output_section
* incremental_got_plt_os
=
3089 this->make_output_section(incremental_got_plt_name
,
3090 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3091 ORDER_INVALID
, false);
3092 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3094 // Add the .gnu_incremental_strtab section.
3095 const char* incremental_strtab_name
=
3096 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3097 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3098 elfcpp::SHT_STRTAB
, 0,
3099 ORDER_INVALID
, false);
3100 Output_data_strtab
* strtab_data
=
3101 new Output_data_strtab(incr
->get_stringpool());
3102 incremental_strtab_os
->add_output_section_data(strtab_data
);
3104 incremental_inputs_os
->set_after_input_sections();
3105 incremental_symtab_os
->set_after_input_sections();
3106 incremental_relocs_os
->set_after_input_sections();
3107 incremental_got_plt_os
->set_after_input_sections();
3109 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3110 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3111 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3112 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3115 // Return whether SEG1 should be before SEG2 in the output file. This
3116 // is based entirely on the segment type and flags. When this is
3117 // called the segment addresses have normally not yet been set.
3120 Layout::segment_precedes(const Output_segment
* seg1
,
3121 const Output_segment
* seg2
)
3123 elfcpp::Elf_Word type1
= seg1
->type();
3124 elfcpp::Elf_Word type2
= seg2
->type();
3126 // The single PT_PHDR segment is required to precede any loadable
3127 // segment. We simply make it always first.
3128 if (type1
== elfcpp::PT_PHDR
)
3130 gold_assert(type2
!= elfcpp::PT_PHDR
);
3133 if (type2
== elfcpp::PT_PHDR
)
3136 // The single PT_INTERP segment is required to precede any loadable
3137 // segment. We simply make it always second.
3138 if (type1
== elfcpp::PT_INTERP
)
3140 gold_assert(type2
!= elfcpp::PT_INTERP
);
3143 if (type2
== elfcpp::PT_INTERP
)
3146 // We then put PT_LOAD segments before any other segments.
3147 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3149 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3152 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3153 // segment, because that is where the dynamic linker expects to find
3154 // it (this is just for efficiency; other positions would also work
3156 if (type1
== elfcpp::PT_TLS
3157 && type2
!= elfcpp::PT_TLS
3158 && type2
!= elfcpp::PT_GNU_RELRO
)
3160 if (type2
== elfcpp::PT_TLS
3161 && type1
!= elfcpp::PT_TLS
3162 && type1
!= elfcpp::PT_GNU_RELRO
)
3165 // We put the PT_GNU_RELRO segment last, because that is where the
3166 // dynamic linker expects to find it (as with PT_TLS, this is just
3168 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3170 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3173 const elfcpp::Elf_Word flags1
= seg1
->flags();
3174 const elfcpp::Elf_Word flags2
= seg2
->flags();
3176 // The order of non-PT_LOAD segments is unimportant. We simply sort
3177 // by the numeric segment type and flags values. There should not
3178 // be more than one segment with the same type and flags.
3179 if (type1
!= elfcpp::PT_LOAD
)
3182 return type1
< type2
;
3183 gold_assert(flags1
!= flags2
);
3184 return flags1
< flags2
;
3187 // If the addresses are set already, sort by load address.
3188 if (seg1
->are_addresses_set())
3190 if (!seg2
->are_addresses_set())
3193 unsigned int section_count1
= seg1
->output_section_count();
3194 unsigned int section_count2
= seg2
->output_section_count();
3195 if (section_count1
== 0 && section_count2
> 0)
3197 if (section_count1
> 0 && section_count2
== 0)
3200 uint64_t paddr1
= (seg1
->are_addresses_set()
3202 : seg1
->first_section_load_address());
3203 uint64_t paddr2
= (seg2
->are_addresses_set()
3205 : seg2
->first_section_load_address());
3207 if (paddr1
!= paddr2
)
3208 return paddr1
< paddr2
;
3210 else if (seg2
->are_addresses_set())
3213 // A segment which holds large data comes after a segment which does
3214 // not hold large data.
3215 if (seg1
->is_large_data_segment())
3217 if (!seg2
->is_large_data_segment())
3220 else if (seg2
->is_large_data_segment())
3223 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3224 // segments come before writable segments. Then writable segments
3225 // with data come before writable segments without data. Then
3226 // executable segments come before non-executable segments. Then
3227 // the unlikely case of a non-readable segment comes before the
3228 // normal case of a readable segment. If there are multiple
3229 // segments with the same type and flags, we require that the
3230 // address be set, and we sort by virtual address and then physical
3232 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3233 return (flags1
& elfcpp::PF_W
) == 0;
3234 if ((flags1
& elfcpp::PF_W
) != 0
3235 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3236 return seg1
->has_any_data_sections();
3237 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3238 return (flags1
& elfcpp::PF_X
) != 0;
3239 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3240 return (flags1
& elfcpp::PF_R
) == 0;
3242 // We shouldn't get here--we shouldn't create segments which we
3243 // can't distinguish. Unless of course we are using a weird linker
3244 // script or overlapping --section-start options. We could also get
3245 // here if plugins want unique segments for subsets of sections.
3246 gold_assert(this->script_options_
->saw_phdrs_clause()
3247 || parameters
->options().any_section_start()
3248 || this->is_unique_segment_for_sections_specified());
3252 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3255 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3257 uint64_t unsigned_off
= off
;
3258 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3259 | (addr
& (abi_pagesize
- 1)));
3260 if (aligned_off
< unsigned_off
)
3261 aligned_off
+= abi_pagesize
;
3265 // Set the file offsets of all the segments, and all the sections they
3266 // contain. They have all been created. LOAD_SEG must be be laid out
3267 // first. Return the offset of the data to follow.
3270 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3271 unsigned int* pshndx
)
3273 // Sort them into the final order. We use a stable sort so that we
3274 // don't randomize the order of indistinguishable segments created
3275 // by linker scripts.
3276 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3277 Layout::Compare_segments(this));
3279 // Find the PT_LOAD segments, and set their addresses and offsets
3280 // and their section's addresses and offsets.
3281 uint64_t start_addr
;
3282 if (parameters
->options().user_set_Ttext())
3283 start_addr
= parameters
->options().Ttext();
3284 else if (parameters
->options().output_is_position_independent())
3287 start_addr
= target
->default_text_segment_address();
3289 uint64_t addr
= start_addr
;
3292 // If LOAD_SEG is NULL, then the file header and segment headers
3293 // will not be loadable. But they still need to be at offset 0 in
3294 // the file. Set their offsets now.
3295 if (load_seg
== NULL
)
3297 for (Data_list::iterator p
= this->special_output_list_
.begin();
3298 p
!= this->special_output_list_
.end();
3301 off
= align_address(off
, (*p
)->addralign());
3302 (*p
)->set_address_and_file_offset(0, off
);
3303 off
+= (*p
)->data_size();
3307 unsigned int increase_relro
= this->increase_relro_
;
3308 if (this->script_options_
->saw_sections_clause())
3311 const bool check_sections
= parameters
->options().check_sections();
3312 Output_segment
* last_load_segment
= NULL
;
3314 unsigned int shndx_begin
= *pshndx
;
3315 unsigned int shndx_load_seg
= *pshndx
;
3317 for (Segment_list::iterator p
= this->segment_list_
.begin();
3318 p
!= this->segment_list_
.end();
3321 if ((*p
)->type() == elfcpp::PT_LOAD
)
3323 if (target
->isolate_execinstr())
3325 // When we hit the segment that should contain the
3326 // file headers, reset the file offset so we place
3327 // it and subsequent segments appropriately.
3328 // We'll fix up the preceding segments below.
3336 shndx_load_seg
= *pshndx
;
3342 // Verify that the file headers fall into the first segment.
3343 if (load_seg
!= NULL
&& load_seg
!= *p
)
3348 bool are_addresses_set
= (*p
)->are_addresses_set();
3349 if (are_addresses_set
)
3351 // When it comes to setting file offsets, we care about
3352 // the physical address.
