1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
7 // This file is part of gold.
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
35 #include "libiberty.h"
39 #include "parameters.h"
43 #include "script-sections.h"
48 #include "gdb-index.h"
49 #include "compressed_output.h"
50 #include "reduced_debug_output.h"
53 #include "descriptors.h"
55 #include "incremental.h"
63 // The total number of free lists used.
64 unsigned int Free_list::num_lists
= 0;
65 // The total number of free list nodes used.
66 unsigned int Free_list::num_nodes
= 0;
67 // The total number of calls to Free_list::remove.
68 unsigned int Free_list::num_removes
= 0;
69 // The total number of nodes visited during calls to Free_list::remove.
70 unsigned int Free_list::num_remove_visits
= 0;
71 // The total number of calls to Free_list::allocate.
72 unsigned int Free_list::num_allocates
= 0;
73 // The total number of nodes visited during calls to Free_list::allocate.
74 unsigned int Free_list::num_allocate_visits
= 0;
76 // Initialize the free list. Creates a single free list node that
77 // describes the entire region of length LEN. If EXTEND is true,
78 // allocate() is allowed to extend the region beyond its initial
82 Free_list::init(off_t len
, bool extend
)
84 this->list_
.push_front(Free_list_node(0, len
));
85 this->last_remove_
= this->list_
.begin();
86 this->extend_
= extend
;
88 ++Free_list::num_lists
;
89 ++Free_list::num_nodes
;
92 // Remove a chunk from the free list. Because we start with a single
93 // node that covers the entire section, and remove chunks from it one
94 // at a time, we do not need to coalesce chunks or handle cases that
95 // span more than one free node. We expect to remove chunks from the
96 // free list in order, and we expect to have only a few chunks of free
97 // space left (corresponding to files that have changed since the last
98 // incremental link), so a simple linear list should provide sufficient
102 Free_list::remove(off_t start
, off_t end
)
106 gold_assert(start
< end
);
108 ++Free_list::num_removes
;
110 Iterator p
= this->last_remove_
;
111 if (p
->start_
> start
)
112 p
= this->list_
.begin();
114 for (; p
!= this->list_
.end(); ++p
)
116 ++Free_list::num_remove_visits
;
117 // Find a node that wholly contains the indicated region.
118 if (p
->start_
<= start
&& p
->end_
>= end
)
120 // Case 1: the indicated region spans the whole node.
121 // Add some fuzz to avoid creating tiny free chunks.
122 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
123 p
= this->list_
.erase(p
);
124 // Case 2: remove a chunk from the start of the node.
125 else if (p
->start_
+ 3 >= start
)
127 // Case 3: remove a chunk from the end of the node.
128 else if (p
->end_
<= end
+ 3)
130 // Case 4: remove a chunk from the middle, and split
131 // the node into two.
134 Free_list_node
newnode(p
->start_
, start
);
136 this->list_
.insert(p
, newnode
);
137 ++Free_list::num_nodes
;
139 this->last_remove_
= p
;
144 // Did not find a node containing the given chunk. This could happen
145 // because a small chunk was already removed due to the fuzz.
146 gold_debug(DEBUG_INCREMENTAL
,
147 "Free_list::remove(%d,%d) not found",
148 static_cast<int>(start
), static_cast<int>(end
));
151 // Allocate a chunk of size LEN from the free list. Returns -1ULL
152 // if a sufficiently large chunk of free space is not found.
153 // We use a simple first-fit algorithm.
156 Free_list::allocate(off_t len
, uint64_t align
, off_t minoff
)
158 gold_debug(DEBUG_INCREMENTAL
,
159 "Free_list::allocate(%08lx, %d, %08lx)",
160 static_cast<long>(len
), static_cast<int>(align
),
161 static_cast<long>(minoff
));
163 return align_address(minoff
, align
);
165 ++Free_list::num_allocates
;
167 // We usually want to drop free chunks smaller than 4 bytes.
168 // If we need to guarantee a minimum hole size, though, we need
169 // to keep track of all free chunks.
170 const int fuzz
= this->min_hole_
> 0 ? 0 : 3;
172 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
174 ++Free_list::num_allocate_visits
;
175 off_t start
= p
->start_
> minoff
? p
->start_
: minoff
;
176 start
= align_address(start
, align
);
177 off_t end
= start
+ len
;
178 if (end
> p
->end_
&& p
->end_
== this->length_
&& this->extend_
)
183 if (end
== p
->end_
|| (end
<= p
->end_
- this->min_hole_
))
185 if (p
->start_
+ fuzz
>= start
&& p
->end_
<= end
+ fuzz
)
186 this->list_
.erase(p
);
187 else if (p
->start_
+ fuzz
>= start
)
189 else if (p
->end_
<= end
+ fuzz
)
193 Free_list_node
newnode(p
->start_
, start
);
195 this->list_
.insert(p
, newnode
);
196 ++Free_list::num_nodes
;
203 off_t start
= align_address(this->length_
, align
);
204 this->length_
= start
+ len
;
210 // Dump the free list (for debugging).
214 gold_info("Free list:\n start end length\n");
215 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
216 gold_info(" %08lx %08lx %08lx", static_cast<long>(p
->start_
),
217 static_cast<long>(p
->end_
),
218 static_cast<long>(p
->end_
- p
->start_
));
221 // Print the statistics for the free lists.
223 Free_list::print_stats()
225 fprintf(stderr
, _("%s: total free lists: %u\n"),
226 program_name
, Free_list::num_lists
);
227 fprintf(stderr
, _("%s: total free list nodes: %u\n"),
228 program_name
, Free_list::num_nodes
);
229 fprintf(stderr
, _("%s: calls to Free_list::remove: %u\n"),
230 program_name
, Free_list::num_removes
);
231 fprintf(stderr
, _("%s: nodes visited: %u\n"),
232 program_name
, Free_list::num_remove_visits
);
233 fprintf(stderr
, _("%s: calls to Free_list::allocate: %u\n"),
234 program_name
, Free_list::num_allocates
);
235 fprintf(stderr
, _("%s: nodes visited: %u\n"),
236 program_name
, Free_list::num_allocate_visits
);
239 // A Hash_task computes the MD5 checksum of an array of char.
240 // It has a blocker on either side (i.e., the task cannot run until
241 // the first is unblocked, and it unblocks the second after running).
243 class Hash_task
: public Task
246 Hash_task(const unsigned char* src
,
249 Task_token
* build_id_blocker
,
250 Task_token
* final_blocker
)
251 : src_(src
), size_(size
), dst_(dst
), build_id_blocker_(build_id_blocker
),
252 final_blocker_(final_blocker
)
257 { md5_buffer(reinterpret_cast<const char*>(src_
), size_
, dst_
); }
262 // Unblock FINAL_BLOCKER_ when done.
264 locks(Task_locker
* tl
)
265 { tl
->add(this, this->final_blocker_
); }
269 { return "Hash_task"; }
272 const unsigned char* const src_
;
274 unsigned char* const dst_
;
275 Task_token
* const build_id_blocker_
;
276 Task_token
* const final_blocker_
;
280 Hash_task::is_runnable()
282 if (this->build_id_blocker_
->is_blocked())
283 return this->build_id_blocker_
;
287 // Layout::Relaxation_debug_check methods.
289 // Check that sections and special data are in reset states.
290 // We do not save states for Output_sections and special Output_data.
291 // So we check that they have not assigned any addresses or offsets.
292 // clean_up_after_relaxation simply resets their addresses and offsets.
294 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
295 const Layout::Section_list
& sections
,
296 const Layout::Data_list
& special_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());
309 // Save information of SECTIONS for checking later.
312 Layout::Relaxation_debug_check::read_sections(
313 const Layout::Section_list
& sections
)
315 for(Layout::Section_list::const_iterator p
= sections
.begin();
319 Output_section
* os
= *p
;
321 info
.output_section
= os
;
322 info
.address
= os
->is_address_valid() ? os
->address() : 0;
323 info
.data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
324 info
.offset
= os
->is_offset_valid()? os
->offset() : -1 ;
325 this->section_infos_
.push_back(info
);
329 // Verify SECTIONS using previously recorded information.
332 Layout::Relaxation_debug_check::verify_sections(
333 const Layout::Section_list
& sections
)
336 for(Layout::Section_list::const_iterator p
= sections
.begin();
340 Output_section
* os
= *p
;
341 uint64_t address
= os
->is_address_valid() ? os
->address() : 0;
342 off_t data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
343 off_t offset
= os
->is_offset_valid()? os
->offset() : -1 ;
345 if (i
>= this->section_infos_
.size())
347 gold_fatal("Section_info of %s missing.\n", os
->name());
349 const Section_info
& info
= this->section_infos_
[i
];
350 if (os
!= info
.output_section
)
351 gold_fatal("Section order changed. Expecting %s but see %s\n",
352 info
.output_section
->name(), os
->name());
353 if (address
!= info
.address
354 || data_size
!= info
.data_size
355 || offset
!= info
.offset
)
356 gold_fatal("Section %s changed.\n", os
->name());
360 // Layout_task_runner methods.
362 // Lay out the sections. This is called after all the input objects
366 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
368 // See if any of the input definitions violate the One Definition Rule.
369 // TODO: if this is too slow, do this as a task, rather than inline.
370 this->symtab_
->detect_odr_violations(task
, this->options_
.output_file_name());
372 Layout
* layout
= this->layout_
;
373 off_t file_size
= layout
->finalize(this->input_objects_
,
378 // Now we know the final size of the output file and we know where
379 // each piece of information goes.
381 if (this->mapfile_
!= NULL
)
383 this->mapfile_
->print_discarded_sections(this->input_objects_
);
384 layout
->print_to_mapfile(this->mapfile_
);
388 if (layout
->incremental_base() == NULL
)
390 of
= new Output_file(parameters
->options().output_file_name());
391 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
392 of
->set_is_temporary();
397 of
= layout
->incremental_base()->output_file();
399 // Apply the incremental relocations for symbols whose values
400 // have changed. We do this before we resize the file and start
401 // writing anything else to it, so that we can read the old
402 // incremental information from the file before (possibly)
404 if (parameters
->incremental_update())
405 layout
->incremental_base()->apply_incremental_relocs(this->symtab_
,
409 of
->resize(file_size
);
412 // Queue up the final set of tasks.
413 gold::queue_final_tasks(this->options_
, this->input_objects_
,
414 this->symtab_
, layout
, workqueue
, of
);
419 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
420 : number_of_input_files_(number_of_input_files
),
421 script_options_(script_options
),
429 unattached_section_list_(),
430 special_output_list_(),
431 section_headers_(NULL
),
433 relro_segment_(NULL
),
434 interp_segment_(NULL
),
436 symtab_section_(NULL
),
437 symtab_xindex_(NULL
),
438 dynsym_section_(NULL
),
439 dynsym_xindex_(NULL
),
440 dynamic_section_(NULL
),
441 dynamic_symbol_(NULL
),
443 eh_frame_section_(NULL
),
444 eh_frame_data_(NULL
),
445 added_eh_frame_data_(false),
446 eh_frame_hdr_section_(NULL
),
447 gdb_index_data_(NULL
),
448 build_id_note_(NULL
),
449 array_of_hashes_(NULL
),
450 size_of_array_of_hashes_(0),
455 output_file_size_(-1),
456 have_added_input_section_(false),
457 sections_are_attached_(false),
458 input_requires_executable_stack_(false),
459 input_with_gnu_stack_note_(false),
460 input_without_gnu_stack_note_(false),
461 has_static_tls_(false),
462 any_postprocessing_sections_(false),
463 resized_signatures_(false),
464 have_stabstr_section_(false),
465 section_ordering_specified_(false),
466 unique_segment_for_sections_specified_(false),
467 incremental_inputs_(NULL
),
468 record_output_section_data_from_script_(false),
469 script_output_section_data_list_(),
470 segment_states_(NULL
),
471 relaxation_debug_check_(NULL
),
472 section_order_map_(),
473 section_segment_map_(),
474 input_section_position_(),
475 input_section_glob_(),
476 incremental_base_(NULL
),
479 // Make space for more than enough segments for a typical file.
480 // This is just for efficiency--it's OK if we wind up needing more.
481 this->segment_list_
.reserve(12);
483 // We expect two unattached Output_data objects: the file header and
484 // the segment headers.
485 this->special_output_list_
.reserve(2);
487 // Initialize structure needed for an incremental build.
488 if (parameters
->incremental())
489 this->incremental_inputs_
= new Incremental_inputs
;
491 // The section name pool is worth optimizing in all cases, because
492 // it is small, but there are often overlaps due to .rel sections.
493 this->namepool_
.set_optimize();
496 // For incremental links, record the base file to be modified.
499 Layout::set_incremental_base(Incremental_binary
* base
)
501 this->incremental_base_
= base
;
502 this->free_list_
.init(base
->output_file()->filesize(), true);
505 // Hash a key we use to look up an output section mapping.
508 Layout::Hash_key::operator()(const Layout::Key
& k
) const
510 return k
.first
+ k
.second
.first
+ k
.second
.second
;
513 // These are the debug sections that are actually used by gdb.
514 // Currently, we've checked versions of gdb up to and including 7.4.
515 // We only check the part of the name that follows ".debug_" or
518 static const char* gdb_sections
[] =
521 "addr", // Fission extension
522 // "aranges", // not used by gdb as of 7.4
530 // "pubnames", // not used by gdb as of 7.4
531 // "pubtypes", // not used by gdb as of 7.4
536 // This is the minimum set of sections needed for line numbers.
538 static const char* lines_only_debug_sections
[] =
541 // "addr", // Fission extension
542 // "aranges", // not used by gdb as of 7.4
550 // "pubnames", // not used by gdb as of 7.4
551 // "pubtypes", // not used by gdb as of 7.4
556 // These sections are the DWARF fast-lookup tables, and are not needed
557 // when building a .gdb_index section.
559 static const char* gdb_fast_lookup_sections
[] =
566 // Returns whether the given debug section is in the list of
567 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
568 // portion of the name following ".debug_" or ".zdebug_".
571 is_gdb_debug_section(const char* suffix
)
573 // We can do this faster: binary search or a hashtable. But why bother?
574 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
575 if (strcmp(suffix
, gdb_sections
[i
]) == 0)
580 // Returns whether the given section is needed for lines-only debugging.
583 is_lines_only_debug_section(const char* suffix
)
585 // We can do this faster: binary search or a hashtable. But why bother?
587 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
589 if (strcmp(suffix
, lines_only_debug_sections
[i
]) == 0)
594 // Returns whether the given section is a fast-lookup section that
595 // will not be needed when building a .gdb_index section.
598 is_gdb_fast_lookup_section(const char* suffix
)
600 // We can do this faster: binary search or a hashtable. But why bother?
602 i
< sizeof(gdb_fast_lookup_sections
)/sizeof(*gdb_fast_lookup_sections
);
604 if (strcmp(suffix
, gdb_fast_lookup_sections
[i
]) == 0)
609 // Sometimes we compress sections. This is typically done for
610 // sections that are not part of normal program execution (such as
611 // .debug_* sections), and where the readers of these sections know
612 // how to deal with compressed sections. This routine doesn't say for
613 // certain whether we'll compress -- it depends on commandline options
614 // as well -- just whether this section is a candidate for compression.
615 // (The Output_compressed_section class decides whether to compress
616 // a given section, and picks the name of the compressed section.)
619 is_compressible_debug_section(const char* secname
)
621 return (is_prefix_of(".debug", secname
));
624 // We may see compressed debug sections in input files. Return TRUE
625 // if this is the name of a compressed debug section.
628 is_compressed_debug_section(const char* secname
)
630 return (is_prefix_of(".zdebug", secname
));
633 // Whether to include this section in the link.
635 template<int size
, bool big_endian
>
637 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
638 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
640 if (!parameters
->options().relocatable()
641 && (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
))
644 switch (shdr
.get_sh_type())
646 case elfcpp::SHT_NULL
:
647 case elfcpp::SHT_SYMTAB
:
648 case elfcpp::SHT_DYNSYM
:
649 case elfcpp::SHT_HASH
:
650 case elfcpp::SHT_DYNAMIC
:
651 case elfcpp::SHT_SYMTAB_SHNDX
:
654 case elfcpp::SHT_STRTAB
:
655 // Discard the sections which have special meanings in the ELF
656 // ABI. Keep others (e.g., .stabstr). We could also do this by
657 // checking the sh_link fields of the appropriate sections.
658 return (strcmp(name
, ".dynstr") != 0
659 && strcmp(name
, ".strtab") != 0
660 && strcmp(name
, ".shstrtab") != 0);
662 case elfcpp::SHT_RELA
:
663 case elfcpp::SHT_REL
:
664 case elfcpp::SHT_GROUP
:
665 // If we are emitting relocations these should be handled
667 gold_assert(!parameters
->options().relocatable());
670 case elfcpp::SHT_PROGBITS
:
671 if (parameters
->options().strip_debug()
672 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
674 if (is_debug_info_section(name
))
677 if (parameters
->options().strip_debug_non_line()
678 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
680 // Debugging sections can only be recognized by name.
681 if (is_prefix_of(".debug_", name
)
682 && !is_lines_only_debug_section(name
+ 7))
684 if (is_prefix_of(".zdebug_", name
)
685 && !is_lines_only_debug_section(name
+ 8))
688 if (parameters
->options().strip_debug_gdb()
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_gdb_debug_section(name
+ 7))
695 if (is_prefix_of(".zdebug_", name
)
696 && !is_gdb_debug_section(name
+ 8))
699 if (parameters
->options().gdb_index()
700 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
702 // When building .gdb_index, we can strip .debug_pubnames,
703 // .debug_pubtypes, and .debug_aranges sections.
704 if (is_prefix_of(".debug_", name
)
705 && is_gdb_fast_lookup_section(name
+ 7))
707 if (is_prefix_of(".zdebug_", name
)
708 && is_gdb_fast_lookup_section(name
+ 8))
711 if (parameters
->options().strip_lto_sections()
712 && !parameters
->options().relocatable()
713 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
715 // Ignore LTO sections containing intermediate code.
716 if (is_prefix_of(".gnu.lto_", name
))
719 // The GNU linker strips .gnu_debuglink sections, so we do too.
720 // This is a feature used to keep debugging information in
722 if (strcmp(name
, ".gnu_debuglink") == 0)
731 // Return an output section named NAME, or NULL if there is none.
