1 // layout.h -- lay out output file sections for gold -*- C++ -*-
2
3 // Copyright (C) 2006-2023 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #ifndef GOLD_LAYOUT_H
24 #define GOLD_LAYOUT_H
25
26 #include <cstring>
27 #include <list>
28 #include <map>
29 #include <string>
30 #include <utility>
31 #include <vector>
32
33 #include "script.h"
34 #include "workqueue.h"
35 #include "object.h"
36 #include "dynobj.h"
37 #include "stringpool.h"
38
39 namespace gold
40 {
41
42 class General_options;
43 class Incremental_inputs;
44 class Incremental_binary;
45 class Input_objects;
46 class Mapfile;
47 class Symbol_table;
48 class Output_section_data;
49 class Output_section;
50 class Output_section_headers;
51 class Output_segment_headers;
52 class Output_file_header;
53 class Output_segment;
54 class Output_data;
55 class Output_data_reloc_generic;
56 class Output_data_dynamic;
57 class Output_symtab_xindex;
58 class Output_reduced_debug_abbrev_section;
59 class Output_reduced_debug_info_section;
60 class Eh_frame;
61 class Gdb_index;
62 class Target;
63 struct Timespec;
64
65 // Return TRUE if SECNAME is the name of a compressed debug section.
66 extern bool
67 is_compressed_debug_section(const char* secname);
68
69 // Return the name of the corresponding uncompressed debug section.
70 extern std::string
71 corresponding_uncompressed_section_name(std::string secname);
72
73 // Maintain a list of free space within a section, segment, or file.
74 // Used for incremental update links.
75
76 class Free_list
77 {
78 public:
79 struct Free_list_node
80 {
81 Free_list_node(off_t start, off_t end)
82 : start_(start), end_(end)
83 { }
84 off_t start_;
85 off_t end_;
86 };
87 typedef std::list<Free_list_node>::const_iterator Const_iterator;
88
89 Free_list()
90 : list_(), last_remove_(list_.begin()), extend_(false), length_(0),
91 min_hole_(0)
92 { }
93
94 // Initialize the free list for a section of length LEN.
95 // If EXTEND is true, free space may be allocated past the end.
96 void
97 init(off_t len, bool extend);
98
99 // Set the minimum hole size that is allowed when allocating
100 // from the free list.
101 void
102 set_min_hole_size(off_t min_hole)
103 { this->min_hole_ = min_hole; }
104
105 // Remove a chunk from the free list.
106 void
107 remove(off_t start, off_t end);
108
109 // Allocate a chunk of space from the free list of length LEN,
110 // with alignment ALIGN, and minimum offset MINOFF.
111 off_t
112 allocate(off_t len, uint64_t align, off_t minoff);
113
114 // Return an iterator for the beginning of the free list.
115 Const_iterator
116 begin() const
117 { return this->list_.begin(); }
118
119 // Return an iterator for the end of the free list.
120 Const_iterator
121 end() const
122 { return this->list_.end(); }
123
124 // Dump the free list (for debugging).
125 void
126 dump();
127
128 // Print usage statistics.
129 static void
130 print_stats();
131
132 private:
133 typedef std::list<Free_list_node>::iterator Iterator;
134
135 // The free list.
136 std::list<Free_list_node> list_;
137
138 // The last node visited during a remove operation.
139 Iterator last_remove_;
140
141 // Whether we can extend past the original length.
142 bool extend_;
143
144 // The total length of the section, segment, or file.
145 off_t length_;
146
147 // The minimum hole size allowed. When allocating from the free list,
148 // we must not leave a hole smaller than this.
149 off_t min_hole_;
150
151 // Statistics:
152 // The total number of free lists used.
153 static unsigned int num_lists;
154 // The total number of free list nodes used.
155 static unsigned int num_nodes;
156 // The total number of calls to Free_list::remove.
157 static unsigned int num_removes;
158 // The total number of nodes visited during calls to Free_list::remove.
159 static unsigned int num_remove_visits;
160 // The total number of calls to Free_list::allocate.
161 static unsigned int num_allocates;
162 // The total number of nodes visited during calls to Free_list::allocate.
163 static unsigned int num_allocate_visits;
164 };
165
166 // This task function handles mapping the input sections to output
167 // sections and laying them out in memory.
168
169 class Layout_task_runner : public Task_function_runner
170 {
171 public:
172 // OPTIONS is the command line options, INPUT_OBJECTS is the list of
173 // input objects, SYMTAB is the symbol table, LAYOUT is the layout
174 // object.
175 Layout_task_runner(const General_options& options,
176 const Input_objects* input_objects,
177 Symbol_table* symtab,
178 Target* target,
179 Layout* layout,
180 Mapfile* mapfile)
181 : options_(options), input_objects_(input_objects), symtab_(symtab),
182 target_(target), layout_(layout), mapfile_(mapfile)
183 { }
184
185 // Run the operation.
186 void
187 run(Workqueue*, const Task*);
188
189 private:
190 Layout_task_runner(const Layout_task_runner&);
191 Layout_task_runner& operator=(const Layout_task_runner&);
192
193 const General_options& options_;
194 const Input_objects* input_objects_;
195 Symbol_table* symtab_;
196 Target* target_;
197 Layout* layout_;
198 Mapfile* mapfile_;
199 };
200
201 // This class holds information about the comdat group or
202 // .gnu.linkonce section that will be kept for a given signature.