3353 addr
= (*p
)->paddr();
3355 else if (parameters
->options().user_set_Ttext()
3356 && ((*p
)->flags() & elfcpp::PF_W
) == 0)
3358 are_addresses_set
= true;
3360 else if (parameters
->options().user_set_Tdata()
3361 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3362 && (!parameters
->options().user_set_Tbss()
3363 || (*p
)->has_any_data_sections()))
3365 addr
= parameters
->options().Tdata();
3366 are_addresses_set
= true;
3368 else if (parameters
->options().user_set_Tbss()
3369 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3370 && !(*p
)->has_any_data_sections())
3372 addr
= parameters
->options().Tbss();
3373 are_addresses_set
= true;
3376 uint64_t orig_addr
= addr
;
3377 uint64_t orig_off
= off
;
3379 uint64_t aligned_addr
= 0;
3380 uint64_t abi_pagesize
= target
->abi_pagesize();
3381 uint64_t common_pagesize
= target
->common_pagesize();
3383 if (!parameters
->options().nmagic()
3384 && !parameters
->options().omagic())
3385 (*p
)->set_minimum_p_align(abi_pagesize
);
3387 if (!are_addresses_set
)
3389 // Skip the address forward one page, maintaining the same
3390 // position within the page. This lets us store both segments
3391 // overlapping on a single page in the file, but the loader will
3392 // put them on different pages in memory. We will revisit this
3393 // decision once we know the size of the segment.
3395 addr
= align_address(addr
, (*p
)->maximum_alignment());
3396 aligned_addr
= addr
;
3400 // This is the segment that will contain the file
3401 // headers, so its offset will have to be exactly zero.
3402 gold_assert(orig_off
== 0);
3404 // If the target wants a fixed minimum distance from the
3405 // text segment to the read-only segment, move up now.
3406 uint64_t min_addr
= start_addr
+ target
->rosegment_gap();
3407 if (addr
< min_addr
)
3410 // But this is not the first segment! To make its
3411 // address congruent with its offset, that address better
3412 // be aligned to the ABI-mandated page size.
3413 addr
= align_address(addr
, abi_pagesize
);
3414 aligned_addr
= addr
;
3418 if ((addr
& (abi_pagesize
- 1)) != 0)
3419 addr
= addr
+ abi_pagesize
;
3421 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3425 if (!parameters
->options().nmagic()
3426 && !parameters
->options().omagic())
3427 off
= align_file_offset(off
, addr
, abi_pagesize
);
3430 // This is -N or -n with a section script which prevents
3431 // us from using a load segment. We need to ensure that
3432 // the file offset is aligned to the alignment of the
3433 // segment. This is because the linker script
3434 // implicitly assumed a zero offset. If we don't align
3435 // here, then the alignment of the sections in the
3436 // linker script may not match the alignment of the
3437 // sections in the set_section_addresses call below,
3438 // causing an error about dot moving backward.
3439 off
= align_address(off
, (*p
)->maximum_alignment());
3442 unsigned int shndx_hold
= *pshndx
;
3443 bool has_relro
= false;
3444 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
3449 // Now that we know the size of this segment, we may be able
3450 // to save a page in memory, at the cost of wasting some
3451 // file space, by instead aligning to the start of a new
3452 // page. Here we use the real machine page size rather than
3453 // the ABI mandated page size. If the segment has been
3454 // aligned so that the relro data ends at a page boundary,
3455 // we do not try to realign it.
3457 if (!are_addresses_set
3459 && aligned_addr
!= addr
3460 && !parameters
->incremental())
3462 uint64_t first_off
= (common_pagesize
3464 & (common_pagesize
- 1)));
3465 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
3468 && ((aligned_addr
& ~ (common_pagesize
- 1))
3469 != (new_addr
& ~ (common_pagesize
- 1)))
3470 && first_off
+ last_off
<= common_pagesize
)
3472 *pshndx
= shndx_hold
;
3473 addr
= align_address(aligned_addr
, common_pagesize
);
3474 addr
= align_address(addr
, (*p
)->maximum_alignment());
3475 if ((addr
& (abi_pagesize
- 1)) != 0)
3476 addr
= addr
+ abi_pagesize
;
3477 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3478 off
= align_file_offset(off
, addr
, abi_pagesize
);
3480 increase_relro
= this->increase_relro_
;
3481 if (this->script_options_
->saw_sections_clause())
3485 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
3494 // Implement --check-sections. We know that the segments
3495 // are sorted by LMA.
3496 if (check_sections
&& last_load_segment
!= NULL
)
3498 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
3499 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3502 unsigned long long lb1
= last_load_segment
->paddr();
3503 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3504 unsigned long long lb2
= (*p
)->paddr();
3505 unsigned long long le2
= lb2
+ (*p
)->memsz();
3506 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3507 "[0x%llx -> 0x%llx]"),
3508 lb1
, le1
, lb2
, le2
);
3511 last_load_segment
= *p
;
3515 if (load_seg
!= NULL
&& target
->isolate_execinstr())
3517 // Process the early segments again, setting their file offsets
3518 // so they land after the segments starting at LOAD_SEG.
3519 off
= align_file_offset(off
, 0, target
->abi_pagesize());
3521 for (Segment_list::iterator p
= this->segment_list_
.begin();
3525 if ((*p
)->type() == elfcpp::PT_LOAD
)
3527 // We repeat the whole job of assigning addresses and
3528 // offsets, but we really only want to change the offsets and
3529 // must ensure that the addresses all come out the same as
3530 // they did the first time through.
3531 bool has_relro
= false;
3532 const uint64_t old_addr
= (*p
)->vaddr();
3533 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
3534 uint64_t new_addr
= (*p
)->set_section_addresses(this, true,
3540 gold_assert(new_addr
== old_end
);
3544 gold_assert(shndx_begin
== shndx_load_seg
);
3547 // Handle the non-PT_LOAD segments, setting their offsets from their
3548 // section's offsets.
3549 for (Segment_list::iterator p
= this->segment_list_
.begin();
3550 p
!= this->segment_list_
.end();
3553 if ((*p
)->type() != elfcpp::PT_LOAD
)
3554 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3559 // Set the TLS offsets for each section in the PT_TLS segment.
3560 if (this->tls_segment_
!= NULL
)
3561 this->tls_segment_
->set_tls_offsets();
3566 // Set the offsets of all the allocated sections when doing a
3567 // relocatable link. This does the same jobs as set_segment_offsets,
3568 // only for a relocatable link.
3571 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3572 unsigned int* pshndx
)
3576 file_header
->set_address_and_file_offset(0, 0);
3577 off
+= file_header
->data_size();
3579 for (Section_list::iterator p
= this->section_list_
.begin();
3580 p
!= this->section_list_
.end();
3583 // We skip unallocated sections here, except that group sections
3584 // have to come first.
3585 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3586 && (*p
)->type() != elfcpp::SHT_GROUP
)
3589 off
= align_address(off
, (*p
)->addralign());
3591 // The linker script might have set the address.
3592 if (!(*p
)->is_address_valid())
3593 (*p
)->set_address(0);
3594 (*p
)->set_file_offset(off
);
3595 (*p
)->finalize_data_size();
3596 off
+= (*p
)->data_size();
3598 (*p
)->set_out_shndx(*pshndx
);
3605 // Set the file offset of all the sections not associated with a
3609 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3611 off_t startoff
= off
;
3614 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3615 p
!= this->unattached_section_list_
.end();
3618 // The symtab section is handled in create_symtab_sections.
3619 if (*p
== this->symtab_section_
)
3622 // If we've already set the data size, don't set it again.
3623 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3626 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3627 && (*p
)->requires_postprocessing())
3629 (*p
)->create_postprocessing_buffer();
3630 this->any_postprocessing_sections_
= true;
3633 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3634 && (*p
)->after_input_sections())
3636 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3637 && (!(*p
)->after_input_sections()
3638 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3640 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3641 && (!(*p
)->after_input_sections()
3642 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3645 if (!parameters
->incremental_update())
3647 off
= align_address(off
, (*p
)->addralign());
3648 (*p
)->set_file_offset(off
);
3649 (*p
)->finalize_data_size();
3653 // Incremental update: allocate file space from free list.