734 Layout::find_output_section(const char* name
) const
736 for (Section_list::const_iterator p
= this->section_list_
.begin();
737 p
!= this->section_list_
.end();
739 if (strcmp((*p
)->name(), name
) == 0)
744 // Return an output segment of type TYPE, with segment flags SET set
745 // and segment flags CLEAR clear. Return NULL if there is none.
748 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
749 elfcpp::Elf_Word clear
) const
751 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
752 p
!= this->segment_list_
.end();
754 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
755 && ((*p
)->flags() & set
) == set
756 && ((*p
)->flags() & clear
) == 0)
761 // When we put a .ctors or .dtors section with more than one word into
762 // a .init_array or .fini_array section, we need to reverse the words
763 // in the .ctors/.dtors section. This is because .init_array executes
764 // constructors front to back, where .ctors executes them back to
765 // front, and vice-versa for .fini_array/.dtors. Although we do want
766 // to remap .ctors/.dtors into .init_array/.fini_array because it can
767 // be more efficient, we don't want to change the order in which
768 // constructors/destructors are run. This set just keeps track of
769 // these sections which need to be reversed. It is only changed by
770 // Layout::layout. It should be a private member of Layout, but that
771 // would require layout.h to #include object.h to get the definition
773 static Unordered_set
<Section_id
, Section_id_hash
> ctors_sections_in_init_array
;
775 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
776 // .init_array/.fini_array section.
779 Layout::is_ctors_in_init_array(Relobj
* relobj
, unsigned int shndx
) const
781 return (ctors_sections_in_init_array
.find(Section_id(relobj
, shndx
))
782 != ctors_sections_in_init_array
.end());
785 // Return the output section to use for section NAME with type TYPE
786 // and section flags FLAGS. NAME must be canonicalized in the string
787 // pool, and NAME_KEY is the key. ORDER is where this should appear
788 // in the output sections. IS_RELRO is true for a relro section.
791 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
792 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
793 Output_section_order order
, bool is_relro
)
795 elfcpp::Elf_Word lookup_type
= type
;
797 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
798 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
799 // .init_array, .fini_array, and .preinit_array sections by name
800 // whatever their type in the input file. We do this because the
801 // types are not always right in the input files.
802 if (lookup_type
== elfcpp::SHT_INIT_ARRAY
803 || lookup_type
== elfcpp::SHT_FINI_ARRAY
804 || lookup_type
== elfcpp::SHT_PREINIT_ARRAY
)
805 lookup_type
= elfcpp::SHT_PROGBITS
;
807 elfcpp::Elf_Xword lookup_flags
= flags
;
809 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
810 // read-write with read-only sections. Some other ELF linkers do
811 // not do this. FIXME: Perhaps there should be an option
813 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
815 const Key
key(name_key
, std::make_pair(lookup_type
, lookup_flags
));
816 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
817 std::pair
<Section_name_map::iterator
, bool> ins(
818 this->section_name_map_
.insert(v
));
821 return ins
.first
->second
;
824 // This is the first time we've seen this name/type/flags
825 // combination. For compatibility with the GNU linker, we
826 // combine sections with contents and zero flags with sections
827 // with non-zero flags. This is a workaround for cases where
828 // assembler code forgets to set section flags. FIXME: Perhaps
829 // there should be an option to control this.
830 Output_section
* os
= NULL
;
832 if (lookup_type
== elfcpp::SHT_PROGBITS
)
836 Output_section
* same_name
= this->find_output_section(name
);
837 if (same_name
!= NULL
838 && (same_name
->type() == elfcpp::SHT_PROGBITS
839 || same_name
->type() == elfcpp::SHT_INIT_ARRAY
840 || same_name
->type() == elfcpp::SHT_FINI_ARRAY
841 || same_name
->type() == elfcpp::SHT_PREINIT_ARRAY
)
842 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
845 else if ((flags
& elfcpp::SHF_TLS
) == 0)
847 elfcpp::Elf_Xword zero_flags
= 0;
848 const Key
zero_key(name_key
, std::make_pair(lookup_type
,
850 Section_name_map::iterator p
=
851 this->section_name_map_
.find(zero_key
);
852 if (p
!= this->section_name_map_
.end())
858 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
860 ins
.first
->second
= os
;
865 // Returns TRUE iff NAME (an input section from RELOBJ) will
866 // be mapped to an output section that should be KEPT.
869 Layout::keep_input_section(const Relobj
* relobj
, const char* name
)
871 if (! this->script_options_
->saw_sections_clause())
874 Script_sections
* ss
= this->script_options_
->script_sections();
875 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
876 Output_section
** output_section_slot
;
877 Script_sections::Section_type script_section_type
;
880 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
881 &script_section_type
, &keep
);
882 return name
!= NULL
&& keep
;
885 // Clear the input section flags that should not be copied to the
889 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags
)
891 // Some flags in the input section should not be automatically
892 // copied to the output section.
893 input_section_flags
&= ~ (elfcpp::SHF_INFO_LINK
896 | elfcpp::SHF_STRINGS
);
898 // We only clear the SHF_LINK_ORDER flag in for
899 // a non-relocatable link.
900 if (!parameters
->options().relocatable())
901 input_section_flags
&= ~elfcpp::SHF_LINK_ORDER
;
903 return input_section_flags
;
906 // Pick the output section to use for section NAME, in input file
907 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
908 // linker created section. IS_INPUT_SECTION is true if we are
909 // choosing an output section for an input section found in a input
910 // file. ORDER is where this section should appear in the output
911 // sections. IS_RELRO is true for a relro section. This will return
912 // NULL if the input section should be discarded.
915 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
916 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
917 bool is_input_section
, Output_section_order order
,
920 // We should not see any input sections after we have attached
921 // sections to segments.
922 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
924 flags
= this->get_output_section_flags(flags
);
926 if (this->script_options_
->saw_sections_clause())
928 // We are using a SECTIONS clause, so the output section is
929 // chosen based only on the name.
931 Script_sections
* ss
= this->script_options_
->script_sections();
932 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
933 Output_section
** output_section_slot
;
934 Script_sections::Section_type script_section_type
;
935 const char* orig_name
= name
;
937 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
938 &script_section_type
, &keep
);
942 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
943 "because it is not allowed by the "
944 "SECTIONS clause of the linker script"),
946 // The SECTIONS clause says to discard this input section.
950 // We can only handle script section types ST_NONE and ST_NOLOAD.
951 switch (script_section_type
)
953 case Script_sections::ST_NONE
:
955 case Script_sections::ST_NOLOAD
:
956 flags
&= elfcpp::SHF_ALLOC
;
962 // If this is an orphan section--one not mentioned in the linker
963 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
964 // default processing below.
966 if (output_section_slot
!= NULL
)
968 if (*output_section_slot
!= NULL
)
970 (*output_section_slot
)->update_flags_for_input_section(flags
);
971 return *output_section_slot
;
974 // We don't put sections found in the linker script into
975 // SECTION_NAME_MAP_. That keeps us from getting confused
976 // if an orphan section is mapped to a section with the same
977 // name as one in the linker script.
979 name
= this->namepool_
.add(name
, false, NULL
);
981 Output_section
* os
= this->make_output_section(name
, type
, flags
,
984 os
->set_found_in_sections_clause();
986 // Special handling for NOLOAD sections.
987 if (script_section_type
== Script_sections::ST_NOLOAD
)
991 // The constructor of Output_section sets addresses of non-ALLOC
992 // sections to 0 by default. We don't want that for NOLOAD
993 // sections even if they have no SHF_ALLOC flag.
994 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
995 && os
->is_address_valid())
997 gold_assert(os
->address() == 0
998 && !os
->is_offset_valid()
999 && !os
->is_data_size_valid());
1000 os
->reset_address_and_file_offset();
1004 *output_section_slot
= os
;
1009 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1011 size_t len
= strlen(name
);
1012 char* uncompressed_name
= NULL
;
1014 // Compressed debug sections should be mapped to the corresponding
1015 // uncompressed section.
1016 if (is_compressed_debug_section(name
))
1018 uncompressed_name
= new char[len
];
1019 uncompressed_name
[0] = '.';
1020 gold_assert(name
[0] == '.' && name
[1] == 'z');
1021 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
1022 uncompressed_name
[len
- 1] = '\0';
1024 name
= uncompressed_name
;
1027 // Turn NAME from the name of the input section into the name of the
1029 if (is_input_section
1030 && !this->script_options_
->saw_sections_clause()
1031 && !parameters
->options().relocatable())
1033 const char *orig_name
= name
;
1034 name
= parameters
->target().output_section_name(relobj
, name
, &len
);
1036 name
= Layout::output_section_name(relobj
, orig_name
, &len
);
1039 Stringpool::Key name_key
;
1040 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
1042 if (uncompressed_name
!= NULL
)
1043 delete[] uncompressed_name
;
1045 // Find or make the output section. The output section is selected
1046 // based on the section name, type, and flags.
1047 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
1050 // For incremental links, record the initial fixed layout of a section
1051 // from the base file, and return a pointer to the Output_section.
1053 template<int size
, bool big_endian
>
1055 Layout::init_fixed_output_section(const char* name
,
1056 elfcpp::Shdr
<size
, big_endian
>& shdr
)
1058 unsigned int sh_type
= shdr
.get_sh_type();
1060 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1061 // PRE_INIT_ARRAY, and NOTE sections.
1062 // All others will be created from scratch and reallocated.
1063 if (!can_incremental_update(sh_type
))
1066 // If we're generating a .gdb_index section, we need to regenerate
1068 if (parameters
->options().gdb_index()
1069 && sh_type
== elfcpp::SHT_PROGBITS
1070 && strcmp(name
, ".gdb_index") == 0)
1073 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
1074 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
1075 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
1076 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
1077 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
1078 shdr
.get_sh_addralign();
1080 // Make the output section.
1081 Stringpool::Key name_key
;
1082 name
= this->namepool_
.add(name
, true, &name_key
);
1083 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
1084 sh_flags
, ORDER_INVALID
, false);
1085 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
1086 if (sh_type
!= elfcpp::SHT_NOBITS
)
1087 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
1091 // Return the index by which an input section should be ordered. This
1092 // is used to sort some .text sections, for compatibility with GNU ld.
1095 Layout::special_ordering_of_input_section(const char* name
)
1097 // The GNU linker has some special handling for some sections that
1098 // wind up in the .text section. Sections that start with these
1099 // prefixes must appear first, and must appear in the order listed
1101 static const char* const text_section_sort
[] =
1110 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1112 if (is_prefix_of(text_section_sort
[i
], name
))
1118 // Return the output section to use for input section SHNDX, with name
1119 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1120 // index of a relocation section which applies to this section, or 0
1121 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1122 // relocation section if there is one. Set *OFF to the offset of this
1123 // input section without the output section. Return NULL if the
1124 // section should be discarded. Set *OFF to -1 if the section
1125 // contents should not be written directly to the output file, but
1126 // will instead receive special handling.
1128 template<int size
, bool big_endian
>
1130 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1131 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1132 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
1136 if (!this->include_section(object
, name
, shdr
))
1139 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
1141 // In a relocatable link a grouped section must not be combined with
1142 // any other sections.
1144 if (parameters
->options().relocatable()
1145 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1147 name
= this->namepool_
.add(name
, true, NULL
);
1148 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
1149 ORDER_INVALID
, false);
1153 // Plugins can choose to place one or more subsets of sections in
1154 // unique segments and this is done by mapping these section subsets
1155 // to unique output sections. Check if this section needs to be
1156 // remapped to a unique output section.
1157 Section_segment_map::iterator it
1158 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1159 if (it
== this->section_segment_map_
.end())
1161 os
= this->choose_output_section(object
, name
, sh_type
,
1162 shdr
.get_sh_flags(), true,
1163 ORDER_INVALID
, false);
1167 // We know the name of the output section, directly call
1168 // get_output_section here by-passing choose_output_section.
1169 elfcpp::Elf_Xword flags
1170 = this->get_output_section_flags(shdr
.get_sh_flags());
1172 const char* os_name
= it
->second
->name
;
1173 Stringpool::Key name_key
;
1174 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1175 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1176 ORDER_INVALID
, false);
1177 if (!os
->is_unique_segment())
1179 os
->set_is_unique_segment();
1180 os
->set_extra_segment_flags(it
->second
->flags
);
1181 os
->set_segment_alignment(it
->second
->align
);
1188 // By default the GNU linker sorts input sections whose names match
1189 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1190 // sections are sorted by name. This is used to implement
1191 // constructor priority ordering. We are compatible. When we put
1192 // .ctor sections in .init_array and .dtor sections in .fini_array,
1193 // we must also sort plain .ctor and .dtor sections.
1194 if (!this->script_options_
->saw_sections_clause()
1195 && !parameters
->options().relocatable()
1196 && (is_prefix_of(".ctors.", name
)
1197 || is_prefix_of(".dtors.", name
)
1198 || is_prefix_of(".init_array.", name
)
1199 || is_prefix_of(".fini_array.", name
)
1200 || (parameters
->options().ctors_in_init_array()
1201 && (strcmp(name
, ".ctors") == 0
1202 || strcmp(name
, ".dtors") == 0))))
1203 os
->set_must_sort_attached_input_sections();
1205 // By default the GNU linker sorts some special text sections ahead
1206 // of others. We are compatible.
1207 if (parameters
->options().text_reorder()
1208 && !this->script_options_
->saw_sections_clause()
1209 && !this->is_section_ordering_specified()
1210 && !parameters
->options().relocatable()
1211 && Layout::special_ordering_of_input_section(name
) >= 0)
1212 os
->set_must_sort_attached_input_sections();
1214 // If this is a .ctors or .ctors.* section being mapped to a
1215 // .init_array section, or a .dtors or .dtors.* section being mapped
1216 // to a .fini_array section, we will need to reverse the words if
1217 // there is more than one. Record this section for later. See
1218 // ctors_sections_in_init_array above.
1219 if (!this->script_options_
->saw_sections_clause()
1220 && !parameters
->options().relocatable()
1221 && shdr
.get_sh_size() > size
/ 8
1222 && (((strcmp(name
, ".ctors") == 0
1223 || is_prefix_of(".ctors.", name
))
1224 && strcmp(os
->name(), ".init_array") == 0)
1225 || ((strcmp(name
, ".dtors") == 0
1226 || is_prefix_of(".dtors.", name
))
1227 && strcmp(os
->name(), ".fini_array") == 0)))
1228 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1230 // FIXME: Handle SHF_LINK_ORDER somewhere.
1232 elfcpp::Elf_Xword orig_flags
= os
->flags();
1234 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1235 this->script_options_
->saw_sections_clause());
1237 // If the flags changed, we may have to change the order.
1238 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1240 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1241 elfcpp::Elf_Xword new_flags
=
1242 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1243 if (orig_flags
!= new_flags
)
1244 os
->set_order(this->default_section_order(os
, false));
1247 this->have_added_input_section_
= true;
1252 // Maps section SECN to SEGMENT s.
1254 Layout::insert_section_segment_map(Const_section_id secn
,
1255 Unique_segment_info
*s
)
1257 gold_assert(this->unique_segment_for_sections_specified_
);
1258 this->section_segment_map_
[secn
] = s
;
1261 // Handle a relocation section when doing a relocatable link.
1263 template<int size
, bool big_endian
>
1265 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
1267 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1268 Output_section
* data_section
,
1269 Relocatable_relocs
* rr
)
1271 gold_assert(parameters
->options().relocatable()
1272 || parameters
->options().emit_relocs());
1274 int sh_type
= shdr
.get_sh_type();
1277 if (sh_type
== elfcpp::SHT_REL
)
1279 else if (sh_type
== elfcpp::SHT_RELA
)
1283 name
+= data_section
->name();
1285 // In a relocatable link relocs for a grouped section must not be
1286 // combined with other reloc sections.
1288 if (!parameters
->options().relocatable()
1289 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
1290 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
1291 shdr
.get_sh_flags(), false,
1292 ORDER_INVALID
, false);
1295 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1296 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1297 ORDER_INVALID
, false);
1300 os
->set_should_link_to_symtab();
1301 os
->set_info_section(data_section
);
1303 Output_section_data
* posd
;
1304 if (sh_type
== elfcpp::SHT_REL
)
1306 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1307 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1311 else if (sh_type
== elfcpp::SHT_RELA
)
1313 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1314 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1321 os
->add_output_section_data(posd
);
1322 rr
->set_output_data(posd
);
1327 // Handle a group section when doing a relocatable link.
1329 template<int size
, bool big_endian
>
1331 Layout::layout_group(Symbol_table
* symtab
,
1332 Sized_relobj_file
<size
, big_endian
>* object
,
1334 const char* group_section_name
,
1335 const char* signature
,
1336 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1337 elfcpp::Elf_Word flags
,
1338 std::vector
<unsigned int>* shndxes
)
1340 gold_assert(parameters
->options().relocatable());
1341 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1342 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1343 Output_section
* os
= this->make_output_section(group_section_name
,
1345 shdr
.get_sh_flags(),
1346 ORDER_INVALID
, false);
1348 // We need to find a symbol with the signature in the symbol table.
1349 // If we don't find one now, we need to look again later.
1350 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1352 os
->set_info_symndx(sym
);
1355 // Reserve some space to minimize reallocations.
1356 if (this->group_signatures_
.empty())
1357 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1359 // We will wind up using a symbol whose name is the signature.
1360 // So just put the signature in the symbol name pool to save it.
1361 signature
= symtab
->canonicalize_name(signature
);
1362 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1365 os
->set_should_link_to_symtab();
1368 section_size_type entry_count
=
1369 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1370 Output_section_data
* posd
=
1371 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1373 os
->add_output_section_data(posd
);
1376 // Special GNU handling of sections name .eh_frame. They will
1377 // normally hold exception frame data as defined by the C++ ABI
1378 // (http://codesourcery.com/cxx-abi/).
1380 template<int size
, bool big_endian
>
1382 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1383 const unsigned char* symbols
,
1385 const unsigned char* symbol_names
,
1386 off_t symbol_names_size
,
1388 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1389 unsigned int reloc_shndx
, unsigned int reloc_type
,
1392 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1393 || shdr
.get_sh_type() == elfcpp::SHT_X86_64_UNWIND
);
1394 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1396 Output_section
* os
= this->make_eh_frame_section(object
);
1400 gold_assert(this->eh_frame_section_
== os
);
1402 elfcpp::Elf_Xword orig_flags
= os
->flags();
1404 if (!parameters
->incremental()
1405 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1414 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1416 // A writable .eh_frame section is a RELRO section.