203
204 class Kept_section
205 {
206 private:
207 // For a comdat group, we build a mapping from the name of each
208 // section in the group to the section index and the size in object.
209 // When we discard a group in some other object file, we use this
210 // map to figure out which kept section the discarded section is
211 // associated with. We then use that mapping when processing relocs
212 // against discarded sections.
213 struct Comdat_section_info
214 {
215 // The section index.
216 unsigned int shndx;
217 // The section size.
218 uint64_t size;
219
220 Comdat_section_info(unsigned int a_shndx, uint64_t a_size)
221 : shndx(a_shndx), size(a_size)
222 { }
223 };
224
225 // Most comdat groups have only one or two sections, so we use a
226 // std::map rather than an Unordered_map to optimize for that case
227 // without paying too heavily for groups with more sections.
228 typedef std::map<std::string, Comdat_section_info> Comdat_group;
229
230 public:
231 Kept_section()
232 : object_(NULL), shndx_(0), is_comdat_(false), is_group_name_(false)
233 { this->u_.linkonce_size = 0; }
234
235 // We need to support copies for the signature map in the Layout
236 // object, but we should never copy an object after it has been
237 // marked as a comdat section.
238 Kept_section(const Kept_section& k)
239 : object_(k.object_), shndx_(k.shndx_), is_comdat_(false),
240 is_group_name_(k.is_group_name_)
241 {
242 gold_assert(!k.is_comdat_);
243 this->u_.linkonce_size = 0;
244 }
245
246 ~Kept_section()
247 {
248 if (this->is_comdat_)
249 delete this->u_.group_sections;
250 }
251
252 // The object where this section lives.
253 Relobj*
254 object() const
255 { return this->object_; }
256
257 // Set the object.
258 void
259 set_object(Relobj* object)
260 {
261 gold_assert(this->object_ == NULL);
262 this->object_ = object;
263 }
264
265 // The section index.
266 unsigned int
267 shndx() const
268 { return this->shndx_; }
269
270 // Set the section index.
271 void
272 set_shndx(unsigned int shndx)
273 {
274 gold_assert(this->shndx_ == 0);
275 this->shndx_ = shndx;
276 }
277
278 // Whether this is a comdat group.
279 bool
280 is_comdat() const
281 { return this->is_comdat_; }
282
283 // Set that this is a comdat group.
284 void
285 set_is_comdat()
286 {
287 gold_assert(!this->is_comdat_);
288 this->is_comdat_ = true;
289 this->u_.group_sections = new Comdat_group();
290 }
291
292 // Whether this is associated with the name of a group or section
293 // rather than the symbol name derived from a linkonce section.
294 bool
295 is_group_name() const
296 { return this->is_group_name_; }
297
298 // Note that this represents a comdat group rather than a single
299 // linkonce section.
300 void
301 set_is_group_name()
302 { this->is_group_name_ = true; }
303
304 // Add a section to the group list.
305 void
306 add_comdat_section(const std::string& name, unsigned int shndx,
307 uint64_t size)
308 {
309 gold_assert(this->is_comdat_);
310 Comdat_section_info sinfo(shndx, size);
311 this->u_.group_sections->insert(std::make_pair(name, sinfo));
312 }
313
314 // Look for a section name in the group list, and return whether it
315 // was found. If found, returns the section index and size.
316 bool
317 find_comdat_section(const std::string& name, unsigned int* pshndx,
318 uint64_t* psize) const
319 {
320 gold_assert(this->is_comdat_);
321 Comdat_group::const_iterator p = this->u_.group_sections->find(name);
322 if (p == this->u_.group_sections->end())
323 return false;
324 *pshndx = p->second.shndx;
325 *psize = p->second.size;
326 return true;
327 }
328
329 // If there is only one section in the group list, return true, and
330 // return the section index and size.
331 bool
332 find_single_comdat_section(unsigned int* pshndx, uint64_t* psize) const
333 {
334 gold_assert(this->is_comdat_);
335 if (this->u_.group_sections->size() != 1)
336 return false;
337 Comdat_group::const_iterator p = this->u_.group_sections->begin();
338 *pshndx = p->second.shndx;
339 *psize = p->second.size;
340 return true;
341 }
342
343 // Return the size of a linkonce section.
344 uint64_t
345 linkonce_size() const
346 {
347 gold_assert(!this->is_comdat_);
348 return this->u_.linkonce_size;
349 }
350
351 // Set the size of a linkonce section.
352 void
353 set_linkonce_size(uint64_t size)
354 {
355 gold_assert(!this->is_comdat_);
356 this->u_.linkonce_size = size;
357 }
358
359 private:
360 // No assignment.
361 Kept_section& operator=(const Kept_section&);
362
363 // The object containing the comdat group or .gnu.linkonce section.
364 Relobj* object_;
365 // Index of the group section for comdats and the section itself for
366 // .gnu.linkonce.
367 unsigned int shndx_;
368 // True if this is for a comdat group rather than a .gnu.linkonce
369 // section.