3654 (*p
)->pre_finalize_data_size();
3655 off_t current_size
= (*p
)->current_data_size();
3656 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3659 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3660 this->free_list_
.dump();
3661 gold_assert((*p
)->output_section() != NULL
);
3662 gold_fallback(_("out of patch space for section %s; "
3663 "relink with --incremental-full"),
3664 (*p
)->output_section()->name());
3666 (*p
)->set_file_offset(off
);
3667 (*p
)->finalize_data_size();
3668 if ((*p
)->data_size() > current_size
)
3670 gold_assert((*p
)->output_section() != NULL
);
3671 gold_fallback(_("%s: section changed size; "
3672 "relink with --incremental-full"),
3673 (*p
)->output_section()->name());
3675 gold_debug(DEBUG_INCREMENTAL
,
3676 "set_section_offsets: %08lx %08lx %s",
3677 static_cast<long>(off
),
3678 static_cast<long>((*p
)->data_size()),
3679 ((*p
)->output_section() != NULL
3680 ? (*p
)->output_section()->name() : "(special)"));
3683 off
+= (*p
)->data_size();
3687 // At this point the name must be set.
3688 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3689 this->namepool_
.add((*p
)->name(), false, NULL
);
3694 // Set the section indexes of all the sections not associated with a
3698 Layout::set_section_indexes(unsigned int shndx
)
3700 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3701 p
!= this->unattached_section_list_
.end();
3704 if (!(*p
)->has_out_shndx())
3706 (*p
)->set_out_shndx(shndx
);
3713 // Set the section addresses according to the linker script. This is
3714 // only called when we see a SECTIONS clause. This returns the
3715 // program segment which should hold the file header and segment
3716 // headers, if any. It will return NULL if they should not be in a
3720 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3722 Script_sections
* ss
= this->script_options_
->script_sections();
3723 gold_assert(ss
->saw_sections_clause());
3724 return this->script_options_
->set_section_addresses(symtab
, this);
3727 // Place the orphan sections in the linker script.
3730 Layout::place_orphan_sections_in_script()
3732 Script_sections
* ss
= this->script_options_
->script_sections();
3733 gold_assert(ss
->saw_sections_clause());
3735 // Place each orphaned output section in the script.
3736 for (Section_list::iterator p
= this->section_list_
.begin();
3737 p
!= this->section_list_
.end();
3740 if (!(*p
)->found_in_sections_clause())
3741 ss
->place_orphan(*p
);
3745 // Count the local symbols in the regular symbol table and the dynamic
3746 // symbol table, and build the respective string pools.
3749 Layout::count_local_symbols(const Task
* task
,
3750 const Input_objects
* input_objects
)
3752 // First, figure out an upper bound on the number of symbols we'll
3753 // be inserting into each pool. This helps us create the pools with
3754 // the right size, to avoid unnecessary hashtable resizing.
3755 unsigned int symbol_count
= 0;
3756 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3757 p
!= input_objects
->relobj_end();
3759 symbol_count
+= (*p
)->local_symbol_count();
3761 // Go from "upper bound" to "estimate." We overcount for two
3762 // reasons: we double-count symbols that occur in more than one
3763 // object file, and we count symbols that are dropped from the
3764 // output. Add it all together and assume we overcount by 100%.
3767 // We assume all symbols will go into both the sympool and dynpool.
3768 this->sympool_
.reserve(symbol_count
);
3769 this->dynpool_
.reserve(symbol_count
);
3771 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3772 p
!= input_objects
->relobj_end();
3775 Task_lock_obj
<Object
> tlo(task
, *p
);
3776 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3780 // Create the symbol table sections. Here we also set the final
3781 // values of the symbols. At this point all the loadable sections are
3782 // fully laid out. SHNUM is the number of sections so far.
3785 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3786 Symbol_table
* symtab
,
3792 if (parameters
->target().get_size() == 32)
3794 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3797 else if (parameters
->target().get_size() == 64)
3799 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3805 // Compute file offsets relative to the start of the symtab section.
3808 // Save space for the dummy symbol at the start of the section. We
3809 // never bother to write this out--it will just be left as zero.
3811 unsigned int local_symbol_index
= 1;
3813 // Add STT_SECTION symbols for each Output section which needs one.
3814 for (Section_list::iterator p
= this->section_list_
.begin();
3815 p
!= this->section_list_
.end();
3818 if (!(*p
)->needs_symtab_index())
3819 (*p
)->set_symtab_index(-1U);
3822 (*p
)->set_symtab_index(local_symbol_index
);
3823 ++local_symbol_index
;
3828 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3829 p
!= input_objects
->relobj_end();
3832 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3834 off
+= (index
- local_symbol_index
) * symsize
;
3835 local_symbol_index
= index
;
3838 unsigned int local_symcount
= local_symbol_index
;
3839 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3842 size_t dyn_global_index
;
3844 if (this->dynsym_section_
== NULL
)
3847 dyn_global_index
= 0;
3852 dyn_global_index
= this->dynsym_section_
->info();
3853 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3854 dynoff
= this->dynsym_section_
->offset() + locsize
;
3855 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3856 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3857 == this->dynsym_section_
->data_size() - locsize
);
3860 off_t global_off
= off
;
3861 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3862 &this->sympool_
, &local_symcount
);
3864 if (!parameters
->options().strip_all())
3866 this->sympool_
.set_string_offsets();
3868 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3869 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3873 this->symtab_section_
= osymtab
;
3875 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3877 osymtab
->add_output_section_data(pos
);
3879 // We generate a .symtab_shndx section if we have more than
3880 // SHN_LORESERVE sections. Technically it is possible that we
3881 // don't need one, because it is possible that there are no
3882 // symbols in any of sections with indexes larger than
3883 // SHN_LORESERVE. That is probably unusual, though, and it is
3884 // easier to always create one than to compute section indexes
3885 // twice (once here, once when writing out the symbols).
3886 if (shnum
>= elfcpp::SHN_LORESERVE
)
3888 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3890 Output_section
* osymtab_xindex
=
3891 this->make_output_section(symtab_xindex_name
,
3892 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3893 ORDER_INVALID
, false);
3895 size_t symcount
= off
/ symsize
;
3896 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3898 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3900 osymtab_xindex
->set_link_section(osymtab
);
3901 osymtab_xindex
->set_addralign(4);
3902 osymtab_xindex
->set_entsize(4);
3904 osymtab_xindex
->set_after_input_sections();
3906 // This tells the driver code to wait until the symbol table
3907 // has written out before writing out the postprocessing
3908 // sections, including the .symtab_shndx section.
3909 this->any_postprocessing_sections_
= true;
3912 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3913 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3918 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3919 ostrtab
->add_output_section_data(pstr
);
3922 if (!parameters
->incremental_update())
3923 symtab_off
= align_address(*poff
, align
);
3926 symtab_off
= this->allocate(off
, align
, *poff
);
3928 gold_fallback(_("out of patch space for symbol table; "
3929 "relink with --incremental-full"));
3930 gold_debug(DEBUG_INCREMENTAL
,
3931 "create_symtab_sections: %08lx %08lx .symtab",
3932 static_cast<long>(symtab_off
),
3933 static_cast<long>(off
));
3936 symtab
->set_file_offset(symtab_off
+ global_off
);
3937 osymtab
->set_file_offset(symtab_off
);
3938 osymtab
->finalize_data_size();
3939 osymtab
->set_link_section(ostrtab
);
3940 osymtab
->set_info(local_symcount
);
3941 osymtab
->set_entsize(symsize
);
3943 if (symtab_off
+ off
> *poff
)
3944 *poff
= symtab_off
+ off
;
3948 // Create the .shstrtab section, which holds the names of the
3949 // sections. At the time this is called, we have created all the
3950 // output sections except .shstrtab itself.
3953 Layout::create_shstrtab()
3955 // FIXME: We don't need to create a .shstrtab section if we are
3956 // stripping everything.
3958 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
3960 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
3961 ORDER_INVALID
, false);
3963 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
3965 // We can't write out this section until we've set all the
3966 // section names, and we don't set the names of compressed
3967 // output sections until relocations are complete. FIXME: With
3968 // the current names we use, this is unnecessary.
