1 // layout.cc -- lay out output file sections for gold
3 // Copyright (C) 2006-2014 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
34 #include "libiberty.h"
38 #include "parameters.h"
42 #include "script-sections.h"
47 #include "gdb-index.h"
48 #include "compressed_output.h"
49 #include "reduced_debug_output.h"
52 #include "descriptors.h"
54 #include "incremental.h"
62 // The total number of free lists used.
63 unsigned int Free_list::num_lists
= 0;
64 // The total number of free list nodes used.
65 unsigned int Free_list::num_nodes
= 0;
66 // The total number of calls to Free_list::remove.
67 unsigned int Free_list::num_removes
= 0;
68 // The total number of nodes visited during calls to Free_list::remove.
69 unsigned int Free_list::num_remove_visits
= 0;
70 // The total number of calls to Free_list::allocate.
71 unsigned int Free_list::num_allocates
= 0;
72 // The total number of nodes visited during calls to Free_list::allocate.
73 unsigned int Free_list::num_allocate_visits
= 0;
75 // Initialize the free list. Creates a single free list node that
76 // describes the entire region of length LEN. If EXTEND is true,
77 // allocate() is allowed to extend the region beyond its initial
81 Free_list::init(off_t len
, bool extend
)
83 this->list_
.push_front(Free_list_node(0, len
));
84 this->last_remove_
= this->list_
.begin();
85 this->extend_
= extend
;
87 ++Free_list::num_lists
;
88 ++Free_list::num_nodes
;
91 // Remove a chunk from the free list. Because we start with a single
92 // node that covers the entire section, and remove chunks from it one
93 // at a time, we do not need to coalesce chunks or handle cases that
94 // span more than one free node. We expect to remove chunks from the
95 // free list in order, and we expect to have only a few chunks of free
96 // space left (corresponding to files that have changed since the last
97 // incremental link), so a simple linear list should provide sufficient
101 Free_list::remove(off_t start
, off_t end
)
105 gold_assert(start
< end
);
107 ++Free_list::num_removes
;
109 Iterator p
= this->last_remove_
;
110 if (p
->start_
> start
)
111 p
= this->list_
.begin();
113 for (; p
!= this->list_
.end(); ++p
)
115 ++Free_list::num_remove_visits
;
116 // Find a node that wholly contains the indicated region.
117 if (p
->start_
<= start
&& p
->end_
>= end
)
119 // Case 1: the indicated region spans the whole node.
120 // Add some fuzz to avoid creating tiny free chunks.
121 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
122 p
= this->list_
.erase(p
);
123 // Case 2: remove a chunk from the start of the node.
124 else if (p
->start_
+ 3 >= start
)
126 // Case 3: remove a chunk from the end of the node.
127 else if (p
->end_
<= end
+ 3)
129 // Case 4: remove a chunk from the middle, and split
130 // the node into two.
133 Free_list_node
newnode(p
->start_
, start
);
135 this->list_
.insert(p
, newnode
);
136 ++Free_list::num_nodes
;
138 this->last_remove_
= p
;
143 // Did not find a node containing the given chunk. This could happen
144 // because a small chunk was already removed due to the fuzz.
145 gold_debug(DEBUG_INCREMENTAL
,
146 "Free_list::remove(%d,%d) not found",
147 static_cast<int>(start
), static_cast<int>(end
));
150 // Allocate a chunk of size LEN from the free list. Returns -1ULL
151 // if a sufficiently large chunk of free space is not found.
152 // We use a simple first-fit algorithm.
155 Free_list::allocate(off_t len
, uint64_t align
, off_t minoff
)
157 gold_debug(DEBUG_INCREMENTAL
,
158 "Free_list::allocate(%08lx, %d, %08lx)",
159 static_cast<long>(len
), static_cast<int>(align
),
160 static_cast<long>(minoff
));
162 return align_address(minoff
, align
);
164 ++Free_list::num_allocates
;
166 // We usually want to drop free chunks smaller than 4 bytes.
167 // If we need to guarantee a minimum hole size, though, we need
168 // to keep track of all free chunks.
169 const int fuzz
= this->min_hole_
> 0 ? 0 : 3;
171 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
173 ++Free_list::num_allocate_visits
;
174 off_t start
= p
->start_
> minoff
? p
->start_
: minoff
;
175 start
= align_address(start
, align
);
176 off_t end
= start
+ len
;
177 if (end
> p
->end_
&& p
->end_
== this->length_
&& this->extend_
)
182 if (end
== p
->end_
|| (end
<= p
->end_
- this->min_hole_
))
184 if (p
->start_
+ fuzz
>= start
&& p
->end_
<= end
+ fuzz
)
185 this->list_
.erase(p
);
186 else if (p
->start_
+ fuzz
>= start
)
188 else if (p
->end_
<= end
+ fuzz
)
192 Free_list_node
newnode(p
->start_
, start
);
194 this->list_
.insert(p
, newnode
);
195 ++Free_list::num_nodes
;
202 off_t start
= align_address(this->length_
, align
);
203 this->length_
= start
+ len
;
209 // Dump the free list (for debugging).
213 gold_info("Free list:\n start end length\n");
214 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
215 gold_info(" %08lx %08lx %08lx", static_cast<long>(p
->start_
),
216 static_cast<long>(p
->end_
),
217 static_cast<long>(p
->end_
- p
->start_
));
220 // Print the statistics for the free lists.
222 Free_list::print_stats()
224 fprintf(stderr
, _("%s: total free lists: %u\n"),
225 program_name
, Free_list::num_lists
);
226 fprintf(stderr
, _("%s: total free list nodes: %u\n"),
227 program_name
, Free_list::num_nodes
);
228 fprintf(stderr
, _("%s: calls to Free_list::remove: %u\n"),
229 program_name
, Free_list::num_removes
);
230 fprintf(stderr
, _("%s: nodes visited: %u\n"),
231 program_name
, Free_list::num_remove_visits
);
232 fprintf(stderr
, _("%s: calls to Free_list::allocate: %u\n"),
233 program_name
, Free_list::num_allocates
);
234 fprintf(stderr
, _("%s: nodes visited: %u\n"),
235 program_name
, Free_list::num_allocate_visits
);
238 // A Hash_task computes the MD5 checksum of an array of char.
239 // It has a blocker on either side (i.e., the task cannot run until
240 // the first is unblocked, and it unblocks the second after running).
242 class Hash_task
: public Task
245 Hash_task(const unsigned char* src
,
248 Task_token
* build_id_blocker
,
249 Task_token
* final_blocker
)
250 : src_(src
), size_(size
), dst_(dst
), build_id_blocker_(build_id_blocker
),
251 final_blocker_(final_blocker
)
256 { md5_buffer(reinterpret_cast<const char*>(src_
), size_
, dst_
); }
261 // Unblock FINAL_BLOCKER_ when done.
263 locks(Task_locker
* tl
)
264 { tl
->add(this, this->final_blocker_
); }
268 { return "Hash_task"; }
271 const unsigned char* const src_
;
273 unsigned char* const dst_
;
274 Task_token
* const build_id_blocker_
;
275 Task_token
* const final_blocker_
;
279 Hash_task::is_runnable()
281 if (this->build_id_blocker_
->is_blocked())
282 return this->build_id_blocker_
;
286 // Layout::Relaxation_debug_check methods.
288 // Check that sections and special data are in reset states.
289 // We do not save states for Output_sections and special Output_data.
290 // So we check that they have not assigned any addresses or offsets.
291 // clean_up_after_relaxation simply resets their addresses and offsets.
293 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
294 const Layout::Section_list
& sections
,
295 const Layout::Data_list
& special_outputs
,
296 const Layout::Data_list
& relax_outputs
)
298 for(Layout::Section_list::const_iterator p
= sections
.begin();
301 gold_assert((*p
)->address_and_file_offset_have_reset_values());
303 for(Layout::Data_list::const_iterator p
= special_outputs
.begin();
304 p
!= special_outputs
.end();
306 gold_assert((*p
)->address_and_file_offset_have_reset_values());
308 gold_assert(relax_outputs
.empty());
311 // Save information of SECTIONS for checking later.
314 Layout::Relaxation_debug_check::read_sections(
315 const Layout::Section_list
& sections
)
317 for(Layout::Section_list::const_iterator p
= sections
.begin();
321 Output_section
* os
= *p
;
323 info
.output_section
= os
;
324 info
.address
= os
->is_address_valid() ? os
->address() : 0;
325 info
.data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
326 info
.offset
= os
->is_offset_valid()? os
->offset() : -1 ;
327 this->section_infos_
.push_back(info
);
331 // Verify SECTIONS using previously recorded information.
334 Layout::Relaxation_debug_check::verify_sections(
335 const Layout::Section_list
& sections
)
338 for(Layout::Section_list::const_iterator p
= sections
.begin();
342 Output_section
* os
= *p
;
343 uint64_t address
= os
->is_address_valid() ? os
->address() : 0;
344 off_t data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
345 off_t offset
= os
->is_offset_valid()? os
->offset() : -1 ;
347 if (i
>= this->section_infos_
.size())
349 gold_fatal("Section_info of %s missing.\n", os
->name());
351 const Section_info
& info
= this->section_infos_
[i
];
352 if (os
!= info
.output_section
)
353 gold_fatal("Section order changed. Expecting %s but see %s\n",
354 info
.output_section
->name(), os
->name());
355 if (address
!= info
.address
356 || data_size
!= info
.data_size
357 || offset
!= info
.offset
)
358 gold_fatal("Section %s changed.\n", os
->name());
362 // Layout_task_runner methods.
364 // Lay out the sections. This is called after all the input objects
368 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
370 // See if any of the input definitions violate the One Definition Rule.
371 // TODO: if this is too slow, do this as a task, rather than inline.
372 this->symtab_
->detect_odr_violations(task
, this->options_
.output_file_name());
374 Layout
* layout
= this->layout_
;
375 off_t file_size
= layout
->finalize(this->input_objects_
,
380 // Now we know the final size of the output file and we know where
381 // each piece of information goes.
383 if (this->mapfile_
!= NULL
)
385 this->mapfile_
->print_discarded_sections(this->input_objects_
);
386 layout
->print_to_mapfile(this->mapfile_
);
390 if (layout
->incremental_base() == NULL
)
392 of
= new Output_file(parameters
->options().output_file_name());
393 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
394 of
->set_is_temporary();
399 of
= layout
->incremental_base()->output_file();
401 // Apply the incremental relocations for symbols whose values
402 // have changed. We do this before we resize the file and start
403 // writing anything else to it, so that we can read the old
404 // incremental information from the file before (possibly)
406 if (parameters
->incremental_update())
407 layout
->incremental_base()->apply_incremental_relocs(this->symtab_
,
411 of
->resize(file_size
);
414 // Queue up the final set of tasks.
415 gold::queue_final_tasks(this->options_
, this->input_objects_
,
416 this->symtab_
, layout
, workqueue
, of
);
421 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
422 : number_of_input_files_(number_of_input_files
),
423 script_options_(script_options
),
431 unattached_section_list_(),
432 special_output_list_(),
433 relax_output_list_(),
434 section_headers_(NULL
),
436 relro_segment_(NULL
),
437 interp_segment_(NULL
),
439 symtab_section_(NULL
),
440 symtab_xindex_(NULL
),
441 dynsym_section_(NULL
),
442 dynsym_xindex_(NULL
),
443 dynamic_section_(NULL
),
444 dynamic_symbol_(NULL
),
446 eh_frame_section_(NULL
),
447 eh_frame_data_(NULL
),
448 added_eh_frame_data_(false),
449 eh_frame_hdr_section_(NULL
),
450 gdb_index_data_(NULL
),
451 build_id_note_(NULL
),
452 array_of_hashes_(NULL
),
453 size_of_array_of_hashes_(0),
458 output_file_size_(-1),
459 have_added_input_section_(false),
460 sections_are_attached_(false),
461 input_requires_executable_stack_(false),
462 input_with_gnu_stack_note_(false),
463 input_without_gnu_stack_note_(false),
464 has_static_tls_(false),
465 any_postprocessing_sections_(false),
466 resized_signatures_(false),
467 have_stabstr_section_(false),
468 section_ordering_specified_(false),
469 unique_segment_for_sections_specified_(false),
470 incremental_inputs_(NULL
),
471 record_output_section_data_from_script_(false),
472 script_output_section_data_list_(),
473 segment_states_(NULL
),
474 relaxation_debug_check_(NULL
),
475 section_order_map_(),
476 section_segment_map_(),
477 input_section_position_(),
478 input_section_glob_(),
479 incremental_base_(NULL
),
482 // Make space for more than enough segments for a typical file.
483 // This is just for efficiency--it's OK if we wind up needing more.
484 this->segment_list_
.reserve(12);
486 // We expect two unattached Output_data objects: the file header and
487 // the segment headers.
488 this->special_output_list_
.reserve(2);
490 // Initialize structure needed for an incremental build.
491 if (parameters
->incremental())
492 this->incremental_inputs_
= new Incremental_inputs
;
494 // The section name pool is worth optimizing in all cases, because
495 // it is small, but there are often overlaps due to .rel sections.
496 this->namepool_
.set_optimize();
499 // For incremental links, record the base file to be modified.
502 Layout::set_incremental_base(Incremental_binary
* base
)
504 this->incremental_base_
= base
;
505 this->free_list_
.init(base
->output_file()->filesize(), true);
508 // Hash a key we use to look up an output section mapping.
511 Layout::Hash_key::operator()(const Layout::Key
& k
) const
513 return k
.first
+ k
.second
.first
+ k
.second
.second
;
516 // These are the debug sections that are actually used by gdb.
517 // Currently, we've checked versions of gdb up to and including 7.4.
518 // We only check the part of the name that follows ".debug_" or
521 static const char* gdb_sections
[] =
524 "addr", // Fission extension
525 // "aranges", // not used by gdb as of 7.4
533 // "pubnames", // not used by gdb as of 7.4
534 // "pubtypes", // not used by gdb as of 7.4
539 // This is the minimum set of sections needed for line numbers.
541 static const char* lines_only_debug_sections
[] =
544 // "addr", // Fission extension
545 // "aranges", // not used by gdb as of 7.4
553 // "pubnames", // not used by gdb as of 7.4
554 // "pubtypes", // not used by gdb as of 7.4
559 // These sections are the DWARF fast-lookup tables, and are not needed
560 // when building a .gdb_index section.
562 static const char* gdb_fast_lookup_sections
[] =
571 // Returns whether the given debug section is in the list of
572 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
573 // portion of the name following ".debug_" or ".zdebug_".
576 is_gdb_debug_section(const char* suffix
)
578 // We can do this faster: binary search or a hashtable. But why bother?
579 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
580 if (strcmp(suffix
, gdb_sections
[i
]) == 0)
585 // Returns whether the given section is needed for lines-only debugging.
588 is_lines_only_debug_section(const char* suffix
)
590 // We can do this faster: binary search or a hashtable. But why bother?
592 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
594 if (strcmp(suffix
, lines_only_debug_sections
[i
]) == 0)
599 // Returns whether the given section is a fast-lookup section that
600 // will not be needed when building a .gdb_index section.
603 is_gdb_fast_lookup_section(const char* suffix
)
605 // We can do this faster: binary search or a hashtable. But why bother?
607 i
< sizeof(gdb_fast_lookup_sections
)/sizeof(*gdb_fast_lookup_sections
);
609 if (strcmp(suffix
, gdb_fast_lookup_sections
[i
]) == 0)
614 // Sometimes we compress sections. This is typically done for
615 // sections that are not part of normal program execution (such as
616 // .debug_* sections), and where the readers of these sections know
617 // how to deal with compressed sections. This routine doesn't say for
618 // certain whether we'll compress -- it depends on commandline options
619 // as well -- just whether this section is a candidate for compression.
620 // (The Output_compressed_section class decides whether to compress
621 // a given section, and picks the name of the compressed section.)
624 is_compressible_debug_section(const char* secname
)
626 return (is_prefix_of(".debug", secname
));
629 // We may see compressed debug sections in input files. Return TRUE
630 // if this is the name of a compressed debug section.
633 is_compressed_debug_section(const char* secname
)
635 return (is_prefix_of(".zdebug", secname
));
638 // Whether to include this section in the link.
640 template<int size
, bool big_endian
>
642 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
643 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
645 if (!parameters
->options().relocatable()
646 && (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
))
649 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
651 if ((sh_type
>= elfcpp::SHT_LOOS
&& sh_type
<= elfcpp::SHT_HIOS
)
652 || (sh_type
>= elfcpp::SHT_LOPROC
&& sh_type
<= elfcpp::SHT_HIPROC
))
653 return parameters
->target().should_include_section(sh_type
);
657 case elfcpp::SHT_NULL
:
658 case elfcpp::SHT_SYMTAB
:
659 case elfcpp::SHT_DYNSYM
:
660 case elfcpp::SHT_HASH
:
661 case elfcpp::SHT_DYNAMIC
:
662 case elfcpp::SHT_SYMTAB_SHNDX
:
665 case elfcpp::SHT_STRTAB
:
666 // Discard the sections which have special meanings in the ELF
667 // ABI. Keep others (e.g., .stabstr). We could also do this by
668 // checking the sh_link fields of the appropriate sections.
669 return (strcmp(name
, ".dynstr") != 0
670 && strcmp(name
, ".strtab") != 0
671 && strcmp(name
, ".shstrtab") != 0);
673 case elfcpp::SHT_RELA
:
674 case elfcpp::SHT_REL
:
675 case elfcpp::SHT_GROUP
:
676 // If we are emitting relocations these should be handled
678 gold_assert(!parameters
->options().relocatable());
681 case elfcpp::SHT_PROGBITS
:
682 if (parameters
->options().strip_debug()
683 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
685 if (is_debug_info_section(name
))
688 if (parameters
->options().strip_debug_non_line()
689 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
691 // Debugging sections can only be recognized by name.
692 if (is_prefix_of(".debug_", name
)
693 && !is_lines_only_debug_section(name
+ 7))
695 if (is_prefix_of(".zdebug_", name
)
696 && !is_lines_only_debug_section(name
+ 8))
699 if (parameters
->options().strip_debug_gdb()
700 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
702 // Debugging sections can only be recognized by name.
703 if (is_prefix_of(".debug_", name
)
704 && !is_gdb_debug_section(name
+ 7))
706 if (is_prefix_of(".zdebug_", name
)
707 && !is_gdb_debug_section(name
+ 8))
710 if (parameters
->options().gdb_index()
711 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
713 // When building .gdb_index, we can strip .debug_pubnames,
714 // .debug_pubtypes, and .debug_aranges sections.
715 if (is_prefix_of(".debug_", name
)
716 && is_gdb_fast_lookup_section(name
+ 7))
718 if (is_prefix_of(".zdebug_", name
)
719 && is_gdb_fast_lookup_section(name
+ 8))
722 if (parameters
->options().strip_lto_sections()
723 && !parameters
->options().relocatable()
724 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
726 // Ignore LTO sections containing intermediate code.