370 bool is_comdat_;
371 // The Kept_sections are values of a mapping, that maps names to
372 // them. This field is true if this struct is associated with the
373 // name of a comdat or .gnu.linkonce, false if it is associated with
374 // the name of a symbol obtained from the .gnu.linkonce.* name
375 // through some heuristics.
376 bool is_group_name_;
377 union
378 {
379 // If the is_comdat_ field is true, this holds a map from names of
380 // the sections in the group to section indexes in object_ and to
381 // section sizes.
382 Comdat_group* group_sections;
383 // If the is_comdat_ field is false, this holds the size of the
384 // single section.
385 uint64_t linkonce_size;
386 } u_;
387 };
388
389 // The ordering for output sections. This controls how output
390 // sections are ordered within a PT_LOAD output segment.
391
392 enum Output_section_order
393 {
394 // Unspecified. Used for non-load segments. Also used for the file
395 // and segment headers.
396 ORDER_INVALID,
397
398 // The PT_INTERP section should come first, so that the dynamic
399 // linker can pick it up quickly.
400 ORDER_INTERP,
401
402 // The .note.gnu.property section comes next so that the PT_NOTE
403 // segment is on the first page of the executable and it won't be
404 // placed between other note sections with different alignments.
405 ORDER_PROPERTY_NOTE,
406
407 // Loadable read-only note sections come after the .note.gnu.property
408 // section.
409 ORDER_RO_NOTE,
410
411 // Put read-only sections used by the dynamic linker early in the
412 // executable to minimize paging.
413 ORDER_DYNAMIC_LINKER,
414
415 // Put reloc sections used by the dynamic linker after other
416 // sections used by the dynamic linker; otherwise, objcopy and strip
417 // get confused.
418 ORDER_DYNAMIC_RELOCS,
419
420 // Put the PLT reloc section after the other dynamic relocs;
421 // otherwise, prelink gets confused.
422 ORDER_DYNAMIC_PLT_RELOCS,
423
424 // The .init section.
425 ORDER_INIT,
426
427 // The PLT.
428 ORDER_PLT,
429
430 // The hot text sections, prefixed by .text.hot.
431 ORDER_TEXT_HOT,
432
433 // The regular text sections.
434 ORDER_TEXT,
435
436 // The startup text sections, prefixed by .text.startup.
437 ORDER_TEXT_STARTUP,
438
439 // The startup text sections, prefixed by .text.startup.
440 ORDER_TEXT_EXIT,
441
442 // The unlikely text sections, prefixed by .text.unlikely.
443 ORDER_TEXT_UNLIKELY,
444
445 // The .fini section.
446 ORDER_FINI,
447
448 // The read-only sections.
449 ORDER_READONLY,
450
451 // The exception frame sections.
452 ORDER_EHFRAME,
453
454 // The TLS sections come first in the data section.
455 ORDER_TLS_DATA,
456 ORDER_TLS_BSS,
457
458 // Local RELRO (read-only after relocation) sections come before
459 // non-local RELRO sections. This data will be fully resolved by
460 // the prelinker.
461 ORDER_RELRO_LOCAL,
462
463 // Non-local RELRO sections are grouped together after local RELRO
464 // sections. All RELRO sections must be adjacent so that they can
465 // all be put into a PT_GNU_RELRO segment.
466 ORDER_RELRO,
467
468 // We permit marking exactly one output section as the last RELRO
469 // section. We do this so that the read-only GOT can be adjacent to
470 // the writable GOT.
471 ORDER_RELRO_LAST,
472
473 // Similarly, we permit marking exactly one output section as the
474 // first non-RELRO section.
475 ORDER_NON_RELRO_FIRST,
476
477 // The regular data sections come after the RELRO sections.
478 ORDER_DATA,
479
480 // Large data sections normally go in large data segments.
481 ORDER_LARGE_DATA,
482
483 // Group writable notes so that we can have a single PT_NOTE
484 // segment.
485 ORDER_RW_NOTE,
486
487 // The small data sections must be at the end of the data sections,
488 // so that they can be adjacent to the small BSS sections.
489 ORDER_SMALL_DATA,
490
491 // The BSS sections start here.
492
493 // The small BSS sections must be at the start of the BSS sections,
494 // so that they can be adjacent to the small data sections.
495 ORDER_SMALL_BSS,
496
497 // The regular BSS sections.
498 ORDER_BSS,
499
500 // The large BSS sections come after the other BSS sections.
501 ORDER_LARGE_BSS,
502
503 // Maximum value.
504 ORDER_MAX
505 };
506
507 // This class handles the details of laying out input sections.
508
509 class Layout
510 {
511 public:
512 Layout(int number_of_input_files, Script_options*);
513
514 ~Layout()
515 {
516 delete this->relaxation_debug_check_;
517 delete this->segment_states_;
518 }
519
520 // For incremental links, record the base file to be modified.
521 void
522 set_incremental_base(Incremental_binary* base);
523
524 Incremental_binary*
525 incremental_base()
526 { return this->incremental_base_; }
527
528 // For incremental links, record the initial fixed layout of a section
529 // from the base file, and return a pointer to the Output_section.