3969 os
->set_after_input_sections();
3972 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
3973 os
->add_output_section_data(posd
);
3978 // Create the section headers. SIZE is 32 or 64. OFF is the file
3982 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
3984 Output_section_headers
* oshdrs
;
3985 oshdrs
= new Output_section_headers(this,
3986 &this->segment_list_
,
3987 &this->section_list_
,
3988 &this->unattached_section_list_
,
3992 if (!parameters
->incremental_update())
3993 off
= align_address(*poff
, oshdrs
->addralign());
3996 oshdrs
->pre_finalize_data_size();
3997 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
3999 gold_fallback(_("out of patch space for section header table; "
4000 "relink with --incremental-full"));
4001 gold_debug(DEBUG_INCREMENTAL
,
4002 "create_shdrs: %08lx %08lx (section header table)",
4003 static_cast<long>(off
),
4004 static_cast<long>(off
+ oshdrs
->data_size()));
4006 oshdrs
->set_address_and_file_offset(0, off
);
4007 off
+= oshdrs
->data_size();
4010 this->section_headers_
= oshdrs
;
4013 // Count the allocated sections.
4016 Layout::allocated_output_section_count() const
4018 size_t section_count
= 0;
4019 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4020 p
!= this->segment_list_
.end();
4022 section_count
+= (*p
)->output_section_count();
4023 return section_count
;
4026 // Create the dynamic symbol table.
4029 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4030 Symbol_table
* symtab
,
4031 Output_section
** pdynstr
,
4032 unsigned int* plocal_dynamic_count
,
4033 std::vector
<Symbol
*>* pdynamic_symbols
,
4034 Versions
* pversions
)
4036 // Count all the symbols in the dynamic symbol table, and set the
4037 // dynamic symbol indexes.
4039 // Skip symbol 0, which is always all zeroes.
4040 unsigned int index
= 1;
4042 // Add STT_SECTION symbols for each Output section which needs one.
4043 for (Section_list::iterator p
= this->section_list_
.begin();
4044 p
!= this->section_list_
.end();
4047 if (!(*p
)->needs_dynsym_index())
4048 (*p
)->set_dynsym_index(-1U);
4051 (*p
)->set_dynsym_index(index
);
4056 // Count the local symbols that need to go in the dynamic symbol table,
4057 // and set the dynamic symbol indexes.
4058 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4059 p
!= input_objects
->relobj_end();
4062 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4066 unsigned int local_symcount
= index
;
4067 *plocal_dynamic_count
= local_symcount
;
4069 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
4070 &this->dynpool_
, pversions
);
4074 const int size
= parameters
->target().get_size();
4077 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4080 else if (size
== 64)
4082 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4088 // Create the dynamic symbol table section.
4090 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4094 ORDER_DYNAMIC_LINKER
,
4097 // Check for NULL as a linker script may discard .dynsym.
4100 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4103 dynsym
->add_output_section_data(odata
);
4105 dynsym
->set_info(local_symcount
);
4106 dynsym
->set_entsize(symsize
);
4107 dynsym
->set_addralign(align
);
4109 this->dynsym_section_
= dynsym
;
4112 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4115 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4116 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4119 // If there are more than SHN_LORESERVE allocated sections, we
4120 // create a .dynsym_shndx section. It is possible that we don't
4121 // need one, because it is possible that there are no dynamic
4122 // symbols in any of the sections with indexes larger than
4123 // SHN_LORESERVE. This is probably unusual, though, and at this
4124 // time we don't know the actual section indexes so it is
4125 // inconvenient to check.
4126 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4128 Output_section
* dynsym_xindex
=
4129 this->choose_output_section(NULL
, ".dynsym_shndx",
4130 elfcpp::SHT_SYMTAB_SHNDX
,
4132 false, ORDER_DYNAMIC_LINKER
, false);
4134 if (dynsym_xindex
!= NULL
)
4136 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4138 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4140 dynsym_xindex
->set_link_section(dynsym
);
4141 dynsym_xindex
->set_addralign(4);
4142 dynsym_xindex
->set_entsize(4);
4144 dynsym_xindex
->set_after_input_sections();
4146 // This tells the driver code to wait until the symbol table
4147 // has written out before writing out the postprocessing
4148 // sections, including the .dynsym_shndx section.
4149 this->any_postprocessing_sections_
= true;
4153 // Create the dynamic string table section.
4155 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4159 ORDER_DYNAMIC_LINKER
,
4164 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4165 dynstr
->add_output_section_data(strdata
);
4168 dynsym
->set_link_section(dynstr
);
4169 if (this->dynamic_section_
!= NULL
)
4170 this->dynamic_section_
->set_link_section(dynstr
);
4174 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4175 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4181 // Create the hash tables.
4183 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4184 || strcmp(parameters
->options().hash_style(), "both") == 0)
4186 unsigned char* phash
;
4187 unsigned int hashlen
;
4188 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
4191 Output_section
* hashsec
=
4192 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4193 elfcpp::SHF_ALLOC
, false,
4194 ORDER_DYNAMIC_LINKER
, false);
4196 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4200 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4201 hashsec
->add_output_section_data(hashdata
);
4203 if (hashsec
!= NULL
)
4206 hashsec
->set_link_section(dynsym
);
4207 hashsec
->set_entsize(4);
4211 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4214 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4215 || strcmp(parameters
->options().hash_style(), "both") == 0)
4217 unsigned char* phash
;
4218 unsigned int hashlen
;
4219 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
4222 Output_section
* hashsec
=
4223 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4224 elfcpp::SHF_ALLOC
, false,
4225 ORDER_DYNAMIC_LINKER
, false);
4227 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4231 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4232 hashsec
->add_output_section_data(hashdata
);
4234 if (hashsec
!= NULL
)
4237 hashsec
->set_link_section(dynsym
);
4239 // For a 64-bit target, the entries in .gnu.hash do not have
4240 // a uniform size, so we only set the entry size for a
4242 if (parameters
->target().get_size() == 32)
4243 hashsec
->set_entsize(4);
4246 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4251 // Assign offsets to each local portion of the dynamic symbol table.
4254 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4256 Output_section
* dynsym
= this->dynsym_section_
;
4260 off_t off
= dynsym
->offset();
4262 // Skip the dummy symbol at the start of the section.
4263 off
+= dynsym
->entsize();
4265 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4266 p
!= input_objects
->relobj_end();
4269 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4270 off
+= count
* dynsym
->entsize();
4274 // Create the version sections.
4277 Layout::create_version_sections(const Versions
* versions
,
4278 const Symbol_table
* symtab
,
4279 unsigned int local_symcount
,
4280 const std::vector
<Symbol
*>& dynamic_symbols
,
4281 const Output_section
* dynstr
)
4283 if (!versions
->any_defs() && !versions
->any_needs())
4286 switch (parameters
->size_and_endianness())
4288 #ifdef HAVE_TARGET_32_LITTLE
4289 case Parameters::TARGET_32_LITTLE
:
4290 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4292 dynamic_symbols
, dynstr
);
4295 #ifdef HAVE_TARGET_32_BIG
4296 case Parameters::TARGET_32_BIG
:
4297 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4299 dynamic_symbols
, dynstr
);
4302 #ifdef HAVE_TARGET_64_LITTLE
4303 case Parameters::TARGET_64_LITTLE
:
4304 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4306 dynamic_symbols
, dynstr
);
4309 #ifdef HAVE_TARGET_64_BIG
4310 case Parameters::TARGET_64_BIG
:
4311 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4313 dynamic_symbols
, dynstr
);
4321 // Create the version sections, sized version.
4323 template<int size
, bool big_endian
>
4325 Layout::sized_create_version_sections(
4326 const Versions
* versions
,
4327 const Symbol_table
* symtab
,
4328 unsigned int local_symcount
,
4329 const std::vector
<Symbol
*>& dynamic_symbols
,
4330 const Output_section
* dynstr
)
4332 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4333 elfcpp::SHT_GNU_versym
,
4336 ORDER_DYNAMIC_LINKER
,
4339 // Check for NULL since a linker script may discard this section.