727 if (is_prefix_of(".gnu.lto_", name
))
730 // The GNU linker strips .gnu_debuglink sections, so we do too.
731 // This is a feature used to keep debugging information in
733 if (strcmp(name
, ".gnu_debuglink") == 0)
742 // Return an output section named NAME, or NULL if there is none.
745 Layout::find_output_section(const char* name
) const
747 for (Section_list::const_iterator p
= this->section_list_
.begin();
748 p
!= this->section_list_
.end();
750 if (strcmp((*p
)->name(), name
) == 0)
755 // Return an output segment of type TYPE, with segment flags SET set
756 // and segment flags CLEAR clear. Return NULL if there is none.
759 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
760 elfcpp::Elf_Word clear
) const
762 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
763 p
!= this->segment_list_
.end();
765 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
766 && ((*p
)->flags() & set
) == set
767 && ((*p
)->flags() & clear
) == 0)
772 // When we put a .ctors or .dtors section with more than one word into
773 // a .init_array or .fini_array section, we need to reverse the words
774 // in the .ctors/.dtors section. This is because .init_array executes
775 // constructors front to back, where .ctors executes them back to
776 // front, and vice-versa for .fini_array/.dtors. Although we do want
777 // to remap .ctors/.dtors into .init_array/.fini_array because it can
778 // be more efficient, we don't want to change the order in which
779 // constructors/destructors are run. This set just keeps track of
780 // these sections which need to be reversed. It is only changed by
781 // Layout::layout. It should be a private member of Layout, but that
782 // would require layout.h to #include object.h to get the definition
784 static Unordered_set
<Section_id
, Section_id_hash
> ctors_sections_in_init_array
;
786 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
787 // .init_array/.fini_array section.
790 Layout::is_ctors_in_init_array(Relobj
* relobj
, unsigned int shndx
) const
792 return (ctors_sections_in_init_array
.find(Section_id(relobj
, shndx
))
793 != ctors_sections_in_init_array
.end());
796 // Return the output section to use for section NAME with type TYPE
797 // and section flags FLAGS. NAME must be canonicalized in the string
798 // pool, and NAME_KEY is the key. ORDER is where this should appear
799 // in the output sections. IS_RELRO is true for a relro section.
802 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
803 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
804 Output_section_order order
, bool is_relro
)
806 elfcpp::Elf_Word lookup_type
= type
;
808 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
809 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
810 // .init_array, .fini_array, and .preinit_array sections by name
811 // whatever their type in the input file. We do this because the
812 // types are not always right in the input files.
813 if (lookup_type
== elfcpp::SHT_INIT_ARRAY
814 || lookup_type
== elfcpp::SHT_FINI_ARRAY
815 || lookup_type
== elfcpp::SHT_PREINIT_ARRAY
)
816 lookup_type
= elfcpp::SHT_PROGBITS
;
818 elfcpp::Elf_Xword lookup_flags
= flags
;
820 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
821 // read-write with read-only sections. Some other ELF linkers do
822 // not do this. FIXME: Perhaps there should be an option
824 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
826 const Key
key(name_key
, std::make_pair(lookup_type
, lookup_flags
));
827 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
828 std::pair
<Section_name_map::iterator
, bool> ins(
829 this->section_name_map_
.insert(v
));
832 return ins
.first
->second
;
835 // This is the first time we've seen this name/type/flags
836 // combination. For compatibility with the GNU linker, we
837 // combine sections with contents and zero flags with sections
838 // with non-zero flags. This is a workaround for cases where
839 // assembler code forgets to set section flags. FIXME: Perhaps
840 // there should be an option to control this.
841 Output_section
* os
= NULL
;
843 if (lookup_type
== elfcpp::SHT_PROGBITS
)
847 Output_section
* same_name
= this->find_output_section(name
);
848 if (same_name
!= NULL
849 && (same_name
->type() == elfcpp::SHT_PROGBITS
850 || same_name
->type() == elfcpp::SHT_INIT_ARRAY
851 || same_name
->type() == elfcpp::SHT_FINI_ARRAY
852 || same_name
->type() == elfcpp::SHT_PREINIT_ARRAY
)
853 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
856 else if ((flags
& elfcpp::SHF_TLS
) == 0)
858 elfcpp::Elf_Xword zero_flags
= 0;
859 const Key
zero_key(name_key
, std::make_pair(lookup_type
,
861 Section_name_map::iterator p
=
862 this->section_name_map_
.find(zero_key
);
863 if (p
!= this->section_name_map_
.end())
869 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
871 ins
.first
->second
= os
;
876 // Returns TRUE iff NAME (an input section from RELOBJ) will
877 // be mapped to an output section that should be KEPT.
880 Layout::keep_input_section(const Relobj
* relobj
, const char* name
)
882 if (! this->script_options_
->saw_sections_clause())
885 Script_sections
* ss
= this->script_options_
->script_sections();
886 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
887 Output_section
** output_section_slot
;
888 Script_sections::Section_type script_section_type
;
891 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
892 &script_section_type
, &keep
);
893 return name
!= NULL
&& keep
;
896 // Clear the input section flags that should not be copied to the
900 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags
)
902 // Some flags in the input section should not be automatically
903 // copied to the output section.
904 input_section_flags
&= ~ (elfcpp::SHF_INFO_LINK
907 | elfcpp::SHF_STRINGS
);
909 // We only clear the SHF_LINK_ORDER flag in for
910 // a non-relocatable link.
911 if (!parameters
->options().relocatable())
912 input_section_flags
&= ~elfcpp::SHF_LINK_ORDER
;
914 return input_section_flags
;
917 // Pick the output section to use for section NAME, in input file
918 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
919 // linker created section. IS_INPUT_SECTION is true if we are
920 // choosing an output section for an input section found in a input
921 // file. ORDER is where this section should appear in the output
922 // sections. IS_RELRO is true for a relro section. This will return
923 // NULL if the input section should be discarded.
926 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
927 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
928 bool is_input_section
, Output_section_order order
,
931 // We should not see any input sections after we have attached
932 // sections to segments.
933 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
935 flags
= this->get_output_section_flags(flags
);
937 if (this->script_options_
->saw_sections_clause())
939 // We are using a SECTIONS clause, so the output section is
940 // chosen based only on the name.
942 Script_sections
* ss
= this->script_options_
->script_sections();
943 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
944 Output_section
** output_section_slot
;
945 Script_sections::Section_type script_section_type
;
946 const char* orig_name
= name
;
948 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
949 &script_section_type
, &keep
);
953 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
954 "because it is not allowed by the "
955 "SECTIONS clause of the linker script"),
957 // The SECTIONS clause says to discard this input section.
961 // We can only handle script section types ST_NONE and ST_NOLOAD.
962 switch (script_section_type
)
964 case Script_sections::ST_NONE
:
966 case Script_sections::ST_NOLOAD
:
967 flags
&= elfcpp::SHF_ALLOC
;
973 // If this is an orphan section--one not mentioned in the linker
974 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
975 // default processing below.
977 if (output_section_slot
!= NULL
)
979 if (*output_section_slot
!= NULL
)
981 (*output_section_slot
)->update_flags_for_input_section(flags
);
982 return *output_section_slot
;
985 // We don't put sections found in the linker script into
986 // SECTION_NAME_MAP_. That keeps us from getting confused
987 // if an orphan section is mapped to a section with the same
988 // name as one in the linker script.
990 name
= this->namepool_
.add(name
, false, NULL
);
992 Output_section
* os
= this->make_output_section(name
, type
, flags
,
995 os
->set_found_in_sections_clause();
997 // Special handling for NOLOAD sections.
998 if (script_section_type
== Script_sections::ST_NOLOAD
)
1000 os
->set_is_noload();
1002 // The constructor of Output_section sets addresses of non-ALLOC
1003 // sections to 0 by default. We don't want that for NOLOAD
1004 // sections even if they have no SHF_ALLOC flag.
1005 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
1006 && os
->is_address_valid())
1008 gold_assert(os
->address() == 0
1009 && !os
->is_offset_valid()
1010 && !os
->is_data_size_valid());
1011 os
->reset_address_and_file_offset();
1015 *output_section_slot
= os
;
1020 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1022 size_t len
= strlen(name
);
1023 char* uncompressed_name
= NULL
;
1025 // Compressed debug sections should be mapped to the corresponding
1026 // uncompressed section.
1027 if (is_compressed_debug_section(name
))
1029 uncompressed_name
= new char[len
];
1030 uncompressed_name
[0] = '.';
1031 gold_assert(name
[0] == '.' && name
[1] == 'z');
1032 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
1033 uncompressed_name
[len
- 1] = '\0';
1035 name
= uncompressed_name
;
1038 // Turn NAME from the name of the input section into the name of the
1040 if (is_input_section
1041 && !this->script_options_
->saw_sections_clause()
1042 && !parameters
->options().relocatable())
1044 const char *orig_name
= name
;
1045 name
= parameters
->target().output_section_name(relobj
, name
, &len
);
1047 name
= Layout::output_section_name(relobj
, orig_name
, &len
);
1050 Stringpool::Key name_key
;
1051 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
1053 if (uncompressed_name
!= NULL
)
1054 delete[] uncompressed_name
;
1056 // Find or make the output section. The output section is selected
1057 // based on the section name, type, and flags.
1058 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
1061 // For incremental links, record the initial fixed layout of a section
1062 // from the base file, and return a pointer to the Output_section.
1064 template<int size
, bool big_endian
>
1066 Layout::init_fixed_output_section(const char* name
,
1067 elfcpp::Shdr
<size
, big_endian
>& shdr
)
1069 unsigned int sh_type
= shdr
.get_sh_type();
1071 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1072 // PRE_INIT_ARRAY, and NOTE sections.
1073 // All others will be created from scratch and reallocated.
1074 if (!can_incremental_update(sh_type
))
1077 // If we're generating a .gdb_index section, we need to regenerate
1079 if (parameters
->options().gdb_index()
1080 && sh_type
== elfcpp::SHT_PROGBITS
1081 && strcmp(name
, ".gdb_index") == 0)
1084 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
1085 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
1086 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
1087 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
1088 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
1089 shdr
.get_sh_addralign();
1091 // Make the output section.
1092 Stringpool::Key name_key
;
1093 name
= this->namepool_
.add(name
, true, &name_key
);
1094 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
1095 sh_flags
, ORDER_INVALID
, false);
1096 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
1097 if (sh_type
!= elfcpp::SHT_NOBITS
)
1098 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
1102 // Return the index by which an input section should be ordered. This
1103 // is used to sort some .text sections, for compatibility with GNU ld.
1106 Layout::special_ordering_of_input_section(const char* name
)
1108 // The GNU linker has some special handling for some sections that
1109 // wind up in the .text section. Sections that start with these
1110 // prefixes must appear first, and must appear in the order listed
1112 static const char* const text_section_sort
[] =
1121 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1123 if (is_prefix_of(text_section_sort
[i
], name
))
1129 // Return the output section to use for input section SHNDX, with name
1130 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1131 // index of a relocation section which applies to this section, or 0
1132 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1133 // relocation section if there is one. Set *OFF to the offset of this
1134 // input section without the output section. Return NULL if the
1135 // section should be discarded. Set *OFF to -1 if the section
1136 // contents should not be written directly to the output file, but
1137 // will instead receive special handling.
1139 template<int size
, bool big_endian
>
1141 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1142 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1143 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
1147 if (!this->include_section(object
, name
, shdr
))
1150 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
1152 // In a relocatable link a grouped section must not be combined with
1153 // any other sections.
1155 if (parameters
->options().relocatable()
1156 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1158 name
= this->namepool_
.add(name
, true, NULL
);
1159 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
1160 ORDER_INVALID
, false);
1164 // Plugins can choose to place one or more subsets of sections in
1165 // unique segments and this is done by mapping these section subsets
1166 // to unique output sections. Check if this section needs to be
1167 // remapped to a unique output section.
1168 Section_segment_map::iterator it
1169 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1170 if (it
== this->section_segment_map_
.end())
1172 os
= this->choose_output_section(object
, name
, sh_type
,
1173 shdr
.get_sh_flags(), true,
1174 ORDER_INVALID
, false);
1178 // We know the name of the output section, directly call
1179 // get_output_section here by-passing choose_output_section.
1180 elfcpp::Elf_Xword flags
1181 = this->get_output_section_flags(shdr
.get_sh_flags());
1183 const char* os_name
= it
->second
->name
;
1184 Stringpool::Key name_key
;
1185 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1186 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1187 ORDER_INVALID
, false);
1188 if (!os
->is_unique_segment())
1190 os
->set_is_unique_segment();
1191 os
->set_extra_segment_flags(it
->second
->flags
);
1192 os
->set_segment_alignment(it
->second
->align
);
1199 // By default the GNU linker sorts input sections whose names match
1200 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1201 // sections are sorted by name. This is used to implement
1202 // constructor priority ordering. We are compatible. When we put
1203 // .ctor sections in .init_array and .dtor sections in .fini_array,
1204 // we must also sort plain .ctor and .dtor sections.
1205 if (!this->script_options_
->saw_sections_clause()
1206 && !parameters
->options().relocatable()
1207 && (is_prefix_of(".ctors.", name
)
1208 || is_prefix_of(".dtors.", name
)
1209 || is_prefix_of(".init_array.", name
)
1210 || is_prefix_of(".fini_array.", name
)
1211 || (parameters
->options().ctors_in_init_array()
1212 && (strcmp(name
, ".ctors") == 0
1213 || strcmp(name
, ".dtors") == 0))))
1214 os
->set_must_sort_attached_input_sections();
1216 // By default the GNU linker sorts some special text sections ahead
1217 // of others. We are compatible.
1218 if (parameters
->options().text_reorder()
1219 && !this->script_options_
->saw_sections_clause()
1220 && !this->is_section_ordering_specified()
1221 && !parameters
->options().relocatable()
1222 && Layout::special_ordering_of_input_section(name
) >= 0)
1223 os
->set_must_sort_attached_input_sections();
1225 // If this is a .ctors or .ctors.* section being mapped to a
1226 // .init_array section, or a .dtors or .dtors.* section being mapped
1227 // to a .fini_array section, we will need to reverse the words if
1228 // there is more than one. Record this section for later. See
1229 // ctors_sections_in_init_array above.
1230 if (!this->script_options_
->saw_sections_clause()
1231 && !parameters
->options().relocatable()
1232 && shdr
.get_sh_size() > size
/ 8
1233 && (((strcmp(name
, ".ctors") == 0
1234 || is_prefix_of(".ctors.", name
))
1235 && strcmp(os
->name(), ".init_array") == 0)
1236 || ((strcmp(name
, ".dtors") == 0
1237 || is_prefix_of(".dtors.", name
))
1238 && strcmp(os
->name(), ".fini_array") == 0)))
1239 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1241 // FIXME: Handle SHF_LINK_ORDER somewhere.
1243 elfcpp::Elf_Xword orig_flags
= os
->flags();
1245 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1246 this->script_options_
->saw_sections_clause());
1248 // If the flags changed, we may have to change the order.
1249 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1251 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1252 elfcpp::Elf_Xword new_flags
=
1253 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1254 if (orig_flags
!= new_flags
)
1255 os
->set_order(this->default_section_order(os
, false));
1258 this->have_added_input_section_
= true;
1263 // Maps section SECN to SEGMENT s.
1265 Layout::insert_section_segment_map(Const_section_id secn
,
1266 Unique_segment_info
*s
)
1268 gold_assert(this->unique_segment_for_sections_specified_
);
1269 this->section_segment_map_
[secn
] = s
;
1272 // Handle a relocation section when doing a relocatable link.
1274 template<int size
, bool big_endian
>
1276 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
1278 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1279 Output_section
* data_section
,
1280 Relocatable_relocs
* rr
)
1282 gold_assert(parameters
->options().relocatable()
1283 || parameters
->options().emit_relocs());
1285 int sh_type
= shdr
.get_sh_type();
1288 if (sh_type
== elfcpp::SHT_REL
)
1290 else if (sh_type
== elfcpp::SHT_RELA
)
1294 name
+= data_section
->name();
1296 // In a relocatable link relocs for a grouped section must not be
1297 // combined with other reloc sections.
1299 if (!parameters
->options().relocatable()
1300 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
1301 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
1302 shdr
.get_sh_flags(), false,
1303 ORDER_INVALID
, false);
1306 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1307 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1308 ORDER_INVALID
, false);
1311 os
->set_should_link_to_symtab();
1312 os
->set_info_section(data_section
);
1314 Output_section_data
* posd
;
1315 if (sh_type
== elfcpp::SHT_REL
)
1317 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1318 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1322 else if (sh_type
== elfcpp::SHT_RELA
)
1324 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1325 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1332 os
->add_output_section_data(posd
);
1333 rr
->set_output_data(posd
);
1338 // Handle a group section when doing a relocatable link.
1340 template<int size
, bool big_endian
>
1342 Layout::layout_group(Symbol_table
* symtab
,
1343 Sized_relobj_file
<size
, big_endian
>* object
,
1345 const char* group_section_name
,
1346 const char* signature
,
1347 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1348 elfcpp::Elf_Word flags
,
1349 std::vector
<unsigned int>* shndxes
)
1351 gold_assert(parameters
->options().relocatable());
1352 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1353 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1354 Output_section
* os
= this->make_output_section(group_section_name
,
1356 shdr
.get_sh_flags(),
1357 ORDER_INVALID
, false);
1359 // We need to find a symbol with the signature in the symbol table.
1360 // If we don't find one now, we need to look again later.
1361 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1363 os
->set_info_symndx(sym
);
1366 // Reserve some space to minimize reallocations.
1367 if (this->group_signatures_
.empty())
1368 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1370 // We will wind up using a symbol whose name is the signature.
1371 // So just put the signature in the symbol name pool to save it.
1372 signature
= symtab
->canonicalize_name(signature
);
1373 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1376 os
->set_should_link_to_symtab();
1379 section_size_type entry_count
=
1380 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1381 Output_section_data
* posd
=
1382 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1384 os
->add_output_section_data(posd
);
1387 // Special GNU handling of sections name .eh_frame. They will
1388 // normally hold exception frame data as defined by the C++ ABI
1389 // (http://codesourcery.com/cxx-abi/).
1391 template<int size
, bool big_endian
>
1393 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1394 const unsigned char* symbols
,
1396 const unsigned char* symbol_names
,
1397 off_t symbol_names_size
,
1399 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1400 unsigned int reloc_shndx
, unsigned int reloc_type
,
1403 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1404 || shdr
.get_sh_type() == elfcpp::SHT_X86_64_UNWIND
);
1405 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1407 Output_section
* os
= this->make_eh_frame_section(object
);
1411 gold_assert(this->eh_frame_section_
== os
);
1413 elfcpp::Elf_Xword orig_flags
= os
->flags();
1415 if (!parameters
->incremental()
1416 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1425 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1427 // A writable .eh_frame section is a RELRO section.