530 template<int size, bool big_endian>
531 Output_section*
532 init_fixed_output_section(const char*, elfcpp::Shdr<size, big_endian>&);
533
534 // Given an input section SHNDX, named NAME, with data in SHDR, from
535 // the object file OBJECT, return the output section where this
536 // input section should go. RELOC_SHNDX is the index of a
537 // relocation section which applies to this section, or 0 if none,
538 // or -1U if more than one. RELOC_TYPE is the type of the
539 // relocation section if there is one. Set *OFFSET to the offset
540 // within the output section.
541 template<int size, bool big_endian>
542 Output_section*
543 layout(Sized_relobj_file<size, big_endian> *object, unsigned int shndx,
544 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
545 unsigned int sh_type, unsigned int reloc_shndx,
546 unsigned int reloc_type, off_t* offset);
547
548 std::map<Section_id, unsigned int>*
549 get_section_order_map()
550 { return &this->section_order_map_; }
551
552 // Struct to store segment info when mapping some input sections to
553 // unique segments using linker plugins. Mapping an input section to
554 // a unique segment is done by first placing such input sections in
555 // unique output sections and then mapping the output section to a
556 // unique segment. NAME is the name of the output section. FLAGS
557 // and ALIGN are the extra flags and alignment of the segment.
558 struct Unique_segment_info
559 {
560 // Identifier for the segment. ELF segments don't have names. This
561 // is used as the name of the output section mapped to the segment.
562 const char* name;
563 // Additional segment flags.
564 uint64_t flags;
565 // Segment alignment.
566 uint64_t align;
567 };
568
569 // Mapping from input section to segment.
570 typedef std::map<Const_section_id, Unique_segment_info*>
571 Section_segment_map;
572
573 // Maps section SECN to SEGMENT s.
574 void
575 insert_section_segment_map(Const_section_id secn, Unique_segment_info *s);
576
577 // Some input sections require special ordering, for compatibility
578 // with GNU ld. Given the name of an input section, return -1 if it
579 // does not require special ordering. Otherwise, return the index
580 // by which it should be ordered compared to other input sections
581 // that require special ordering.
582 static int
583 special_ordering_of_input_section(const char* name);
584
585 bool
586 is_section_ordering_specified()
587 { return this->section_ordering_specified_; }
588
589 void
590 set_section_ordering_specified()
591 { this->section_ordering_specified_ = true; }
592
593 bool
594 is_unique_segment_for_sections_specified() const
595 { return this->unique_segment_for_sections_specified_; }
596
597 void
598 set_unique_segment_for_sections_specified()
599 { this->unique_segment_for_sections_specified_ = true; }
600
601 bool
602 is_lto_slim_object () const
603 { return this->lto_slim_object_; }
604
605 void
606 set_lto_slim_object ()
607 { this->lto_slim_object_ = true; }
608
609 // For incremental updates, allocate a block of memory from the
610 // free list. Find a block starting at or after MINOFF.
611 off_t
612 allocate(off_t len, uint64_t align, off_t minoff)
613 { return this->free_list_.allocate(len, align, minoff); }
614
615 unsigned int
616 find_section_order_index(const std::string&);
617
618 // Read the sequence of input sections from the file specified with
619 // linker option --section-ordering-file.
620 void
621 read_layout_from_file();
622
623 // Layout an input reloc section when doing a relocatable link. The
624 // section is RELOC_SHNDX in OBJECT, with data in SHDR.
625 // DATA_SECTION is the reloc section to which it refers. RR is the
626 // relocatable information.
627 template<int size, bool big_endian>
628 Output_section*
629 layout_reloc(Sized_relobj_file<size, big_endian>* object,
630 unsigned int reloc_shndx,
631 const elfcpp::Shdr<size, big_endian>& shdr,
632 Output_section* data_section,
633 Relocatable_relocs* rr);
634
635 // Layout a group section when doing a relocatable link.
636 template<int size, bool big_endian>
637 void
638 layout_group(Symbol_table* symtab,
639 Sized_relobj_file<size, big_endian>* object,
640 unsigned int group_shndx,
641 const char* group_section_name,
642 const char* signature,
643 const elfcpp::Shdr<size, big_endian>& shdr,
644 elfcpp::Elf_Word flags,
645 std::vector<unsigned int>* shndxes);
646
647 // Like layout, only for exception frame sections. OBJECT is an
648 // object file. SYMBOLS is the contents of the symbol table
649 // section, with size SYMBOLS_SIZE. SYMBOL_NAMES is the contents of
650 // the symbol name section, with size SYMBOL_NAMES_SIZE. SHNDX is a
651 // .eh_frame section in OBJECT. SHDR is the section header.
652 // RELOC_SHNDX is the index of a relocation section which applies to
653 // this section, or 0 if none, or -1U if more than one. RELOC_TYPE
654 // is the type of the relocation section if there is one. This
655 // returns the output section, and sets *OFFSET to the offset.
656 template<int size, bool big_endian>
657 Output_section*
658 layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
659 const unsigned char* symbols,
660 off_t symbols_size,
661 const unsigned char* symbol_names,
662 off_t symbol_names_size,
663 unsigned int shndx,
664 const elfcpp::Shdr<size, big_endian>& shdr,
665 unsigned int reloc_shndx, unsigned int reloc_type,
666 off_t* offset);
667
668 // After processing all input files, we call this to make sure that
669 // the optimized .eh_frame sections have been added to the output
670 // section.