4342 unsigned char* vbuf
;
4344 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4350 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4353 vsec
->add_output_section_data(vdata
);
4354 vsec
->set_entsize(2);
4355 vsec
->set_link_section(this->dynsym_section_
);
4358 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4359 if (odyn
!= NULL
&& vsec
!= NULL
)
4360 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4362 if (versions
->any_defs())
4364 Output_section
* vdsec
;
4365 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4366 elfcpp::SHT_GNU_verdef
,
4368 false, ORDER_DYNAMIC_LINKER
, false);
4372 unsigned char* vdbuf
;
4373 unsigned int vdsize
;
4374 unsigned int vdentries
;
4375 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4379 Output_section_data
* vddata
=
4380 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4382 vdsec
->add_output_section_data(vddata
);
4383 vdsec
->set_link_section(dynstr
);
4384 vdsec
->set_info(vdentries
);
4388 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4389 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4394 if (versions
->any_needs())
4396 Output_section
* vnsec
;
4397 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4398 elfcpp::SHT_GNU_verneed
,
4400 false, ORDER_DYNAMIC_LINKER
, false);
4404 unsigned char* vnbuf
;
4405 unsigned int vnsize
;
4406 unsigned int vnentries
;
4407 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4411 Output_section_data
* vndata
=
4412 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4414 vnsec
->add_output_section_data(vndata
);
4415 vnsec
->set_link_section(dynstr
);
4416 vnsec
->set_info(vnentries
);
4420 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4421 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
4427 // Create the .interp section and PT_INTERP segment.
4430 Layout::create_interp(const Target
* target
)
4432 gold_assert(this->interp_segment_
== NULL
);
4434 const char* interp
= parameters
->options().dynamic_linker();
4437 interp
= target
->dynamic_linker();
4438 gold_assert(interp
!= NULL
);
4441 size_t len
= strlen(interp
) + 1;
4443 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
4445 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
4446 elfcpp::SHT_PROGBITS
,
4448 false, ORDER_INTERP
,
4451 osec
->add_output_section_data(odata
);
4454 // Add dynamic tags for the PLT and the dynamic relocs. This is
4455 // called by the target-specific code. This does nothing if not doing
4458 // USE_REL is true for REL relocs rather than RELA relocs.
4460 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4462 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4463 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4464 // some targets have multiple reloc sections in PLT_REL.
4466 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4467 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4470 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4474 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
4475 const Output_data
* plt_rel
,
4476 const Output_data_reloc_generic
* dyn_rel
,
4477 bool add_debug
, bool dynrel_includes_plt
)
4479 Output_data_dynamic
* odyn
= this->dynamic_data_
;
4483 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
4484 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
4486 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
4488 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
4489 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
4490 odyn
->add_constant(elfcpp::DT_PLTREL
,
4491 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
4494 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
4495 || (dynrel_includes_plt
4497 && plt_rel
->output_section() != NULL
))
4499 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
4500 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
4501 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
4503 ? dyn_rel
->output_section()
4504 : plt_rel
->output_section()));
4505 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
4506 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
4507 odyn
->add_section_size(size_tag
,
4508 dyn_rel
->output_section(),
4509 plt_rel
->output_section());
4510 else if (have_dyn_rel
)
4511 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
4513 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
4514 const int size
= parameters
->target().get_size();
4519 rel_tag
= elfcpp::DT_RELENT
;
4521 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
4522 else if (size
== 64)
4523 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
4529 rel_tag
= elfcpp::DT_RELAENT
;
4531 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
4532 else if (size
== 64)
4533 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
4537 odyn
->add_constant(rel_tag
, rel_size
);
4539 if (parameters
->options().combreloc() && have_dyn_rel
)
4541 size_t c
= dyn_rel
->relative_reloc_count();
4543 odyn
->add_constant((use_rel
4544 ? elfcpp::DT_RELCOUNT
4545 : elfcpp::DT_RELACOUNT
),
4550 if (add_debug
&& !parameters
->options().shared())
4552 // The value of the DT_DEBUG tag is filled in by the dynamic
4553 // linker at run time, and used by the debugger.
4554 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
4558 // Finish the .dynamic section and PT_DYNAMIC segment.
4561 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
4562 const Symbol_table
* symtab
)
4564 if (!this->script_options_
->saw_phdrs_clause()
4565 && this->dynamic_section_
!= NULL
)
4567 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
4570 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
4571 elfcpp::PF_R
| elfcpp::PF_W
);
4574 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4578 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
4579 p
!= input_objects
->dynobj_end();
4582 if (!(*p
)->is_needed() && (*p
)->as_needed())
4584 // This dynamic object was linked with --as-needed, but it
4589 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4592 if (parameters
->options().shared())
4594 const char* soname
= parameters
->options().soname();
4596 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4599 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4600 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4601 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4603 sym
= symtab
->lookup(parameters
->options().fini());
4604 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4605 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4607 // Look for .init_array, .preinit_array and .fini_array by checking
4609 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4610 p
!= this->section_list_
.end();
4612 switch((*p
)->type())
4614 case elfcpp::SHT_FINI_ARRAY
:
4615 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4616 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4618 case elfcpp::SHT_INIT_ARRAY
:
4619 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4620 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4622 case elfcpp::SHT_PREINIT_ARRAY
:
4623 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4624 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4630 // Add a DT_RPATH entry if needed.
4631 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4634 std::string rpath_val
;
4635 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4639 if (rpath_val
.empty())
4640 rpath_val
= p
->name();
4643 // Eliminate duplicates.
4644 General_options::Dir_list::const_iterator q
;
4645 for (q
= rpath
.begin(); q
!= p
; ++q
)
4646 if (q
->name() == p
->name())
4651 rpath_val
+= p
->name();
4656 if (!parameters
->options().enable_new_dtags())
4657 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4659 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4662 // Look for text segments that have dynamic relocations.
4663 bool have_textrel
= false;
4664 if (!this->script_options_
->saw_sections_clause())
4666 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4667 p
!= this->segment_list_
.end();
4670 if ((*p
)->type() == elfcpp::PT_LOAD
4671 && ((*p
)->flags() & elfcpp::PF_W
) == 0
4672 && (*p
)->has_dynamic_reloc())
4674 have_textrel
= true;
4681 // We don't know the section -> segment mapping, so we are
4682 // conservative and just look for readonly sections with
4683 // relocations. If those sections wind up in writable segments,
4684 // then we have created an unnecessary DT_TEXTREL entry.
4685 for (Section_list::const_iterator p
= this->section_list_
.begin();
4686 p
!= this->section_list_
.end();
4689 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4690 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4691 && (*p
)->has_dynamic_reloc())
4693 have_textrel
= true;
4699 if (parameters
->options().filter() != NULL
)
4700 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
4701 if (parameters
->options().any_auxiliary())
4703 for (options::String_set::const_iterator p
=
4704 parameters
->options().auxiliary_begin();
4705 p
!= parameters
->options().auxiliary_end();
4707 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
4710 // Add a DT_FLAGS entry if necessary.
4711 unsigned int flags
= 0;
4714 // Add a DT_TEXTREL for compatibility with older loaders.
4715 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4716 flags
|= elfcpp::DF_TEXTREL
;
4718 if (parameters
->options().text())
4719 gold_error(_("read-only segment has dynamic relocations"));
4720 else if (parameters
->options().warn_shared_textrel()
4721 && parameters
->options().shared())
4722 gold_warning(_("shared library text segment is not shareable"));
4724 if (parameters
->options().shared() && this->has_static_tls())
4725 flags
|= elfcpp::DF_STATIC_TLS
;
4726 if (parameters
->options().origin())
4727 flags
|= elfcpp::DF_ORIGIN
;
4728 if (parameters
->options().Bsymbolic())
4730 flags
|= elfcpp::DF_SYMBOLIC
;
4731 // Add DT_SYMBOLIC for compatibility with older loaders.