1417 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1418 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1421 os
->set_order(ORDER_RELRO
);
1424 // We found a .eh_frame section we are going to optimize, so now
1425 // we can add the set of optimized sections to the output
1426 // section. We need to postpone adding this until we've found a
1427 // section we can optimize so that the .eh_frame section in
1428 // crtbegin.o winds up at the start of the output section.
1429 if (!this->added_eh_frame_data_
)
1431 os
->add_output_section_data(this->eh_frame_data_
);
1432 this->added_eh_frame_data_
= true;
1438 // We couldn't handle this .eh_frame section for some reason.
1439 // Add it as a normal section.
1440 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1441 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1442 reloc_shndx
, saw_sections_clause
);
1443 this->have_added_input_section_
= true;
1445 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1446 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1447 os
->set_order(this->default_section_order(os
, false));
1453 // Create and return the magic .eh_frame section. Create
1454 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1455 // input .eh_frame section; it may be NULL.
1458 Layout::make_eh_frame_section(const Relobj
* object
)
1460 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1462 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1463 elfcpp::SHT_PROGBITS
,
1464 elfcpp::SHF_ALLOC
, false,
1465 ORDER_EHFRAME
, false);
1469 if (this->eh_frame_section_
== NULL
)
1471 this->eh_frame_section_
= os
;
1472 this->eh_frame_data_
= new Eh_frame();
1474 // For incremental linking, we do not optimize .eh_frame sections
1475 // or create a .eh_frame_hdr section.
1476 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1478 Output_section
* hdr_os
=
1479 this->choose_output_section(NULL
, ".eh_frame_hdr",
1480 elfcpp::SHT_PROGBITS
,
1481 elfcpp::SHF_ALLOC
, false,
1482 ORDER_EHFRAME
, false);
1486 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1487 this->eh_frame_data_
);
1488 hdr_os
->add_output_section_data(hdr_posd
);
1490 hdr_os
->set_after_input_sections();
1492 if (!this->script_options_
->saw_phdrs_clause())
1494 Output_segment
* hdr_oseg
;
1495 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1497 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1501 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1509 // Add an exception frame for a PLT. This is called from target code.
1512 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1513 size_t cie_length
, const unsigned char* fde_data
,
1516 if (parameters
->incremental())
1518 // FIXME: Maybe this could work some day....
1521 Output_section
* os
= this->make_eh_frame_section(NULL
);
1524 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1525 fde_data
, fde_length
);
1526 if (!this->added_eh_frame_data_
)
1528 os
->add_output_section_data(this->eh_frame_data_
);
1529 this->added_eh_frame_data_
= true;
1533 // Scan a .debug_info or .debug_types section, and add summary
1534 // information to the .gdb_index section.
1536 template<int size
, bool big_endian
>
1538 Layout::add_to_gdb_index(bool is_type_unit
,
1539 Sized_relobj
<size
, big_endian
>* object
,
1540 const unsigned char* symbols
,
1543 unsigned int reloc_shndx
,
1544 unsigned int reloc_type
)
1546 if (this->gdb_index_data_
== NULL
)
1548 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1549 elfcpp::SHT_PROGBITS
, 0,
1550 false, ORDER_INVALID
,
1555 this->gdb_index_data_
= new Gdb_index(os
);
1556 os
->add_output_section_data(this->gdb_index_data_
);
1557 os
->set_after_input_sections();
1560 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1561 symbols_size
, shndx
, reloc_shndx
,
1565 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1566 // the output section.
1569 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1570 elfcpp::Elf_Xword flags
,
1571 Output_section_data
* posd
,
1572 Output_section_order order
, bool is_relro
)
1574 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1575 false, order
, is_relro
);
1577 os
->add_output_section_data(posd
);
1581 // Map section flags to segment flags.
1584 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1586 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1587 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1588 ret
|= elfcpp::PF_W
;
1589 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1590 ret
|= elfcpp::PF_X
;
1594 // Make a new Output_section, and attach it to segments as
1595 // appropriate. ORDER is the order in which this section should
1596 // appear in the output segment. IS_RELRO is true if this is a relro
1597 // (read-only after relocations) section.
1600 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1601 elfcpp::Elf_Xword flags
,
1602 Output_section_order order
, bool is_relro
)
1605 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1606 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1607 && is_compressible_debug_section(name
))
1608 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1610 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1611 && parameters
->options().strip_debug_non_line()
1612 && strcmp(".debug_abbrev", name
) == 0)
1614 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1616 if (this->debug_info_
)
1617 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1619 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1620 && parameters
->options().strip_debug_non_line()
1621 && strcmp(".debug_info", name
) == 0)
1623 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1625 if (this->debug_abbrev_
)
1626 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1630 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1631 // not have correct section types. Force them here.
1632 if (type
== elfcpp::SHT_PROGBITS
)
1634 if (is_prefix_of(".init_array", name
))
1635 type
= elfcpp::SHT_INIT_ARRAY
;
1636 else if (is_prefix_of(".preinit_array", name
))
1637 type
= elfcpp::SHT_PREINIT_ARRAY
;
1638 else if (is_prefix_of(".fini_array", name
))
1639 type
= elfcpp::SHT_FINI_ARRAY
;
1642 // FIXME: const_cast is ugly.
1643 Target
* target
= const_cast<Target
*>(¶meters
->target());
1644 os
= target
->make_output_section(name
, type
, flags
);
1647 // With -z relro, we have to recognize the special sections by name.
1648 // There is no other way.
1649 bool is_relro_local
= false;
1650 if (!this->script_options_
->saw_sections_clause()
1651 && parameters
->options().relro()
1652 && (flags
& elfcpp::SHF_ALLOC
) != 0
1653 && (flags
& elfcpp::SHF_WRITE
) != 0)
1655 if (type
== elfcpp::SHT_PROGBITS
)
1657 if ((flags
& elfcpp::SHF_TLS
) != 0)
1659 else if (strcmp(name
, ".data.rel.ro") == 0)
1661 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1664 is_relro_local
= true;
1666 else if (strcmp(name
, ".ctors") == 0
1667 || strcmp(name
, ".dtors") == 0
1668 || strcmp(name
, ".jcr") == 0)
1671 else if (type
== elfcpp::SHT_INIT_ARRAY
1672 || type
== elfcpp::SHT_FINI_ARRAY
1673 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1680 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1681 order
= this->default_section_order(os
, is_relro_local
);
1683 os
->set_order(order
);
1685 parameters
->target().new_output_section(os
);
1687 this->section_list_
.push_back(os
);
1689 // The GNU linker by default sorts some sections by priority, so we
1690 // do the same. We need to know that this might happen before we
1691 // attach any input sections.
1692 if (!this->script_options_
->saw_sections_clause()
1693 && !parameters
->options().relocatable()
1694 && (strcmp(name
, ".init_array") == 0
1695 || strcmp(name
, ".fini_array") == 0
1696 || (!parameters
->options().ctors_in_init_array()
1697 && (strcmp(name
, ".ctors") == 0
1698 || strcmp(name
, ".dtors") == 0))))
1699 os
->set_may_sort_attached_input_sections();
1701 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1702 // sections before other .text sections. We are compatible. We
1703 // need to know that this might happen before we attach any input
1705 if (parameters
->options().text_reorder()
1706 && !this->script_options_
->saw_sections_clause()
1707 && !this->is_section_ordering_specified()
1708 && !parameters
->options().relocatable()
1709 && strcmp(name
, ".text") == 0)
1710 os
->set_may_sort_attached_input_sections();
1712 // GNU linker sorts section by name with --sort-section=name.
1713 if (strcmp(parameters
->options().sort_section(), "name") == 0)
1714 os
->set_must_sort_attached_input_sections();
1716 // Check for .stab*str sections, as .stab* sections need to link to
1718 if (type
== elfcpp::SHT_STRTAB
1719 && !this->have_stabstr_section_
1720 && strncmp(name
, ".stab", 5) == 0
1721 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1722 this->have_stabstr_section_
= true;
1724 // During a full incremental link, we add patch space to most
1725 // PROGBITS and NOBITS sections. Flag those that may be
1726 // arbitrarily padded.
1727 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1728 && order
!= ORDER_INTERP
1729 && order
!= ORDER_INIT
1730 && order
!= ORDER_PLT
1731 && order
!= ORDER_FINI
1732 && order
!= ORDER_RELRO_LAST
1733 && order
!= ORDER_NON_RELRO_FIRST
1734 && strcmp(name
, ".eh_frame") != 0
1735 && strcmp(name
, ".ctors") != 0
1736 && strcmp(name
, ".dtors") != 0
1737 && strcmp(name
, ".jcr") != 0)
1739 os
->set_is_patch_space_allowed();
1741 // Certain sections require "holes" to be filled with
1742 // specific fill patterns. These fill patterns may have
1743 // a minimum size, so we must prevent allocations from the
1744 // free list that leave a hole smaller than the minimum.
1745 if (strcmp(name
, ".debug_info") == 0)
1746 os
->set_free_space_fill(new Output_fill_debug_info(false));
1747 else if (strcmp(name
, ".debug_types") == 0)
1748 os
->set_free_space_fill(new Output_fill_debug_info(true));
1749 else if (strcmp(name
, ".debug_line") == 0)
1750 os
->set_free_space_fill(new Output_fill_debug_line());
1753 // If we have already attached the sections to segments, then we
1754 // need to attach this one now. This happens for sections created
1755 // directly by the linker.
1756 if (this->sections_are_attached_
)
1757 this->attach_section_to_segment(¶meters
->target(), os
);
1762 // Return the default order in which a section should be placed in an
1763 // output segment. This function captures a lot of the ideas in
1764 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1765 // linker created section is normally set when the section is created;
1766 // this function is used for input sections.
1768 Output_section_order
1769 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1771 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1772 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1773 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1774 bool is_bss
= false;
1779 case elfcpp::SHT_PROGBITS
:
1781 case elfcpp::SHT_NOBITS
:
1784 case elfcpp::SHT_RELA
:
1785 case elfcpp::SHT_REL
:
1787 return ORDER_DYNAMIC_RELOCS
;
1789 case elfcpp::SHT_HASH
:
1790 case elfcpp::SHT_DYNAMIC
:
1791 case elfcpp::SHT_SHLIB
:
1792 case elfcpp::SHT_DYNSYM
:
1793 case elfcpp::SHT_GNU_HASH
:
1794 case elfcpp::SHT_GNU_verdef
:
1795 case elfcpp::SHT_GNU_verneed
:
1796 case elfcpp::SHT_GNU_versym
:
1798 return ORDER_DYNAMIC_LINKER
;
1800 case elfcpp::SHT_NOTE
:
1801 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1804 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1805 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1807 if (!is_bss
&& !is_write
)
1811 if (strcmp(os
->name(), ".init") == 0)
1813 else if (strcmp(os
->name(), ".fini") == 0)
1816 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1820 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1822 if (os
->is_small_section())
1823 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1824 if (os
->is_large_section())
1825 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1827 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1830 // Attach output sections to segments. This is called after we have
1831 // seen all the input sections.
1834 Layout::attach_sections_to_segments(const Target
* target
)
1836 for (Section_list::iterator p
= this->section_list_
.begin();
1837 p
!= this->section_list_
.end();
1839 this->attach_section_to_segment(target
, *p
);
1841 this->sections_are_attached_
= true;
1844 // Attach an output section to a segment.
1847 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1849 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1850 this->unattached_section_list_
.push_back(os
);
1852 this->attach_allocated_section_to_segment(target
, os
);
1855 // Attach an allocated output section to a segment.
1858 Layout::attach_allocated_section_to_segment(const Target
* target
,
1861 elfcpp::Elf_Xword flags
= os
->flags();
1862 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1864 if (parameters
->options().relocatable())
1867 // If we have a SECTIONS clause, we can't handle the attachment to
1868 // segments until after we've seen all the sections.
1869 if (this->script_options_
->saw_sections_clause())
1872 gold_assert(!this->script_options_
->saw_phdrs_clause());
1874 // This output section goes into a PT_LOAD segment.
1876 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1878 // If this output section's segment has extra flags that need to be set,
1879 // coming from a linker plugin, do that.
1880 seg_flags
|= os
->extra_segment_flags();
1882 // Check for --section-start.
1884 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1886 // In general the only thing we really care about for PT_LOAD
1887 // segments is whether or not they are writable or executable,
1888 // so that is how we search for them.
1889 // Large data sections also go into their own PT_LOAD segment.
1890 // People who need segments sorted on some other basis will
1891 // have to use a linker script.
1893 Segment_list::const_iterator p
;
1894 if (!os
->is_unique_segment())
1896 for (p
= this->segment_list_
.begin();
1897 p
!= this->segment_list_
.end();
1900 if ((*p
)->type() != elfcpp::PT_LOAD
)
1902 if ((*p
)->is_unique_segment())
1904 if (!parameters
->options().omagic()
1905 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1907 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
1908 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1910 // If -Tbss was specified, we need to separate the data and BSS
1912 if (parameters
->options().user_set_Tbss())
1914 if ((os
->type() == elfcpp::SHT_NOBITS
)
1915 == (*p
)->has_any_data_sections())
1918 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1923 if ((*p
)->are_addresses_set())
1926 (*p
)->add_initial_output_data(os
);
1927 (*p
)->update_flags_for_output_section(seg_flags
);
1928 (*p
)->set_addresses(addr
, addr
);
1932 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1937 if (p
== this->segment_list_
.end()
1938 || os
->is_unique_segment())
1940 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1942 if (os
->is_large_data_section())
1943 oseg
->set_is_large_data_segment();
1944 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1946 oseg
->set_addresses(addr
, addr
);
1947 // Check if segment should be marked unique. For segments marked
1948 // unique by linker plugins, set the new alignment if specified.
1949 if (os
->is_unique_segment())
1951 oseg
->set_is_unique_segment();
1952 if (os
->segment_alignment() != 0)
1953 oseg
->set_minimum_p_align(os
->segment_alignment());
1957 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1959 if (os
->type() == elfcpp::SHT_NOTE
)
1961 // See if we already have an equivalent PT_NOTE segment.
1962 for (p
= this->segment_list_
.begin();
1963 p
!= segment_list_
.end();
1966 if ((*p
)->type() == elfcpp::PT_NOTE
1967 && (((*p
)->flags() & elfcpp::PF_W
)
1968 == (seg_flags
& elfcpp::PF_W
)))
1970 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1975 if (p
== this->segment_list_
.end())
1977 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1979 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1983 // If we see a loadable SHF_TLS section, we create a PT_TLS
1984 // segment. There can only be one such segment.
1985 if ((flags
& elfcpp::SHF_TLS
) != 0)
1987 if (this->tls_segment_
== NULL
)
1988 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1989 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1992 // If -z relro is in effect, and we see a relro section, we create a
1993 // PT_GNU_RELRO segment. There can only be one such segment.
1994 if (os
->is_relro() && parameters
->options().relro())
1996 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1997 if (this->relro_segment_
== NULL
)
1998 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1999 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2002 // If we see a section named .interp, put it into a PT_INTERP
2003 // segment. This seems broken to me, but this is what GNU ld does,
2004 // and glibc expects it.
2005 if (strcmp(os
->name(), ".interp") == 0
2006 && !this->script_options_
->saw_phdrs_clause())
2008 if (this->interp_segment_
== NULL
)
2009 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
2011 gold_warning(_("multiple '.interp' sections in input files "
2012 "may cause confusing PT_INTERP segment"));
2013 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
2017 // Make an output section for a script.
2020 Layout::make_output_section_for_script(
2022 Script_sections::Section_type section_type
)
2024 name
= this->namepool_
.add(name
, false, NULL
);
2025 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
2026 if (section_type
== Script_sections::ST_NOLOAD
)
2028 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
2029 sh_flags
, ORDER_INVALID
,
2031 os
->set_found_in_sections_clause();
2032 if (section_type
== Script_sections::ST_NOLOAD
)
2033 os
->set_is_noload();
2037 // Return the number of segments we expect to see.
2040 Layout::expected_segment_count() const
2042 size_t ret
= this->segment_list_
.size();
2044 // If we didn't see a SECTIONS clause in a linker script, we should
2045 // already have the complete list of segments. Otherwise we ask the
2046 // SECTIONS clause how many segments it expects, and add in the ones
2047 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2049 if (!this->script_options_
->saw_sections_clause())
2053 const Script_sections
* ss
= this->script_options_
->script_sections();
2054 return ret
+ ss
->expected_segment_count(this);
2058 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2059 // is whether we saw a .note.GNU-stack section in the object file.
2060 // GNU_STACK_FLAGS is the section flags. The flags give the
2061 // protection required for stack memory. We record this in an
2062 // executable as a PT_GNU_STACK segment. If an object file does not
2063 // have a .note.GNU-stack segment, we must assume that it is an old
2064 // object. On some targets that will force an executable stack.
2067 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2070 if (!seen_gnu_stack
)
2072 this->input_without_gnu_stack_note_
= true;
2073 if (parameters
->options().warn_execstack()
2074 && parameters
->target().is_default_stack_executable())
2075 gold_warning(_("%s: missing .note.GNU-stack section"
2076 " implies executable stack"),
2077 obj
->name().c_str());
2081 this->input_with_gnu_stack_note_
= true;
2082 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2084 this->input_requires_executable_stack_
= true;
2085 if (parameters
->options().warn_execstack()
2086 || parameters
->options().is_stack_executable())
2087 gold_warning(_("%s: requires executable stack"),
2088 obj
->name().c_str());
2093 // Create automatic note sections.
2096 Layout::create_notes()
2098 this->create_gold_note();
2099 this->create_executable_stack_info();
2100 this->create_build_id();
2103 // Create the dynamic sections which are needed before we read the
2107 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2109 if (parameters
->doing_static_link())
2112 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2113 elfcpp::SHT_DYNAMIC
,
2115 | elfcpp::SHF_WRITE
),
2119 // A linker script may discard .dynamic, so check for NULL.