671 void
672 finalize_eh_frame_section();
673
674 // Add .eh_frame information for a PLT. The FDE must start with a
675 // 4-byte PC-relative reference to the start of the PLT, followed by
676 // a 4-byte size of PLT.
677 void
678 add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
679 size_t cie_length, const unsigned char* fde_data,
680 size_t fde_length);
681
682 // Remove all post-map .eh_frame information for a PLT.
683 void
684 remove_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
685 size_t cie_length);
686
687 // Scan a .debug_info or .debug_types section, and add summary
688 // information to the .gdb_index section.
689 template<int size, bool big_endian>
690 void
691 add_to_gdb_index(bool is_type_unit,
692 Sized_relobj<size, big_endian>* object,
693 const unsigned char* symbols,
694 off_t symbols_size,
695 unsigned int shndx,
696 unsigned int reloc_shndx,
697 unsigned int reloc_type);
698
699 // Handle a GNU stack note. This is called once per input object
700 // file. SEEN_GNU_STACK is true if the object file has a
701 // .note.GNU-stack section. GNU_STACK_FLAGS is the section flags
702 // from that section if there was one.
703 void
704 layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
705 const Object*);
706
707 // Layout a .note.gnu.property section.
708 void
709 layout_gnu_property(unsigned int note_type,
710 unsigned int pr_type,
711 size_t pr_datasz,
712 const unsigned char* pr_data,
713 const Object* object);
714
715 // Merge per-object properties with program properties.
716 void
717 merge_gnu_properties(const Object* object);
718
719 // Add a target-specific property for the output .note.gnu.property section.
720 void
721 add_gnu_property(unsigned int note_type,
722 unsigned int pr_type,
723 size_t pr_datasz,
724 const unsigned char* pr_data);
725
726 // Add an Output_section_data to the layout. This is used for
727 // special sections like the GOT section. ORDER is where the
728 // section should wind up in the output segment. IS_RELRO is true
729 // for relro sections.
730 Output_section*
731 add_output_section_data(const char* name, elfcpp::Elf_Word type,
732 elfcpp::Elf_Xword flags,
733 Output_section_data*, Output_section_order order,
734 bool is_relro);
735
736 // Increase the size of the relro segment by this much.
737 void
738 increase_relro(unsigned int s)
739 { this->increase_relro_ += s; }
740
741 // Create dynamic sections if necessary.
742 void
743 create_initial_dynamic_sections(Symbol_table*);
744
745 // Define __start and __stop symbols for output sections.
746 void
747 define_section_symbols(Symbol_table*);
748
749 // Create automatic note sections.
750 void
751 create_notes();
752
753 // Create sections for linker scripts.
754 void
755 create_script_sections()
756 { this->script_options_->create_script_sections(this); }
757
758 // Define symbols from any linker script.
759 void
760 define_script_symbols(Symbol_table* symtab)
761 { this->script_options_->add_symbols_to_table(symtab); }
762
763 // Define symbols for group signatures.
764 void
765 define_group_signatures(Symbol_table*);
766
767 // Return the Stringpool used for symbol names.
768 const Stringpool*
769 sympool() const
770 { return &this->sympool_; }
771
772 // Return the Stringpool used for dynamic symbol names and dynamic
773 // tags.
774 const Stringpool*
775 dynpool() const
776 { return &this->dynpool_; }
777
778 // Return the .dynamic output section. This is only valid after the
779 // layout has been finalized.
780 Output_section*
781 dynamic_section() const
782 { return this->dynamic_section_; }
783
784 // Return the symtab_xindex section used to hold large section
785 // indexes for the normal symbol table.
786 Output_symtab_xindex*
787 symtab_xindex() const
788 { return this->symtab_xindex_; }
789
790 // Return the dynsym_xindex section used to hold large section
791 // indexes for the dynamic symbol table.
792 Output_symtab_xindex*
793 dynsym_xindex() const
794 { return this->dynsym_xindex_; }
795
796 // Return whether a section is a .gnu.linkonce section, given the
797 // section name.
798 static inline bool
799 is_linkonce(const char* name)
800 { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
801
802 // Whether we have added an input section.
803 bool
804 have_added_input_section() const
805 { return this->have_added_input_section_; }
806
807 // Return true if a section is a debugging section.
808 static inline bool
809 is_debug_info_section(const char* name)
810 {
811 // Debugging sections can only be recognized by name.
812 return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
813 || strncmp(name, ".zdebug", sizeof(".zdebug") - 1) == 0
814 || strncmp(name, ".gnu.linkonce.wi.",
815 sizeof(".gnu.linkonce.wi.") - 1) == 0
816 || strncmp(name, ".line", sizeof(".line") - 1) == 0
817 || strncmp(name, ".stab", sizeof(".stab") - 1) == 0
818 || strncmp(name, ".pdr", sizeof(".pdr") - 1) == 0);
819 }
820
821 // Return true if RELOBJ is an input file whose base name matches
822 // FILE_NAME. The base name must have an extension of ".o", and
823 // must be exactly FILE_NAME.o or FILE_NAME, one character, ".o".