1428 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1429 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1432 os
->set_order(ORDER_RELRO
);
1435 // We found a .eh_frame section we are going to optimize, so now
1436 // we can add the set of optimized sections to the output
1437 // section. We need to postpone adding this until we've found a
1438 // section we can optimize so that the .eh_frame section in
1439 // crtbegin.o winds up at the start of the output section.
1440 if (!this->added_eh_frame_data_
)
1442 os
->add_output_section_data(this->eh_frame_data_
);
1443 this->added_eh_frame_data_
= true;
1449 // We couldn't handle this .eh_frame section for some reason.
1450 // Add it as a normal section.
1451 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1452 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1453 reloc_shndx
, saw_sections_clause
);
1454 this->have_added_input_section_
= true;
1456 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1457 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1458 os
->set_order(this->default_section_order(os
, false));
1464 // Create and return the magic .eh_frame section. Create
1465 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1466 // input .eh_frame section; it may be NULL.
1469 Layout::make_eh_frame_section(const Relobj
* object
)
1471 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1473 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1474 elfcpp::SHT_PROGBITS
,
1475 elfcpp::SHF_ALLOC
, false,
1476 ORDER_EHFRAME
, false);
1480 if (this->eh_frame_section_
== NULL
)
1482 this->eh_frame_section_
= os
;
1483 this->eh_frame_data_
= new Eh_frame();
1485 // For incremental linking, we do not optimize .eh_frame sections
1486 // or create a .eh_frame_hdr section.
1487 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1489 Output_section
* hdr_os
=
1490 this->choose_output_section(NULL
, ".eh_frame_hdr",
1491 elfcpp::SHT_PROGBITS
,
1492 elfcpp::SHF_ALLOC
, false,
1493 ORDER_EHFRAME
, false);
1497 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1498 this->eh_frame_data_
);
1499 hdr_os
->add_output_section_data(hdr_posd
);
1501 hdr_os
->set_after_input_sections();
1503 if (!this->script_options_
->saw_phdrs_clause())
1505 Output_segment
* hdr_oseg
;
1506 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1508 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1512 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1520 // Add an exception frame for a PLT. This is called from target code.
1523 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1524 size_t cie_length
, const unsigned char* fde_data
,
1527 if (parameters
->incremental())
1529 // FIXME: Maybe this could work some day....
1532 Output_section
* os
= this->make_eh_frame_section(NULL
);
1535 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1536 fde_data
, fde_length
);
1537 if (!this->added_eh_frame_data_
)
1539 os
->add_output_section_data(this->eh_frame_data_
);
1540 this->added_eh_frame_data_
= true;
1544 // Scan a .debug_info or .debug_types section, and add summary
1545 // information to the .gdb_index section.
1547 template<int size
, bool big_endian
>
1549 Layout::add_to_gdb_index(bool is_type_unit
,
1550 Sized_relobj
<size
, big_endian
>* object
,
1551 const unsigned char* symbols
,
1554 unsigned int reloc_shndx
,
1555 unsigned int reloc_type
)
1557 if (this->gdb_index_data_
== NULL
)
1559 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1560 elfcpp::SHT_PROGBITS
, 0,
1561 false, ORDER_INVALID
,
1566 this->gdb_index_data_
= new Gdb_index(os
);
1567 os
->add_output_section_data(this->gdb_index_data_
);
1568 os
->set_after_input_sections();
1571 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1572 symbols_size
, shndx
, reloc_shndx
,
1576 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1577 // the output section.
1580 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1581 elfcpp::Elf_Xword flags
,
1582 Output_section_data
* posd
,
1583 Output_section_order order
, bool is_relro
)
1585 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1586 false, order
, is_relro
);
1588 os
->add_output_section_data(posd
);
1592 // Map section flags to segment flags.
1595 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1597 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1598 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1599 ret
|= elfcpp::PF_W
;
1600 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1601 ret
|= elfcpp::PF_X
;
1605 // Make a new Output_section, and attach it to segments as
1606 // appropriate. ORDER is the order in which this section should
1607 // appear in the output segment. IS_RELRO is true if this is a relro
1608 // (read-only after relocations) section.
1611 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1612 elfcpp::Elf_Xword flags
,
1613 Output_section_order order
, bool is_relro
)
1616 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1617 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1618 && is_compressible_debug_section(name
))
1619 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1621 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1622 && parameters
->options().strip_debug_non_line()
1623 && strcmp(".debug_abbrev", name
) == 0)
1625 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1627 if (this->debug_info_
)
1628 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1630 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1631 && parameters
->options().strip_debug_non_line()
1632 && strcmp(".debug_info", name
) == 0)
1634 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1636 if (this->debug_abbrev_
)
1637 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1641 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1642 // not have correct section types. Force them here.
1643 if (type
== elfcpp::SHT_PROGBITS
)
1645 if (is_prefix_of(".init_array", name
))
1646 type
= elfcpp::SHT_INIT_ARRAY
;
1647 else if (is_prefix_of(".preinit_array", name
))
1648 type
= elfcpp::SHT_PREINIT_ARRAY
;
1649 else if (is_prefix_of(".fini_array", name
))
1650 type
= elfcpp::SHT_FINI_ARRAY
;
1653 // FIXME: const_cast is ugly.
1654 Target
* target
= const_cast<Target
*>(¶meters
->target());
1655 os
= target
->make_output_section(name
, type
, flags
);
1658 // With -z relro, we have to recognize the special sections by name.
1659 // There is no other way.
1660 bool is_relro_local
= false;
1661 if (!this->script_options_
->saw_sections_clause()
1662 && parameters
->options().relro()
1663 && (flags
& elfcpp::SHF_ALLOC
) != 0
1664 && (flags
& elfcpp::SHF_WRITE
) != 0)
1666 if (type
== elfcpp::SHT_PROGBITS
)
1668 if ((flags
& elfcpp::SHF_TLS
) != 0)
1670 else if (strcmp(name
, ".data.rel.ro") == 0)
1672 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1675 is_relro_local
= true;
1677 else if (strcmp(name
, ".ctors") == 0
1678 || strcmp(name
, ".dtors") == 0
1679 || strcmp(name
, ".jcr") == 0)
1682 else if (type
== elfcpp::SHT_INIT_ARRAY
1683 || type
== elfcpp::SHT_FINI_ARRAY
1684 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1691 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1692 order
= this->default_section_order(os
, is_relro_local
);
1694 os
->set_order(order
);
1696 parameters
->target().new_output_section(os
);
1698 this->section_list_
.push_back(os
);
1700 // The GNU linker by default sorts some sections by priority, so we
1701 // do the same. We need to know that this might happen before we
1702 // attach any input sections.
1703 if (!this->script_options_
->saw_sections_clause()
1704 && !parameters
->options().relocatable()
1705 && (strcmp(name
, ".init_array") == 0
1706 || strcmp(name
, ".fini_array") == 0
1707 || (!parameters
->options().ctors_in_init_array()
1708 && (strcmp(name
, ".ctors") == 0
1709 || strcmp(name
, ".dtors") == 0))))
1710 os
->set_may_sort_attached_input_sections();
1712 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1713 // sections before other .text sections. We are compatible. We
1714 // need to know that this might happen before we attach any input
1716 if (parameters
->options().text_reorder()
1717 && !this->script_options_
->saw_sections_clause()
1718 && !this->is_section_ordering_specified()
1719 && !parameters
->options().relocatable()
1720 && strcmp(name
, ".text") == 0)
1721 os
->set_may_sort_attached_input_sections();
1723 // GNU linker sorts section by name with --sort-section=name.
1724 if (strcmp(parameters
->options().sort_section(), "name") == 0)
1725 os
->set_must_sort_attached_input_sections();
1727 // Check for .stab*str sections, as .stab* sections need to link to
1729 if (type
== elfcpp::SHT_STRTAB
1730 && !this->have_stabstr_section_
1731 && strncmp(name
, ".stab", 5) == 0
1732 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1733 this->have_stabstr_section_
= true;
1735 // During a full incremental link, we add patch space to most
1736 // PROGBITS and NOBITS sections. Flag those that may be
1737 // arbitrarily padded.
1738 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1739 && order
!= ORDER_INTERP
1740 && order
!= ORDER_INIT
1741 && order
!= ORDER_PLT
1742 && order
!= ORDER_FINI
1743 && order
!= ORDER_RELRO_LAST
1744 && order
!= ORDER_NON_RELRO_FIRST
1745 && strcmp(name
, ".eh_frame") != 0
1746 && strcmp(name
, ".ctors") != 0
1747 && strcmp(name
, ".dtors") != 0
1748 && strcmp(name
, ".jcr") != 0)
1750 os
->set_is_patch_space_allowed();
1752 // Certain sections require "holes" to be filled with
1753 // specific fill patterns. These fill patterns may have
1754 // a minimum size, so we must prevent allocations from the
1755 // free list that leave a hole smaller than the minimum.
1756 if (strcmp(name
, ".debug_info") == 0)
1757 os
->set_free_space_fill(new Output_fill_debug_info(false));
1758 else if (strcmp(name
, ".debug_types") == 0)
1759 os
->set_free_space_fill(new Output_fill_debug_info(true));
1760 else if (strcmp(name
, ".debug_line") == 0)
1761 os
->set_free_space_fill(new Output_fill_debug_line());
1764 // If we have already attached the sections to segments, then we
1765 // need to attach this one now. This happens for sections created
1766 // directly by the linker.
1767 if (this->sections_are_attached_
)
1768 this->attach_section_to_segment(¶meters
->target(), os
);
1773 // Return the default order in which a section should be placed in an
1774 // output segment. This function captures a lot of the ideas in
1775 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1776 // linker created section is normally set when the section is created;
1777 // this function is used for input sections.
1779 Output_section_order
1780 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1782 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1783 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1784 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1785 bool is_bss
= false;
1790 case elfcpp::SHT_PROGBITS
:
1792 case elfcpp::SHT_NOBITS
:
1795 case elfcpp::SHT_RELA
:
1796 case elfcpp::SHT_REL
:
1798 return ORDER_DYNAMIC_RELOCS
;
1800 case elfcpp::SHT_HASH
:
1801 case elfcpp::SHT_DYNAMIC
:
1802 case elfcpp::SHT_SHLIB
:
1803 case elfcpp::SHT_DYNSYM
:
1804 case elfcpp::SHT_GNU_HASH
:
1805 case elfcpp::SHT_GNU_verdef
:
1806 case elfcpp::SHT_GNU_verneed
:
1807 case elfcpp::SHT_GNU_versym
:
1809 return ORDER_DYNAMIC_LINKER
;
1811 case elfcpp::SHT_NOTE
:
1812 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1815 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1816 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1818 if (!is_bss
&& !is_write
)
1822 if (strcmp(os
->name(), ".init") == 0)
1824 else if (strcmp(os
->name(), ".fini") == 0)
1827 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1831 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1833 if (os
->is_small_section())
1834 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1835 if (os
->is_large_section())
1836 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1838 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1841 // Attach output sections to segments. This is called after we have
1842 // seen all the input sections.
1845 Layout::attach_sections_to_segments(const Target
* target
)
1847 for (Section_list::iterator p
= this->section_list_
.begin();
1848 p
!= this->section_list_
.end();
1850 this->attach_section_to_segment(target
, *p
);
1852 this->sections_are_attached_
= true;
1855 // Attach an output section to a segment.
1858 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1860 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1861 this->unattached_section_list_
.push_back(os
);
1863 this->attach_allocated_section_to_segment(target
, os
);
1866 // Attach an allocated output section to a segment.
1869 Layout::attach_allocated_section_to_segment(const Target
* target
,
1872 elfcpp::Elf_Xword flags
= os
->flags();
1873 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1875 if (parameters
->options().relocatable())
1878 // If we have a SECTIONS clause, we can't handle the attachment to
1879 // segments until after we've seen all the sections.
1880 if (this->script_options_
->saw_sections_clause())
1883 gold_assert(!this->script_options_
->saw_phdrs_clause());
1885 // This output section goes into a PT_LOAD segment.
1887 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1889 // If this output section's segment has extra flags that need to be set,
1890 // coming from a linker plugin, do that.
1891 seg_flags
|= os
->extra_segment_flags();
1893 // Check for --section-start.
1895 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1897 // In general the only thing we really care about for PT_LOAD
1898 // segments is whether or not they are writable or executable,
1899 // so that is how we search for them.
1900 // Large data sections also go into their own PT_LOAD segment.
1901 // People who need segments sorted on some other basis will
1902 // have to use a linker script.
1904 Segment_list::const_iterator p
;
1905 if (!os
->is_unique_segment())
1907 for (p
= this->segment_list_
.begin();
1908 p
!= this->segment_list_
.end();
1911 if ((*p
)->type() != elfcpp::PT_LOAD
)
1913 if ((*p
)->is_unique_segment())
1915 if (!parameters
->options().omagic()
1916 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1918 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
1919 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1921 // If -Tbss was specified, we need to separate the data and BSS
1923 if (parameters
->options().user_set_Tbss())
1925 if ((os
->type() == elfcpp::SHT_NOBITS
)
1926 == (*p
)->has_any_data_sections())
1929 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1934 if ((*p
)->are_addresses_set())
1937 (*p
)->add_initial_output_data(os
);
1938 (*p
)->update_flags_for_output_section(seg_flags
);
1939 (*p
)->set_addresses(addr
, addr
);
1943 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1948 if (p
== this->segment_list_
.end()
1949 || os
->is_unique_segment())
1951 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1953 if (os
->is_large_data_section())
1954 oseg
->set_is_large_data_segment();
1955 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1957 oseg
->set_addresses(addr
, addr
);
1958 // Check if segment should be marked unique. For segments marked
1959 // unique by linker plugins, set the new alignment if specified.
1960 if (os
->is_unique_segment())
1962 oseg
->set_is_unique_segment();
1963 if (os
->segment_alignment() != 0)
1964 oseg
->set_minimum_p_align(os
->segment_alignment());
1968 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1970 if (os
->type() == elfcpp::SHT_NOTE
)
1972 // See if we already have an equivalent PT_NOTE segment.
1973 for (p
= this->segment_list_
.begin();
1974 p
!= segment_list_
.end();
1977 if ((*p
)->type() == elfcpp::PT_NOTE
1978 && (((*p
)->flags() & elfcpp::PF_W
)
1979 == (seg_flags
& elfcpp::PF_W
)))
1981 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1986 if (p
== this->segment_list_
.end())
1988 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1990 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1994 // If we see a loadable SHF_TLS section, we create a PT_TLS
1995 // segment. There can only be one such segment.
1996 if ((flags
& elfcpp::SHF_TLS
) != 0)
1998 if (this->tls_segment_
== NULL
)
1999 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
2000 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2003 // If -z relro is in effect, and we see a relro section, we create a
2004 // PT_GNU_RELRO segment. There can only be one such segment.
2005 if (os
->is_relro() && parameters
->options().relro())
2007 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
2008 if (this->relro_segment_
== NULL
)
2009 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
2010 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2013 // If we see a section named .interp, put it into a PT_INTERP
2014 // segment. This seems broken to me, but this is what GNU ld does,
2015 // and glibc expects it.
2016 if (strcmp(os
->name(), ".interp") == 0
2017 && !this->script_options_
->saw_phdrs_clause())
2019 if (this->interp_segment_
== NULL
)
2020 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
2022 gold_warning(_("multiple '.interp' sections in input files "
2023 "may cause confusing PT_INTERP segment"));
2024 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2028 // Make an output section for a script.
2031 Layout::make_output_section_for_script(
2033 Script_sections::Section_type section_type
)
2035 name
= this->namepool_
.add(name
, false, NULL
);
2036 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
2037 if (section_type
== Script_sections::ST_NOLOAD
)
2039 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
2040 sh_flags
, ORDER_INVALID
,
2042 os
->set_found_in_sections_clause();
2043 if (section_type
== Script_sections::ST_NOLOAD
)
2044 os
->set_is_noload();
2048 // Return the number of segments we expect to see.
2051 Layout::expected_segment_count() const
2053 size_t ret
= this->segment_list_
.size();
2055 // If we didn't see a SECTIONS clause in a linker script, we should
2056 // already have the complete list of segments. Otherwise we ask the
2057 // SECTIONS clause how many segments it expects, and add in the ones
2058 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2060 if (!this->script_options_
->saw_sections_clause())
2064 const Script_sections
* ss
= this->script_options_
->script_sections();
2065 return ret
+ ss
->expected_segment_count(this);
2069 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2070 // is whether we saw a .note.GNU-stack section in the object file.
2071 // GNU_STACK_FLAGS is the section flags. The flags give the
2072 // protection required for stack memory. We record this in an
2073 // executable as a PT_GNU_STACK segment. If an object file does not
2074 // have a .note.GNU-stack segment, we must assume that it is an old
2075 // object. On some targets that will force an executable stack.
2078 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2081 if (!seen_gnu_stack
)
2083 this->input_without_gnu_stack_note_
= true;
2084 if (parameters
->options().warn_execstack()
2085 && parameters
->target().is_default_stack_executable())
2086 gold_warning(_("%s: missing .note.GNU-stack section"
2087 " implies executable stack"),
2088 obj
->name().c_str());
2092 this->input_with_gnu_stack_note_
= true;
2093 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2095 this->input_requires_executable_stack_
= true;
2096 if (parameters
->options().warn_execstack()
2097 || parameters
->options().is_stack_executable())
2098 gold_warning(_("%s: requires executable stack"),
2099 obj
->name().c_str());
2104 // Create automatic note sections.
2107 Layout::create_notes()
2109 this->create_gold_note();
2110 this->create_executable_stack_info();
2111 this->create_build_id();
2114 // Create the dynamic sections which are needed before we read the
2118 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2120 if (parameters
->doing_static_link())
2123 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2124 elfcpp::SHT_DYNAMIC
,
2126 | elfcpp::SHF_WRITE
),
2130 // A linker script may discard .dynamic, so check for NULL.
2131 if (this->dynamic_section_
!= NULL
)
2133 this->dynamic_symbol_
=
2134 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2135 Symbol_table::PREDEFINED
,
2136 this->dynamic_section_
, 0, 0,
2137 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2138 elfcpp::STV_HIDDEN
, 0, false, false);
2140 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2142 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2146 // For each output section whose name can be represented as C symbol,
2147 // define __start and __stop symbols for the section. This is a GNU
2151 Layout::define_section_symbols(Symbol_table
* symtab
)
2153 for (Section_list::const_iterator p
= this->section_list_
.begin();
2154 p
!= this->section_list_
.end();
2157 const char* const name
= (*p
)->name();
2158 if (is_cident(name
))
2160 const std::string
name_string(name
);
2161 const std::string
start_name(cident_section_start_prefix
2163 const std::string
stop_name(cident_section_stop_prefix
2166 symtab
->define_in_output_data(start_name
.c_str(),
2168 Symbol_table::PREDEFINED
,
2174 elfcpp::STV_DEFAULT
,
2176 false, // offset_is_from_end
2177 true); // only_if_ref
2179 symtab
->define_in_output_data(stop_name
.c_str(),
2181 Symbol_table::PREDEFINED
,
2187 elfcpp::STV_DEFAULT
,
2189 true, // offset_is_from_end
2190 true); // only_if_ref
2195 // Define symbols for group signatures.