2120 if (this->dynamic_section_
!= NULL
)
2122 this->dynamic_symbol_
=
2123 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2124 Symbol_table::PREDEFINED
,
2125 this->dynamic_section_
, 0, 0,
2126 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2127 elfcpp::STV_HIDDEN
, 0, false, false);
2129 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2131 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2135 // For each output section whose name can be represented as C symbol,
2136 // define __start and __stop symbols for the section. This is a GNU
2140 Layout::define_section_symbols(Symbol_table
* symtab
)
2142 for (Section_list::const_iterator p
= this->section_list_
.begin();
2143 p
!= this->section_list_
.end();
2146 const char* const name
= (*p
)->name();
2147 if (is_cident(name
))
2149 const std::string
name_string(name
);
2150 const std::string
start_name(cident_section_start_prefix
2152 const std::string
stop_name(cident_section_stop_prefix
2155 symtab
->define_in_output_data(start_name
.c_str(),
2157 Symbol_table::PREDEFINED
,
2163 elfcpp::STV_DEFAULT
,
2165 false, // offset_is_from_end
2166 true); // only_if_ref
2168 symtab
->define_in_output_data(stop_name
.c_str(),
2170 Symbol_table::PREDEFINED
,
2176 elfcpp::STV_DEFAULT
,
2178 true, // offset_is_from_end
2179 true); // only_if_ref
2184 // Define symbols for group signatures.
2187 Layout::define_group_signatures(Symbol_table
* symtab
)
2189 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2190 p
!= this->group_signatures_
.end();
2193 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2195 p
->section
->set_info_symndx(sym
);
2198 // Force the name of the group section to the group
2199 // signature, and use the group's section symbol as the
2200 // signature symbol.
2201 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2203 const char* name
= this->namepool_
.add(p
->signature
,
2205 p
->section
->set_name(name
);
2207 p
->section
->set_needs_symtab_index();
2208 p
->section
->set_info_section_symndx(p
->section
);
2212 this->group_signatures_
.clear();
2215 // Find the first read-only PT_LOAD segment, creating one if
2219 Layout::find_first_load_seg(const Target
* target
)
2221 Output_segment
* best
= NULL
;
2222 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2223 p
!= this->segment_list_
.end();
2226 if ((*p
)->type() == elfcpp::PT_LOAD
2227 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2228 && (parameters
->options().omagic()
2229 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2230 && (!target
->isolate_execinstr()
2231 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2233 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2240 gold_assert(!this->script_options_
->saw_phdrs_clause());
2242 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2247 // Save states of all current output segments. Store saved states
2248 // in SEGMENT_STATES.
2251 Layout::save_segments(Segment_states
* segment_states
)
2253 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2254 p
!= this->segment_list_
.end();
2257 Output_segment
* segment
= *p
;
2259 Output_segment
* copy
= new Output_segment(*segment
);
2260 (*segment_states
)[segment
] = copy
;
2264 // Restore states of output segments and delete any segment not found in
2268 Layout::restore_segments(const Segment_states
* segment_states
)
2270 // Go through the segment list and remove any segment added in the
2272 this->tls_segment_
= NULL
;
2273 this->relro_segment_
= NULL
;
2274 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2275 while (list_iter
!= this->segment_list_
.end())
2277 Output_segment
* segment
= *list_iter
;
2278 Segment_states::const_iterator states_iter
=
2279 segment_states
->find(segment
);
2280 if (states_iter
!= segment_states
->end())
2282 const Output_segment
* copy
= states_iter
->second
;
2283 // Shallow copy to restore states.
2286 // Also fix up TLS and RELRO segment pointers as appropriate.
2287 if (segment
->type() == elfcpp::PT_TLS
)
2288 this->tls_segment_
= segment
;
2289 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2290 this->relro_segment_
= segment
;
2296 list_iter
= this->segment_list_
.erase(list_iter
);
2297 // This is a segment created during section layout. It should be
2298 // safe to remove it since we should have removed all pointers to it.
2304 // Clean up after relaxation so that sections can be laid out again.
2307 Layout::clean_up_after_relaxation()
2309 // Restore the segments to point state just prior to the relaxation loop.
2310 Script_sections
* script_section
= this->script_options_
->script_sections();
2311 script_section
->release_segments();
2312 this->restore_segments(this->segment_states_
);
2314 // Reset section addresses and file offsets
2315 for (Section_list::iterator p
= this->section_list_
.begin();
2316 p
!= this->section_list_
.end();
2319 (*p
)->restore_states();
2321 // If an input section changes size because of relaxation,
2322 // we need to adjust the section offsets of all input sections.
2323 // after such a section.
2324 if ((*p
)->section_offsets_need_adjustment())
2325 (*p
)->adjust_section_offsets();
2327 (*p
)->reset_address_and_file_offset();
2330 // Reset special output object address and file offsets.
2331 for (Data_list::iterator p
= this->special_output_list_
.begin();
2332 p
!= this->special_output_list_
.end();
2334 (*p
)->reset_address_and_file_offset();
2336 // A linker script may have created some output section data objects.
2337 // They are useless now.
2338 for (Output_section_data_list::const_iterator p
=
2339 this->script_output_section_data_list_
.begin();
2340 p
!= this->script_output_section_data_list_
.end();
2343 this->script_output_section_data_list_
.clear();
2346 // Prepare for relaxation.
2349 Layout::prepare_for_relaxation()
2351 // Create an relaxation debug check if in debugging mode.
2352 if (is_debugging_enabled(DEBUG_RELAXATION
))
2353 this->relaxation_debug_check_
= new Relaxation_debug_check();
2355 // Save segment states.
2356 this->segment_states_
= new Segment_states();
2357 this->save_segments(this->segment_states_
);
2359 for(Section_list::const_iterator p
= this->section_list_
.begin();
2360 p
!= this->section_list_
.end();
2362 (*p
)->save_states();
2364 if (is_debugging_enabled(DEBUG_RELAXATION
))
2365 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2366 this->section_list_
, this->special_output_list_
);
2368 // Also enable recording of output section data from scripts.
2369 this->record_output_section_data_from_script_
= true;
2372 // Relaxation loop body: If target has no relaxation, this runs only once
2373 // Otherwise, the target relaxation hook is called at the end of
2374 // each iteration. If the hook returns true, it means re-layout of
2375 // section is required.
2377 // The number of segments created by a linking script without a PHDRS
2378 // clause may be affected by section sizes and alignments. There is
2379 // a remote chance that relaxation causes different number of PT_LOAD
2380 // segments are created and sections are attached to different segments.
2381 // Therefore, we always throw away all segments created during section
2382 // layout. In order to be able to restart the section layout, we keep
2383 // a copy of the segment list right before the relaxation loop and use
2384 // that to restore the segments.
2386 // PASS is the current relaxation pass number.
2387 // SYMTAB is a symbol table.
2388 // PLOAD_SEG is the address of a pointer for the load segment.
2389 // PHDR_SEG is a pointer to the PHDR segment.
2390 // SEGMENT_HEADERS points to the output segment header.
2391 // FILE_HEADER points to the output file header.
2392 // PSHNDX is the address to store the output section index.
2395 Layout::relaxation_loop_body(
2398 Symbol_table
* symtab
,
2399 Output_segment
** pload_seg
,
2400 Output_segment
* phdr_seg
,
2401 Output_segment_headers
* segment_headers
,
2402 Output_file_header
* file_header
,
2403 unsigned int* pshndx
)
2405 // If this is not the first iteration, we need to clean up after
2406 // relaxation so that we can lay out the sections again.
2408 this->clean_up_after_relaxation();
2410 // If there is a SECTIONS clause, put all the input sections into
2411 // the required order.
2412 Output_segment
* load_seg
;
2413 if (this->script_options_
->saw_sections_clause())
2414 load_seg
= this->set_section_addresses_from_script(symtab
);
2415 else if (parameters
->options().relocatable())
2418 load_seg
= this->find_first_load_seg(target
);
2420 if (parameters
->options().oformat_enum()
2421 != General_options::OBJECT_FORMAT_ELF
)
2424 // If the user set the address of the text segment, that may not be
2425 // compatible with putting the segment headers and file headers into
2427 if (parameters
->options().user_set_Ttext()
2428 && parameters
->options().Ttext() % target
->abi_pagesize() != 0)
2434 gold_assert(phdr_seg
== NULL
2436 || this->script_options_
->saw_sections_clause());
2438 // If the address of the load segment we found has been set by
2439 // --section-start rather than by a script, then adjust the VMA and
2440 // LMA downward if possible to include the file and section headers.
2441 uint64_t header_gap
= 0;
2442 if (load_seg
!= NULL
2443 && load_seg
->are_addresses_set()
2444 && !this->script_options_
->saw_sections_clause()
2445 && !parameters
->options().relocatable())
2447 file_header
->finalize_data_size();
2448 segment_headers
->finalize_data_size();
2449 size_t sizeof_headers
= (file_header
->data_size()
2450 + segment_headers
->data_size());
2451 const uint64_t abi_pagesize
= target
->abi_pagesize();
2452 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2453 hdr_paddr
&= ~(abi_pagesize
- 1);
2454 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2455 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2459 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2460 load_seg
->paddr() - subtract
);
2461 header_gap
= subtract
- sizeof_headers
;
2465 // Lay out the segment headers.
2466 if (!parameters
->options().relocatable())
2468 gold_assert(segment_headers
!= NULL
);
2469 if (header_gap
!= 0 && load_seg
!= NULL
)
2471 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2472 load_seg
->add_initial_output_data(z
);
2474 if (load_seg
!= NULL
)
2475 load_seg
->add_initial_output_data(segment_headers
);
2476 if (phdr_seg
!= NULL
)
2477 phdr_seg
->add_initial_output_data(segment_headers
);
2480 // Lay out the file header.
2481 if (load_seg
!= NULL
)
2482 load_seg
->add_initial_output_data(file_header
);
2484 if (this->script_options_
->saw_phdrs_clause()
2485 && !parameters
->options().relocatable())
2487 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2488 // clause in a linker script.
2489 Script_sections
* ss
= this->script_options_
->script_sections();
2490 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2493 // We set the output section indexes in set_segment_offsets and
2494 // set_section_indexes.
2497 // Set the file offsets of all the segments, and all the sections
2500 if (!parameters
->options().relocatable())
2501 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2503 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2505 // Verify that the dummy relaxation does not change anything.
2506 if (is_debugging_enabled(DEBUG_RELAXATION
))
2509 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2511 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2514 *pload_seg
= load_seg
;
2518 // Search the list of patterns and find the postion of the given section
2519 // name in the output section. If the section name matches a glob
2520 // pattern and a non-glob name, then the non-glob position takes
2521 // precedence. Return 0 if no match is found.
2524 Layout::find_section_order_index(const std::string
& section_name
)
2526 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2527 map_it
= this->input_section_position_
.find(section_name
);
2528 if (map_it
!= this->input_section_position_
.end())
2529 return map_it
->second
;
2531 // Absolute match failed. Linear search the glob patterns.
2532 std::vector
<std::string
>::iterator it
;
2533 for (it
= this->input_section_glob_
.begin();
2534 it
!= this->input_section_glob_
.end();
2537 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2539 map_it
= this->input_section_position_
.find(*it
);
2540 gold_assert(map_it
!= this->input_section_position_
.end());
2541 return map_it
->second
;
2547 // Read the sequence of input sections from the file specified with
2548 // option --section-ordering-file.
2551 Layout::read_layout_from_file()
2553 const char* filename
= parameters
->options().section_ordering_file();
2559 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2560 filename
, strerror(errno
));
2562 std::getline(in
, line
); // this chops off the trailing \n, if any
2563 unsigned int position
= 1;
2564 this->set_section_ordering_specified();
2568 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2569 line
.resize(line
.length() - 1);
2570 // Ignore comments, beginning with '#'
2573 std::getline(in
, line
);
2576 this->input_section_position_
[line
] = position
;
2577 // Store all glob patterns in a vector.
2578 if (is_wildcard_string(line
.c_str()))
2579 this->input_section_glob_
.push_back(line
);
2581 std::getline(in
, line
);
2585 // Finalize the layout. When this is called, we have created all the
2586 // output sections and all the output segments which are based on
2587 // input sections. We have several things to do, and we have to do
2588 // them in the right order, so that we get the right results correctly
2591 // 1) Finalize the list of output segments and create the segment
2594 // 2) Finalize the dynamic symbol table and associated sections.
2596 // 3) Determine the final file offset of all the output segments.
2598 // 4) Determine the final file offset of all the SHF_ALLOC output
2601 // 5) Create the symbol table sections and the section name table
2604 // 6) Finalize the symbol table: set symbol values to their final
2605 // value and make a final determination of which symbols are going
2606 // into the output symbol table.
2608 // 7) Create the section table header.
2610 // 8) Determine the final file offset of all the output sections which
2611 // are not SHF_ALLOC, including the section table header.
2613 // 9) Finalize the ELF file header.
2615 // This function returns the size of the output file.
2618 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2619 Target
* target
, const Task
* task
)
2621 target
->finalize_sections(this, input_objects
, symtab
);
2623 this->count_local_symbols(task
, input_objects
);
2625 this->link_stabs_sections();
2627 Output_segment
* phdr_seg
= NULL
;
2628 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2630 // There was a dynamic object in the link. We need to create
2631 // some information for the dynamic linker.
2633 // Create the PT_PHDR segment which will hold the program
2635 if (!this->script_options_
->saw_phdrs_clause())
2636 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2638 // Create the dynamic symbol table, including the hash table.
2639 Output_section
* dynstr
;
2640 std::vector
<Symbol
*> dynamic_symbols
;
2641 unsigned int local_dynamic_count
;
2642 Versions
versions(*this->script_options()->version_script_info(),
2644 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2645 &local_dynamic_count
, &dynamic_symbols
,
2648 // Create the .interp section to hold the name of the
2649 // interpreter, and put it in a PT_INTERP segment. Don't do it
2650 // if we saw a .interp section in an input file.
2651 if ((!parameters
->options().shared()
2652 || parameters
->options().dynamic_linker() != NULL
)
2653 && this->interp_segment_
== NULL
)
2654 this->create_interp(target
);
2656 // Finish the .dynamic section to hold the dynamic data, and put
2657 // it in a PT_DYNAMIC segment.
2658 this->finish_dynamic_section(input_objects
, symtab
);
2660 // We should have added everything we need to the dynamic string
2662 this->dynpool_
.set_string_offsets();
2664 // Create the version sections. We can't do this until the
2665 // dynamic string table is complete.
2666 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2667 dynamic_symbols
, dynstr
);
2669 // Set the size of the _DYNAMIC symbol. We can't do this until
2670 // after we call create_version_sections.
2671 this->set_dynamic_symbol_size(symtab
);
2674 // Create segment headers.
2675 Output_segment_headers
* segment_headers
=
2676 (parameters
->options().relocatable()
2678 : new Output_segment_headers(this->segment_list_
));
2680 // Lay out the file header.
2681 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
2684 this->special_output_list_
.push_back(file_header
);
2685 if (segment_headers
!= NULL
)
2686 this->special_output_list_
.push_back(segment_headers
);
2688 // Find approriate places for orphan output sections if we are using
2690 if (this->script_options_
->saw_sections_clause())
2691 this->place_orphan_sections_in_script();
2693 Output_segment
* load_seg
;
2698 // Take a snapshot of the section layout as needed.
2699 if (target
->may_relax())
2700 this->prepare_for_relaxation();
2702 // Run the relaxation loop to lay out sections.
2705 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2706 phdr_seg
, segment_headers
, file_header
,
2710 while (target
->may_relax()
2711 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2713 // If there is a load segment that contains the file and program headers,
2714 // provide a symbol __ehdr_start pointing there.
2715 // A program can use this to examine itself robustly.
2716 if (load_seg
!= NULL
)
2717 symtab
->define_in_output_segment("__ehdr_start", NULL
,
2718 Symbol_table::PREDEFINED
, load_seg
, 0, 0,
2719 elfcpp::STT_NOTYPE
, elfcpp::STB_GLOBAL
,
2720 elfcpp::STV_HIDDEN
, 0,
2721 Symbol::SEGMENT_START
, true);
2723 // Set the file offsets of all the non-data sections we've seen so
2724 // far which don't have to wait for the input sections. We need
2725 // this in order to finalize local symbols in non-allocated
2727 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2729 // Set the section indexes of all unallocated sections seen so far,
2730 // in case any of them are somehow referenced by a symbol.
2731 shndx
= this->set_section_indexes(shndx
);
2733 // Create the symbol table sections.
2734 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2735 if (!parameters
->doing_static_link())
2736 this->assign_local_dynsym_offsets(input_objects
);
2738 // Process any symbol assignments from a linker script. This must
2739 // be called after the symbol table has been finalized.
2740 this->script_options_
->finalize_symbols(symtab
, this);
2742 // Create the incremental inputs sections.
2743 if (this->incremental_inputs_
)
2745 this->incremental_inputs_
->finalize();
2746 this->create_incremental_info_sections(symtab
);
2749 // Create the .shstrtab section.
2750 Output_section
* shstrtab_section
= this->create_shstrtab();
2752 // Set the file offsets of the rest of the non-data sections which
2753 // don't have to wait for the input sections.
2754 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2756 // Now that all sections have been created, set the section indexes
2757 // for any sections which haven't been done yet.
2758 shndx
= this->set_section_indexes(shndx
);
2760 // Create the section table header.
2761 this->create_shdrs(shstrtab_section
, &off
);
2763 // If there are no sections which require postprocessing, we can
2764 // handle the section names now, and avoid a resize later.
2765 if (!this->any_postprocessing_sections_
)
2767 off
= this->set_section_offsets(off
,
2768 POSTPROCESSING_SECTIONS_PASS
);
2770 this->set_section_offsets(off
,
2771 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2774 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2776 // Now we know exactly where everything goes in the output file
2777 // (except for non-allocated sections which require postprocessing).
2778 Output_data::layout_complete();
2780 this->output_file_size_
= off
;
2785 // Create a note header following the format defined in the ELF ABI.
2786 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2787 // of the section to create, DESCSZ is the size of the descriptor.
2788 // ALLOCATE is true if the section should be allocated in memory.
2789 // This returns the new note section. It sets *TRAILING_PADDING to
2790 // the number of trailing zero bytes required.
2793 Layout::create_note(const char* name
, int note_type
,
2794 const char* section_name
, size_t descsz
,
2795 bool allocate
, size_t* trailing_padding
)
2797 // Authorities all agree that the values in a .note field should
2798 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2799 // they differ on what the alignment is for 64-bit binaries.
2800 // The GABI says unambiguously they take 8-byte alignment:
2801 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2802 // Other documentation says alignment should always be 4 bytes:
2803 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2804 // GNU ld and GNU readelf both support the latter (at least as of
2805 // version 2.16.91), and glibc always generates the latter for
2806 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2808 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2809 const int size
= parameters
->target().get_size();
2811 const int size
= 32;
2814 // The contents of the .note section.