4732 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4734 if (parameters
->options().now())
4735 flags
|= elfcpp::DF_BIND_NOW
;
4737 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4740 if (parameters
->options().initfirst())
4741 flags
|= elfcpp::DF_1_INITFIRST
;
4742 if (parameters
->options().interpose())
4743 flags
|= elfcpp::DF_1_INTERPOSE
;
4744 if (parameters
->options().loadfltr())
4745 flags
|= elfcpp::DF_1_LOADFLTR
;
4746 if (parameters
->options().nodefaultlib())
4747 flags
|= elfcpp::DF_1_NODEFLIB
;
4748 if (parameters
->options().nodelete())
4749 flags
|= elfcpp::DF_1_NODELETE
;
4750 if (parameters
->options().nodlopen())
4751 flags
|= elfcpp::DF_1_NOOPEN
;
4752 if (parameters
->options().nodump())
4753 flags
|= elfcpp::DF_1_NODUMP
;
4754 if (!parameters
->options().shared())
4755 flags
&= ~(elfcpp::DF_1_INITFIRST
4756 | elfcpp::DF_1_NODELETE
4757 | elfcpp::DF_1_NOOPEN
);
4758 if (parameters
->options().origin())
4759 flags
|= elfcpp::DF_1_ORIGIN
;
4760 if (parameters
->options().now())
4761 flags
|= elfcpp::DF_1_NOW
;
4762 if (parameters
->options().Bgroup())
4763 flags
|= elfcpp::DF_1_GROUP
;
4765 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4768 // Set the size of the _DYNAMIC symbol table to be the size of the
4772 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4774 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4777 odyn
->finalize_data_size();
4778 if (this->dynamic_symbol_
== NULL
)
4780 off_t data_size
= odyn
->data_size();
4781 const int size
= parameters
->target().get_size();
4783 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4784 else if (size
== 64)
4785 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4790 // The mapping of input section name prefixes to output section names.
4791 // In some cases one prefix is itself a prefix of another prefix; in
4792 // such a case the longer prefix must come first. These prefixes are
4793 // based on the GNU linker default ELF linker script.
4795 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4796 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4797 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4799 MAPPING_INIT(".text.", ".text"),
4800 MAPPING_INIT(".rodata.", ".rodata"),
4801 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4802 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4803 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4804 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4805 MAPPING_INIT(".data.", ".data"),
4806 MAPPING_INIT(".bss.", ".bss"),
4807 MAPPING_INIT(".tdata.", ".tdata"),
4808 MAPPING_INIT(".tbss.", ".tbss"),
4809 MAPPING_INIT(".init_array.", ".init_array"),
4810 MAPPING_INIT(".fini_array.", ".fini_array"),
4811 MAPPING_INIT(".sdata.", ".sdata"),
4812 MAPPING_INIT(".sbss.", ".sbss"),
4813 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4814 // differently depending on whether it is creating a shared library.
4815 MAPPING_INIT(".sdata2.", ".sdata"),
4816 MAPPING_INIT(".sbss2.", ".sbss"),
4817 MAPPING_INIT(".lrodata.", ".lrodata"),
4818 MAPPING_INIT(".ldata.", ".ldata"),
4819 MAPPING_INIT(".lbss.", ".lbss"),
4820 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4821 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4822 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4823 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4824 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4825 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4826 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4827 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4828 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4829 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4830 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4831 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4832 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4833 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4834 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4835 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4836 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4837 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4838 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4839 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4840 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4843 #undef MAPPING_INIT_EXACT
4845 const int Layout::section_name_mapping_count
=
4846 (sizeof(Layout::section_name_mapping
)
4847 / sizeof(Layout::section_name_mapping
[0]));
4849 // Choose the output section name to use given an input section name.
4850 // Set *PLEN to the length of the name. *PLEN is initialized to the
4854 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
4857 // gcc 4.3 generates the following sorts of section names when it
4858 // needs a section name specific to a function:
4864 // .data.rel.local.FN
4866 // .data.rel.ro.local.FN
4873 // The GNU linker maps all of those to the part before the .FN,
4874 // except that .data.rel.local.FN is mapped to .data, and
4875 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4876 // beginning with .data.rel.ro.local are grouped together.
4878 // For an anonymous namespace, the string FN can contain a '.'.
4880 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4881 // GNU linker maps to .rodata.
4883 // The .data.rel.ro sections are used with -z relro. The sections
4884 // are recognized by name. We use the same names that the GNU
4885 // linker does for these sections.
4887 // It is hard to handle this in a principled way, so we don't even
4888 // try. We use a table of mappings. If the input section name is
4889 // not found in the table, we simply use it as the output section
4892 const Section_name_mapping
* psnm
= section_name_mapping
;
4893 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4895 if (psnm
->fromlen
> 0)
4897 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4899 *plen
= psnm
->tolen
;
4905 if (strcmp(name
, psnm
->from
) == 0)
4907 *plen
= psnm
->tolen
;
4913 // As an additional complication, .ctors sections are output in
4914 // either .ctors or .init_array sections, and .dtors sections are
4915 // output in either .dtors or .fini_array sections.
4916 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
4918 if (parameters
->options().ctors_in_init_array())
4921 return name
[1] == 'c' ? ".init_array" : ".fini_array";
4926 return name
[1] == 'c' ? ".ctors" : ".dtors";
4929 if (parameters
->options().ctors_in_init_array()
4930 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
4932 // To make .init_array/.fini_array work with gcc we must exclude
4933 // .ctors and .dtors sections from the crtbegin and crtend
4936 || (!Layout::match_file_name(relobj
, "crtbegin")
4937 && !Layout::match_file_name(relobj
, "crtend")))
4940 return name
[1] == 'c' ? ".init_array" : ".fini_array";
4947 // Return true if RELOBJ is an input file whose base name matches
4948 // FILE_NAME. The base name must have an extension of ".o", and must
4949 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
4950 // to match crtbegin.o as well as crtbeginS.o without getting confused
4951 // by other possibilities. Overall matching the file name this way is
4952 // a dreadful hack, but the GNU linker does it in order to better
4953 // support gcc, and we need to be compatible.
4956 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
4958 const std::string
& file_name(relobj
->name());
4959 const char* base_name
= lbasename(file_name
.c_str());
4960 size_t match_len
= strlen(match
);
4961 if (strncmp(base_name
, match
, match_len
) != 0)
4963 size_t base_len
= strlen(base_name
);
4964 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
4966 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
4969 // Check if a comdat group or .gnu.linkonce section with the given
4970 // NAME is selected for the link. If there is already a section,
4971 // *KEPT_SECTION is set to point to the existing section and the
4972 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4973 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4974 // *KEPT_SECTION is set to the internal copy and the function returns
4978 Layout::find_or_add_kept_section(const std::string
& name
,
4983 Kept_section
** kept_section
)
4985 // It's normal to see a couple of entries here, for the x86 thunk
4986 // sections. If we see more than a few, we're linking a C++
4987 // program, and we resize to get more space to minimize rehashing.
4988 if (this->signatures_
.size() > 4
4989 && !this->resized_signatures_
)
4991 reserve_unordered_map(&this->signatures_
,
4992 this->number_of_input_files_
* 64);
4993 this->resized_signatures_
= true;
4996 Kept_section candidate
;
4997 std::pair
<Signatures::iterator
, bool> ins
=
4998 this->signatures_
.insert(std::make_pair(name
, candidate
));
5000 if (kept_section
!= NULL
)
5001 *kept_section
= &ins
.first
->second
;
5004 // This is the first time we've seen this signature.
5005 ins
.first
->second
.set_object(object
);
5006 ins
.first
->second
.set_shndx(shndx
);
5008 ins
.first
->second
.set_is_comdat();
5010 ins
.first
->second
.set_is_group_name();
5014 // We have already seen this signature.
5016 if (ins
.first
->second
.is_group_name())
5018 // We've already seen a real section group with this signature.
5019 // If the kept group is from a plugin object, and we're in the
5020 // replacement phase, accept the new one as a replacement.
5021 if (ins
.first
->second
.object() == NULL
5022 && parameters
->options().plugins()->in_replacement_phase())
5024 ins
.first
->second
.set_object(object
);
5025 ins
.first
->second
.set_shndx(shndx
);
5030 else if (is_group_name
)
5032 // This is a real section group, and we've already seen a
5033 // linkonce section with this signature. Record that we've seen
5034 // a section group, and don't include this section group.