2198 Layout::define_group_signatures(Symbol_table
* symtab
)
2200 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2201 p
!= this->group_signatures_
.end();
2204 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2206 p
->section
->set_info_symndx(sym
);
2209 // Force the name of the group section to the group
2210 // signature, and use the group's section symbol as the
2211 // signature symbol.
2212 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2214 const char* name
= this->namepool_
.add(p
->signature
,
2216 p
->section
->set_name(name
);
2218 p
->section
->set_needs_symtab_index();
2219 p
->section
->set_info_section_symndx(p
->section
);
2223 this->group_signatures_
.clear();
2226 // Find the first read-only PT_LOAD segment, creating one if
2230 Layout::find_first_load_seg(const Target
* target
)
2232 Output_segment
* best
= NULL
;
2233 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2234 p
!= this->segment_list_
.end();
2237 if ((*p
)->type() == elfcpp::PT_LOAD
2238 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2239 && (parameters
->options().omagic()
2240 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2241 && (!target
->isolate_execinstr()
2242 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2244 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2251 gold_assert(!this->script_options_
->saw_phdrs_clause());
2253 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2258 // Save states of all current output segments. Store saved states
2259 // in SEGMENT_STATES.
2262 Layout::save_segments(Segment_states
* segment_states
)
2264 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2265 p
!= this->segment_list_
.end();
2268 Output_segment
* segment
= *p
;
2270 Output_segment
* copy
= new Output_segment(*segment
);
2271 (*segment_states
)[segment
] = copy
;
2275 // Restore states of output segments and delete any segment not found in
2279 Layout::restore_segments(const Segment_states
* segment_states
)
2281 // Go through the segment list and remove any segment added in the
2283 this->tls_segment_
= NULL
;
2284 this->relro_segment_
= NULL
;
2285 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2286 while (list_iter
!= this->segment_list_
.end())
2288 Output_segment
* segment
= *list_iter
;
2289 Segment_states::const_iterator states_iter
=
2290 segment_states
->find(segment
);
2291 if (states_iter
!= segment_states
->end())
2293 const Output_segment
* copy
= states_iter
->second
;
2294 // Shallow copy to restore states.
2297 // Also fix up TLS and RELRO segment pointers as appropriate.
2298 if (segment
->type() == elfcpp::PT_TLS
)
2299 this->tls_segment_
= segment
;
2300 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2301 this->relro_segment_
= segment
;
2307 list_iter
= this->segment_list_
.erase(list_iter
);
2308 // This is a segment created during section layout. It should be
2309 // safe to remove it since we should have removed all pointers to it.
2315 // Clean up after relaxation so that sections can be laid out again.
2318 Layout::clean_up_after_relaxation()
2320 // Restore the segments to point state just prior to the relaxation loop.
2321 Script_sections
* script_section
= this->script_options_
->script_sections();
2322 script_section
->release_segments();
2323 this->restore_segments(this->segment_states_
);
2325 // Reset section addresses and file offsets
2326 for (Section_list::iterator p
= this->section_list_
.begin();
2327 p
!= this->section_list_
.end();
2330 (*p
)->restore_states();
2332 // If an input section changes size because of relaxation,
2333 // we need to adjust the section offsets of all input sections.
2334 // after such a section.
2335 if ((*p
)->section_offsets_need_adjustment())
2336 (*p
)->adjust_section_offsets();
2338 (*p
)->reset_address_and_file_offset();
2341 // Reset special output object address and file offsets.
2342 for (Data_list::iterator p
= this->special_output_list_
.begin();
2343 p
!= this->special_output_list_
.end();
2345 (*p
)->reset_address_and_file_offset();
2347 // A linker script may have created some output section data objects.
2348 // They are useless now.
2349 for (Output_section_data_list::const_iterator p
=
2350 this->script_output_section_data_list_
.begin();
2351 p
!= this->script_output_section_data_list_
.end();
2354 this->script_output_section_data_list_
.clear();
2356 // Special-case fill output objects are recreated each time through
2357 // the relaxation loop.
2358 this->reset_relax_output();
2362 Layout::reset_relax_output()
2364 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
2365 p
!= this->relax_output_list_
.end();
2368 this->relax_output_list_
.clear();
2371 // Prepare for relaxation.
2374 Layout::prepare_for_relaxation()
2376 // Create an relaxation debug check if in debugging mode.
2377 if (is_debugging_enabled(DEBUG_RELAXATION
))
2378 this->relaxation_debug_check_
= new Relaxation_debug_check();
2380 // Save segment states.
2381 this->segment_states_
= new Segment_states();
2382 this->save_segments(this->segment_states_
);
2384 for(Section_list::const_iterator p
= this->section_list_
.begin();
2385 p
!= this->section_list_
.end();
2387 (*p
)->save_states();
2389 if (is_debugging_enabled(DEBUG_RELAXATION
))
2390 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2391 this->section_list_
, this->special_output_list_
,
2392 this->relax_output_list_
);
2394 // Also enable recording of output section data from scripts.
2395 this->record_output_section_data_from_script_
= true;
2398 // If the user set the address of the text segment, that may not be
2399 // compatible with putting the segment headers and file headers into
2400 // that segment. For isolate_execinstr() targets, it's the rodata
2401 // segment rather than text where we might put the headers.
2403 load_seg_unusable_for_headers(const Target
* target
)
2405 const General_options
& options
= parameters
->options();
2406 if (target
->isolate_execinstr())
2407 return (options
.user_set_Trodata_segment()
2408 && options
.Trodata_segment() % target
->abi_pagesize() != 0);
2410 return (options
.user_set_Ttext()
2411 && options
.Ttext() % target
->abi_pagesize() != 0);
2414 // Relaxation loop body: If target has no relaxation, this runs only once
2415 // Otherwise, the target relaxation hook is called at the end of
2416 // each iteration. If the hook returns true, it means re-layout of
2417 // section is required.
2419 // The number of segments created by a linking script without a PHDRS
2420 // clause may be affected by section sizes and alignments. There is
2421 // a remote chance that relaxation causes different number of PT_LOAD
2422 // segments are created and sections are attached to different segments.
2423 // Therefore, we always throw away all segments created during section
2424 // layout. In order to be able to restart the section layout, we keep
2425 // a copy of the segment list right before the relaxation loop and use
2426 // that to restore the segments.
2428 // PASS is the current relaxation pass number.
2429 // SYMTAB is a symbol table.
2430 // PLOAD_SEG is the address of a pointer for the load segment.
2431 // PHDR_SEG is a pointer to the PHDR segment.
2432 // SEGMENT_HEADERS points to the output segment header.
2433 // FILE_HEADER points to the output file header.
2434 // PSHNDX is the address to store the output section index.
2437 Layout::relaxation_loop_body(
2440 Symbol_table
* symtab
,
2441 Output_segment
** pload_seg
,
2442 Output_segment
* phdr_seg
,
2443 Output_segment_headers
* segment_headers
,
2444 Output_file_header
* file_header
,
2445 unsigned int* pshndx
)
2447 // If this is not the first iteration, we need to clean up after
2448 // relaxation so that we can lay out the sections again.
2450 this->clean_up_after_relaxation();
2452 // If there is a SECTIONS clause, put all the input sections into
2453 // the required order.
2454 Output_segment
* load_seg
;
2455 if (this->script_options_
->saw_sections_clause())
2456 load_seg
= this->set_section_addresses_from_script(symtab
);
2457 else if (parameters
->options().relocatable())
2460 load_seg
= this->find_first_load_seg(target
);
2462 if (parameters
->options().oformat_enum()
2463 != General_options::OBJECT_FORMAT_ELF
)
2466 if (load_seg_unusable_for_headers(target
))
2472 gold_assert(phdr_seg
== NULL
2474 || this->script_options_
->saw_sections_clause());
2476 // If the address of the load segment we found has been set by
2477 // --section-start rather than by a script, then adjust the VMA and
2478 // LMA downward if possible to include the file and section headers.
2479 uint64_t header_gap
= 0;
2480 if (load_seg
!= NULL
2481 && load_seg
->are_addresses_set()
2482 && !this->script_options_
->saw_sections_clause()
2483 && !parameters
->options().relocatable())
2485 file_header
->finalize_data_size();
2486 segment_headers
->finalize_data_size();
2487 size_t sizeof_headers
= (file_header
->data_size()
2488 + segment_headers
->data_size());
2489 const uint64_t abi_pagesize
= target
->abi_pagesize();
2490 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2491 hdr_paddr
&= ~(abi_pagesize
- 1);
2492 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2493 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2497 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2498 load_seg
->paddr() - subtract
);
2499 header_gap
= subtract
- sizeof_headers
;
2503 // Lay out the segment headers.
2504 if (!parameters
->options().relocatable())
2506 gold_assert(segment_headers
!= NULL
);
2507 if (header_gap
!= 0 && load_seg
!= NULL
)
2509 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2510 load_seg
->add_initial_output_data(z
);
2512 if (load_seg
!= NULL
)
2513 load_seg
->add_initial_output_data(segment_headers
);
2514 if (phdr_seg
!= NULL
)
2515 phdr_seg
->add_initial_output_data(segment_headers
);
2518 // Lay out the file header.
2519 if (load_seg
!= NULL
)
2520 load_seg
->add_initial_output_data(file_header
);
2522 if (this->script_options_
->saw_phdrs_clause()
2523 && !parameters
->options().relocatable())
2525 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2526 // clause in a linker script.
2527 Script_sections
* ss
= this->script_options_
->script_sections();
2528 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2531 // We set the output section indexes in set_segment_offsets and
2532 // set_section_indexes.
2535 // Set the file offsets of all the segments, and all the sections
2538 if (!parameters
->options().relocatable())
2539 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2541 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2543 // Verify that the dummy relaxation does not change anything.
2544 if (is_debugging_enabled(DEBUG_RELAXATION
))
2547 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2549 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2552 *pload_seg
= load_seg
;
2556 // Search the list of patterns and find the postion of the given section
2557 // name in the output section. If the section name matches a glob
2558 // pattern and a non-glob name, then the non-glob position takes
2559 // precedence. Return 0 if no match is found.
2562 Layout::find_section_order_index(const std::string
& section_name
)
2564 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2565 map_it
= this->input_section_position_
.find(section_name
);
2566 if (map_it
!= this->input_section_position_
.end())
2567 return map_it
->second
;
2569 // Absolute match failed. Linear search the glob patterns.
2570 std::vector
<std::string
>::iterator it
;
2571 for (it
= this->input_section_glob_
.begin();
2572 it
!= this->input_section_glob_
.end();
2575 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2577 map_it
= this->input_section_position_
.find(*it
);
2578 gold_assert(map_it
!= this->input_section_position_
.end());
2579 return map_it
->second
;
2585 // Read the sequence of input sections from the file specified with
2586 // option --section-ordering-file.
2589 Layout::read_layout_from_file()
2591 const char* filename
= parameters
->options().section_ordering_file();
2597 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2598 filename
, strerror(errno
));
2600 std::getline(in
, line
); // this chops off the trailing \n, if any
2601 unsigned int position
= 1;
2602 this->set_section_ordering_specified();
2606 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2607 line
.resize(line
.length() - 1);
2608 // Ignore comments, beginning with '#'
2611 std::getline(in
, line
);
2614 this->input_section_position_
[line
] = position
;
2615 // Store all glob patterns in a vector.
2616 if (is_wildcard_string(line
.c_str()))
2617 this->input_section_glob_
.push_back(line
);
2619 std::getline(in
, line
);
2623 // Finalize the layout. When this is called, we have created all the
2624 // output sections and all the output segments which are based on
2625 // input sections. We have several things to do, and we have to do
2626 // them in the right order, so that we get the right results correctly
2629 // 1) Finalize the list of output segments and create the segment
2632 // 2) Finalize the dynamic symbol table and associated sections.
2634 // 3) Determine the final file offset of all the output segments.
2636 // 4) Determine the final file offset of all the SHF_ALLOC output
2639 // 5) Create the symbol table sections and the section name table
2642 // 6) Finalize the symbol table: set symbol values to their final
2643 // value and make a final determination of which symbols are going
2644 // into the output symbol table.
2646 // 7) Create the section table header.
2648 // 8) Determine the final file offset of all the output sections which
2649 // are not SHF_ALLOC, including the section table header.
2651 // 9) Finalize the ELF file header.
2653 // This function returns the size of the output file.
2656 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2657 Target
* target
, const Task
* task
)
2659 target
->finalize_sections(this, input_objects
, symtab
);
2661 this->count_local_symbols(task
, input_objects
);
2663 this->link_stabs_sections();
2665 Output_segment
* phdr_seg
= NULL
;
2666 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2668 // There was a dynamic object in the link. We need to create
2669 // some information for the dynamic linker.
2671 // Create the PT_PHDR segment which will hold the program
2673 if (!this->script_options_
->saw_phdrs_clause())
2674 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2676 // Create the dynamic symbol table, including the hash table.
2677 Output_section
* dynstr
;
2678 std::vector
<Symbol
*> dynamic_symbols
;
2679 unsigned int local_dynamic_count
;
2680 Versions
versions(*this->script_options()->version_script_info(),
2682 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2683 &local_dynamic_count
, &dynamic_symbols
,
2686 // Create the .interp section to hold the name of the
2687 // interpreter, and put it in a PT_INTERP segment. Don't do it
2688 // if we saw a .interp section in an input file.
2689 if ((!parameters
->options().shared()
2690 || parameters
->options().dynamic_linker() != NULL
)
2691 && this->interp_segment_
== NULL
)
2692 this->create_interp(target
);
2694 // Finish the .dynamic section to hold the dynamic data, and put
2695 // it in a PT_DYNAMIC segment.
2696 this->finish_dynamic_section(input_objects
, symtab
);
2698 // We should have added everything we need to the dynamic string
2700 this->dynpool_
.set_string_offsets();
2702 // Create the version sections. We can't do this until the
2703 // dynamic string table is complete.
2704 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2705 dynamic_symbols
, dynstr
);
2707 // Set the size of the _DYNAMIC symbol. We can't do this until
2708 // after we call create_version_sections.
2709 this->set_dynamic_symbol_size(symtab
);
2712 // Create segment headers.
2713 Output_segment_headers
* segment_headers
=
2714 (parameters
->options().relocatable()
2716 : new Output_segment_headers(this->segment_list_
));
2718 // Lay out the file header.
2719 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
2722 this->special_output_list_
.push_back(file_header
);
2723 if (segment_headers
!= NULL
)
2724 this->special_output_list_
.push_back(segment_headers
);
2726 // Find approriate places for orphan output sections if we are using
2728 if (this->script_options_
->saw_sections_clause())
2729 this->place_orphan_sections_in_script();
2731 Output_segment
* load_seg
;
2736 // Take a snapshot of the section layout as needed.
2737 if (target
->may_relax())
2738 this->prepare_for_relaxation();
2740 // Run the relaxation loop to lay out sections.
2743 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2744 phdr_seg
, segment_headers
, file_header
,
2748 while (target
->may_relax()
2749 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2751 // If there is a load segment that contains the file and program headers,
2752 // provide a symbol __ehdr_start pointing there.
2753 // A program can use this to examine itself robustly.
2754 Symbol
*ehdr_start
= symtab
->lookup("__ehdr_start");
2755 if (ehdr_start
!= NULL
&& ehdr_start
->is_predefined())
2757 if (load_seg
!= NULL
)
2758 ehdr_start
->set_output_segment(load_seg
, Symbol::SEGMENT_START
);
2760 ehdr_start
->set_undefined();
2763 // Set the file offsets of all the non-data sections we've seen so
2764 // far which don't have to wait for the input sections. We need
2765 // this in order to finalize local symbols in non-allocated
2767 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2769 // Set the section indexes of all unallocated sections seen so far,
2770 // in case any of them are somehow referenced by a symbol.
2771 shndx
= this->set_section_indexes(shndx
);
2773 // Create the symbol table sections.
2774 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2775 if (!parameters
->doing_static_link())
2776 this->assign_local_dynsym_offsets(input_objects
);
2778 // Process any symbol assignments from a linker script. This must
2779 // be called after the symbol table has been finalized.
2780 this->script_options_
->finalize_symbols(symtab
, this);
2782 // Create the incremental inputs sections.
2783 if (this->incremental_inputs_
)
2785 this->incremental_inputs_
->finalize();
2786 this->create_incremental_info_sections(symtab
);
2789 // Create the .shstrtab section.
2790 Output_section
* shstrtab_section
= this->create_shstrtab();
2792 // Set the file offsets of the rest of the non-data sections which
2793 // don't have to wait for the input sections.
2794 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2796 // Now that all sections have been created, set the section indexes
2797 // for any sections which haven't been done yet.
2798 shndx
= this->set_section_indexes(shndx
);
2800 // Create the section table header.
2801 this->create_shdrs(shstrtab_section
, &off
);
2803 // If there are no sections which require postprocessing, we can
2804 // handle the section names now, and avoid a resize later.
2805 if (!this->any_postprocessing_sections_
)
2807 off
= this->set_section_offsets(off
,
2808 POSTPROCESSING_SECTIONS_PASS
);
2810 this->set_section_offsets(off
,
2811 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2814 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2816 // Now we know exactly where everything goes in the output file
2817 // (except for non-allocated sections which require postprocessing).
2818 Output_data::layout_complete();
2820 this->output_file_size_
= off
;
2825 // Create a note header following the format defined in the ELF ABI.
2826 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2827 // of the section to create, DESCSZ is the size of the descriptor.
2828 // ALLOCATE is true if the section should be allocated in memory.
2829 // This returns the new note section. It sets *TRAILING_PADDING to
2830 // the number of trailing zero bytes required.
2833 Layout::create_note(const char* name
, int note_type
,
2834 const char* section_name
, size_t descsz
,
2835 bool allocate
, size_t* trailing_padding
)
2837 // Authorities all agree that the values in a .note field should
2838 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2839 // they differ on what the alignment is for 64-bit binaries.
2840 // The GABI says unambiguously they take 8-byte alignment:
2841 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2842 // Other documentation says alignment should always be 4 bytes:
2843 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2844 // GNU ld and GNU readelf both support the latter (at least as of
2845 // version 2.16.91), and glibc always generates the latter for
2846 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2848 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2849 const int size
= parameters
->target().get_size();
2851 const int size
= 32;
2854 // The contents of the .note section.