2815 size_t namesz
= strlen(name
) + 1;
2816 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2817 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2819 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2821 unsigned char* buffer
= new unsigned char[notehdrsz
];
2822 memset(buffer
, 0, notehdrsz
);
2824 bool is_big_endian
= parameters
->target().is_big_endian();
2830 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2831 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2832 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2836 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2837 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2838 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2841 else if (size
== 64)
2845 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2846 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2847 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2851 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2852 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2853 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2859 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2861 elfcpp::Elf_Xword flags
= 0;
2862 Output_section_order order
= ORDER_INVALID
;
2865 flags
= elfcpp::SHF_ALLOC
;
2866 order
= ORDER_RO_NOTE
;
2868 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2870 flags
, false, order
, false);
2874 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2877 os
->add_output_section_data(posd
);
2879 *trailing_padding
= aligned_descsz
- descsz
;
2884 // For an executable or shared library, create a note to record the
2885 // version of gold used to create the binary.
2888 Layout::create_gold_note()
2890 if (parameters
->options().relocatable()
2891 || parameters
->incremental_update())
2894 std::string desc
= std::string("gold ") + gold::get_version_string();
2896 size_t trailing_padding
;
2897 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2898 ".note.gnu.gold-version", desc
.size(),
2899 false, &trailing_padding
);
2903 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2904 os
->add_output_section_data(posd
);
2906 if (trailing_padding
> 0)
2908 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2909 os
->add_output_section_data(posd
);
2913 // Record whether the stack should be executable. This can be set
2914 // from the command line using the -z execstack or -z noexecstack
2915 // options. Otherwise, if any input file has a .note.GNU-stack
2916 // section with the SHF_EXECINSTR flag set, the stack should be
2917 // executable. Otherwise, if at least one input file a
2918 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2919 // section, we use the target default for whether the stack should be
2920 // executable. Otherwise, we don't generate a stack note. When
2921 // generating a object file, we create a .note.GNU-stack section with
2922 // the appropriate marking. When generating an executable or shared
2923 // library, we create a PT_GNU_STACK segment.
2926 Layout::create_executable_stack_info()
2928 bool is_stack_executable
;
2929 if (parameters
->options().is_execstack_set())
2930 is_stack_executable
= parameters
->options().is_stack_executable();
2931 else if (!this->input_with_gnu_stack_note_
)
2935 if (this->input_requires_executable_stack_
)
2936 is_stack_executable
= true;
2937 else if (this->input_without_gnu_stack_note_
)
2938 is_stack_executable
=
2939 parameters
->target().is_default_stack_executable();
2941 is_stack_executable
= false;
2944 if (parameters
->options().relocatable())
2946 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2947 elfcpp::Elf_Xword flags
= 0;
2948 if (is_stack_executable
)
2949 flags
|= elfcpp::SHF_EXECINSTR
;
2950 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2951 ORDER_INVALID
, false);
2955 if (this->script_options_
->saw_phdrs_clause())
2957 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2958 if (is_stack_executable
)
2959 flags
|= elfcpp::PF_X
;
2960 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2964 // If --build-id was used, set up the build ID note.
2967 Layout::create_build_id()
2969 if (!parameters
->options().user_set_build_id())
2972 const char* style
= parameters
->options().build_id();
2973 if (strcmp(style
, "none") == 0)
2976 // Set DESCSZ to the size of the note descriptor. When possible,
2977 // set DESC to the note descriptor contents.
2980 if (strcmp(style
, "md5") == 0)
2982 else if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
2984 else if (strcmp(style
, "uuid") == 0)
2986 const size_t uuidsz
= 128 / 8;
2988 char buffer
[uuidsz
];
2989 memset(buffer
, 0, uuidsz
);
2991 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2993 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2997 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2998 release_descriptor(descriptor
, true);
3000 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
3001 else if (static_cast<size_t>(got
) != uuidsz
)
3002 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3006 desc
.assign(buffer
, uuidsz
);
3009 else if (strncmp(style
, "0x", 2) == 0)
3012 const char* p
= style
+ 2;
3015 if (hex_p(p
[0]) && hex_p(p
[1]))
3017 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
3021 else if (*p
== '-' || *p
== ':')
3024 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3027 descsz
= desc
.size();
3030 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
3033 size_t trailing_padding
;
3034 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
3035 ".note.gnu.build-id", descsz
, true,
3042 // We know the value already, so we fill it in now.
3043 gold_assert(desc
.size() == descsz
);
3045 Output_section_data
* posd
= new Output_data_const(desc
, 4);
3046 os
->add_output_section_data(posd
);
3048 if (trailing_padding
!= 0)
3050 posd
= new Output_data_zero_fill(trailing_padding
, 0);
3051 os
->add_output_section_data(posd
);
3056 // We need to compute a checksum after we have completed the
3058 gold_assert(trailing_padding
== 0);
3059 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3060 os
->add_output_section_data(this->build_id_note_
);
3064 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3065 // field of the former should point to the latter. I'm not sure who
3066 // started this, but the GNU linker does it, and some tools depend
3070 Layout::link_stabs_sections()
3072 if (!this->have_stabstr_section_
)
3075 for (Section_list::iterator p
= this->section_list_
.begin();
3076 p
!= this->section_list_
.end();
3079 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3082 const char* name
= (*p
)->name();
3083 if (strncmp(name
, ".stab", 5) != 0)
3086 size_t len
= strlen(name
);
3087 if (strcmp(name
+ len
- 3, "str") != 0)
3090 std::string
stab_name(name
, len
- 3);
3091 Output_section
* stab_sec
;
3092 stab_sec
= this->find_output_section(stab_name
.c_str());
3093 if (stab_sec
!= NULL
)
3094 stab_sec
->set_link_section(*p
);
3098 // Create .gnu_incremental_inputs and related sections needed
3099 // for the next run of incremental linking to check what has changed.
3102 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3104 Incremental_inputs
* incr
= this->incremental_inputs_
;
3106 gold_assert(incr
!= NULL
);
3108 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3109 incr
->create_data_sections(symtab
);
3111 // Add the .gnu_incremental_inputs section.
3112 const char* incremental_inputs_name
=
3113 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3114 Output_section
* incremental_inputs_os
=
3115 this->make_output_section(incremental_inputs_name
,
3116 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3117 ORDER_INVALID
, false);
3118 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3120 // Add the .gnu_incremental_symtab section.
3121 const char* incremental_symtab_name
=
3122 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3123 Output_section
* incremental_symtab_os
=
3124 this->make_output_section(incremental_symtab_name
,
3125 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3126 ORDER_INVALID
, false);
3127 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3128 incremental_symtab_os
->set_entsize(4);
3130 // Add the .gnu_incremental_relocs section.
3131 const char* incremental_relocs_name
=
3132 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3133 Output_section
* incremental_relocs_os
=
3134 this->make_output_section(incremental_relocs_name
,
3135 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3136 ORDER_INVALID
, false);
3137 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3138 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3140 // Add the .gnu_incremental_got_plt section.
3141 const char* incremental_got_plt_name
=
3142 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3143 Output_section
* incremental_got_plt_os
=
3144 this->make_output_section(incremental_got_plt_name
,
3145 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3146 ORDER_INVALID
, false);
3147 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3149 // Add the .gnu_incremental_strtab section.
3150 const char* incremental_strtab_name
=
3151 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3152 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3153 elfcpp::SHT_STRTAB
, 0,
3154 ORDER_INVALID
, false);
3155 Output_data_strtab
* strtab_data
=
3156 new Output_data_strtab(incr
->get_stringpool());
3157 incremental_strtab_os
->add_output_section_data(strtab_data
);
3159 incremental_inputs_os
->set_after_input_sections();
3160 incremental_symtab_os
->set_after_input_sections();
3161 incremental_relocs_os
->set_after_input_sections();
3162 incremental_got_plt_os
->set_after_input_sections();
3164 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3165 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3166 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3167 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3170 // Return whether SEG1 should be before SEG2 in the output file. This
3171 // is based entirely on the segment type and flags. When this is
3172 // called the segment addresses have normally not yet been set.
3175 Layout::segment_precedes(const Output_segment
* seg1
,
3176 const Output_segment
* seg2
)
3178 elfcpp::Elf_Word type1
= seg1
->type();
3179 elfcpp::Elf_Word type2
= seg2
->type();
3181 // The single PT_PHDR segment is required to precede any loadable
3182 // segment. We simply make it always first.
3183 if (type1
== elfcpp::PT_PHDR
)
3185 gold_assert(type2
!= elfcpp::PT_PHDR
);
3188 if (type2
== elfcpp::PT_PHDR
)
3191 // The single PT_INTERP segment is required to precede any loadable
3192 // segment. We simply make it always second.
3193 if (type1
== elfcpp::PT_INTERP
)
3195 gold_assert(type2
!= elfcpp::PT_INTERP
);
3198 if (type2
== elfcpp::PT_INTERP
)
3201 // We then put PT_LOAD segments before any other segments.
3202 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3204 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3207 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3208 // segment, because that is where the dynamic linker expects to find
3209 // it (this is just for efficiency; other positions would also work
3211 if (type1
== elfcpp::PT_TLS
3212 && type2
!= elfcpp::PT_TLS
3213 && type2
!= elfcpp::PT_GNU_RELRO
)
3215 if (type2
== elfcpp::PT_TLS
3216 && type1
!= elfcpp::PT_TLS
3217 && type1
!= elfcpp::PT_GNU_RELRO
)
3220 // We put the PT_GNU_RELRO segment last, because that is where the
3221 // dynamic linker expects to find it (as with PT_TLS, this is just
3223 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3225 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3228 const elfcpp::Elf_Word flags1
= seg1
->flags();
3229 const elfcpp::Elf_Word flags2
= seg2
->flags();
3231 // The order of non-PT_LOAD segments is unimportant. We simply sort
3232 // by the numeric segment type and flags values. There should not
3233 // be more than one segment with the same type and flags, except
3234 // when a linker script specifies such.
3235 if (type1
!= elfcpp::PT_LOAD
)
3238 return type1
< type2
;
3239 gold_assert(flags1
!= flags2
3240 || this->script_options_
->saw_phdrs_clause());
3241 return flags1
< flags2
;
3244 // If the addresses are set already, sort by load address.
3245 if (seg1
->are_addresses_set())
3247 if (!seg2
->are_addresses_set())
3250 unsigned int section_count1
= seg1
->output_section_count();
3251 unsigned int section_count2
= seg2
->output_section_count();
3252 if (section_count1
== 0 && section_count2
> 0)
3254 if (section_count1
> 0 && section_count2
== 0)
3257 uint64_t paddr1
= (seg1
->are_addresses_set()
3259 : seg1
->first_section_load_address());
3260 uint64_t paddr2
= (seg2
->are_addresses_set()
3262 : seg2
->first_section_load_address());
3264 if (paddr1
!= paddr2
)
3265 return paddr1
< paddr2
;
3267 else if (seg2
->are_addresses_set())
3270 // A segment which holds large data comes after a segment which does
3271 // not hold large data.
3272 if (seg1
->is_large_data_segment())
3274 if (!seg2
->is_large_data_segment())
3277 else if (seg2
->is_large_data_segment())
3280 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3281 // segments come before writable segments. Then writable segments
3282 // with data come before writable segments without data. Then
3283 // executable segments come before non-executable segments. Then
3284 // the unlikely case of a non-readable segment comes before the
3285 // normal case of a readable segment. If there are multiple
3286 // segments with the same type and flags, we require that the
3287 // address be set, and we sort by virtual address and then physical
3289 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3290 return (flags1
& elfcpp::PF_W
) == 0;
3291 if ((flags1
& elfcpp::PF_W
) != 0
3292 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3293 return seg1
->has_any_data_sections();
3294 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3295 return (flags1
& elfcpp::PF_X
) != 0;
3296 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3297 return (flags1
& elfcpp::PF_R
) == 0;
3299 // We shouldn't get here--we shouldn't create segments which we
3300 // can't distinguish. Unless of course we are using a weird linker
3301 // script or overlapping --section-start options. We could also get
3302 // here if plugins want unique segments for subsets of sections.
3303 gold_assert(this->script_options_
->saw_phdrs_clause()
3304 || parameters
->options().any_section_start()
3305 || this->is_unique_segment_for_sections_specified());
3309 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3312 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3314 uint64_t unsigned_off
= off
;
3315 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3316 | (addr
& (abi_pagesize
- 1)));
3317 if (aligned_off
< unsigned_off
)
3318 aligned_off
+= abi_pagesize
;
3322 // Set the file offsets of all the segments, and all the sections they
3323 // contain. They have all been created. LOAD_SEG must be be laid out
3324 // first. Return the offset of the data to follow.
3327 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3328 unsigned int* pshndx
)
3330 // Sort them into the final order. We use a stable sort so that we
3331 // don't randomize the order of indistinguishable segments created
3332 // by linker scripts.
3333 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3334 Layout::Compare_segments(this));
3336 // Find the PT_LOAD segments, and set their addresses and offsets
3337 // and their section's addresses and offsets.
3338 uint64_t start_addr
;
3339 if (parameters
->options().user_set_Ttext())
3340 start_addr
= parameters
->options().Ttext();
3341 else if (parameters
->options().output_is_position_independent())
3344 start_addr
= target
->default_text_segment_address();
3346 uint64_t addr
= start_addr
;
3349 // If LOAD_SEG is NULL, then the file header and segment headers
3350 // will not be loadable. But they still need to be at offset 0 in
3351 // the file. Set their offsets now.
3352 if (load_seg
== NULL
)
3354 for (Data_list::iterator p
= this->special_output_list_
.begin();
3355 p
!= this->special_output_list_
.end();
3358 off
= align_address(off
, (*p
)->addralign());
3359 (*p
)->set_address_and_file_offset(0, off
);
3360 off
+= (*p
)->data_size();
3364 unsigned int increase_relro
= this->increase_relro_
;
3365 if (this->script_options_
->saw_sections_clause())
3368 const bool check_sections
= parameters
->options().check_sections();
3369 Output_segment
* last_load_segment
= NULL
;
3371 unsigned int shndx_begin
= *pshndx
;
3372 unsigned int shndx_load_seg
= *pshndx
;
3374 for (Segment_list::iterator p
= this->segment_list_
.begin();
3375 p
!= this->segment_list_
.end();
3378 if ((*p
)->type() == elfcpp::PT_LOAD
)
3380 if (target
->isolate_execinstr())
3382 // When we hit the segment that should contain the
3383 // file headers, reset the file offset so we place
3384 // it and subsequent segments appropriately.
3385 // We'll fix up the preceding segments below.
3393 shndx_load_seg
= *pshndx
;
3399 // Verify that the file headers fall into the first segment.
3400 if (load_seg
!= NULL
&& load_seg
!= *p
)
3405 bool are_addresses_set
= (*p
)->are_addresses_set();
3406 if (are_addresses_set
)
3408 // When it comes to setting file offsets, we care about
3409 // the physical address.
3410 addr
= (*p
)->paddr();
3412 else if (parameters
->options().user_set_Ttext()
3413 && (parameters
->options().omagic()
3414 || ((*p
)->flags() & elfcpp::PF_W
) == 0))
3416 are_addresses_set
= true;
3418 else if (parameters
->options().user_set_Tdata()
3419 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3420 && (!parameters
->options().user_set_Tbss()
3421 || (*p
)->has_any_data_sections()))
3423 addr
= parameters
->options().Tdata();
3424 are_addresses_set
= true;
3426 else if (parameters
->options().user_set_Tbss()
3427 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3428 && !(*p
)->has_any_data_sections())
3430 addr
= parameters
->options().Tbss();
3431 are_addresses_set
= true;
3434 uint64_t orig_addr
= addr
;
3435 uint64_t orig_off
= off
;
3437 uint64_t aligned_addr
= 0;
3438 uint64_t abi_pagesize
= target
->abi_pagesize();
3439 uint64_t common_pagesize
= target
->common_pagesize();
3441 if (!parameters
->options().nmagic()
3442 && !parameters
->options().omagic())
3443 (*p
)->set_minimum_p_align(abi_pagesize
);
3445 if (!are_addresses_set
)
3447 // Skip the address forward one page, maintaining the same
3448 // position within the page. This lets us store both segments
3449 // overlapping on a single page in the file, but the loader will
3450 // put them on different pages in memory. We will revisit this
3451 // decision once we know the size of the segment.
3453 addr
= align_address(addr
, (*p
)->maximum_alignment());
3454 aligned_addr
= addr
;
3458 // This is the segment that will contain the file
3459 // headers, so its offset will have to be exactly zero.
3460 gold_assert(orig_off
== 0);
3462 // If the target wants a fixed minimum distance from the
3463 // text segment to the read-only segment, move up now.
3465 start_addr
+ (parameters
->options().user_set_rosegment_gap()
3466 ? parameters
->options().rosegment_gap()
3467 : target
->rosegment_gap());
3468 if (addr
< min_addr
)
3471 // But this is not the first segment! To make its
3472 // address congruent with its offset, that address better
3473 // be aligned to the ABI-mandated page size.
3474 addr
= align_address(addr
, abi_pagesize
);
3475 aligned_addr
= addr
;
3479 if ((addr
& (abi_pagesize
- 1)) != 0)
3480 addr
= addr
+ abi_pagesize
;
3482 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3486 if (!parameters
->options().nmagic()
3487 && !parameters
->options().omagic())
3489 // Here we are also taking care of the case when
3490 // the maximum segment alignment is larger than the page size.
3491 off
= align_file_offset(off
, addr
,
3492 std::max(abi_pagesize
,
3493 (*p
)->maximum_alignment()));
3497 // This is -N or -n with a section script which prevents
3498 // us from using a load segment. We need to ensure that
3499 // the file offset is aligned to the alignment of the
3500 // segment. This is because the linker script
3501 // implicitly assumed a zero offset. If we don't align
3502 // here, then the alignment of the sections in the
3503 // linker script may not match the alignment of the
3504 // sections in the set_section_addresses call below,
3505 // causing an error about dot moving backward.
3506 off
= align_address(off
, (*p
)->maximum_alignment());
3509 unsigned int shndx_hold
= *pshndx
;
3510 bool has_relro
= false;
3511 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
3516 // Now that we know the size of this segment, we may be able
3517 // to save a page in memory, at the cost of wasting some
3518 // file space, by instead aligning to the start of a new
3519 // page. Here we use the real machine page size rather than
3520 // the ABI mandated page size. If the segment has been
3521 // aligned so that the relro data ends at a page boundary,
3522 // we do not try to realign it.