824 static bool
825 match_file_name(const Relobj* relobj, const char* file_name);
826
827 // Return whether section SHNDX in RELOBJ is a .ctors/.dtors section
828 // with more than one word being mapped to a .init_array/.fini_array
829 // section.
830 bool
831 is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const;
832
833 // Check if a comdat group or .gnu.linkonce section with the given
834 // NAME is selected for the link. If there is already a section,
835 // *KEPT_SECTION is set to point to the signature and the function
836 // returns false. Otherwise, OBJECT, SHNDX,IS_COMDAT, and
837 // IS_GROUP_NAME are recorded for this NAME in the layout object,
838 // *KEPT_SECTION is set to the internal copy and the function return
839 // false.
840 bool
841 find_or_add_kept_section(const std::string& name, Relobj* object,
842 unsigned int shndx, bool is_comdat,
843 bool is_group_name, Kept_section** kept_section);
844
845 // Finalize the layout after all the input sections have been added.
846 off_t
847 finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
848
849 // Return whether any sections require postprocessing.
850 bool
851 any_postprocessing_sections() const
852 { return this->any_postprocessing_sections_; }
853
854 // Return the size of the output file.
855 off_t
856 output_file_size() const
857 { return this->output_file_size_; }
858
859 // Return the TLS segment. This will return NULL if there isn't
860 // one.
861 Output_segment*
862 tls_segment() const
863 { return this->tls_segment_; }
864
865 // Return the normal symbol table.
866 Output_section*
867 symtab_section() const
868 {
869 gold_assert(this->symtab_section_ != NULL);
870 return this->symtab_section_;
871 }
872
873 // Return the file offset of the normal symbol table.
874 off_t
875 symtab_section_offset() const;
876
877 // Return the section index of the normal symbol tabl.e
878 unsigned int
879 symtab_section_shndx() const;
880
881 // Return the dynamic symbol table.
882 Output_section*
883 dynsym_section() const
884 {
885 gold_assert(this->dynsym_section_ != NULL);
886 return this->dynsym_section_;
887 }
888
889 // Return the dynamic tags.
890 Output_data_dynamic*
891 dynamic_data() const
892 { return this->dynamic_data_; }
893
894 // Write out the output sections.
895 void
896 write_output_sections(Output_file* of) const;
897
898 // Write out data not associated with an input file or the symbol
899 // table.
900 void
901 write_data(const Symbol_table*, Output_file*) const;
902
903 // Write out output sections which can not be written until all the
904 // input sections are complete.
905 void
906 write_sections_after_input_sections(Output_file* of);
907
908 // Return an output section named NAME, or NULL if there is none.
909 Output_section*
910 find_output_section(const char* name) const;
911
912 // Return an output segment of type TYPE, with segment flags SET set
913 // and segment flags CLEAR clear. Return NULL if there is none.
914 Output_segment*
915 find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
916 elfcpp::Elf_Word clear) const;
917
918 // Return the number of segments we expect to produce.
919 size_t
920 expected_segment_count() const;
921
922 // Set a flag to indicate that an object file uses the static TLS model.
923 void
924 set_has_static_tls()
925 { this->has_static_tls_ = true; }
926
927 // Return true if any object file uses the static TLS model.
928 bool
929 has_static_tls() const
930 { return this->has_static_tls_; }
931
932 // Return the options which may be set by a linker script.
933 Script_options*
934 script_options()
935 { return this->script_options_; }
936
937 const Script_options*
938 script_options() const
939 { return this->script_options_; }
940
941 // Return the object managing inputs in incremental build. NULL in
942 // non-incremental builds.
943 Incremental_inputs*
944 incremental_inputs() const
945 { return this->incremental_inputs_; }
946
947 // For the target-specific code to add dynamic tags which are common
948 // to most targets.
949 void
950 add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
951 const Output_data* plt_rel,
952 const Output_data_reloc_generic* dyn_rel,
953 bool add_debug, bool dynrel_includes_plt,
954 bool custom_relcount);
955
956 // Add a target-specific dynamic tag with constant value.
957 void
958 add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val);
959
960 // Compute and write out the build ID if needed.
961 void
962 write_build_id(Output_file*, unsigned char*, size_t) const;
963
964 // Rewrite output file in binary format.
965 void
966 write_binary(Output_file* in) const;
967
968 // Print output sections to the map file.
969 void
970 print_to_mapfile(Mapfile*) const;
971
972 // Dump statistical information to stderr.
973 void
974 print_stats() const;
975
976 // A list of segments.
977
978 typedef std::vector<Output_segment*> Segment_list;
979
980 // A list of sections.
981
982 typedef std::vector<Output_section*> Section_list;
983
984 // The list of information to write out which is not attached to
985 // either a section or a segment.
986 typedef std::vector<Output_data*> Data_list;
987
988 // Store the allocated sections into the section list. This is used
989 // by the linker script code.
990 void
991 get_allocated_sections(Section_list*) const;
992
993 // Store the executable sections into the section list.
994 void
995 get_executable_sections(Section_list*) const;
996
997 // Make a section for a linker script to hold data.
998 Output_section*
999 make_output_section_for_script(const char* name,
1000 Script_sections::Section_type section_type);
1001
1002 // Make a segment. This is used by the linker script code.