2855 size_t namesz
= strlen(name
) + 1;
2856 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2857 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2859 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2861 unsigned char* buffer
= new unsigned char[notehdrsz
];
2862 memset(buffer
, 0, notehdrsz
);
2864 bool is_big_endian
= parameters
->target().is_big_endian();
2870 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2871 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2872 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2876 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2877 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2878 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2881 else if (size
== 64)
2885 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2886 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2887 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2891 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2892 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2893 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2899 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2901 elfcpp::Elf_Xword flags
= 0;
2902 Output_section_order order
= ORDER_INVALID
;
2905 flags
= elfcpp::SHF_ALLOC
;
2906 order
= ORDER_RO_NOTE
;
2908 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2910 flags
, false, order
, false);
2914 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2917 os
->add_output_section_data(posd
);
2919 *trailing_padding
= aligned_descsz
- descsz
;
2924 // For an executable or shared library, create a note to record the
2925 // version of gold used to create the binary.
2928 Layout::create_gold_note()
2930 if (parameters
->options().relocatable()
2931 || parameters
->incremental_update())
2934 std::string desc
= std::string("gold ") + gold::get_version_string();
2936 size_t trailing_padding
;
2937 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2938 ".note.gnu.gold-version", desc
.size(),
2939 false, &trailing_padding
);
2943 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2944 os
->add_output_section_data(posd
);
2946 if (trailing_padding
> 0)
2948 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2949 os
->add_output_section_data(posd
);
2953 // Record whether the stack should be executable. This can be set
2954 // from the command line using the -z execstack or -z noexecstack
2955 // options. Otherwise, if any input file has a .note.GNU-stack
2956 // section with the SHF_EXECINSTR flag set, the stack should be
2957 // executable. Otherwise, if at least one input file a
2958 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2959 // section, we use the target default for whether the stack should be
2960 // executable. Otherwise, we don't generate a stack note. When
2961 // generating a object file, we create a .note.GNU-stack section with
2962 // the appropriate marking. When generating an executable or shared
2963 // library, we create a PT_GNU_STACK segment.
2966 Layout::create_executable_stack_info()
2968 bool is_stack_executable
;
2969 if (parameters
->options().is_execstack_set())
2970 is_stack_executable
= parameters
->options().is_stack_executable();
2971 else if (!this->input_with_gnu_stack_note_
)
2975 if (this->input_requires_executable_stack_
)
2976 is_stack_executable
= true;
2977 else if (this->input_without_gnu_stack_note_
)
2978 is_stack_executable
=
2979 parameters
->target().is_default_stack_executable();
2981 is_stack_executable
= false;
2984 if (parameters
->options().relocatable())
2986 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2987 elfcpp::Elf_Xword flags
= 0;
2988 if (is_stack_executable
)
2989 flags
|= elfcpp::SHF_EXECINSTR
;
2990 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2991 ORDER_INVALID
, false);
2995 if (this->script_options_
->saw_phdrs_clause())
2997 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2998 if (is_stack_executable
)
2999 flags
|= elfcpp::PF_X
;
3000 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
3004 // If --build-id was used, set up the build ID note.
3007 Layout::create_build_id()
3009 if (!parameters
->options().user_set_build_id())
3012 const char* style
= parameters
->options().build_id();
3013 if (strcmp(style
, "none") == 0)
3016 // Set DESCSZ to the size of the note descriptor. When possible,
3017 // set DESC to the note descriptor contents.
3020 if (strcmp(style
, "md5") == 0)
3022 else if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
3024 else if (strcmp(style
, "uuid") == 0)
3026 const size_t uuidsz
= 128 / 8;
3028 char buffer
[uuidsz
];
3029 memset(buffer
, 0, uuidsz
);
3031 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
3033 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3037 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
3038 release_descriptor(descriptor
, true);
3040 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
3041 else if (static_cast<size_t>(got
) != uuidsz
)
3042 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3046 desc
.assign(buffer
, uuidsz
);
3049 else if (strncmp(style
, "0x", 2) == 0)
3052 const char* p
= style
+ 2;
3055 if (hex_p(p
[0]) && hex_p(p
[1]))
3057 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
3061 else if (*p
== '-' || *p
== ':')
3064 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3067 descsz
= desc
.size();
3070 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
3073 size_t trailing_padding
;
3074 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
3075 ".note.gnu.build-id", descsz
, true,
3082 // We know the value already, so we fill it in now.
3083 gold_assert(desc
.size() == descsz
);
3085 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3086 os
->add_output_section_data(posd
);
3088 if (trailing_padding
!= 0)
3090 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3091 os
->add_output_section_data(posd
);
3096 // We need to compute a checksum after we have completed the
3098 gold_assert(trailing_padding
== 0);
3099 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3100 os
->add_output_section_data(this->build_id_note_
);
3104 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3105 // field of the former should point to the latter. I'm not sure who
3106 // started this, but the GNU linker does it, and some tools depend
3110 Layout::link_stabs_sections()
3112 if (!this->have_stabstr_section_
)
3115 for (Section_list::iterator p
= this->section_list_
.begin();
3116 p
!= this->section_list_
.end();
3119 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3122 const char* name
= (*p
)->name();
3123 if (strncmp(name
, ".stab", 5) != 0)
3126 size_t len
= strlen(name
);
3127 if (strcmp(name
+ len
- 3, "str") != 0)
3130 std::string
stab_name(name
, len
- 3);
3131 Output_section
* stab_sec
;
3132 stab_sec
= this->find_output_section(stab_name
.c_str());
3133 if (stab_sec
!= NULL
)
3134 stab_sec
->set_link_section(*p
);
3138 // Create .gnu_incremental_inputs and related sections needed
3139 // for the next run of incremental linking to check what has changed.
3142 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3144 Incremental_inputs
* incr
= this->incremental_inputs_
;
3146 gold_assert(incr
!= NULL
);
3148 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3149 incr
->create_data_sections(symtab
);
3151 // Add the .gnu_incremental_inputs section.
3152 const char* incremental_inputs_name
=
3153 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3154 Output_section
* incremental_inputs_os
=
3155 this->make_output_section(incremental_inputs_name
,
3156 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3157 ORDER_INVALID
, false);
3158 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3160 // Add the .gnu_incremental_symtab section.
3161 const char* incremental_symtab_name
=
3162 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3163 Output_section
* incremental_symtab_os
=
3164 this->make_output_section(incremental_symtab_name
,
3165 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3166 ORDER_INVALID
, false);
3167 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3168 incremental_symtab_os
->set_entsize(4);
3170 // Add the .gnu_incremental_relocs section.
3171 const char* incremental_relocs_name
=
3172 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3173 Output_section
* incremental_relocs_os
=
3174 this->make_output_section(incremental_relocs_name
,
3175 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3176 ORDER_INVALID
, false);
3177 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3178 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3180 // Add the .gnu_incremental_got_plt section.
3181 const char* incremental_got_plt_name
=
3182 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3183 Output_section
* incremental_got_plt_os
=
3184 this->make_output_section(incremental_got_plt_name
,
3185 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3186 ORDER_INVALID
, false);
3187 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3189 // Add the .gnu_incremental_strtab section.
3190 const char* incremental_strtab_name
=
3191 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3192 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3193 elfcpp::SHT_STRTAB
, 0,
3194 ORDER_INVALID
, false);
3195 Output_data_strtab
* strtab_data
=
3196 new Output_data_strtab(incr
->get_stringpool());
3197 incremental_strtab_os
->add_output_section_data(strtab_data
);
3199 incremental_inputs_os
->set_after_input_sections();
3200 incremental_symtab_os
->set_after_input_sections();
3201 incremental_relocs_os
->set_after_input_sections();
3202 incremental_got_plt_os
->set_after_input_sections();
3204 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3205 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3206 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3207 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3210 // Return whether SEG1 should be before SEG2 in the output file. This
3211 // is based entirely on the segment type and flags. When this is
3212 // called the segment addresses have normally not yet been set.
3215 Layout::segment_precedes(const Output_segment
* seg1
,
3216 const Output_segment
* seg2
)
3218 elfcpp::Elf_Word type1
= seg1
->type();
3219 elfcpp::Elf_Word type2
= seg2
->type();
3221 // The single PT_PHDR segment is required to precede any loadable
3222 // segment. We simply make it always first.
3223 if (type1
== elfcpp::PT_PHDR
)
3225 gold_assert(type2
!= elfcpp::PT_PHDR
);
3228 if (type2
== elfcpp::PT_PHDR
)
3231 // The single PT_INTERP segment is required to precede any loadable
3232 // segment. We simply make it always second.
3233 if (type1
== elfcpp::PT_INTERP
)
3235 gold_assert(type2
!= elfcpp::PT_INTERP
);
3238 if (type2
== elfcpp::PT_INTERP
)
3241 // We then put PT_LOAD segments before any other segments.
3242 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3244 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3247 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3248 // segment, because that is where the dynamic linker expects to find
3249 // it (this is just for efficiency; other positions would also work
3251 if (type1
== elfcpp::PT_TLS
3252 && type2
!= elfcpp::PT_TLS
3253 && type2
!= elfcpp::PT_GNU_RELRO
)
3255 if (type2
== elfcpp::PT_TLS
3256 && type1
!= elfcpp::PT_TLS
3257 && type1
!= elfcpp::PT_GNU_RELRO
)
3260 // We put the PT_GNU_RELRO segment last, because that is where the
3261 // dynamic linker expects to find it (as with PT_TLS, this is just
3263 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3265 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3268 const elfcpp::Elf_Word flags1
= seg1
->flags();
3269 const elfcpp::Elf_Word flags2
= seg2
->flags();
3271 // The order of non-PT_LOAD segments is unimportant. We simply sort
3272 // by the numeric segment type and flags values. There should not
3273 // be more than one segment with the same type and flags, except
3274 // when a linker script specifies such.
3275 if (type1
!= elfcpp::PT_LOAD
)
3278 return type1
< type2
;
3279 gold_assert(flags1
!= flags2
3280 || this->script_options_
->saw_phdrs_clause());
3281 return flags1
< flags2
;
3284 // If the addresses are set already, sort by load address.
3285 if (seg1
->are_addresses_set())
3287 if (!seg2
->are_addresses_set())
3290 unsigned int section_count1
= seg1
->output_section_count();
3291 unsigned int section_count2
= seg2
->output_section_count();
3292 if (section_count1
== 0 && section_count2
> 0)
3294 if (section_count1
> 0 && section_count2
== 0)
3297 uint64_t paddr1
= (seg1
->are_addresses_set()
3299 : seg1
->first_section_load_address());
3300 uint64_t paddr2
= (seg2
->are_addresses_set()
3302 : seg2
->first_section_load_address());
3304 if (paddr1
!= paddr2
)
3305 return paddr1
< paddr2
;
3307 else if (seg2
->are_addresses_set())
3310 // A segment which holds large data comes after a segment which does
3311 // not hold large data.
3312 if (seg1
->is_large_data_segment())
3314 if (!seg2
->is_large_data_segment())
3317 else if (seg2
->is_large_data_segment())
3320 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3321 // segments come before writable segments. Then writable segments
3322 // with data come before writable segments without data. Then
3323 // executable segments come before non-executable segments. Then
3324 // the unlikely case of a non-readable segment comes before the
3325 // normal case of a readable segment. If there are multiple
3326 // segments with the same type and flags, we require that the
3327 // address be set, and we sort by virtual address and then physical
3329 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3330 return (flags1
& elfcpp::PF_W
) == 0;
3331 if ((flags1
& elfcpp::PF_W
) != 0
3332 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3333 return seg1
->has_any_data_sections();
3334 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3335 return (flags1
& elfcpp::PF_X
) != 0;
3336 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3337 return (flags1
& elfcpp::PF_R
) == 0;
3339 // We shouldn't get here--we shouldn't create segments which we
3340 // can't distinguish. Unless of course we are using a weird linker
3341 // script or overlapping --section-start options. We could also get
3342 // here if plugins want unique segments for subsets of sections.
3343 gold_assert(this->script_options_
->saw_phdrs_clause()
3344 || parameters
->options().any_section_start()
3345 || this->is_unique_segment_for_sections_specified());
3349 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3352 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3354 uint64_t unsigned_off
= off
;
3355 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3356 | (addr
& (abi_pagesize
- 1)));
3357 if (aligned_off
< unsigned_off
)
3358 aligned_off
+= abi_pagesize
;
3362 // On targets where the text segment contains only executable code,
3363 // a non-executable segment is never the text segment.
3366 is_text_segment(const Target
* target
, const Output_segment
* seg
)
3368 elfcpp::Elf_Xword flags
= seg
->flags();
3369 if ((flags
& elfcpp::PF_W
) != 0)
3371 if ((flags
& elfcpp::PF_X
) == 0)
3372 return !target
->isolate_execinstr();
3376 // Set the file offsets of all the segments, and all the sections they
3377 // contain. They have all been created. LOAD_SEG must be be laid out
3378 // first. Return the offset of the data to follow.
3381 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3382 unsigned int* pshndx
)
3384 // Sort them into the final order. We use a stable sort so that we
3385 // don't randomize the order of indistinguishable segments created
3386 // by linker scripts.
3387 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3388 Layout::Compare_segments(this));
3390 // Find the PT_LOAD segments, and set their addresses and offsets
3391 // and their section's addresses and offsets.
3392 uint64_t start_addr
;
3393 if (parameters
->options().user_set_Ttext())
3394 start_addr
= parameters
->options().Ttext();
3395 else if (parameters
->options().output_is_position_independent())
3398 start_addr
= target
->default_text_segment_address();
3400 uint64_t addr
= start_addr
;
3403 // If LOAD_SEG is NULL, then the file header and segment headers
3404 // will not be loadable. But they still need to be at offset 0 in
3405 // the file. Set their offsets now.
3406 if (load_seg
== NULL
)
3408 for (Data_list::iterator p
= this->special_output_list_
.begin();
3409 p
!= this->special_output_list_
.end();
3412 off
= align_address(off
, (*p
)->addralign());
3413 (*p
)->set_address_and_file_offset(0, off
);
3414 off
+= (*p
)->data_size();
3418 unsigned int increase_relro
= this->increase_relro_
;
3419 if (this->script_options_
->saw_sections_clause())
3422 const bool check_sections
= parameters
->options().check_sections();
3423 Output_segment
* last_load_segment
= NULL
;
3425 unsigned int shndx_begin
= *pshndx
;
3426 unsigned int shndx_load_seg
= *pshndx
;
3428 for (Segment_list::iterator p
= this->segment_list_
.begin();
3429 p
!= this->segment_list_
.end();
3432 if ((*p
)->type() == elfcpp::PT_LOAD
)
3434 if (target
->isolate_execinstr())
3436 // When we hit the segment that should contain the
3437 // file headers, reset the file offset so we place
3438 // it and subsequent segments appropriately.
3439 // We'll fix up the preceding segments below.
3447 shndx_load_seg
= *pshndx
;
3453 // Verify that the file headers fall into the first segment.
3454 if (load_seg
!= NULL
&& load_seg
!= *p
)
3459 bool are_addresses_set
= (*p
)->are_addresses_set();
3460 if (are_addresses_set
)
3462 // When it comes to setting file offsets, we care about
3463 // the physical address.
3464 addr
= (*p
)->paddr();
3466 else if (parameters
->options().user_set_Ttext()
3467 && (parameters
->options().omagic()
3468 || is_text_segment(target
, *p
)))
3470 are_addresses_set
= true;
3472 else if (parameters
->options().user_set_Trodata_segment()
3473 && ((*p
)->flags() & (elfcpp::PF_W
| elfcpp::PF_X
)) == 0)
3475 addr
= parameters
->options().Trodata_segment();
3476 are_addresses_set
= true;
3478 else if (parameters
->options().user_set_Tdata()
3479 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3480 && (!parameters
->options().user_set_Tbss()
3481 || (*p
)->has_any_data_sections()))
3483 addr
= parameters
->options().Tdata();
3484 are_addresses_set
= true;
3486 else if (parameters
->options().user_set_Tbss()
3487 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3488 && !(*p
)->has_any_data_sections())
3490 addr
= parameters
->options().Tbss();
3491 are_addresses_set
= true;
3494 uint64_t orig_addr
= addr
;
3495 uint64_t orig_off
= off
;
3497 uint64_t aligned_addr
= 0;
3498 uint64_t abi_pagesize
= target
->abi_pagesize();
3499 uint64_t common_pagesize
= target
->common_pagesize();
3501 if (!parameters
->options().nmagic()
3502 && !parameters
->options().omagic())
3503 (*p
)->set_minimum_p_align(abi_pagesize
);
3505 if (!are_addresses_set
)
3507 // Skip the address forward one page, maintaining the same
3508 // position within the page. This lets us store both segments
3509 // overlapping on a single page in the file, but the loader will
3510 // put them on different pages in memory. We will revisit this
3511 // decision once we know the size of the segment.
3513 addr
= align_address(addr
, (*p
)->maximum_alignment());
3514 aligned_addr
= addr
;
3518 // This is the segment that will contain the file
3519 // headers, so its offset will have to be exactly zero.
3520 gold_assert(orig_off
== 0);
3522 // If the target wants a fixed minimum distance from the
3523 // text segment to the read-only segment, move up now.
3525 start_addr
+ (parameters
->options().user_set_rosegment_gap()
3526 ? parameters
->options().rosegment_gap()
3527 : target
->rosegment_gap());
3528 if (addr
< min_addr
)
3531 // But this is not the first segment! To make its
3532 // address congruent with its offset, that address better
3533 // be aligned to the ABI-mandated page size.
3534 addr
= align_address(addr
, abi_pagesize
);
3535 aligned_addr
= addr
;
3539 if ((addr
& (abi_pagesize
- 1)) != 0)
3540 addr
= addr
+ abi_pagesize
;
3542 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3546 if (!parameters
->options().nmagic()
3547 && !parameters
->options().omagic())
3549 // Here we are also taking care of the case when
3550 // the maximum segment alignment is larger than the page size.
3551 off
= align_file_offset(off
, addr
,
3552 std::max(abi_pagesize
,
3553 (*p
)->maximum_alignment()));
3557 // This is -N or -n with a section script which prevents
3558 // us from using a load segment. We need to ensure that
3559 // the file offset is aligned to the alignment of the
3560 // segment. This is because the linker script
3561 // implicitly assumed a zero offset. If we don't align
3562 // here, then the alignment of the sections in the
3563 // linker script may not match the alignment of the
3564 // sections in the set_section_addresses call below,
3565 // causing an error about dot moving backward.