3524 if (!are_addresses_set
3526 && aligned_addr
!= addr
3527 && !parameters
->incremental())
3529 uint64_t first_off
= (common_pagesize
3531 & (common_pagesize
- 1)));
3532 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
3535 && ((aligned_addr
& ~ (common_pagesize
- 1))
3536 != (new_addr
& ~ (common_pagesize
- 1)))
3537 && first_off
+ last_off
<= common_pagesize
)
3539 *pshndx
= shndx_hold
;
3540 addr
= align_address(aligned_addr
, common_pagesize
);
3541 addr
= align_address(addr
, (*p
)->maximum_alignment());
3542 if ((addr
& (abi_pagesize
- 1)) != 0)
3543 addr
= addr
+ abi_pagesize
;
3544 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3545 off
= align_file_offset(off
, addr
, abi_pagesize
);
3547 increase_relro
= this->increase_relro_
;
3548 if (this->script_options_
->saw_sections_clause())
3552 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
3561 // Implement --check-sections. We know that the segments
3562 // are sorted by LMA.
3563 if (check_sections
&& last_load_segment
!= NULL
)
3565 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
3566 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3569 unsigned long long lb1
= last_load_segment
->paddr();
3570 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3571 unsigned long long lb2
= (*p
)->paddr();
3572 unsigned long long le2
= lb2
+ (*p
)->memsz();
3573 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3574 "[0x%llx -> 0x%llx]"),
3575 lb1
, le1
, lb2
, le2
);
3578 last_load_segment
= *p
;
3582 if (load_seg
!= NULL
&& target
->isolate_execinstr())
3584 // Process the early segments again, setting their file offsets
3585 // so they land after the segments starting at LOAD_SEG.
3586 off
= align_file_offset(off
, 0, target
->abi_pagesize());
3588 for (Segment_list::iterator p
= this->segment_list_
.begin();
3592 if ((*p
)->type() == elfcpp::PT_LOAD
)
3594 // We repeat the whole job of assigning addresses and
3595 // offsets, but we really only want to change the offsets and
3596 // must ensure that the addresses all come out the same as
3597 // they did the first time through.
3598 bool has_relro
= false;
3599 const uint64_t old_addr
= (*p
)->vaddr();
3600 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
3601 uint64_t new_addr
= (*p
)->set_section_addresses(this, true,
3607 gold_assert(new_addr
== old_end
);
3611 gold_assert(shndx_begin
== shndx_load_seg
);
3614 // Handle the non-PT_LOAD segments, setting their offsets from their
3615 // section's offsets.
3616 for (Segment_list::iterator p
= this->segment_list_
.begin();
3617 p
!= this->segment_list_
.end();
3620 if ((*p
)->type() != elfcpp::PT_LOAD
)
3621 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3626 // Set the TLS offsets for each section in the PT_TLS segment.
3627 if (this->tls_segment_
!= NULL
)
3628 this->tls_segment_
->set_tls_offsets();
3633 // Set the offsets of all the allocated sections when doing a
3634 // relocatable link. This does the same jobs as set_segment_offsets,
3635 // only for a relocatable link.
3638 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3639 unsigned int* pshndx
)
3643 file_header
->set_address_and_file_offset(0, 0);
3644 off
+= file_header
->data_size();
3646 for (Section_list::iterator p
= this->section_list_
.begin();
3647 p
!= this->section_list_
.end();
3650 // We skip unallocated sections here, except that group sections
3651 // have to come first.
3652 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3653 && (*p
)->type() != elfcpp::SHT_GROUP
)
3656 off
= align_address(off
, (*p
)->addralign());
3658 // The linker script might have set the address.
3659 if (!(*p
)->is_address_valid())
3660 (*p
)->set_address(0);
3661 (*p
)->set_file_offset(off
);
3662 (*p
)->finalize_data_size();
3663 if ((*p
)->type() != elfcpp::SHT_NOBITS
)
3664 off
+= (*p
)->data_size();
3666 (*p
)->set_out_shndx(*pshndx
);
3673 // Set the file offset of all the sections not associated with a
3677 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3679 off_t startoff
= off
;
3682 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3683 p
!= this->unattached_section_list_
.end();
3686 // The symtab section is handled in create_symtab_sections.
3687 if (*p
== this->symtab_section_
)
3690 // If we've already set the data size, don't set it again.
3691 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3694 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3695 && (*p
)->requires_postprocessing())
3697 (*p
)->create_postprocessing_buffer();
3698 this->any_postprocessing_sections_
= true;
3701 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3702 && (*p
)->after_input_sections())
3704 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3705 && (!(*p
)->after_input_sections()
3706 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3708 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3709 && (!(*p
)->after_input_sections()
3710 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3713 if (!parameters
->incremental_update())
3715 off
= align_address(off
, (*p
)->addralign());
3716 (*p
)->set_file_offset(off
);
3717 (*p
)->finalize_data_size();
3721 // Incremental update: allocate file space from free list.
3722 (*p
)->pre_finalize_data_size();
3723 off_t current_size
= (*p
)->current_data_size();
3724 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3727 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3728 this->free_list_
.dump();
3729 gold_assert((*p
)->output_section() != NULL
);
3730 gold_fallback(_("out of patch space for section %s; "
3731 "relink with --incremental-full"),
3732 (*p
)->output_section()->name());
3734 (*p
)->set_file_offset(off
);
3735 (*p
)->finalize_data_size();
3736 if ((*p
)->data_size() > current_size
)
3738 gold_assert((*p
)->output_section() != NULL
);
3739 gold_fallback(_("%s: section changed size; "
3740 "relink with --incremental-full"),
3741 (*p
)->output_section()->name());
3743 gold_debug(DEBUG_INCREMENTAL
,
3744 "set_section_offsets: %08lx %08lx %s",
3745 static_cast<long>(off
),
3746 static_cast<long>((*p
)->data_size()),
3747 ((*p
)->output_section() != NULL
3748 ? (*p
)->output_section()->name() : "(special)"));
3751 off
+= (*p
)->data_size();
3755 // At this point the name must be set.
3756 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3757 this->namepool_
.add((*p
)->name(), false, NULL
);
3762 // Set the section indexes of all the sections not associated with a
3766 Layout::set_section_indexes(unsigned int shndx
)
3768 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3769 p
!= this->unattached_section_list_
.end();
3772 if (!(*p
)->has_out_shndx())
3774 (*p
)->set_out_shndx(shndx
);
3781 // Set the section addresses according to the linker script. This is
3782 // only called when we see a SECTIONS clause. This returns the
3783 // program segment which should hold the file header and segment
3784 // headers, if any. It will return NULL if they should not be in a
3788 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3790 Script_sections
* ss
= this->script_options_
->script_sections();
3791 gold_assert(ss
->saw_sections_clause());
3792 return this->script_options_
->set_section_addresses(symtab
, this);
3795 // Place the orphan sections in the linker script.
3798 Layout::place_orphan_sections_in_script()
3800 Script_sections
* ss
= this->script_options_
->script_sections();
3801 gold_assert(ss
->saw_sections_clause());
3803 // Place each orphaned output section in the script.
3804 for (Section_list::iterator p
= this->section_list_
.begin();
3805 p
!= this->section_list_
.end();
3808 if (!(*p
)->found_in_sections_clause())
3809 ss
->place_orphan(*p
);
3813 // Count the local symbols in the regular symbol table and the dynamic
3814 // symbol table, and build the respective string pools.
3817 Layout::count_local_symbols(const Task
* task
,
3818 const Input_objects
* input_objects
)
3820 // First, figure out an upper bound on the number of symbols we'll
3821 // be inserting into each pool. This helps us create the pools with
3822 // the right size, to avoid unnecessary hashtable resizing.
3823 unsigned int symbol_count
= 0;
3824 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3825 p
!= input_objects
->relobj_end();
3827 symbol_count
+= (*p
)->local_symbol_count();
3829 // Go from "upper bound" to "estimate." We overcount for two
3830 // reasons: we double-count symbols that occur in more than one
3831 // object file, and we count symbols that are dropped from the
3832 // output. Add it all together and assume we overcount by 100%.
3835 // We assume all symbols will go into both the sympool and dynpool.
3836 this->sympool_
.reserve(symbol_count
);
3837 this->dynpool_
.reserve(symbol_count
);
3839 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3840 p
!= input_objects
->relobj_end();
3843 Task_lock_obj
<Object
> tlo(task
, *p
);
3844 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3848 // Create the symbol table sections. Here we also set the final
3849 // values of the symbols. At this point all the loadable sections are
3850 // fully laid out. SHNUM is the number of sections so far.
3853 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3854 Symbol_table
* symtab
,
3860 if (parameters
->target().get_size() == 32)
3862 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3865 else if (parameters
->target().get_size() == 64)
3867 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3873 // Compute file offsets relative to the start of the symtab section.
3876 // Save space for the dummy symbol at the start of the section. We
3877 // never bother to write this out--it will just be left as zero.
3879 unsigned int local_symbol_index
= 1;
3881 // Add STT_SECTION symbols for each Output section which needs one.
3882 for (Section_list::iterator p
= this->section_list_
.begin();
3883 p
!= this->section_list_
.end();
3886 if (!(*p
)->needs_symtab_index())
3887 (*p
)->set_symtab_index(-1U);
3890 (*p
)->set_symtab_index(local_symbol_index
);
3891 ++local_symbol_index
;
3896 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3897 p
!= input_objects
->relobj_end();
3900 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3902 off
+= (index
- local_symbol_index
) * symsize
;
3903 local_symbol_index
= index
;
3906 unsigned int local_symcount
= local_symbol_index
;
3907 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3910 size_t dyn_global_index
;
3912 if (this->dynsym_section_
== NULL
)
3915 dyn_global_index
= 0;
3920 dyn_global_index
= this->dynsym_section_
->info();
3921 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3922 dynoff
= this->dynsym_section_
->offset() + locsize
;
3923 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3924 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3925 == this->dynsym_section_
->data_size() - locsize
);
3928 off_t global_off
= off
;
3929 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3930 &this->sympool_
, &local_symcount
);
3932 if (!parameters
->options().strip_all())
3934 this->sympool_
.set_string_offsets();
3936 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3937 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3941 this->symtab_section_
= osymtab
;
3943 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3945 osymtab
->add_output_section_data(pos
);
3947 // We generate a .symtab_shndx section if we have more than
3948 // SHN_LORESERVE sections. Technically it is possible that we
3949 // don't need one, because it is possible that there are no
3950 // symbols in any of sections with indexes larger than
3951 // SHN_LORESERVE. That is probably unusual, though, and it is
3952 // easier to always create one than to compute section indexes
3953 // twice (once here, once when writing out the symbols).
3954 if (shnum
>= elfcpp::SHN_LORESERVE
)
3956 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3958 Output_section
* osymtab_xindex
=
3959 this->make_output_section(symtab_xindex_name
,
3960 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3961 ORDER_INVALID
, false);
3963 size_t symcount
= off
/ symsize
;
3964 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3966 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3968 osymtab_xindex
->set_link_section(osymtab
);
3969 osymtab_xindex
->set_addralign(4);
3970 osymtab_xindex
->set_entsize(4);
3972 osymtab_xindex
->set_after_input_sections();
3974 // This tells the driver code to wait until the symbol table
3975 // has written out before writing out the postprocessing
3976 // sections, including the .symtab_shndx section.
3977 this->any_postprocessing_sections_
= true;
3980 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3981 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3986 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3987 ostrtab
->add_output_section_data(pstr
);
3990 if (!parameters
->incremental_update())
3991 symtab_off
= align_address(*poff
, align
);
3994 symtab_off
= this->allocate(off
, align
, *poff
);
3996 gold_fallback(_("out of patch space for symbol table; "
3997 "relink with --incremental-full"));
3998 gold_debug(DEBUG_INCREMENTAL
,
3999 "create_symtab_sections: %08lx %08lx .symtab",
4000 static_cast<long>(symtab_off
),
4001 static_cast<long>(off
));
4004 symtab
->set_file_offset(symtab_off
+ global_off
);
4005 osymtab
->set_file_offset(symtab_off
);
4006 osymtab
->finalize_data_size();
4007 osymtab
->set_link_section(ostrtab
);
4008 osymtab
->set_info(local_symcount
);
4009 osymtab
->set_entsize(symsize
);
4011 if (symtab_off
+ off
> *poff
)
4012 *poff
= symtab_off
+ off
;
4016 // Create the .shstrtab section, which holds the names of the
4017 // sections. At the time this is called, we have created all the
4018 // output sections except .shstrtab itself.
4021 Layout::create_shstrtab()
4023 // FIXME: We don't need to create a .shstrtab section if we are
4024 // stripping everything.
4026 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
4028 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
4029 ORDER_INVALID
, false);
4031 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
4033 // We can't write out this section until we've set all the
4034 // section names, and we don't set the names of compressed
4035 // output sections until relocations are complete. FIXME: With
4036 // the current names we use, this is unnecessary.
4037 os
->set_after_input_sections();
4040 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
4041 os
->add_output_section_data(posd
);
4046 // Create the section headers. SIZE is 32 or 64. OFF is the file
4050 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
4052 Output_section_headers
* oshdrs
;
4053 oshdrs
= new Output_section_headers(this,
4054 &this->segment_list_
,
4055 &this->section_list_
,
4056 &this->unattached_section_list_
,
4060 if (!parameters
->incremental_update())
4061 off
= align_address(*poff
, oshdrs
->addralign());
4064 oshdrs
->pre_finalize_data_size();
4065 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
4067 gold_fallback(_("out of patch space for section header table; "
4068 "relink with --incremental-full"));
4069 gold_debug(DEBUG_INCREMENTAL
,
4070 "create_shdrs: %08lx %08lx (section header table)",
4071 static_cast<long>(off
),
4072 static_cast<long>(off
+ oshdrs
->data_size()));
4074 oshdrs
->set_address_and_file_offset(0, off
);
4075 off
+= oshdrs
->data_size();
4078 this->section_headers_
= oshdrs
;
4081 // Count the allocated sections.
4084 Layout::allocated_output_section_count() const
4086 size_t section_count
= 0;
4087 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4088 p
!= this->segment_list_
.end();
4090 section_count
+= (*p
)->output_section_count();
4091 return section_count
;
4094 // Create the dynamic symbol table.
4097 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4098 Symbol_table
* symtab
,
4099 Output_section
** pdynstr
,
4100 unsigned int* plocal_dynamic_count
,
4101 std::vector
<Symbol
*>* pdynamic_symbols
,
4102 Versions
* pversions
)
4104 // Count all the symbols in the dynamic symbol table, and set the
4105 // dynamic symbol indexes.
4107 // Skip symbol 0, which is always all zeroes.
4108 unsigned int index
= 1;
4110 // Add STT_SECTION symbols for each Output section which needs one.
4111 for (Section_list::iterator p
= this->section_list_
.begin();
4112 p
!= this->section_list_
.end();
4115 if (!(*p
)->needs_dynsym_index())
4116 (*p
)->set_dynsym_index(-1U);
4119 (*p
)->set_dynsym_index(index
);
4124 // Count the local symbols that need to go in the dynamic symbol table,
4125 // and set the dynamic symbol indexes.
4126 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4127 p
!= input_objects
->relobj_end();
4130 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4134 unsigned int local_symcount
= index
;
4135 *plocal_dynamic_count
= local_symcount
;
4137 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
4138 &this->dynpool_
, pversions
);
4142 const int size
= parameters
->target().get_size();
4145 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4148 else if (size
== 64)
4150 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4156 // Create the dynamic symbol table section.
4158 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4162 ORDER_DYNAMIC_LINKER
,
4165 // Check for NULL as a linker script may discard .dynsym.
4168 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4171 dynsym
->add_output_section_data(odata
);
4173 dynsym
->set_info(local_symcount
);
4174 dynsym
->set_entsize(symsize
);
4175 dynsym
->set_addralign(align
);
4177 this->dynsym_section_
= dynsym
;
4180 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4183 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4184 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4187 // If there are more than SHN_LORESERVE allocated sections, we
4188 // create a .dynsym_shndx section. It is possible that we don't
4189 // need one, because it is possible that there are no dynamic
4190 // symbols in any of the sections with indexes larger than
4191 // SHN_LORESERVE. This is probably unusual, though, and at this
4192 // time we don't know the actual section indexes so it is
4193 // inconvenient to check.
4194 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4196 Output_section
* dynsym_xindex
=
4197 this->choose_output_section(NULL
, ".dynsym_shndx",
4198 elfcpp::SHT_SYMTAB_SHNDX
,
4200 false, ORDER_DYNAMIC_LINKER
, false);
4202 if (dynsym_xindex
!= NULL
)
4204 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4206 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4208 dynsym_xindex
->set_link_section(dynsym
);
4209 dynsym_xindex
->set_addralign(4);
4210 dynsym_xindex
->set_entsize(4);
4212 dynsym_xindex
->set_after_input_sections();
4214 // This tells the driver code to wait until the symbol table
4215 // has written out before writing out the postprocessing
4216 // sections, including the .dynsym_shndx section.
4217 this->any_postprocessing_sections_
= true;
4221 // Create the dynamic string table section.
4223 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4227 ORDER_DYNAMIC_LINKER
,
4232 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4233 dynstr
->add_output_section_data(strdata
);
4236 dynsym
->set_link_section(dynstr
);
4237 if (this->dynamic_section_
!= NULL
)
4238 this->dynamic_section_
->set_link_section(dynstr
);
4242 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4243 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4247 // Create the hash tables.
4249 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4250 || strcmp(parameters
->options().hash_style(), "both") == 0)
4252 unsigned char* phash
;
4253 unsigned int hashlen
;
4254 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
4257 Output_section
* hashsec
=
4258 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4259 elfcpp::SHF_ALLOC
, false,
4260 ORDER_DYNAMIC_LINKER
, false);
4262 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4266 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4267 hashsec
->add_output_section_data(hashdata
);
4269 if (hashsec
!= NULL
)
4272 hashsec
->set_link_section(dynsym
);
4273 hashsec
->set_entsize(4);
4277 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4280 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4281 || strcmp(parameters
->options().hash_style(), "both") == 0)
4283 unsigned char* phash
;
4284 unsigned int hashlen
;
4285 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
4288 Output_section
* hashsec
=
4289 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4290 elfcpp::SHF_ALLOC
, false,
4291 ORDER_DYNAMIC_LINKER
, false);
4293 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4297 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4298 hashsec
->add_output_section_data(hashdata
);
4300 if (hashsec
!= NULL
)
4303 hashsec
->set_link_section(dynsym
);
4305 // For a 64-bit target, the entries in .gnu.hash do not have
4306 // a uniform size, so we only set the entry size for a
4308 if (parameters
->target().get_size() == 32)
4309 hashsec
->set_entsize(4);
4312 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4317 // Assign offsets to each local portion of the dynamic symbol table.