1003 Output_segment*
1004 make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
1005
1006 // Return the number of segments.
1007 size_t
1008 segment_count() const
1009 { return this->segment_list_.size(); }
1010
1011 // Map from section flags to segment flags.
1012 static elfcpp::Elf_Word
1013 section_flags_to_segment(elfcpp::Elf_Xword flags);
1014
1015 // Attach sections to segments.
1016 void
1017 attach_sections_to_segments(const Target*);
1018
1019 // For relaxation clean up, we need to know output section data created
1020 // from a linker script.
1021 void
1022 new_output_section_data_from_script(Output_section_data* posd)
1023 {
1024 if (this->record_output_section_data_from_script_)
1025 this->script_output_section_data_list_.push_back(posd);
1026 }
1027
1028 // Return section list.
1029 const Section_list&
1030 section_list() const
1031 { return this->section_list_; }
1032
1033 // Returns TRUE iff NAME (an input section from RELOBJ) will
1034 // be mapped to an output section that should be KEPT.
1035 bool
1036 keep_input_section(const Relobj*, const char*);
1037
1038 // Add a special output object that will be recreated afresh
1039 // if there is another relaxation iteration.
1040 void
1041 add_relax_output(Output_data* data)
1042 { this->relax_output_list_.push_back(data); }
1043
1044 // Clear out (and free) everything added by add_relax_output.
1045 void
1046 reset_relax_output();
1047
1048 private:
1049 Layout(const Layout&);
1050 Layout& operator=(const Layout&);
1051
1052 // Mapping from input section names to output section names.
1053 struct Section_name_mapping
1054 {
1055 const char* from;
1056 int fromlen;
1057 const char* to;
1058 int tolen;
1059 };
1060 static const Section_name_mapping section_name_mapping[];
1061 static const int section_name_mapping_count;
1062 static const Section_name_mapping text_section_name_mapping[];
1063 static const int text_section_name_mapping_count;
1064
1065 // Find section name NAME in map and return the mapped name if found
1066 // with the length set in PLEN.
1067 static const char* match_section_name(const Section_name_mapping* map,
1068 const int count, const char* name,
1069 size_t* plen);
1070
1071 // During a relocatable link, a list of group sections and
1072 // signatures.
1073 struct Group_signature
1074 {
1075 // The group section.
1076 Output_section* section;
1077 // The signature.
1078 const char* signature;
1079
1080 Group_signature()
1081 : section(NULL), signature(NULL)
1082 { }
1083
1084 Group_signature(Output_section* sectiona, const char* signaturea)
1085 : section(sectiona), signature(signaturea)
1086 { }
1087 };
1088 typedef std::vector<Group_signature> Group_signatures;
1089
1090 // Create a note section, filling in the header.
1091 Output_section*
1092 create_note(const char* name, int note_type, const char* section_name,
1093 size_t descsz, bool allocate, size_t* trailing_padding);
1094
1095 // Create a note section for gnu program properties.
1096 void
1097 create_gnu_properties_note();
1098
1099 // Create a note section for gold version.
1100 void
1101 create_gold_note();
1102
1103 // Record whether the stack must be executable, and a user-supplied size.
1104 void
1105 create_stack_segment();
1106
1107 // Create a build ID note if needed.
1108 void
1109 create_build_id();
1110
1111 // Create a package metadata note if needed.
1112 void
1113 create_package_metadata();
1114
1115 // Link .stab and .stabstr sections.
1116 void
1117 link_stabs_sections();
1118
1119 // Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
1120 // for the next run of incremental linking to check what has changed.
1121 void
1122 create_incremental_info_sections(Symbol_table*);
1123
1124 // Find the first read-only PT_LOAD segment, creating one if
1125 // necessary.
1126 Output_segment*
1127 find_first_load_seg(const Target*);
1128
1129 // Count the local symbols in the regular symbol table and the dynamic
1130 // symbol table, and build the respective string pools.
1131 void
1132 count_local_symbols(const Task*, const Input_objects*);
1133
1134 // Create the output sections for the symbol table.
1135 void
1136 create_symtab_sections(const Input_objects*, Symbol_table*,
1137 unsigned int, off_t*, unsigned int);
1138
1139 // Create the .shstrtab section.
1140 Output_section*
1141 create_shstrtab();
1142
1143 // Create the section header table.
1144 void
1145 create_shdrs(const Output_section* shstrtab_section, off_t*);
1146
1147 // Create the dynamic symbol table.
1148 void
1149 create_dynamic_symtab(const Input_objects*, Symbol_table*,
1150 Output_section** pdynstr,
1151 unsigned int* plocal_dynamic_count,
1152 unsigned int* pforced_local_dynamic_count,
1153 std::vector<Symbol*>* pdynamic_symbols,
1154 Versions* versions);
1155
1156 // Assign offsets to each local portion of the dynamic symbol table.
1157 void
1158 assign_local_dynsym_offsets(const Input_objects*);
1159
1160 // Finish the .dynamic section and PT_DYNAMIC segment.
1161 void
1162 finish_dynamic_section(const Input_objects*, const Symbol_table*);
1163
1164 // Set the size of the _DYNAMIC symbol.