3566 off
= align_address(off
, (*p
)->maximum_alignment());
3569 unsigned int shndx_hold
= *pshndx
;
3570 bool has_relro
= false;
3571 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
3577 // Now that we know the size of this segment, we may be able
3578 // to save a page in memory, at the cost of wasting some
3579 // file space, by instead aligning to the start of a new
3580 // page. Here we use the real machine page size rather than
3581 // the ABI mandated page size. If the segment has been
3582 // aligned so that the relro data ends at a page boundary,
3583 // we do not try to realign it.
3585 if (!are_addresses_set
3587 && aligned_addr
!= addr
3588 && !parameters
->incremental())
3590 uint64_t first_off
= (common_pagesize
3592 & (common_pagesize
- 1)));
3593 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
3596 && ((aligned_addr
& ~ (common_pagesize
- 1))
3597 != (new_addr
& ~ (common_pagesize
- 1)))
3598 && first_off
+ last_off
<= common_pagesize
)
3600 *pshndx
= shndx_hold
;
3601 addr
= align_address(aligned_addr
, common_pagesize
);
3602 addr
= align_address(addr
, (*p
)->maximum_alignment());
3603 if ((addr
& (abi_pagesize
- 1)) != 0)
3604 addr
= addr
+ abi_pagesize
;
3605 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3606 off
= align_file_offset(off
, addr
, abi_pagesize
);
3608 increase_relro
= this->increase_relro_
;
3609 if (this->script_options_
->saw_sections_clause())
3613 new_addr
= (*p
)->set_section_addresses(target
, this,
3623 // Implement --check-sections. We know that the segments
3624 // are sorted by LMA.
3625 if (check_sections
&& last_load_segment
!= NULL
)
3627 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
3628 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3631 unsigned long long lb1
= last_load_segment
->paddr();
3632 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3633 unsigned long long lb2
= (*p
)->paddr();
3634 unsigned long long le2
= lb2
+ (*p
)->memsz();
3635 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3636 "[0x%llx -> 0x%llx]"),
3637 lb1
, le1
, lb2
, le2
);
3640 last_load_segment
= *p
;
3644 if (load_seg
!= NULL
&& target
->isolate_execinstr())
3646 // Process the early segments again, setting their file offsets
3647 // so they land after the segments starting at LOAD_SEG.
3648 off
= align_file_offset(off
, 0, target
->abi_pagesize());
3650 this->reset_relax_output();
3652 for (Segment_list::iterator p
= this->segment_list_
.begin();
3656 if ((*p
)->type() == elfcpp::PT_LOAD
)
3658 // We repeat the whole job of assigning addresses and
3659 // offsets, but we really only want to change the offsets and
3660 // must ensure that the addresses all come out the same as
3661 // they did the first time through.
3662 bool has_relro
= false;
3663 const uint64_t old_addr
= (*p
)->vaddr();
3664 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
3665 uint64_t new_addr
= (*p
)->set_section_addresses(target
, this,
3671 gold_assert(new_addr
== old_end
);
3675 gold_assert(shndx_begin
== shndx_load_seg
);
3678 // Handle the non-PT_LOAD segments, setting their offsets from their
3679 // section's offsets.
3680 for (Segment_list::iterator p
= this->segment_list_
.begin();
3681 p
!= this->segment_list_
.end();
3684 if ((*p
)->type() != elfcpp::PT_LOAD
)
3685 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3690 // Set the TLS offsets for each section in the PT_TLS segment.
3691 if (this->tls_segment_
!= NULL
)
3692 this->tls_segment_
->set_tls_offsets();
3697 // Set the offsets of all the allocated sections when doing a
3698 // relocatable link. This does the same jobs as set_segment_offsets,
3699 // only for a relocatable link.
3702 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3703 unsigned int* pshndx
)
3707 file_header
->set_address_and_file_offset(0, 0);
3708 off
+= file_header
->data_size();
3710 for (Section_list::iterator p
= this->section_list_
.begin();
3711 p
!= this->section_list_
.end();
3714 // We skip unallocated sections here, except that group sections
3715 // have to come first.
3716 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3717 && (*p
)->type() != elfcpp::SHT_GROUP
)
3720 off
= align_address(off
, (*p
)->addralign());
3722 // The linker script might have set the address.
3723 if (!(*p
)->is_address_valid())
3724 (*p
)->set_address(0);
3725 (*p
)->set_file_offset(off
);
3726 (*p
)->finalize_data_size();
3727 if ((*p
)->type() != elfcpp::SHT_NOBITS
)
3728 off
+= (*p
)->data_size();
3730 (*p
)->set_out_shndx(*pshndx
);
3737 // Set the file offset of all the sections not associated with a
3741 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3743 off_t startoff
= off
;
3746 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3747 p
!= this->unattached_section_list_
.end();
3750 // The symtab section is handled in create_symtab_sections.
3751 if (*p
== this->symtab_section_
)
3754 // If we've already set the data size, don't set it again.
3755 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3758 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3759 && (*p
)->requires_postprocessing())
3761 (*p
)->create_postprocessing_buffer();
3762 this->any_postprocessing_sections_
= true;
3765 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3766 && (*p
)->after_input_sections())
3768 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3769 && (!(*p
)->after_input_sections()
3770 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3772 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3773 && (!(*p
)->after_input_sections()
3774 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3777 if (!parameters
->incremental_update())
3779 off
= align_address(off
, (*p
)->addralign());
3780 (*p
)->set_file_offset(off
);
3781 (*p
)->finalize_data_size();
3785 // Incremental update: allocate file space from free list.
3786 (*p
)->pre_finalize_data_size();
3787 off_t current_size
= (*p
)->current_data_size();
3788 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3791 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3792 this->free_list_
.dump();
3793 gold_assert((*p
)->output_section() != NULL
);
3794 gold_fallback(_("out of patch space for section %s; "
3795 "relink with --incremental-full"),
3796 (*p
)->output_section()->name());
3798 (*p
)->set_file_offset(off
);
3799 (*p
)->finalize_data_size();
3800 if ((*p
)->data_size() > current_size
)
3802 gold_assert((*p
)->output_section() != NULL
);
3803 gold_fallback(_("%s: section changed size; "
3804 "relink with --incremental-full"),
3805 (*p
)->output_section()->name());
3807 gold_debug(DEBUG_INCREMENTAL
,
3808 "set_section_offsets: %08lx %08lx %s",
3809 static_cast<long>(off
),
3810 static_cast<long>((*p
)->data_size()),
3811 ((*p
)->output_section() != NULL
3812 ? (*p
)->output_section()->name() : "(special)"));
3815 off
+= (*p
)->data_size();
3819 // At this point the name must be set.
3820 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3821 this->namepool_
.add((*p
)->name(), false, NULL
);
3826 // Set the section indexes of all the sections not associated with a
3830 Layout::set_section_indexes(unsigned int shndx
)
3832 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3833 p
!= this->unattached_section_list_
.end();
3836 if (!(*p
)->has_out_shndx())
3838 (*p
)->set_out_shndx(shndx
);
3845 // Set the section addresses according to the linker script. This is
3846 // only called when we see a SECTIONS clause. This returns the
3847 // program segment which should hold the file header and segment
3848 // headers, if any. It will return NULL if they should not be in a
3852 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3854 Script_sections
* ss
= this->script_options_
->script_sections();
3855 gold_assert(ss
->saw_sections_clause());
3856 return this->script_options_
->set_section_addresses(symtab
, this);
3859 // Place the orphan sections in the linker script.
3862 Layout::place_orphan_sections_in_script()
3864 Script_sections
* ss
= this->script_options_
->script_sections();
3865 gold_assert(ss
->saw_sections_clause());
3867 // Place each orphaned output section in the script.
3868 for (Section_list::iterator p
= this->section_list_
.begin();
3869 p
!= this->section_list_
.end();
3872 if (!(*p
)->found_in_sections_clause())
3873 ss
->place_orphan(*p
);
3877 // Count the local symbols in the regular symbol table and the dynamic
3878 // symbol table, and build the respective string pools.
3881 Layout::count_local_symbols(const Task
* task
,
3882 const Input_objects
* input_objects
)
3884 // First, figure out an upper bound on the number of symbols we'll
3885 // be inserting into each pool. This helps us create the pools with
3886 // the right size, to avoid unnecessary hashtable resizing.
3887 unsigned int symbol_count
= 0;
3888 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3889 p
!= input_objects
->relobj_end();
3891 symbol_count
+= (*p
)->local_symbol_count();
3893 // Go from "upper bound" to "estimate." We overcount for two
3894 // reasons: we double-count symbols that occur in more than one
3895 // object file, and we count symbols that are dropped from the
3896 // output. Add it all together and assume we overcount by 100%.
3899 // We assume all symbols will go into both the sympool and dynpool.
3900 this->sympool_
.reserve(symbol_count
);
3901 this->dynpool_
.reserve(symbol_count
);
3903 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3904 p
!= input_objects
->relobj_end();
3907 Task_lock_obj
<Object
> tlo(task
, *p
);
3908 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3912 // Create the symbol table sections. Here we also set the final
3913 // values of the symbols. At this point all the loadable sections are
3914 // fully laid out. SHNUM is the number of sections so far.
3917 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3918 Symbol_table
* symtab
,
3924 if (parameters
->target().get_size() == 32)
3926 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3929 else if (parameters
->target().get_size() == 64)
3931 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3937 // Compute file offsets relative to the start of the symtab section.
3940 // Save space for the dummy symbol at the start of the section. We
3941 // never bother to write this out--it will just be left as zero.
3943 unsigned int local_symbol_index
= 1;
3945 // Add STT_SECTION symbols for each Output section which needs one.
3946 for (Section_list::iterator p
= this->section_list_
.begin();
3947 p
!= this->section_list_
.end();
3950 if (!(*p
)->needs_symtab_index())
3951 (*p
)->set_symtab_index(-1U);
3954 (*p
)->set_symtab_index(local_symbol_index
);
3955 ++local_symbol_index
;
3960 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3961 p
!= input_objects
->relobj_end();
3964 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3966 off
+= (index
- local_symbol_index
) * symsize
;
3967 local_symbol_index
= index
;
3970 unsigned int local_symcount
= local_symbol_index
;
3971 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3974 size_t dyn_global_index
;
3976 if (this->dynsym_section_
== NULL
)
3979 dyn_global_index
= 0;
3984 dyn_global_index
= this->dynsym_section_
->info();
3985 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3986 dynoff
= this->dynsym_section_
->offset() + locsize
;
3987 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3988 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3989 == this->dynsym_section_
->data_size() - locsize
);
3992 off_t global_off
= off
;
3993 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3994 &this->sympool_
, &local_symcount
);
3996 if (!parameters
->options().strip_all())
3998 this->sympool_
.set_string_offsets();
4000 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
4001 Output_section
* osymtab
= this->make_output_section(symtab_name
,
4005 this->symtab_section_
= osymtab
;
4007 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
4009 osymtab
->add_output_section_data(pos
);
4011 // We generate a .symtab_shndx section if we have more than
4012 // SHN_LORESERVE sections. Technically it is possible that we
4013 // don't need one, because it is possible that there are no
4014 // symbols in any of sections with indexes larger than
4015 // SHN_LORESERVE. That is probably unusual, though, and it is
4016 // easier to always create one than to compute section indexes
4017 // twice (once here, once when writing out the symbols).
4018 if (shnum
>= elfcpp::SHN_LORESERVE
)
4020 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
4022 Output_section
* osymtab_xindex
=
4023 this->make_output_section(symtab_xindex_name
,
4024 elfcpp::SHT_SYMTAB_SHNDX
, 0,
4025 ORDER_INVALID
, false);
4027 size_t symcount
= off
/ symsize
;
4028 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
4030 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
4032 osymtab_xindex
->set_link_section(osymtab
);
4033 osymtab_xindex
->set_addralign(4);
4034 osymtab_xindex
->set_entsize(4);
4036 osymtab_xindex
->set_after_input_sections();
4038 // This tells the driver code to wait until the symbol table
4039 // has written out before writing out the postprocessing
4040 // sections, including the .symtab_shndx section.
4041 this->any_postprocessing_sections_
= true;
4044 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
4045 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
4050 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
4051 ostrtab
->add_output_section_data(pstr
);
4054 if (!parameters
->incremental_update())
4055 symtab_off
= align_address(*poff
, align
);
4058 symtab_off
= this->allocate(off
, align
, *poff
);
4060 gold_fallback(_("out of patch space for symbol table; "
4061 "relink with --incremental-full"));
4062 gold_debug(DEBUG_INCREMENTAL
,
4063 "create_symtab_sections: %08lx %08lx .symtab",
4064 static_cast<long>(symtab_off
),
4065 static_cast<long>(off
));
4068 symtab
->set_file_offset(symtab_off
+ global_off
);
4069 osymtab
->set_file_offset(symtab_off
);
4070 osymtab
->finalize_data_size();
4071 osymtab
->set_link_section(ostrtab
);
4072 osymtab
->set_info(local_symcount
);
4073 osymtab
->set_entsize(symsize
);
4075 if (symtab_off
+ off
> *poff
)
4076 *poff
= symtab_off
+ off
;
4080 // Create the .shstrtab section, which holds the names of the
4081 // sections. At the time this is called, we have created all the
4082 // output sections except .shstrtab itself.
4085 Layout::create_shstrtab()
4087 // FIXME: We don't need to create a .shstrtab section if we are
4088 // stripping everything.
4090 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
4092 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
4093 ORDER_INVALID
, false);
4095 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
4097 // We can't write out this section until we've set all the
4098 // section names, and we don't set the names of compressed
4099 // output sections until relocations are complete. FIXME: With
4100 // the current names we use, this is unnecessary.
4101 os
->set_after_input_sections();
4104 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
4105 os
->add_output_section_data(posd
);
4110 // Create the section headers. SIZE is 32 or 64. OFF is the file
4114 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
4116 Output_section_headers
* oshdrs
;
4117 oshdrs
= new Output_section_headers(this,
4118 &this->segment_list_
,
4119 &this->section_list_
,
4120 &this->unattached_section_list_
,
4124 if (!parameters
->incremental_update())
4125 off
= align_address(*poff
, oshdrs
->addralign());
4128 oshdrs
->pre_finalize_data_size();
4129 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
4131 gold_fallback(_("out of patch space for section header table; "
4132 "relink with --incremental-full"));
4133 gold_debug(DEBUG_INCREMENTAL
,
4134 "create_shdrs: %08lx %08lx (section header table)",
4135 static_cast<long>(off
),
4136 static_cast<long>(off
+ oshdrs
->data_size()));
4138 oshdrs
->set_address_and_file_offset(0, off
);
4139 off
+= oshdrs
->data_size();
4142 this->section_headers_
= oshdrs
;
4145 // Count the allocated sections.
4148 Layout::allocated_output_section_count() const
4150 size_t section_count
= 0;
4151 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4152 p
!= this->segment_list_
.end();
4154 section_count
+= (*p
)->output_section_count();
4155 return section_count
;
4158 // Create the dynamic symbol table.
4161 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4162 Symbol_table
* symtab
,
4163 Output_section
** pdynstr
,
4164 unsigned int* plocal_dynamic_count
,
4165 std::vector
<Symbol
*>* pdynamic_symbols
,
4166 Versions
* pversions
)
4168 // Count all the symbols in the dynamic symbol table, and set the
4169 // dynamic symbol indexes.
4171 // Skip symbol 0, which is always all zeroes.
4172 unsigned int index
= 1;
4174 // Add STT_SECTION symbols for each Output section which needs one.
4175 for (Section_list::iterator p
= this->section_list_
.begin();
4176 p
!= this->section_list_
.end();
4179 if (!(*p
)->needs_dynsym_index())
4180 (*p
)->set_dynsym_index(-1U);
4183 (*p
)->set_dynsym_index(index
);
4188 // Count the local symbols that need to go in the dynamic symbol table,
4189 // and set the dynamic symbol indexes.
4190 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4191 p
!= input_objects
->relobj_end();
4194 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4198 unsigned int local_symcount
= index
;
4199 *plocal_dynamic_count
= local_symcount
;
4201 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
4202 &this->dynpool_
, pversions
);
4206 const int size
= parameters
->target().get_size();
4209 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4212 else if (size
== 64)
4214 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4220 // Create the dynamic symbol table section.
4222 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4226 ORDER_DYNAMIC_LINKER
,
4229 // Check for NULL as a linker script may discard .dynsym.
4232 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4235 dynsym
->add_output_section_data(odata
);
4237 dynsym
->set_info(local_symcount
);
4238 dynsym
->set_entsize(symsize
);
4239 dynsym
->set_addralign(align
);
4241 this->dynsym_section_
= dynsym
;
4244 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4247 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4248 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4251 // If there are more than SHN_LORESERVE allocated sections, we
4252 // create a .dynsym_shndx section. It is possible that we don't
4253 // need one, because it is possible that there are no dynamic
4254 // symbols in any of the sections with indexes larger than
4255 // SHN_LORESERVE. This is probably unusual, though, and at this
4256 // time we don't know the actual section indexes so it is
4257 // inconvenient to check.
4258 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4260 Output_section
* dynsym_xindex
=
4261 this->choose_output_section(NULL
, ".dynsym_shndx",
4262 elfcpp::SHT_SYMTAB_SHNDX
,
4264 false, ORDER_DYNAMIC_LINKER
, false);
4266 if (dynsym_xindex
!= NULL
)
4268 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4270 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4272 dynsym_xindex
->set_link_section(dynsym
);
4273 dynsym_xindex
->set_addralign(4);
4274 dynsym_xindex
->set_entsize(4);
4276 dynsym_xindex
->set_after_input_sections();
4278 // This tells the driver code to wait until the symbol table
4279 // has written out before writing out the postprocessing
4280 // sections, including the .dynsym_shndx section.
4281 this->any_postprocessing_sections_
= true;
4285 // Create the dynamic string table section.
4287 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4291 ORDER_DYNAMIC_LINKER
,
4296 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4297 dynstr
->add_output_section_data(strdata
);
4300 dynsym
->set_link_section(dynstr
);
4301 if (this->dynamic_section_
!= NULL
)
4302 this->dynamic_section_
->set_link_section(dynstr
);
4306 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4307 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4311 // Create the hash tables. The Gnu-style hash table must be
4312 // built first, because it changes the order of the symbols
4313 // in the dynamic symbol table.
4315 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4316 || strcmp(parameters
->options().hash_style(), "both") == 0)
4318 unsigned char* phash
;
4319 unsigned int hashlen
;
4320 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
4323 Output_section
* hashsec
=
4324 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4325 elfcpp::SHF_ALLOC
, false,
4326 ORDER_DYNAMIC_LINKER
, false);
4328 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4332 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4333 hashsec
->add_output_section_data(hashdata
);
4335 if (hashsec
!= NULL
)
4338 hashsec
->set_link_section(dynsym
);
4340 // For a 64-bit target, the entries in .gnu.hash do not have
4341 // a uniform size, so we only set the entry size for a
4343 if (parameters
->target().get_size() == 32)
4344 hashsec
->set_entsize(4);
4347 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4351 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4352 || strcmp(parameters
->options().hash_style(), "both") == 0)
4354 unsigned char* phash
;
4355 unsigned int hashlen
;
4356 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
4359 Output_section
* hashsec
=
4360 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4361 elfcpp::SHF_ALLOC
, false,
4362 ORDER_DYNAMIC_LINKER
, false);
4364 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4368 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4369 hashsec
->add_output_section_data(hashdata
);
4371 if (hashsec
!= NULL
)
4374 hashsec
->set_link_section(dynsym
);
4375 hashsec
->set_entsize(4);
4379 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4383 // Assign offsets to each local portion of the dynamic symbol table.