4320 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4322 Output_section
* dynsym
= this->dynsym_section_
;
4326 off_t off
= dynsym
->offset();
4328 // Skip the dummy symbol at the start of the section.
4329 off
+= dynsym
->entsize();
4331 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4332 p
!= input_objects
->relobj_end();
4335 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4336 off
+= count
* dynsym
->entsize();
4340 // Create the version sections.
4343 Layout::create_version_sections(const Versions
* versions
,
4344 const Symbol_table
* symtab
,
4345 unsigned int local_symcount
,
4346 const std::vector
<Symbol
*>& dynamic_symbols
,
4347 const Output_section
* dynstr
)
4349 if (!versions
->any_defs() && !versions
->any_needs())
4352 switch (parameters
->size_and_endianness())
4354 #ifdef HAVE_TARGET_32_LITTLE
4355 case Parameters::TARGET_32_LITTLE
:
4356 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4358 dynamic_symbols
, dynstr
);
4361 #ifdef HAVE_TARGET_32_BIG
4362 case Parameters::TARGET_32_BIG
:
4363 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4365 dynamic_symbols
, dynstr
);
4368 #ifdef HAVE_TARGET_64_LITTLE
4369 case Parameters::TARGET_64_LITTLE
:
4370 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4372 dynamic_symbols
, dynstr
);
4375 #ifdef HAVE_TARGET_64_BIG
4376 case Parameters::TARGET_64_BIG
:
4377 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4379 dynamic_symbols
, dynstr
);
4387 // Create the version sections, sized version.
4389 template<int size
, bool big_endian
>
4391 Layout::sized_create_version_sections(
4392 const Versions
* versions
,
4393 const Symbol_table
* symtab
,
4394 unsigned int local_symcount
,
4395 const std::vector
<Symbol
*>& dynamic_symbols
,
4396 const Output_section
* dynstr
)
4398 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4399 elfcpp::SHT_GNU_versym
,
4402 ORDER_DYNAMIC_LINKER
,
4405 // Check for NULL since a linker script may discard this section.
4408 unsigned char* vbuf
;
4410 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4416 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4419 vsec
->add_output_section_data(vdata
);
4420 vsec
->set_entsize(2);
4421 vsec
->set_link_section(this->dynsym_section_
);
4424 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4425 if (odyn
!= NULL
&& vsec
!= NULL
)
4426 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4428 if (versions
->any_defs())
4430 Output_section
* vdsec
;
4431 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4432 elfcpp::SHT_GNU_verdef
,
4434 false, ORDER_DYNAMIC_LINKER
, false);
4438 unsigned char* vdbuf
;
4439 unsigned int vdsize
;
4440 unsigned int vdentries
;
4441 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4445 Output_section_data
* vddata
=
4446 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4448 vdsec
->add_output_section_data(vddata
);
4449 vdsec
->set_link_section(dynstr
);
4450 vdsec
->set_info(vdentries
);
4454 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4455 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4460 if (versions
->any_needs())
4462 Output_section
* vnsec
;
4463 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4464 elfcpp::SHT_GNU_verneed
,
4466 false, ORDER_DYNAMIC_LINKER
, false);
4470 unsigned char* vnbuf
;
4471 unsigned int vnsize
;
4472 unsigned int vnentries
;
4473 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4477 Output_section_data
* vndata
=
4478 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4480 vnsec
->add_output_section_data(vndata
);
4481 vnsec
->set_link_section(dynstr
);
4482 vnsec
->set_info(vnentries
);
4486 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4487 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
4493 // Create the .interp section and PT_INTERP segment.
4496 Layout::create_interp(const Target
* target
)
4498 gold_assert(this->interp_segment_
== NULL
);
4500 const char* interp
= parameters
->options().dynamic_linker();
4503 interp
= target
->dynamic_linker();
4504 gold_assert(interp
!= NULL
);
4507 size_t len
= strlen(interp
) + 1;
4509 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
4511 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
4512 elfcpp::SHT_PROGBITS
,
4514 false, ORDER_INTERP
,
4517 osec
->add_output_section_data(odata
);
4520 // Add dynamic tags for the PLT and the dynamic relocs. This is
4521 // called by the target-specific code. This does nothing if not doing
4524 // USE_REL is true for REL relocs rather than RELA relocs.
4526 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4528 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4529 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4530 // some targets have multiple reloc sections in PLT_REL.
4532 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4533 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4536 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4540 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
4541 const Output_data
* plt_rel
,
4542 const Output_data_reloc_generic
* dyn_rel
,
4543 bool add_debug
, bool dynrel_includes_plt
)
4545 Output_data_dynamic
* odyn
= this->dynamic_data_
;
4549 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
4550 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
4552 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
4554 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
4555 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
4556 odyn
->add_constant(elfcpp::DT_PLTREL
,
4557 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
4560 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
4561 || (dynrel_includes_plt
4563 && plt_rel
->output_section() != NULL
))
4565 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
4566 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
4567 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
4569 ? dyn_rel
->output_section()
4570 : plt_rel
->output_section()));
4571 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
4572 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
4573 odyn
->add_section_size(size_tag
,
4574 dyn_rel
->output_section(),
4575 plt_rel
->output_section());
4576 else if (have_dyn_rel
)
4577 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
4579 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
4580 const int size
= parameters
->target().get_size();
4585 rel_tag
= elfcpp::DT_RELENT
;
4587 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
4588 else if (size
== 64)
4589 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
4595 rel_tag
= elfcpp::DT_RELAENT
;
4597 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
4598 else if (size
== 64)
4599 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
4603 odyn
->add_constant(rel_tag
, rel_size
);
4605 if (parameters
->options().combreloc() && have_dyn_rel
)
4607 size_t c
= dyn_rel
->relative_reloc_count();
4609 odyn
->add_constant((use_rel
4610 ? elfcpp::DT_RELCOUNT
4611 : elfcpp::DT_RELACOUNT
),
4616 if (add_debug
&& !parameters
->options().shared())
4618 // The value of the DT_DEBUG tag is filled in by the dynamic
4619 // linker at run time, and used by the debugger.
4620 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
4624 // Finish the .dynamic section and PT_DYNAMIC segment.
4627 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
4628 const Symbol_table
* symtab
)
4630 if (!this->script_options_
->saw_phdrs_clause()
4631 && this->dynamic_section_
!= NULL
)
4633 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
4636 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
4637 elfcpp::PF_R
| elfcpp::PF_W
);
4640 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4644 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
4645 p
!= input_objects
->dynobj_end();
4648 if (!(*p
)->is_needed() && (*p
)->as_needed())
4650 // This dynamic object was linked with --as-needed, but it
4655 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4658 if (parameters
->options().shared())
4660 const char* soname
= parameters
->options().soname();
4662 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4665 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4666 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4667 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4669 sym
= symtab
->lookup(parameters
->options().fini());
4670 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4671 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4673 // Look for .init_array, .preinit_array and .fini_array by checking
4675 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4676 p
!= this->section_list_
.end();
4678 switch((*p
)->type())
4680 case elfcpp::SHT_FINI_ARRAY
:
4681 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4682 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4684 case elfcpp::SHT_INIT_ARRAY
:
4685 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4686 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4688 case elfcpp::SHT_PREINIT_ARRAY
:
4689 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4690 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4696 // Add a DT_RPATH entry if needed.
4697 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4700 std::string rpath_val
;
4701 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4705 if (rpath_val
.empty())
4706 rpath_val
= p
->name();
4709 // Eliminate duplicates.
4710 General_options::Dir_list::const_iterator q
;
4711 for (q
= rpath
.begin(); q
!= p
; ++q
)
4712 if (q
->name() == p
->name())
4717 rpath_val
+= p
->name();
4722 if (!parameters
->options().enable_new_dtags())
4723 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4725 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4728 // Look for text segments that have dynamic relocations.
4729 bool have_textrel
= false;
4730 if (!this->script_options_
->saw_sections_clause())
4732 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4733 p
!= this->segment_list_
.end();
4736 if ((*p
)->type() == elfcpp::PT_LOAD
4737 && ((*p
)->flags() & elfcpp::PF_W
) == 0
4738 && (*p
)->has_dynamic_reloc())
4740 have_textrel
= true;
4747 // We don't know the section -> segment mapping, so we are
4748 // conservative and just look for readonly sections with
4749 // relocations. If those sections wind up in writable segments,
4750 // then we have created an unnecessary DT_TEXTREL entry.
4751 for (Section_list::const_iterator p
= this->section_list_
.begin();
4752 p
!= this->section_list_
.end();
4755 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4756 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4757 && (*p
)->has_dynamic_reloc())
4759 have_textrel
= true;
4765 if (parameters
->options().filter() != NULL
)
4766 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
4767 if (parameters
->options().any_auxiliary())
4769 for (options::String_set::const_iterator p
=
4770 parameters
->options().auxiliary_begin();
4771 p
!= parameters
->options().auxiliary_end();
4773 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
4776 // Add a DT_FLAGS entry if necessary.
4777 unsigned int flags
= 0;
4780 // Add a DT_TEXTREL for compatibility with older loaders.
4781 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4782 flags
|= elfcpp::DF_TEXTREL
;
4784 if (parameters
->options().text())
4785 gold_error(_("read-only segment has dynamic relocations"));
4786 else if (parameters
->options().warn_shared_textrel()
4787 && parameters
->options().shared())
4788 gold_warning(_("shared library text segment is not shareable"));
4790 if (parameters
->options().shared() && this->has_static_tls())
4791 flags
|= elfcpp::DF_STATIC_TLS
;
4792 if (parameters
->options().origin())
4793 flags
|= elfcpp::DF_ORIGIN
;
4794 if (parameters
->options().Bsymbolic())
4796 flags
|= elfcpp::DF_SYMBOLIC
;
4797 // Add DT_SYMBOLIC for compatibility with older loaders.
4798 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4800 if (parameters
->options().now())
4801 flags
|= elfcpp::DF_BIND_NOW
;
4803 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4806 if (parameters
->options().initfirst())
4807 flags
|= elfcpp::DF_1_INITFIRST
;
4808 if (parameters
->options().interpose())
4809 flags
|= elfcpp::DF_1_INTERPOSE
;
4810 if (parameters
->options().loadfltr())
4811 flags
|= elfcpp::DF_1_LOADFLTR
;
4812 if (parameters
->options().nodefaultlib())
4813 flags
|= elfcpp::DF_1_NODEFLIB
;
4814 if (parameters
->options().nodelete())
4815 flags
|= elfcpp::DF_1_NODELETE
;
4816 if (parameters
->options().nodlopen())
4817 flags
|= elfcpp::DF_1_NOOPEN
;
4818 if (parameters
->options().nodump())
4819 flags
|= elfcpp::DF_1_NODUMP
;
4820 if (!parameters
->options().shared())
4821 flags
&= ~(elfcpp::DF_1_INITFIRST
4822 | elfcpp::DF_1_NODELETE
4823 | elfcpp::DF_1_NOOPEN
);
4824 if (parameters
->options().origin())
4825 flags
|= elfcpp::DF_1_ORIGIN
;
4826 if (parameters
->options().now())
4827 flags
|= elfcpp::DF_1_NOW
;
4828 if (parameters
->options().Bgroup())
4829 flags
|= elfcpp::DF_1_GROUP
;
4831 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4834 // Set the size of the _DYNAMIC symbol table to be the size of the
4838 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4840 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4843 odyn
->finalize_data_size();
4844 if (this->dynamic_symbol_
== NULL
)
4846 off_t data_size
= odyn
->data_size();
4847 const int size
= parameters
->target().get_size();
4849 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4850 else if (size
== 64)
4851 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4856 // The mapping of input section name prefixes to output section names.
4857 // In some cases one prefix is itself a prefix of another prefix; in
4858 // such a case the longer prefix must come first. These prefixes are
4859 // based on the GNU linker default ELF linker script.
4861 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4862 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4863 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4865 MAPPING_INIT(".text.", ".text"),
4866 MAPPING_INIT(".rodata.", ".rodata"),
4867 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4868 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4869 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4870 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4871 MAPPING_INIT(".data.", ".data"),
4872 MAPPING_INIT(".bss.", ".bss"),
4873 MAPPING_INIT(".tdata.", ".tdata"),
4874 MAPPING_INIT(".tbss.", ".tbss"),
4875 MAPPING_INIT(".init_array.", ".init_array"),
4876 MAPPING_INIT(".fini_array.", ".fini_array"),
4877 MAPPING_INIT(".sdata.", ".sdata"),
4878 MAPPING_INIT(".sbss.", ".sbss"),
4879 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4880 // differently depending on whether it is creating a shared library.
4881 MAPPING_INIT(".sdata2.", ".sdata"),
4882 MAPPING_INIT(".sbss2.", ".sbss"),
4883 MAPPING_INIT(".lrodata.", ".lrodata"),
4884 MAPPING_INIT(".ldata.", ".ldata"),
4885 MAPPING_INIT(".lbss.", ".lbss"),
4886 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4887 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4888 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4889 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4890 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4891 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4892 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4893 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4894 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4895 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4896 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4897 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4898 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4899 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4900 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4901 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4902 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4903 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4904 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4905 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4906 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4909 #undef MAPPING_INIT_EXACT
4911 const int Layout::section_name_mapping_count
=
4912 (sizeof(Layout::section_name_mapping
)
4913 / sizeof(Layout::section_name_mapping
[0]));
4915 // Choose the output section name to use given an input section name.
4916 // Set *PLEN to the length of the name. *PLEN is initialized to the
4920 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
4923 // gcc 4.3 generates the following sorts of section names when it
4924 // needs a section name specific to a function:
4930 // .data.rel.local.FN
4932 // .data.rel.ro.local.FN
4939 // The GNU linker maps all of those to the part before the .FN,
4940 // except that .data.rel.local.FN is mapped to .data, and
4941 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4942 // beginning with .data.rel.ro.local are grouped together.
4944 // For an anonymous namespace, the string FN can contain a '.'.
4946 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4947 // GNU linker maps to .rodata.
4949 // The .data.rel.ro sections are used with -z relro. The sections
4950 // are recognized by name. We use the same names that the GNU
4951 // linker does for these sections.
4953 // It is hard to handle this in a principled way, so we don't even
4954 // try. We use a table of mappings. If the input section name is
4955 // not found in the table, we simply use it as the output section
4958 const Section_name_mapping
* psnm
= section_name_mapping
;
4959 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4961 if (psnm
->fromlen
> 0)
4963 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4965 *plen
= psnm
->tolen
;
4971 if (strcmp(name
, psnm
->from
) == 0)
4973 *plen
= psnm
->tolen
;
4979 // As an additional complication, .ctors sections are output in
4980 // either .ctors or .init_array sections, and .dtors sections are
4981 // output in either .dtors or .fini_array sections.
4982 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
4984 if (parameters
->options().ctors_in_init_array())
4987 return name
[1] == 'c' ? ".init_array" : ".fini_array";
4992 return name
[1] == 'c' ? ".ctors" : ".dtors";
4995 if (parameters
->options().ctors_in_init_array()
4996 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
4998 // To make .init_array/.fini_array work with gcc we must exclude
4999 // .ctors and .dtors sections from the crtbegin and crtend
5002 || (!Layout::match_file_name(relobj
, "crtbegin")
5003 && !Layout::match_file_name(relobj
, "crtend")))
5006 return name
[1] == 'c' ? ".init_array" : ".fini_array";
5013 // Return true if RELOBJ is an input file whose base name matches
5014 // FILE_NAME. The base name must have an extension of ".o", and must
5015 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5016 // to match crtbegin.o as well as crtbeginS.o without getting confused
5017 // by other possibilities. Overall matching the file name this way is
5018 // a dreadful hack, but the GNU linker does it in order to better
5019 // support gcc, and we need to be compatible.
5022 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
5024 const std::string
& file_name(relobj
->name());
5025 const char* base_name
= lbasename(file_name
.c_str());
5026 size_t match_len
= strlen(match
);
5027 if (strncmp(base_name
, match
, match_len
) != 0)
5029 size_t base_len
= strlen(base_name
);
5030 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
5032 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
5035 // Check if a comdat group or .gnu.linkonce section with the given
5036 // NAME is selected for the link. If there is already a section,
5037 // *KEPT_SECTION is set to point to the existing section and the
5038 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5039 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5040 // *KEPT_SECTION is set to the internal copy and the function returns
5044 Layout::find_or_add_kept_section(const std::string
& name
,
5049 Kept_section
** kept_section
)
5051 // It's normal to see a couple of entries here, for the x86 thunk
5052 // sections. If we see more than a few, we're linking a C++
5053 // program, and we resize to get more space to minimize rehashing.
5054 if (this->signatures_
.size() > 4
5055 && !this->resized_signatures_
)
5057 reserve_unordered_map(&this->signatures_
,
5058 this->number_of_input_files_
* 64);
5059 this->resized_signatures_
= true;
5062 Kept_section candidate
;
5063 std::pair
<Signatures::iterator
, bool> ins
=
5064 this->signatures_
.insert(std::make_pair(name
, candidate
));
5066 if (kept_section
!= NULL
)
5067 *kept_section
= &ins
.first
->second
;
5070 // This is the first time we've seen this signature.
5071 ins
.first
->second
.set_object(object
);
5072 ins
.first
->second
.set_shndx(shndx
);
5074 ins
.first
->second
.set_is_comdat();
5076 ins
.first
->second
.set_is_group_name();
5080 // We have already seen this signature.
5082 if (ins
.first
->second
.is_group_name())
5084 // We've already seen a real section group with this signature.
5085 // If the kept group is from a plugin object, and we're in the
5086 // replacement phase, accept the new one as a replacement.
5087 if (ins
.first
->second
.object() == NULL
5088 && parameters
->options().plugins()->in_replacement_phase())
5090 ins
.first
->second
.set_object(object
);
5091 ins
.first
->second
.set_shndx(shndx
);
5096 else if (is_group_name
)
5098 // This is a real section group, and we've already seen a
5099 // linkonce section with this signature. Record that we've seen
5100 // a section group, and don't include this section group.
5101 ins
.first
->second
.set_is_group_name();
5106 // We've already seen a linkonce section and this is a linkonce
5107 // section. These don't block each other--this may be the same
5108 // symbol name with different section types.
5113 // Store the allocated sections into the section list.