5035 ins
.first
->second
.set_is_group_name();
5040 // We've already seen a linkonce section and this is a linkonce
5041 // section. These don't block each other--this may be the same
5042 // symbol name with different section types.
5047 // Store the allocated sections into the section list.
5050 Layout::get_allocated_sections(Section_list
* section_list
) const
5052 for (Section_list::const_iterator p
= this->section_list_
.begin();
5053 p
!= this->section_list_
.end();
5055 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5056 section_list
->push_back(*p
);
5059 // Store the executable sections into the section list.
5062 Layout::get_executable_sections(Section_list
* section_list
) const
5064 for (Section_list::const_iterator p
= this->section_list_
.begin();
5065 p
!= this->section_list_
.end();
5067 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5068 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5069 section_list
->push_back(*p
);
5072 // Create an output segment.
5075 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5077 gold_assert(!parameters
->options().relocatable());
5078 Output_segment
* oseg
= new Output_segment(type
, flags
);
5079 this->segment_list_
.push_back(oseg
);
5081 if (type
== elfcpp::PT_TLS
)
5082 this->tls_segment_
= oseg
;
5083 else if (type
== elfcpp::PT_GNU_RELRO
)
5084 this->relro_segment_
= oseg
;
5085 else if (type
== elfcpp::PT_INTERP
)
5086 this->interp_segment_
= oseg
;
5091 // Return the file offset of the normal symbol table.
5094 Layout::symtab_section_offset() const
5096 if (this->symtab_section_
!= NULL
)
5097 return this->symtab_section_
->offset();
5101 // Return the section index of the normal symbol table. It may have
5102 // been stripped by the -s/--strip-all option.
5105 Layout::symtab_section_shndx() const
5107 if (this->symtab_section_
!= NULL
)
5108 return this->symtab_section_
->out_shndx();
5112 // Write out the Output_sections. Most won't have anything to write,
5113 // since most of the data will come from input sections which are
5114 // handled elsewhere. But some Output_sections do have Output_data.
5117 Layout::write_output_sections(Output_file
* of
) const
5119 for (Section_list::const_iterator p
= this->section_list_
.begin();
5120 p
!= this->section_list_
.end();
5123 if (!(*p
)->after_input_sections())
5128 // Write out data not associated with a section or the symbol table.
5131 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5133 if (!parameters
->options().strip_all())
5135 const Output_section
* symtab_section
= this->symtab_section_
;
5136 for (Section_list::const_iterator p
= this->section_list_
.begin();
5137 p
!= this->section_list_
.end();
5140 if ((*p
)->needs_symtab_index())
5142 gold_assert(symtab_section
!= NULL
);
5143 unsigned int index
= (*p
)->symtab_index();
5144 gold_assert(index
> 0 && index
!= -1U);
5145 off_t off
= (symtab_section
->offset()
5146 + index
* symtab_section
->entsize());
5147 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5152 const Output_section
* dynsym_section
= this->dynsym_section_
;
5153 for (Section_list::const_iterator p
= this->section_list_
.begin();
5154 p
!= this->section_list_
.end();
5157 if ((*p
)->needs_dynsym_index())
5159 gold_assert(dynsym_section
!= NULL
);
5160 unsigned int index
= (*p
)->dynsym_index();
5161 gold_assert(index
> 0 && index
!= -1U);
5162 off_t off
= (dynsym_section
->offset()
5163 + index
* dynsym_section
->entsize());
5164 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5168 // Write out the Output_data which are not in an Output_section.
5169 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5170 p
!= this->special_output_list_
.end();
5175 // Write out the Output_sections which can only be written after the
5176 // input sections are complete.
5179 Layout::write_sections_after_input_sections(Output_file
* of
)
5181 // Determine the final section offsets, and thus the final output
5182 // file size. Note we finalize the .shstrab last, to allow the
5183 // after_input_section sections to modify their section-names before
5185 if (this->any_postprocessing_sections_
)
5187 off_t off
= this->output_file_size_
;
5188 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5190 // Now that we've finalized the names, we can finalize the shstrab.
5192 this->set_section_offsets(off
,
5193 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5195 if (off
> this->output_file_size_
)
5198 this->output_file_size_
= off
;
5202 for (Section_list::const_iterator p
= this->section_list_
.begin();
5203 p
!= this->section_list_
.end();
5206 if ((*p
)->after_input_sections())
5210 this->section_headers_
->write(of
);
5213 // If the build ID requires computing a checksum, do so here, and
5214 // write it out. We compute a checksum over the entire file because
5215 // that is simplest.
5218 Layout::write_build_id(Output_file
* of
) const
5220 if (this->build_id_note_
== NULL
)
5223 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
5225 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5226 this->build_id_note_
->data_size());
5228 const char* style
= parameters
->options().build_id();
5229 if (strcmp(style
, "sha1") == 0)
5232 sha1_init_ctx(&ctx
);
5233 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
5234 sha1_finish_ctx(&ctx
, ov
);
5236 else if (strcmp(style
, "md5") == 0)
5240 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
5241 md5_finish_ctx(&ctx
, ov
);
5246 of
->write_output_view(this->build_id_note_
->offset(),
5247 this->build_id_note_
->data_size(),
5250 of
->free_input_view(0, this->output_file_size_
, iv
);
5253 // Write out a binary file. This is called after the link is
5254 // complete. IN is the temporary output file we used to generate the
5255 // ELF code. We simply walk through the segments, read them from
5256 // their file offset in IN, and write them to their load address in
5257 // the output file. FIXME: with a bit more work, we could support
5258 // S-records and/or Intel hex format here.
5261 Layout::write_binary(Output_file
* in
) const
5263 gold_assert(parameters
->options().oformat_enum()
5264 == General_options::OBJECT_FORMAT_BINARY
);
5266 // Get the size of the binary file.
5267 uint64_t max_load_address
= 0;
5268 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5269 p
!= this->segment_list_
.end();
5272 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5274 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5275 if (max_paddr
> max_load_address
)
5276 max_load_address
= max_paddr
;
5280 Output_file
out(parameters
->options().output_file_name());
5281 out
.open(max_load_address
);
5283 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5284 p
!= this->segment_list_
.end();
5287 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5289 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5291 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5293 memcpy(vout
, vin
, (*p
)->filesz());
5294 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5295 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5302 // Print the output sections to the map file.
5305 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5307 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5308 p
!= this->segment_list_
.end();
5310 (*p
)->print_sections_to_mapfile(mapfile
);
5313 // Print statistical information to stderr. This is used for --stats.
5316 Layout::print_stats() const
5318 this->namepool_
.print_stats("section name pool");
5319 this->sympool_
.print_stats("output symbol name pool");
5320 this->dynpool_
.print_stats("dynamic name pool");
5322 for (Section_list::const_iterator p
= this->section_list_
.begin();
5323 p
!= this->section_list_
.end();
5325 (*p
)->print_merge_stats();
5328 // Write_sections_task methods.
5330 // We can always run this task.
5333 Write_sections_task::is_runnable()
5338 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5342 Write_sections_task::locks(Task_locker
* tl
)
5344 tl
->add(this, this->output_sections_blocker_
);
5345 tl
->add(this, this->final_blocker_
);
5348 // Run the task--write out the data.
5351 Write_sections_task::run(Workqueue
*)
5353 this->layout_
->write_output_sections(this->of_
);
5356 // Write_data_task methods.
5358 // We can always run this task.
5361 Write_data_task::is_runnable()
5366 // We need to unlock FINAL_BLOCKER when finished.
5369 Write_data_task::locks(Task_locker
* tl
)
5371 tl
->add(this, this->final_blocker_
);
5374 // Run the task--write out the data.
5377 Write_data_task::run(Workqueue
*)
5379 this->layout_
->write_data(this->symtab_
, this->of_
);
5382 // Write_symbols_task methods.
5384 // We can always run this task.
5387 Write_symbols_task::is_runnable()
5392 // We need to unlock FINAL_BLOCKER when finished.