4386 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4388 Output_section
* dynsym
= this->dynsym_section_
;
4392 off_t off
= dynsym
->offset();
4394 // Skip the dummy symbol at the start of the section.
4395 off
+= dynsym
->entsize();
4397 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4398 p
!= input_objects
->relobj_end();
4401 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4402 off
+= count
* dynsym
->entsize();
4406 // Create the version sections.
4409 Layout::create_version_sections(const Versions
* versions
,
4410 const Symbol_table
* symtab
,
4411 unsigned int local_symcount
,
4412 const std::vector
<Symbol
*>& dynamic_symbols
,
4413 const Output_section
* dynstr
)
4415 if (!versions
->any_defs() && !versions
->any_needs())
4418 switch (parameters
->size_and_endianness())
4420 #ifdef HAVE_TARGET_32_LITTLE
4421 case Parameters::TARGET_32_LITTLE
:
4422 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4424 dynamic_symbols
, dynstr
);
4427 #ifdef HAVE_TARGET_32_BIG
4428 case Parameters::TARGET_32_BIG
:
4429 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4431 dynamic_symbols
, dynstr
);
4434 #ifdef HAVE_TARGET_64_LITTLE
4435 case Parameters::TARGET_64_LITTLE
:
4436 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4438 dynamic_symbols
, dynstr
);
4441 #ifdef HAVE_TARGET_64_BIG
4442 case Parameters::TARGET_64_BIG
:
4443 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4445 dynamic_symbols
, dynstr
);
4453 // Create the version sections, sized version.
4455 template<int size
, bool big_endian
>
4457 Layout::sized_create_version_sections(
4458 const Versions
* versions
,
4459 const Symbol_table
* symtab
,
4460 unsigned int local_symcount
,
4461 const std::vector
<Symbol
*>& dynamic_symbols
,
4462 const Output_section
* dynstr
)
4464 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4465 elfcpp::SHT_GNU_versym
,
4468 ORDER_DYNAMIC_LINKER
,
4471 // Check for NULL since a linker script may discard this section.
4474 unsigned char* vbuf
;
4476 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4482 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4485 vsec
->add_output_section_data(vdata
);
4486 vsec
->set_entsize(2);
4487 vsec
->set_link_section(this->dynsym_section_
);
4490 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4491 if (odyn
!= NULL
&& vsec
!= NULL
)
4492 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4494 if (versions
->any_defs())
4496 Output_section
* vdsec
;
4497 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4498 elfcpp::SHT_GNU_verdef
,
4500 false, ORDER_DYNAMIC_LINKER
, false);
4504 unsigned char* vdbuf
;
4505 unsigned int vdsize
;
4506 unsigned int vdentries
;
4507 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4511 Output_section_data
* vddata
=
4512 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4514 vdsec
->add_output_section_data(vddata
);
4515 vdsec
->set_link_section(dynstr
);
4516 vdsec
->set_info(vdentries
);
4520 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4521 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4526 if (versions
->any_needs())
4528 Output_section
* vnsec
;
4529 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4530 elfcpp::SHT_GNU_verneed
,
4532 false, ORDER_DYNAMIC_LINKER
, false);
4536 unsigned char* vnbuf
;
4537 unsigned int vnsize
;
4538 unsigned int vnentries
;
4539 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4543 Output_section_data
* vndata
=
4544 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4546 vnsec
->add_output_section_data(vndata
);
4547 vnsec
->set_link_section(dynstr
);
4548 vnsec
->set_info(vnentries
);
4552 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4553 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
4559 // Create the .interp section and PT_INTERP segment.
4562 Layout::create_interp(const Target
* target
)
4564 gold_assert(this->interp_segment_
== NULL
);
4566 const char* interp
= parameters
->options().dynamic_linker();
4569 interp
= target
->dynamic_linker();
4570 gold_assert(interp
!= NULL
);
4573 size_t len
= strlen(interp
) + 1;
4575 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
4577 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
4578 elfcpp::SHT_PROGBITS
,
4580 false, ORDER_INTERP
,
4583 osec
->add_output_section_data(odata
);
4586 // Add dynamic tags for the PLT and the dynamic relocs. This is
4587 // called by the target-specific code. This does nothing if not doing
4590 // USE_REL is true for REL relocs rather than RELA relocs.
4592 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4594 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4595 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4596 // some targets have multiple reloc sections in PLT_REL.
4598 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4599 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4602 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4606 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
4607 const Output_data
* plt_rel
,
4608 const Output_data_reloc_generic
* dyn_rel
,
4609 bool add_debug
, bool dynrel_includes_plt
)
4611 Output_data_dynamic
* odyn
= this->dynamic_data_
;
4615 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
4616 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
4618 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
4620 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
4621 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
4622 odyn
->add_constant(elfcpp::DT_PLTREL
,
4623 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
4626 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
4627 || (dynrel_includes_plt
4629 && plt_rel
->output_section() != NULL
))
4631 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
4632 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
4633 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
4635 ? dyn_rel
->output_section()
4636 : plt_rel
->output_section()));
4637 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
4638 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
4639 odyn
->add_section_size(size_tag
,
4640 dyn_rel
->output_section(),
4641 plt_rel
->output_section());
4642 else if (have_dyn_rel
)
4643 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
4645 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
4646 const int size
= parameters
->target().get_size();
4651 rel_tag
= elfcpp::DT_RELENT
;
4653 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
4654 else if (size
== 64)
4655 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
4661 rel_tag
= elfcpp::DT_RELAENT
;
4663 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
4664 else if (size
== 64)
4665 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
4669 odyn
->add_constant(rel_tag
, rel_size
);
4671 if (parameters
->options().combreloc() && have_dyn_rel
)
4673 size_t c
= dyn_rel
->relative_reloc_count();
4675 odyn
->add_constant((use_rel
4676 ? elfcpp::DT_RELCOUNT
4677 : elfcpp::DT_RELACOUNT
),
4682 if (add_debug
&& !parameters
->options().shared())
4684 // The value of the DT_DEBUG tag is filled in by the dynamic
4685 // linker at run time, and used by the debugger.
4686 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
4690 // Finish the .dynamic section and PT_DYNAMIC segment.
4693 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
4694 const Symbol_table
* symtab
)
4696 if (!this->script_options_
->saw_phdrs_clause()
4697 && this->dynamic_section_
!= NULL
)
4699 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
4702 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
4703 elfcpp::PF_R
| elfcpp::PF_W
);
4706 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4710 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
4711 p
!= input_objects
->dynobj_end();
4714 if (!(*p
)->is_needed() && (*p
)->as_needed())
4716 // This dynamic object was linked with --as-needed, but it
4721 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4724 if (parameters
->options().shared())
4726 const char* soname
= parameters
->options().soname();
4728 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4731 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4732 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4733 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4735 sym
= symtab
->lookup(parameters
->options().fini());
4736 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4737 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4739 // Look for .init_array, .preinit_array and .fini_array by checking
4741 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4742 p
!= this->section_list_
.end();
4744 switch((*p
)->type())
4746 case elfcpp::SHT_FINI_ARRAY
:
4747 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4748 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4750 case elfcpp::SHT_INIT_ARRAY
:
4751 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4752 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4754 case elfcpp::SHT_PREINIT_ARRAY
:
4755 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4756 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4762 // Add a DT_RPATH entry if needed.
4763 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4766 std::string rpath_val
;
4767 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4771 if (rpath_val
.empty())
4772 rpath_val
= p
->name();
4775 // Eliminate duplicates.
4776 General_options::Dir_list::const_iterator q
;
4777 for (q
= rpath
.begin(); q
!= p
; ++q
)
4778 if (q
->name() == p
->name())
4783 rpath_val
+= p
->name();
4788 if (!parameters
->options().enable_new_dtags())
4789 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4791 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4794 // Look for text segments that have dynamic relocations.
4795 bool have_textrel
= false;
4796 if (!this->script_options_
->saw_sections_clause())
4798 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4799 p
!= this->segment_list_
.end();
4802 if ((*p
)->type() == elfcpp::PT_LOAD
4803 && ((*p
)->flags() & elfcpp::PF_W
) == 0
4804 && (*p
)->has_dynamic_reloc())
4806 have_textrel
= true;
4813 // We don't know the section -> segment mapping, so we are
4814 // conservative and just look for readonly sections with
4815 // relocations. If those sections wind up in writable segments,
4816 // then we have created an unnecessary DT_TEXTREL entry.
4817 for (Section_list::const_iterator p
= this->section_list_
.begin();
4818 p
!= this->section_list_
.end();
4821 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4822 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4823 && (*p
)->has_dynamic_reloc())
4825 have_textrel
= true;
4831 if (parameters
->options().filter() != NULL
)
4832 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
4833 if (parameters
->options().any_auxiliary())
4835 for (options::String_set::const_iterator p
=
4836 parameters
->options().auxiliary_begin();
4837 p
!= parameters
->options().auxiliary_end();
4839 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
4842 // Add a DT_FLAGS entry if necessary.
4843 unsigned int flags
= 0;
4846 // Add a DT_TEXTREL for compatibility with older loaders.
4847 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4848 flags
|= elfcpp::DF_TEXTREL
;
4850 if (parameters
->options().text())
4851 gold_error(_("read-only segment has dynamic relocations"));
4852 else if (parameters
->options().warn_shared_textrel()
4853 && parameters
->options().shared())
4854 gold_warning(_("shared library text segment is not shareable"));
4856 if (parameters
->options().shared() && this->has_static_tls())
4857 flags
|= elfcpp::DF_STATIC_TLS
;
4858 if (parameters
->options().origin())
4859 flags
|= elfcpp::DF_ORIGIN
;
4860 if (parameters
->options().Bsymbolic())
4862 flags
|= elfcpp::DF_SYMBOLIC
;
4863 // Add DT_SYMBOLIC for compatibility with older loaders.
4864 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4866 if (parameters
->options().now())
4867 flags
|= elfcpp::DF_BIND_NOW
;
4869 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4872 if (parameters
->options().initfirst())
4873 flags
|= elfcpp::DF_1_INITFIRST
;
4874 if (parameters
->options().interpose())
4875 flags
|= elfcpp::DF_1_INTERPOSE
;
4876 if (parameters
->options().loadfltr())
4877 flags
|= elfcpp::DF_1_LOADFLTR
;
4878 if (parameters
->options().nodefaultlib())
4879 flags
|= elfcpp::DF_1_NODEFLIB
;
4880 if (parameters
->options().nodelete())
4881 flags
|= elfcpp::DF_1_NODELETE
;
4882 if (parameters
->options().nodlopen())
4883 flags
|= elfcpp::DF_1_NOOPEN
;
4884 if (parameters
->options().nodump())
4885 flags
|= elfcpp::DF_1_NODUMP
;
4886 if (!parameters
->options().shared())
4887 flags
&= ~(elfcpp::DF_1_INITFIRST
4888 | elfcpp::DF_1_NODELETE
4889 | elfcpp::DF_1_NOOPEN
);
4890 if (parameters
->options().origin())
4891 flags
|= elfcpp::DF_1_ORIGIN
;
4892 if (parameters
->options().now())
4893 flags
|= elfcpp::DF_1_NOW
;
4894 if (parameters
->options().Bgroup())
4895 flags
|= elfcpp::DF_1_GROUP
;
4897 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4900 // Set the size of the _DYNAMIC symbol table to be the size of the
4904 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4906 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4909 odyn
->finalize_data_size();
4910 if (this->dynamic_symbol_
== NULL
)
4912 off_t data_size
= odyn
->data_size();
4913 const int size
= parameters
->target().get_size();
4915 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4916 else if (size
== 64)
4917 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4922 // The mapping of input section name prefixes to output section names.
4923 // In some cases one prefix is itself a prefix of another prefix; in
4924 // such a case the longer prefix must come first. These prefixes are
4925 // based on the GNU linker default ELF linker script.
4927 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4928 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4929 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4931 MAPPING_INIT(".text.", ".text"),
4932 MAPPING_INIT(".rodata.", ".rodata"),
4933 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4934 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4935 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4936 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4937 MAPPING_INIT(".data.", ".data"),
4938 MAPPING_INIT(".bss.", ".bss"),
4939 MAPPING_INIT(".tdata.", ".tdata"),
4940 MAPPING_INIT(".tbss.", ".tbss"),
4941 MAPPING_INIT(".init_array.", ".init_array"),
4942 MAPPING_INIT(".fini_array.", ".fini_array"),
4943 MAPPING_INIT(".sdata.", ".sdata"),
4944 MAPPING_INIT(".sbss.", ".sbss"),
4945 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4946 // differently depending on whether it is creating a shared library.
4947 MAPPING_INIT(".sdata2.", ".sdata"),
4948 MAPPING_INIT(".sbss2.", ".sbss"),
4949 MAPPING_INIT(".lrodata.", ".lrodata"),
4950 MAPPING_INIT(".ldata.", ".ldata"),
4951 MAPPING_INIT(".lbss.", ".lbss"),
4952 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4953 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4954 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4955 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4956 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4957 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4958 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4959 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4960 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4961 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4962 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4963 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4964 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4965 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4966 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4967 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4968 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4969 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4970 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4971 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4972 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4975 #undef MAPPING_INIT_EXACT
4977 const int Layout::section_name_mapping_count
=
4978 (sizeof(Layout::section_name_mapping
)
4979 / sizeof(Layout::section_name_mapping
[0]));
4981 // Choose the output section name to use given an input section name.
4982 // Set *PLEN to the length of the name. *PLEN is initialized to the
4986 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
4989 // gcc 4.3 generates the following sorts of section names when it
4990 // needs a section name specific to a function:
4996 // .data.rel.local.FN
4998 // .data.rel.ro.local.FN
5005 // The GNU linker maps all of those to the part before the .FN,
5006 // except that .data.rel.local.FN is mapped to .data, and
5007 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5008 // beginning with .data.rel.ro.local are grouped together.
5010 // For an anonymous namespace, the string FN can contain a '.'.
5012 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5013 // GNU linker maps to .rodata.
5015 // The .data.rel.ro sections are used with -z relro. The sections
5016 // are recognized by name. We use the same names that the GNU
5017 // linker does for these sections.
5019 // It is hard to handle this in a principled way, so we don't even
5020 // try. We use a table of mappings. If the input section name is
5021 // not found in the table, we simply use it as the output section
5024 const Section_name_mapping
* psnm
= section_name_mapping
;
5025 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
5027 if (psnm
->fromlen
> 0)
5029 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
5031 *plen
= psnm
->tolen
;
5037 if (strcmp(name
, psnm
->from
) == 0)
5039 *plen
= psnm
->tolen
;
5045 // As an additional complication, .ctors sections are output in
5046 // either .ctors or .init_array sections, and .dtors sections are
5047 // output in either .dtors or .fini_array sections.
5048 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
5050 if (parameters
->options().ctors_in_init_array())
5053 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5058 return name
[1] == 'c' ? ".ctors" : ".dtors";
5061 if (parameters
->options().ctors_in_init_array()
5062 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
5064 // To make .init_array/.fini_array work with gcc we must exclude
5065 // .ctors and .dtors sections from the crtbegin and crtend
5068 || (!Layout::match_file_name(relobj
, "crtbegin")
5069 && !Layout::match_file_name(relobj
, "crtend")))
5072 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5079 // Return true if RELOBJ is an input file whose base name matches
5080 // FILE_NAME. The base name must have an extension of ".o", and must
5081 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5082 // to match crtbegin.o as well as crtbeginS.o without getting confused
5083 // by other possibilities. Overall matching the file name this way is
5084 // a dreadful hack, but the GNU linker does it in order to better
5085 // support gcc, and we need to be compatible.
5088 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
5090 const std::string
& file_name(relobj
->name());
5091 const char* base_name
= lbasename(file_name
.c_str());
5092 size_t match_len
= strlen(match
);
5093 if (strncmp(base_name
, match
, match_len
) != 0)
5095 size_t base_len
= strlen(base_name
);
5096 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
5098 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
5101 // Check if a comdat group or .gnu.linkonce section with the given
5102 // NAME is selected for the link. If there is already a section,
5103 // *KEPT_SECTION is set to point to the existing section and the
5104 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5105 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5106 // *KEPT_SECTION is set to the internal copy and the function returns
5110 Layout::find_or_add_kept_section(const std::string
& name
,
5115 Kept_section
** kept_section
)
5117 // It's normal to see a couple of entries here, for the x86 thunk
5118 // sections. If we see more than a few, we're linking a C++
5119 // program, and we resize to get more space to minimize rehashing.
5120 if (this->signatures_
.size() > 4
5121 && !this->resized_signatures_
)
5123 reserve_unordered_map(&this->signatures_
,
5124 this->number_of_input_files_
* 64);
5125 this->resized_signatures_
= true;
5128 Kept_section candidate
;
5129 std::pair
<Signatures::iterator
, bool> ins
=
5130 this->signatures_
.insert(std::make_pair(name
, candidate
));
5132 if (kept_section
!= NULL
)
5133 *kept_section
= &ins
.first
->second
;
5136 // This is the first time we've seen this signature.
5137 ins
.first
->second
.set_object(object
);
5138 ins
.first
->second
.set_shndx(shndx
);
5140 ins
.first
->second
.set_is_comdat();
5142 ins
.first
->second
.set_is_group_name();
5146 // We have already seen this signature.
5148 if (ins
.first
->second
.is_group_name())
5150 // We've already seen a real section group with this signature.
5151 // If the kept group is from a plugin object, and we're in the
5152 // replacement phase, accept the new one as a replacement.
5153 if (ins
.first
->second
.object() == NULL
5154 && parameters
->options().plugins()->in_replacement_phase())
5156 ins
.first
->second
.set_object(object
);
5157 ins
.first
->second
.set_shndx(shndx
);
5162 else if (is_group_name
)
5164 // This is a real section group, and we've already seen a
5165 // linkonce section with this signature. Record that we've seen
5166 // a section group, and don't include this section group.
5167 ins
.first
->second
.set_is_group_name();
5172 // We've already seen a linkonce section and this is a linkonce
5173 // section. These don't block each other--this may be the same
5174 // symbol name with different section types.
5179 // Store the allocated sections into the section list.