5116 Layout::get_allocated_sections(Section_list
* section_list
) const
5118 for (Section_list::const_iterator p
= this->section_list_
.begin();
5119 p
!= this->section_list_
.end();
5121 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5122 section_list
->push_back(*p
);
5125 // Store the executable sections into the section list.
5128 Layout::get_executable_sections(Section_list
* section_list
) const
5130 for (Section_list::const_iterator p
= this->section_list_
.begin();
5131 p
!= this->section_list_
.end();
5133 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5134 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5135 section_list
->push_back(*p
);
5138 // Create an output segment.
5141 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5143 gold_assert(!parameters
->options().relocatable());
5144 Output_segment
* oseg
= new Output_segment(type
, flags
);
5145 this->segment_list_
.push_back(oseg
);
5147 if (type
== elfcpp::PT_TLS
)
5148 this->tls_segment_
= oseg
;
5149 else if (type
== elfcpp::PT_GNU_RELRO
)
5150 this->relro_segment_
= oseg
;
5151 else if (type
== elfcpp::PT_INTERP
)
5152 this->interp_segment_
= oseg
;
5157 // Return the file offset of the normal symbol table.
5160 Layout::symtab_section_offset() const
5162 if (this->symtab_section_
!= NULL
)
5163 return this->symtab_section_
->offset();
5167 // Return the section index of the normal symbol table. It may have
5168 // been stripped by the -s/--strip-all option.
5171 Layout::symtab_section_shndx() const
5173 if (this->symtab_section_
!= NULL
)
5174 return this->symtab_section_
->out_shndx();
5178 // Write out the Output_sections. Most won't have anything to write,
5179 // since most of the data will come from input sections which are
5180 // handled elsewhere. But some Output_sections do have Output_data.
5183 Layout::write_output_sections(Output_file
* of
) const
5185 for (Section_list::const_iterator p
= this->section_list_
.begin();
5186 p
!= this->section_list_
.end();
5189 if (!(*p
)->after_input_sections())
5194 // Write out data not associated with a section or the symbol table.
5197 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5199 if (!parameters
->options().strip_all())
5201 const Output_section
* symtab_section
= this->symtab_section_
;
5202 for (Section_list::const_iterator p
= this->section_list_
.begin();
5203 p
!= this->section_list_
.end();
5206 if ((*p
)->needs_symtab_index())
5208 gold_assert(symtab_section
!= NULL
);
5209 unsigned int index
= (*p
)->symtab_index();
5210 gold_assert(index
> 0 && index
!= -1U);
5211 off_t off
= (symtab_section
->offset()
5212 + index
* symtab_section
->entsize());
5213 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5218 const Output_section
* dynsym_section
= this->dynsym_section_
;
5219 for (Section_list::const_iterator p
= this->section_list_
.begin();
5220 p
!= this->section_list_
.end();
5223 if ((*p
)->needs_dynsym_index())
5225 gold_assert(dynsym_section
!= NULL
);
5226 unsigned int index
= (*p
)->dynsym_index();
5227 gold_assert(index
> 0 && index
!= -1U);
5228 off_t off
= (dynsym_section
->offset()
5229 + index
* dynsym_section
->entsize());
5230 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5234 // Write out the Output_data which are not in an Output_section.
5235 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5236 p
!= this->special_output_list_
.end();
5241 // Write out the Output_sections which can only be written after the
5242 // input sections are complete.
5245 Layout::write_sections_after_input_sections(Output_file
* of
)
5247 // Determine the final section offsets, and thus the final output
5248 // file size. Note we finalize the .shstrab last, to allow the
5249 // after_input_section sections to modify their section-names before
5251 if (this->any_postprocessing_sections_
)
5253 off_t off
= this->output_file_size_
;
5254 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5256 // Now that we've finalized the names, we can finalize the shstrab.
5258 this->set_section_offsets(off
,
5259 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5261 if (off
> this->output_file_size_
)
5264 this->output_file_size_
= off
;
5268 for (Section_list::const_iterator p
= this->section_list_
.begin();
5269 p
!= this->section_list_
.end();
5272 if ((*p
)->after_input_sections())
5276 this->section_headers_
->write(of
);
5279 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5280 // or as a "tree" where each chunk of the string is hashed and then those
5281 // hashes are put into a (much smaller) string which is hashed with sha1.
5282 // We compute a checksum over the entire file because that is simplest.
5285 Layout::queue_build_id_tasks(Workqueue
* workqueue
, Task_token
* build_id_blocker
,
5288 const size_t filesize
= (this->output_file_size() <= 0 ? 0
5289 : static_cast<size_t>(this->output_file_size()));
5290 if (this->build_id_note_
!= NULL
5291 && strcmp(parameters
->options().build_id(), "tree") == 0
5292 && parameters
->options().build_id_chunk_size_for_treehash() > 0
5295 parameters
->options().build_id_min_file_size_for_treehash()))
5297 static const size_t MD5_OUTPUT_SIZE_IN_BYTES
= 16;
5298 const size_t chunk_size
=
5299 parameters
->options().build_id_chunk_size_for_treehash();
5300 const size_t num_hashes
= ((filesize
- 1) / chunk_size
) + 1;
5301 Task_token
* post_hash_tasks_blocker
= new Task_token(true);
5302 post_hash_tasks_blocker
->add_blockers(num_hashes
);
5303 this->size_of_array_of_hashes_
= num_hashes
* MD5_OUTPUT_SIZE_IN_BYTES
;
5304 const unsigned char* src
= of
->get_input_view(0, filesize
);
5305 this->input_view_
= src
;
5306 unsigned char *dst
= new unsigned char[this->size_of_array_of_hashes_
];
5307 this->array_of_hashes_
= dst
;
5308 for (size_t i
= 0, src_offset
= 0; i
< num_hashes
;
5309 i
++, dst
+= MD5_OUTPUT_SIZE_IN_BYTES
, src_offset
+= chunk_size
)
5311 size_t size
= std::min(chunk_size
, filesize
- src_offset
);
5312 workqueue
->queue(new Hash_task(src
+ src_offset
,
5316 post_hash_tasks_blocker
));
5318 return post_hash_tasks_blocker
;
5320 return build_id_blocker
;
5323 // If a tree-style build ID was requested, the parallel part of that computation
5324 // is already done, and the final hash-of-hashes is computed here. For other
5325 // types of build IDs, all the work is done here.
5328 Layout::write_build_id(Output_file
* of
) const
5330 if (this->build_id_note_
== NULL
)
5333 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5334 this->build_id_note_
->data_size());
5336 if (this->array_of_hashes_
== NULL
)
5338 const size_t output_file_size
= this->output_file_size();
5339 const unsigned char* iv
= of
->get_input_view(0, output_file_size
);
5340 const char* style
= parameters
->options().build_id();
5342 // If we get here with style == "tree" then the output must be
5343 // too small for chunking, and we use SHA-1 in that case.
5344 if ((strcmp(style
, "sha1") == 0) || (strcmp(style
, "tree") == 0))
5345 sha1_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5346 else if (strcmp(style
, "md5") == 0)
5347 md5_buffer(reinterpret_cast<const char*>(iv
), output_file_size
, ov
);
5351 of
->free_input_view(0, output_file_size
, iv
);
5355 // Non-overlapping substrings of the output file have been hashed.
5356 // Compute SHA-1 hash of the hashes.
5357 sha1_buffer(reinterpret_cast<const char*>(this->array_of_hashes_
),
5358 this->size_of_array_of_hashes_
, ov
);
5359 delete[] this->array_of_hashes_
;
5360 of
->free_input_view(0, this->output_file_size(), this->input_view_
);
5363 of
->write_output_view(this->build_id_note_
->offset(),
5364 this->build_id_note_
->data_size(),
5368 // Write out a binary file. This is called after the link is
5369 // complete. IN is the temporary output file we used to generate the
5370 // ELF code. We simply walk through the segments, read them from
5371 // their file offset in IN, and write them to their load address in
5372 // the output file. FIXME: with a bit more work, we could support
5373 // S-records and/or Intel hex format here.
5376 Layout::write_binary(Output_file
* in
) const
5378 gold_assert(parameters
->options().oformat_enum()
5379 == General_options::OBJECT_FORMAT_BINARY
);
5381 // Get the size of the binary file.
5382 uint64_t max_load_address
= 0;
5383 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5384 p
!= this->segment_list_
.end();
5387 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5389 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5390 if (max_paddr
> max_load_address
)
5391 max_load_address
= max_paddr
;
5395 Output_file
out(parameters
->options().output_file_name());
5396 out
.open(max_load_address
);
5398 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5399 p
!= this->segment_list_
.end();
5402 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5404 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5406 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5408 memcpy(vout
, vin
, (*p
)->filesz());
5409 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5410 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5417 // Print the output sections to the map file.
5420 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5422 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5423 p
!= this->segment_list_
.end();
5425 (*p
)->print_sections_to_mapfile(mapfile
);
5428 // Print statistical information to stderr. This is used for --stats.
5431 Layout::print_stats() const
5433 this->namepool_
.print_stats("section name pool");
5434 this->sympool_
.print_stats("output symbol name pool");
5435 this->dynpool_
.print_stats("dynamic name pool");
5437 for (Section_list::const_iterator p
= this->section_list_
.begin();
5438 p
!= this->section_list_
.end();
5440 (*p
)->print_merge_stats();
5443 // Write_sections_task methods.
5445 // We can always run this task.
5448 Write_sections_task::is_runnable()
5453 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5457 Write_sections_task::locks(Task_locker
* tl
)
5459 tl
->add(this, this->output_sections_blocker_
);
5460 tl
->add(this, this->final_blocker_
);
5463 // Run the task--write out the data.
5466 Write_sections_task::run(Workqueue
*)
5468 this->layout_
->write_output_sections(this->of_
);
5471 // Write_data_task methods.
5473 // We can always run this task.
5476 Write_data_task::is_runnable()
5481 // We need to unlock FINAL_BLOCKER when finished.
5484 Write_data_task::locks(Task_locker
* tl
)
5486 tl
->add(this, this->final_blocker_
);
5489 // Run the task--write out the data.
5492 Write_data_task::run(Workqueue
*)
5494 this->layout_
->write_data(this->symtab_
, this->of_
);
5497 // Write_symbols_task methods.
5499 // We can always run this task.
5502 Write_symbols_task::is_runnable()
5507 // We need to unlock FINAL_BLOCKER when finished.
5510 Write_symbols_task::locks(Task_locker
* tl
)
5512 tl
->add(this, this->final_blocker_
);
5515 // Run the task--write out the symbols.
5518 Write_symbols_task::run(Workqueue
*)
5520 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
5521 this->layout_
->symtab_xindex(),
5522 this->layout_
->dynsym_xindex(), this->of_
);
5525 // Write_after_input_sections_task methods.
5527 // We can only run this task after the input sections have completed.
5530 Write_after_input_sections_task::is_runnable()
5532 if (this->input_sections_blocker_
->is_blocked())
5533 return this->input_sections_blocker_
;
5537 // We need to unlock FINAL_BLOCKER when finished.
5540 Write_after_input_sections_task::locks(Task_locker
* tl
)
5542 tl
->add(this, this->final_blocker_
);
5548 Write_after_input_sections_task::run(Workqueue
*)
5550 this->layout_
->write_sections_after_input_sections(this->of_
);
5553 // Close_task_runner methods.
5555 // Finish up the build ID computation, if necessary, and write a binary file,
5556 // if necessary. Then close the output file.
5559 Close_task_runner::run(Workqueue
*, const Task
*)
5561 // At this point the multi-threaded part of the build ID computation,
5562 // if any, is done. See queue_build_id_tasks().
5563 this->layout_
->write_build_id(this->of_
);
5565 // If we've been asked to create a binary file, we do so here.
5566 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
5567 this->layout_
->write_binary(this->of_
);
5572 // Instantiate the templates we need. We could use the configure
5573 // script to restrict this to only the ones for implemented targets.
5575 #ifdef HAVE_TARGET_32_LITTLE
5578 Layout::init_fixed_output_section
<32, false>(
5580 elfcpp::Shdr
<32, false>& shdr
);
5583 #ifdef HAVE_TARGET_32_BIG
5586 Layout::init_fixed_output_section
<32, true>(
5588 elfcpp::Shdr
<32, true>& shdr
);
5591 #ifdef HAVE_TARGET_64_LITTLE
5594 Layout::init_fixed_output_section
<64, false>(
5596 elfcpp::Shdr
<64, false>& shdr
);
5599 #ifdef HAVE_TARGET_64_BIG
5602 Layout::init_fixed_output_section
<64, true>(
5604 elfcpp::Shdr
<64, true>& shdr
);
5607 #ifdef HAVE_TARGET_32_LITTLE
5610 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
5613 const elfcpp::Shdr
<32, false>& shdr
,
5614 unsigned int, unsigned int, off_t
*);
5617 #ifdef HAVE_TARGET_32_BIG
5620 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
5623 const elfcpp::Shdr
<32, true>& shdr
,
5624 unsigned int, unsigned int, off_t
*);
5627 #ifdef HAVE_TARGET_64_LITTLE
5630 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
5633 const elfcpp::Shdr
<64, false>& shdr
,
5634 unsigned int, unsigned int, off_t
*);
5637 #ifdef HAVE_TARGET_64_BIG
5640 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
5643 const elfcpp::Shdr
<64, true>& shdr
,
5644 unsigned int, unsigned int, off_t
*);
5647 #ifdef HAVE_TARGET_32_LITTLE
5650 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
5651 unsigned int reloc_shndx
,
5652 const elfcpp::Shdr
<32, false>& shdr
,
5653 Output_section
* data_section
,
5654 Relocatable_relocs
* rr
);
5657 #ifdef HAVE_TARGET_32_BIG
5660 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
5661 unsigned int reloc_shndx
,
5662 const elfcpp::Shdr
<32, true>& shdr
,
5663 Output_section
* data_section
,
5664 Relocatable_relocs
* rr
);
5667 #ifdef HAVE_TARGET_64_LITTLE
5670 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
5671 unsigned int reloc_shndx
,
5672 const elfcpp::Shdr
<64, false>& shdr
,
5673 Output_section
* data_section
,
5674 Relocatable_relocs
* rr
);
5677 #ifdef HAVE_TARGET_64_BIG
5680 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
5681 unsigned int reloc_shndx
,
5682 const elfcpp::Shdr
<64, true>& shdr
,
5683 Output_section
* data_section
,
5684 Relocatable_relocs
* rr
);
5687 #ifdef HAVE_TARGET_32_LITTLE
5690 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
5691 Sized_relobj_file
<32, false>* object
,
5693 const char* group_section_name
,
5694 const char* signature
,
5695 const elfcpp::Shdr
<32, false>& shdr
,
5696 elfcpp::Elf_Word flags
,
5697 std::vector
<unsigned int>* shndxes
);
5700 #ifdef HAVE_TARGET_32_BIG
5703 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
5704 Sized_relobj_file
<32, true>* object
,
5706 const char* group_section_name
,
5707 const char* signature
,
5708 const elfcpp::Shdr
<32, true>& shdr
,
5709 elfcpp::Elf_Word flags
,
5710 std::vector
<unsigned int>* shndxes
);
5713 #ifdef HAVE_TARGET_64_LITTLE
5716 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
5717 Sized_relobj_file
<64, false>* object
,
5719 const char* group_section_name
,
5720 const char* signature
,
5721 const elfcpp::Shdr
<64, false>& shdr
,
5722 elfcpp::Elf_Word flags
,
5723 std::vector
<unsigned int>* shndxes
);
5726 #ifdef HAVE_TARGET_64_BIG
5729 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
5730 Sized_relobj_file
<64, true>* object
,
5732 const char* group_section_name
,
5733 const char* signature
,
5734 const elfcpp::Shdr
<64, true>& shdr
,
5735 elfcpp::Elf_Word flags
,
5736 std::vector
<unsigned int>* shndxes
);
5739 #ifdef HAVE_TARGET_32_LITTLE
5742 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
5743 const unsigned char* symbols
,
5745 const unsigned char* symbol_names
,
5746 off_t symbol_names_size
,
5748 const elfcpp::Shdr
<32, false>& shdr
,
5749 unsigned int reloc_shndx
,
5750 unsigned int reloc_type
,
5754 #ifdef HAVE_TARGET_32_BIG
5757 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
5758 const unsigned char* symbols
,
5760 const unsigned char* symbol_names
,
5761 off_t symbol_names_size
,
5763 const elfcpp::Shdr
<32, true>& shdr
,
5764 unsigned int reloc_shndx
,
5765 unsigned int reloc_type
,
5769 #ifdef HAVE_TARGET_64_LITTLE
5772 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
5773 const unsigned char* symbols
,
5775 const unsigned char* symbol_names
,
5776 off_t symbol_names_size
,
5778 const elfcpp::Shdr
<64, false>& shdr
,
5779 unsigned int reloc_shndx
,
5780 unsigned int reloc_type
,
5784 #ifdef HAVE_TARGET_64_BIG
5787 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
5788 const unsigned char* symbols
,
5790 const unsigned char* symbol_names
,
5791 off_t symbol_names_size
,
5793 const elfcpp::Shdr
<64, true>& shdr
,
5794 unsigned int reloc_shndx
,
5795 unsigned int reloc_type
,
5799 #ifdef HAVE_TARGET_32_LITTLE
5802 Layout::add_to_gdb_index(bool is_type_unit
,
5803 Sized_relobj
<32, false>* object
,
5804 const unsigned char* symbols
,
5807 unsigned int reloc_shndx
,
5808 unsigned int reloc_type
);
5811 #ifdef HAVE_TARGET_32_BIG
5814 Layout::add_to_gdb_index(bool is_type_unit
,
5815 Sized_relobj
<32, true>* object
,
5816 const unsigned char* symbols
,
5819 unsigned int reloc_shndx
,
5820 unsigned int reloc_type
);
5823 #ifdef HAVE_TARGET_64_LITTLE
5826 Layout::add_to_gdb_index(bool is_type_unit
,
5827 Sized_relobj
<64, false>* object
,
5828 const unsigned char* symbols
,
5831 unsigned int reloc_shndx
,
5832 unsigned int reloc_type
);
5835 #ifdef HAVE_TARGET_64_BIG
5838 Layout::add_to_gdb_index(bool is_type_unit
,
5839 Sized_relobj
<64, true>* object
,
5840 const unsigned char* symbols
,
5843 unsigned int reloc_shndx
,
5844 unsigned int reloc_type
);
5847 } // End namespace gold.