5395 Write_symbols_task::locks(Task_locker
* tl
)
5397 tl
->add(this, this->final_blocker_
);
5400 // Run the task--write out the symbols.
5403 Write_symbols_task::run(Workqueue
*)
5405 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
5406 this->layout_
->symtab_xindex(),
5407 this->layout_
->dynsym_xindex(), this->of_
);
5410 // Write_after_input_sections_task methods.
5412 // We can only run this task after the input sections have completed.
5415 Write_after_input_sections_task::is_runnable()
5417 if (this->input_sections_blocker_
->is_blocked())
5418 return this->input_sections_blocker_
;
5422 // We need to unlock FINAL_BLOCKER when finished.
5425 Write_after_input_sections_task::locks(Task_locker
* tl
)
5427 tl
->add(this, this->final_blocker_
);
5433 Write_after_input_sections_task::run(Workqueue
*)
5435 this->layout_
->write_sections_after_input_sections(this->of_
);
5438 // Close_task_runner methods.
5440 // Run the task--close the file.
5443 Close_task_runner::run(Workqueue
*, const Task
*)
5445 // If we need to compute a checksum for the BUILD if, we do so here.
5446 this->layout_
->write_build_id(this->of_
);
5448 // If we've been asked to create a binary file, we do so here.
5449 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
5450 this->layout_
->write_binary(this->of_
);
5455 // Instantiate the templates we need. We could use the configure
5456 // script to restrict this to only the ones for implemented targets.
5458 #ifdef HAVE_TARGET_32_LITTLE
5461 Layout::init_fixed_output_section
<32, false>(
5463 elfcpp::Shdr
<32, false>& shdr
);
5466 #ifdef HAVE_TARGET_32_BIG
5469 Layout::init_fixed_output_section
<32, true>(
5471 elfcpp::Shdr
<32, true>& shdr
);
5474 #ifdef HAVE_TARGET_64_LITTLE
5477 Layout::init_fixed_output_section
<64, false>(
5479 elfcpp::Shdr
<64, false>& shdr
);
5482 #ifdef HAVE_TARGET_64_BIG
5485 Layout::init_fixed_output_section
<64, true>(
5487 elfcpp::Shdr
<64, true>& shdr
);
5490 #ifdef HAVE_TARGET_32_LITTLE
5493 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
5496 const elfcpp::Shdr
<32, false>& shdr
,
5497 unsigned int, unsigned int, off_t
*);
5500 #ifdef HAVE_TARGET_32_BIG
5503 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
5506 const elfcpp::Shdr
<32, true>& shdr
,
5507 unsigned int, unsigned int, off_t
*);
5510 #ifdef HAVE_TARGET_64_LITTLE
5513 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
5516 const elfcpp::Shdr
<64, false>& shdr
,
5517 unsigned int, unsigned int, off_t
*);
5520 #ifdef HAVE_TARGET_64_BIG
5523 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
5526 const elfcpp::Shdr
<64, true>& shdr
,
5527 unsigned int, unsigned int, off_t
*);
5530 #ifdef HAVE_TARGET_32_LITTLE
5533 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
5534 unsigned int reloc_shndx
,
5535 const elfcpp::Shdr
<32, false>& shdr
,
5536 Output_section
* data_section
,
5537 Relocatable_relocs
* rr
);
5540 #ifdef HAVE_TARGET_32_BIG
5543 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
5544 unsigned int reloc_shndx
,
5545 const elfcpp::Shdr
<32, true>& shdr
,
5546 Output_section
* data_section
,
5547 Relocatable_relocs
* rr
);
5550 #ifdef HAVE_TARGET_64_LITTLE
5553 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
5554 unsigned int reloc_shndx
,
5555 const elfcpp::Shdr
<64, false>& shdr
,
5556 Output_section
* data_section
,
5557 Relocatable_relocs
* rr
);
5560 #ifdef HAVE_TARGET_64_BIG
5563 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
5564 unsigned int reloc_shndx
,
5565 const elfcpp::Shdr
<64, true>& shdr
,
5566 Output_section
* data_section
,
5567 Relocatable_relocs
* rr
);
5570 #ifdef HAVE_TARGET_32_LITTLE
5573 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
5574 Sized_relobj_file
<32, false>* object
,
5576 const char* group_section_name
,
5577 const char* signature
,
5578 const elfcpp::Shdr
<32, false>& shdr
,
5579 elfcpp::Elf_Word flags
,
5580 std::vector
<unsigned int>* shndxes
);
5583 #ifdef HAVE_TARGET_32_BIG
5586 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
5587 Sized_relobj_file
<32, true>* object
,
5589 const char* group_section_name
,
5590 const char* signature
,
5591 const elfcpp::Shdr
<32, true>& shdr
,
5592 elfcpp::Elf_Word flags
,
5593 std::vector
<unsigned int>* shndxes
);
5596 #ifdef HAVE_TARGET_64_LITTLE
5599 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
5600 Sized_relobj_file
<64, false>* object
,
5602 const char* group_section_name
,
5603 const char* signature
,
5604 const elfcpp::Shdr
<64, false>& shdr
,
5605 elfcpp::Elf_Word flags
,
5606 std::vector
<unsigned int>* shndxes
);
5609 #ifdef HAVE_TARGET_64_BIG
5612 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
5613 Sized_relobj_file
<64, true>* object
,
5615 const char* group_section_name
,
5616 const char* signature
,
5617 const elfcpp::Shdr
<64, true>& shdr
,
5618 elfcpp::Elf_Word flags
,
5619 std::vector
<unsigned int>* shndxes
);
5622 #ifdef HAVE_TARGET_32_LITTLE
5625 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
5626 const unsigned char* symbols
,
5628 const unsigned char* symbol_names
,
5629 off_t symbol_names_size
,
5631 const elfcpp::Shdr
<32, false>& shdr
,
5632 unsigned int reloc_shndx
,
5633 unsigned int reloc_type
,
5637 #ifdef HAVE_TARGET_32_BIG
5640 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
5641 const unsigned char* symbols
,
5643 const unsigned char* symbol_names
,
5644 off_t symbol_names_size
,
5646 const elfcpp::Shdr
<32, true>& shdr
,
5647 unsigned int reloc_shndx
,
5648 unsigned int reloc_type
,
5652 #ifdef HAVE_TARGET_64_LITTLE
5655 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
5656 const unsigned char* symbols
,
5658 const unsigned char* symbol_names
,
5659 off_t symbol_names_size
,
5661 const elfcpp::Shdr
<64, false>& shdr
,
5662 unsigned int reloc_shndx
,
5663 unsigned int reloc_type
,
5667 #ifdef HAVE_TARGET_64_BIG
5670 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
5671 const unsigned char* symbols
,
5673 const unsigned char* symbol_names
,
5674 off_t symbol_names_size
,
5676 const elfcpp::Shdr
<64, true>& shdr
,
5677 unsigned int reloc_shndx
,
5678 unsigned int reloc_type
,
5682 #ifdef HAVE_TARGET_32_LITTLE
5685 Layout::add_to_gdb_index(bool is_type_unit
,
5686 Sized_relobj
<32, false>* object
,
5687 const unsigned char* symbols
,
5690 unsigned int reloc_shndx
,
5691 unsigned int reloc_type
);
5694 #ifdef HAVE_TARGET_32_BIG
5697 Layout::add_to_gdb_index(bool is_type_unit
,
5698 Sized_relobj
<32, true>* object
,
5699 const unsigned char* symbols
,
5702 unsigned int reloc_shndx
,
5703 unsigned int reloc_type
);
5706 #ifdef HAVE_TARGET_64_LITTLE
5709 Layout::add_to_gdb_index(bool is_type_unit
,
5710 Sized_relobj
<64, false>* object
,
5711 const unsigned char* symbols
,
5714 unsigned int reloc_shndx
,
5715 unsigned int reloc_type
);
5718 #ifdef HAVE_TARGET_64_BIG
5721 Layout::add_to_gdb_index(bool is_type_unit
,
5722 Sized_relobj
<64, true>* object
,
5723 const unsigned char* symbols
,
5726 unsigned int reloc_shndx
,
5727 unsigned int reloc_type
);
5730 } // End namespace gold.