5182 Layout::get_allocated_sections(Section_list
* section_list
) const
5184 for (Section_list::const_iterator p
= this->section_list_
.begin();
5185 p
!= this->section_list_
.end();
5187 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5188 section_list
->push_back(*p
);
5191 // Store the executable sections into the section list.
5194 Layout::get_executable_sections(Section_list
* section_list
) const
5196 for (Section_list::const_iterator p
= this->section_list_
.begin();
5197 p
!= this->section_list_
.end();
5199 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5200 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5201 section_list
->push_back(*p
);
5204 // Create an output segment.
5207 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5209 gold_assert(!parameters
->options().relocatable());
5210 Output_segment
* oseg
= new Output_segment(type
, flags
);
5211 this->segment_list_
.push_back(oseg
);
5213 if (type
== elfcpp::PT_TLS
)
5214 this->tls_segment_
= oseg
;
5215 else if (type
== elfcpp::PT_GNU_RELRO
)
5216 this->relro_segment_
= oseg
;
5217 else if (type
== elfcpp::PT_INTERP
)
5218 this->interp_segment_
= oseg
;
5223 // Return the file offset of the normal symbol table.
5226 Layout::symtab_section_offset() const
5228 if (this->symtab_section_
!= NULL
)
5229 return this->symtab_section_
->offset();
5233 // Return the section index of the normal symbol table. It may have
5234 // been stripped by the -s/--strip-all option.
5237 Layout::symtab_section_shndx() const
5239 if (this->symtab_section_
!= NULL
)
5240 return this->symtab_section_
->out_shndx();
5244 // Write out the Output_sections. Most won't have anything to write,
5245 // since most of the data will come from input sections which are
5246 // handled elsewhere. But some Output_sections do have Output_data.
5249 Layout::write_output_sections(Output_file
* of
) const
5251 for (Section_list::const_iterator p
= this->section_list_
.begin();
5252 p
!= this->section_list_
.end();
5255 if (!(*p
)->after_input_sections())
5260 // Write out data not associated with a section or the symbol table.
5263 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5265 if (!parameters
->options().strip_all())
5267 const Output_section
* symtab_section
= this->symtab_section_
;
5268 for (Section_list::const_iterator p
= this->section_list_
.begin();
5269 p
!= this->section_list_
.end();
5272 if ((*p
)->needs_symtab_index())
5274 gold_assert(symtab_section
!= NULL
);
5275 unsigned int index
= (*p
)->symtab_index();
5276 gold_assert(index
> 0 && index
!= -1U);
5277 off_t off
= (symtab_section
->offset()
5278 + index
* symtab_section
->entsize());
5279 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5284 const Output_section
* dynsym_section
= this->dynsym_section_
;
5285 for (Section_list::const_iterator p
= this->section_list_
.begin();
5286 p
!= this->section_list_
.end();
5289 if ((*p
)->needs_dynsym_index())
5291 gold_assert(dynsym_section
!= NULL
);
5292 unsigned int index
= (*p
)->dynsym_index();
5293 gold_assert(index
> 0 && index
!= -1U);
5294 off_t off
= (dynsym_section
->offset()
5295 + index
* dynsym_section
->entsize());
5296 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5300 // Write out the Output_data which are not in an Output_section.
5301 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5302 p
!= this->special_output_list_
.end();
5306 // Write out the Output_data which are not in an Output_section
5307 // and are regenerated in each iteration of relaxation.
5308 for (Data_list::const_iterator p
= this->relax_output_list_
.begin();
5309 p
!= this->relax_output_list_
.end();
5314 // Write out the Output_sections which can only be written after the
5315 // input sections are complete.
5318 Layout::write_sections_after_input_sections(Output_file
* of
)
5320 // Determine the final section offsets, and thus the final output
5321 // file size. Note we finalize the .shstrab last, to allow the
5322 // after_input_section sections to modify their section-names before
5324 if (this->any_postprocessing_sections_
)
5326 off_t off
= this->output_file_size_
;
5327 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5329 // Now that we've finalized the names, we can finalize the shstrab.
5331 this->set_section_offsets(off
,
5332 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5334 if (off
> this->output_file_size_
)
5337 this->output_file_size_
= off
;
5341 for (Section_list::const_iterator p
= this->section_list_
.begin();
5342 p
!= this->section_list_
.end();
5345 if ((*p
)->after_input_sections())
5349 this->section_headers_
->write(of
);
5352 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5353 // or as a "tree" where each chunk of the string is hashed and then those
5354 // hashes are put into a (much smaller) string which is hashed with sha1.
5355 // We compute a checksum over the entire file because that is simplest.
5358 Layout::queue_build_id_tasks(Workqueue
* workqueue
, Task_token
* build_id_blocker
,
5361 const size_t filesize
= (this->output_file_size() <= 0 ? 0
5362 : static_cast<size_t>(this->output_file_size()));
5363 if (this->build_id_note_
!= NULL
5364 && strcmp(parameters
->options().build_id(), "tree") == 0
5365 && parameters
->options().build_id_chunk_size_for_treehash() > 0
5368 parameters
->options().build_id_min_file_size_for_treehash()))
5370 static const size_t MD5_OUTPUT_SIZE_IN_BYTES
= 16;
5371 const size_t chunk_size
=
5372 parameters
->options().build_id_chunk_size_for_treehash();
5373 const size_t num_hashes
= ((filesize
- 1) / chunk_size
) + 1;
5374 Task_token
* post_hash_tasks_blocker
= new Task_token(true);
5375 post_hash_tasks_blocker
->add_blockers(num_hashes
);
5376 this->size_of_array_of_hashes_
= num_hashes
* MD5_OUTPUT_SIZE_IN_BYTES
;
5377 const unsigned char* src
= of
->get_input_view(0, filesize
);
5378 this->input_view_
= src
;
5379 unsigned char *dst
= new unsigned char[this->size_of_array_of_hashes_
];
5380 this->array_of_hashes_
= dst
;
5381 for (size_t i
= 0, src_offset
= 0; i
< num_hashes
;
5382 i
++, dst
+= MD5_OUTPUT_SIZE_IN_BYTES
, src_offset
+= chunk_size
)
5384 size_t size
= std::min(chunk_size
, filesize
- src_offset
);
5385 workqueue
->queue(new Hash_task(src
+ src_offset
,
5389 post_hash_tasks_blocker
));
5391 return post_hash_tasks_blocker
;
5393 return build_id_blocker
;
5396 // If a tree-style build ID was requested, the parallel part of that computation
5397 // is already done, and the final hash-of-hashes is computed here. For other
5398 // types of build IDs, all the work is done here.
5401 Layout::write_build_id(Output_file
* of
) const
5403 if (this->build_id_note_
== NULL
)
5406 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5407 this->build_id_note_
->data_size());
5409 if (this->array_of_hashes_
== NULL
)
5411 const size_t output_file_size
= this->output_file_size();
5412 const unsigned char* iv
= of
->get_input_view(0, output_file_size
);
5413 const char* style
= parameters
->options().build_id();
5415 // If we get here with style == "tree" then the output must be
5416 // too small for chunking, and we use SHA-1 in that case.
5417 if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
5418 sha1_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5419 else if (strcmp(style
, "md5") == 0)
5420 md5_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5424 of
->free_input_view(0, output_file_size
, iv
);
5428 // Non-overlapping substrings of the output file have been hashed.
5429 // Compute SHA-1 hash of the hashes.
5430 sha1_buffer(reinterpret_cast<const char*>(this->array_of_hashes_
),
5431 this->size_of_array_of_hashes_
, ov
);
5432 delete[] this->array_of_hashes_
;
5433 of
->free_input_view(0, this->output_file_size(), this->input_view_
);
5436 of
->write_output_view(this->build_id_note_
->offset(),
5437 this->build_id_note_
->data_size(),
5441 // Write out a binary file. This is called after the link is
5442 // complete. IN is the temporary output file we used to generate the
5443 // ELF code. We simply walk through the segments, read them from
5444 // their file offset in IN, and write them to their load address in
5445 // the output file. FIXME: with a bit more work, we could support
5446 // S-records and/or Intel hex format here.
5449 Layout::write_binary(Output_file
* in
) const
5451 gold_assert(parameters
->options().oformat_enum()
5452 == General_options::OBJECT_FORMAT_BINARY
);
5454 // Get the size of the binary file.
5455 uint64_t max_load_address
= 0;
5456 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5457 p
!= this->segment_list_
.end();
5460 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5462 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5463 if (max_paddr
> max_load_address
)
5464 max_load_address
= max_paddr
;
5468 Output_file
out(parameters
->options().output_file_name());
5469 out
.open(max_load_address
);
5471 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5472 p
!= this->segment_list_
.end();
5475 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5477 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5479 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5481 memcpy(vout
, vin
, (*p
)->filesz());
5482 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5483 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5490 // Print the output sections to the map file.
5493 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5495 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5496 p
!= this->segment_list_
.end();
5498 (*p
)->print_sections_to_mapfile(mapfile
);
5499 for (Section_list::const_iterator p
= this->unattached_section_list_
.begin();
5500 p
!= this->unattached_section_list_
.end();
5502 (*p
)->print_to_mapfile(mapfile
);
5505 // Print statistical information to stderr. This is used for --stats.
5508 Layout::print_stats() const
5510 this->namepool_
.print_stats("section name pool");
5511 this->sympool_
.print_stats("output symbol name pool");
5512 this->dynpool_
.print_stats("dynamic name pool");
5514 for (Section_list::const_iterator p
= this->section_list_
.begin();
5515 p
!= this->section_list_
.end();
5517 (*p
)->print_merge_stats();
5520 // Write_sections_task methods.
5522 // We can always run this task.
5525 Write_sections_task::is_runnable()
5530 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5534 Write_sections_task::locks(Task_locker
* tl
)
5536 tl
->add(this, this->output_sections_blocker_
);
5537 if (this->input_sections_blocker_
!= NULL
)
5538 tl
->add(this, this->input_sections_blocker_
);
5539 tl
->add(this, this->final_blocker_
);
5542 // Run the task--write out the data.
5545 Write_sections_task::run(Workqueue
*)
5547 this->layout_
->write_output_sections(this->of_
);
5550 // Write_data_task methods.
5552 // We can always run this task.
5555 Write_data_task::is_runnable()
5560 // We need to unlock FINAL_BLOCKER when finished.
5563 Write_data_task::locks(Task_locker
* tl
)
5565 tl
->add(this, this->final_blocker_
);
5568 // Run the task--write out the data.
5571 Write_data_task::run(Workqueue
*)
5573 this->layout_
->write_data(this->symtab_
, this->of_
);
5576 // Write_symbols_task methods.
5578 // We can always run this task.
5581 Write_symbols_task::is_runnable()
5586 // We need to unlock FINAL_BLOCKER when finished.
5589 Write_symbols_task::locks(Task_locker
* tl
)
5591 tl
->add(this, this->final_blocker_
);
5594 // Run the task--write out the symbols.
5597 Write_symbols_task::run(Workqueue
*)
5599 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
5600 this->layout_
->symtab_xindex(),
5601 this->layout_
->dynsym_xindex(), this->of_
);
5604 // Write_after_input_sections_task methods.
5606 // We can only run this task after the input sections have completed.
5609 Write_after_input_sections_task::is_runnable()
5611 if (this->input_sections_blocker_
->is_blocked())
5612 return this->input_sections_blocker_
;
5616 // We need to unlock FINAL_BLOCKER when finished.
5619 Write_after_input_sections_task::locks(Task_locker
* tl
)
5621 tl
->add(this, this->final_blocker_
);
5627 Write_after_input_sections_task::run(Workqueue
*)
5629 this->layout_
->write_sections_after_input_sections(this->of_
);
5632 // Close_task_runner methods.
5634 // Finish up the build ID computation, if necessary, and write a binary file,
5635 // if necessary. Then close the output file.
5638 Close_task_runner::run(Workqueue
*, const Task
*)
5640 // At this point the multi-threaded part of the build ID computation,
5641 // if any, is done. See queue_build_id_tasks().
5642 this->layout_
->write_build_id(this->of_
);
5644 // If we've been asked to create a binary file, we do so here.
5645 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
5646 this->layout_
->write_binary(this->of_
);
5651 // Instantiate the templates we need. We could use the configure
5652 // script to restrict this to only the ones for implemented targets.
5654 #ifdef HAVE_TARGET_32_LITTLE
5657 Layout::init_fixed_output_section
<32, false>(
5659 elfcpp::Shdr
<32, false>& shdr
);
5662 #ifdef HAVE_TARGET_32_BIG
5665 Layout::init_fixed_output_section
<32, true>(
5667 elfcpp::Shdr
<32, true>& shdr
);
5670 #ifdef HAVE_TARGET_64_LITTLE
5673 Layout::init_fixed_output_section
<64, false>(
5675 elfcpp::Shdr
<64, false>& shdr
);
5678 #ifdef HAVE_TARGET_64_BIG
5681 Layout::init_fixed_output_section
<64, true>(
5683 elfcpp::Shdr
<64, true>& shdr
);
5686 #ifdef HAVE_TARGET_32_LITTLE
5689 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
5692 const elfcpp::Shdr
<32, false>& shdr
,
5693 unsigned int, unsigned int, off_t
*);
5696 #ifdef HAVE_TARGET_32_BIG
5699 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
5702 const elfcpp::Shdr
<32, true>& shdr
,
5703 unsigned int, unsigned int, off_t
*);
5706 #ifdef HAVE_TARGET_64_LITTLE
5709 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
5712 const elfcpp::Shdr
<64, false>& shdr
,
5713 unsigned int, unsigned int, off_t
*);
5716 #ifdef HAVE_TARGET_64_BIG
5719 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
5722 const elfcpp::Shdr
<64, true>& shdr
,
5723 unsigned int, unsigned int, off_t
*);
5726 #ifdef HAVE_TARGET_32_LITTLE
5729 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
5730 unsigned int reloc_shndx
,
5731 const elfcpp::Shdr
<32, false>& shdr
,
5732 Output_section
* data_section
,
5733 Relocatable_relocs
* rr
);
5736 #ifdef HAVE_TARGET_32_BIG
5739 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
5740 unsigned int reloc_shndx
,
5741 const elfcpp::Shdr
<32, true>& shdr
,
5742 Output_section
* data_section
,
5743 Relocatable_relocs
* rr
);
5746 #ifdef HAVE_TARGET_64_LITTLE
5749 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
5750 unsigned int reloc_shndx
,
5751 const elfcpp::Shdr
<64, false>& shdr
,
5752 Output_section
* data_section
,
5753 Relocatable_relocs
* rr
);
5756 #ifdef HAVE_TARGET_64_BIG
5759 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
5760 unsigned int reloc_shndx
,
5761 const elfcpp::Shdr
<64, true>& shdr
,
5762 Output_section
* data_section
,
5763 Relocatable_relocs
* rr
);
5766 #ifdef HAVE_TARGET_32_LITTLE
5769 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
5770 Sized_relobj_file
<32, false>* object
,
5772 const char* group_section_name
,
5773 const char* signature
,
5774 const elfcpp::Shdr
<32, false>& shdr
,
5775 elfcpp::Elf_Word flags
,
5776 std::vector
<unsigned int>* shndxes
);
5779 #ifdef HAVE_TARGET_32_BIG
5782 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
5783 Sized_relobj_file
<32, true>* object
,
5785 const char* group_section_name
,
5786 const char* signature
,
5787 const elfcpp::Shdr
<32, true>& shdr
,
5788 elfcpp::Elf_Word flags
,
5789 std::vector
<unsigned int>* shndxes
);
5792 #ifdef HAVE_TARGET_64_LITTLE
5795 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
5796 Sized_relobj_file
<64, false>* object
,
5798 const char* group_section_name
,
5799 const char* signature
,
5800 const elfcpp::Shdr
<64, false>& shdr
,
5801 elfcpp::Elf_Word flags
,
5802 std::vector
<unsigned int>* shndxes
);
5805 #ifdef HAVE_TARGET_64_BIG
5808 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
5809 Sized_relobj_file
<64, true>* object
,
5811 const char* group_section_name
,
5812 const char* signature
,
5813 const elfcpp::Shdr
<64, true>& shdr
,
5814 elfcpp::Elf_Word flags
,
5815 std::vector
<unsigned int>* shndxes
);
5818 #ifdef HAVE_TARGET_32_LITTLE
5821 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
5822 const unsigned char* symbols
,
5824 const unsigned char* symbol_names
,
5825 off_t symbol_names_size
,
5827 const elfcpp::Shdr
<32, false>& shdr
,
5828 unsigned int reloc_shndx
,
5829 unsigned int reloc_type
,
5833 #ifdef HAVE_TARGET_32_BIG
5836 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
5837 const unsigned char* symbols
,
5839 const unsigned char* symbol_names
,
5840 off_t symbol_names_size
,
5842 const elfcpp::Shdr
<32, true>& shdr
,
5843 unsigned int reloc_shndx
,
5844 unsigned int reloc_type
,
5848 #ifdef HAVE_TARGET_64_LITTLE
5851 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
5852 const unsigned char* symbols
,
5854 const unsigned char* symbol_names
,
5855 off_t symbol_names_size
,
5857 const elfcpp::Shdr
<64, false>& shdr
,
5858 unsigned int reloc_shndx
,
5859 unsigned int reloc_type
,
5863 #ifdef HAVE_TARGET_64_BIG
5866 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
5867 const unsigned char* symbols
,
5869 const unsigned char* symbol_names
,
5870 off_t symbol_names_size
,
5872 const elfcpp::Shdr
<64, true>& shdr
,
5873 unsigned int reloc_shndx
,
5874 unsigned int reloc_type
,
5878 #ifdef HAVE_TARGET_32_LITTLE
5881 Layout::add_to_gdb_index(bool is_type_unit
,
5882 Sized_relobj
<32, false>* object
,
5883 const unsigned char* symbols
,
5886 unsigned int reloc_shndx
,
5887 unsigned int reloc_type
);
5890 #ifdef HAVE_TARGET_32_BIG
5893 Layout::add_to_gdb_index(bool is_type_unit
,
5894 Sized_relobj
<32, true>* object
,
5895 const unsigned char* symbols
,
5898 unsigned int reloc_shndx
,
5899 unsigned int reloc_type
);
5902 #ifdef HAVE_TARGET_64_LITTLE
5905 Layout::add_to_gdb_index(bool is_type_unit
,
5906 Sized_relobj
<64, false>* object
,
5907 const unsigned char* symbols
,
5910 unsigned int reloc_shndx
,
5911 unsigned int reloc_type
);
5914 #ifdef HAVE_TARGET_64_BIG
5917 Layout::add_to_gdb_index(bool is_type_unit
,
5918 Sized_relobj
<64, true>* object
,
5919 const unsigned char* symbols
,
5922 unsigned int reloc_shndx
,
5923 unsigned int reloc_type
);
5926 } // End namespace gold.