1165 void
1166 set_dynamic_symbol_size(const Symbol_table*);
1167
1168 // Create the .interp section and PT_INTERP segment.
1169 void
1170 create_interp(const Target* target);
1171
1172 // Create the version sections.
1173 void
1174 create_version_sections(const Versions*,
1175 const Symbol_table*,
1176 unsigned int local_symcount,
1177 const std::vector<Symbol*>& dynamic_symbols,
1178 const Output_section* dynstr);
1179
1180 template<int size, bool big_endian>
1181 void
1182 sized_create_version_sections(const Versions* versions,
1183 const Symbol_table*,
1184 unsigned int local_symcount,
1185 const std::vector<Symbol*>& dynamic_symbols,
1186 const Output_section* dynstr);
1187
1188 // Return whether to include this section in the link.
1189 template<int size, bool big_endian>
1190 bool
1191 include_section(Sized_relobj_file<size, big_endian>* object, const char* name,
1192 const elfcpp::Shdr<size, big_endian>&);
1193
1194 // Return the output section name to use given an input section
1195 // name. Set *PLEN to the length of the name. *PLEN must be
1196 // initialized to the length of NAME.
1197 static const char*
1198 output_section_name(const Relobj*, const char* name, size_t* plen);
1199
1200 // Return the number of allocated output sections.
1201 size_t
1202 allocated_output_section_count() const;
1203
1204 // Return the output section for NAME, TYPE and FLAGS.
1205 Output_section*
1206 get_output_section(const char* name, Stringpool::Key name_key,
1207 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
1208 Output_section_order order, bool is_relro);
1209
1210 // Clear the input section flags that should not be copied to the
1211 // output section.
1212 elfcpp::Elf_Xword
1213 get_output_section_flags (elfcpp::Elf_Xword input_section_flags);
1214
1215 // Choose the output section for NAME in RELOBJ.
1216 Output_section*
1217 choose_output_section(const Relobj* relobj, const char* name,
1218 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
1219 bool is_input_section, Output_section_order order,
1220 bool is_relro, bool is_reloc, bool match_input_spec);
1221
1222 // Create a new Output_section.
1223 Output_section*
1224 make_output_section(const char* name, elfcpp::Elf_Word type,
1225 elfcpp::Elf_Xword flags, Output_section_order order,
1226 bool is_relro);
1227
1228 // Attach a section to a segment.
1229 void
1230 attach_section_to_segment(const Target*, Output_section*);
1231
1232 // Get section order.
1233 Output_section_order
1234 default_section_order(Output_section*, bool is_relro_local);
1235
1236 // Attach an allocated section to a segment.
1237 void
1238 attach_allocated_section_to_segment(const Target*, Output_section*);
1239
1240 // Make the .eh_frame section.
1241 Output_section*
1242 make_eh_frame_section(const Relobj*);
1243
1244 // Set the final file offsets of all the segments.
1245 off_t
1246 set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
1247
1248 // Set the file offsets of the sections when doing a relocatable
1249 // link.
1250 off_t
1251 set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
1252
1253 // Set the final file offsets of all the sections not associated
1254 // with a segment. We set section offsets in three passes: the
1255 // first handles all allocated sections, the second sections that
1256 // require postprocessing, and the last the late-bound STRTAB
1257 // sections (probably only shstrtab, which is the one we care about
1258 // because it holds section names).
1259 enum Section_offset_pass
1260 {
1261 BEFORE_INPUT_SECTIONS_PASS,
1262 POSTPROCESSING_SECTIONS_PASS,
1263 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
1264 };
1265 off_t
1266 set_section_offsets(off_t, Section_offset_pass pass);
1267
1268 // Set the final section indexes of all the sections not associated
1269 // with a segment. Returns the next unused index.
1270 unsigned int
1271 set_section_indexes(unsigned int pshndx);
1272
1273 // Set the section addresses when using a script.
1274 Output_segment*
1275 set_section_addresses_from_script(Symbol_table*);
1276
1277 // Find appropriate places or orphan sections in a script.
1278 void
1279 place_orphan_sections_in_script();
1280
1281 // Return whether SEG1 comes before SEG2 in the output file.
1282 bool
1283 segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
1284
1285 // Use to save and restore segments during relaxation.
1286 typedef Unordered_map<const Output_segment*, const Output_segment*>
1287 Segment_states;
1288
1289 // Save states of current output segments.
1290 void
1291 save_segments(Segment_states*);
1292
1293 // Restore output segment states.
1294 void
1295 restore_segments(const Segment_states*);
1296
1297 // Clean up after relaxation so that it is possible to lay out the
1298 // sections and segments again.
1299 void
1300 clean_up_after_relaxation();
1301
1302 // Doing preparation work for relaxation. This is factored out to make
1303 // Layout::finalized a bit smaller and easier to read.
1304 void
1305 prepare_for_relaxation();
1306
1307 // Main body of the relaxation loop, which lays out the section.
1308 off_t
1309 relaxation_loop_body(int, Target*, Symbol_table*, Output_segment**,
1310 Output_segment*, Output_segment_headers*,
1311 Output_file_header*, unsigned int*);
1312
1313 // A mapping used for kept comdats/.gnu.linkonce group signatures.
1314 typedef Unordered_map<std::string, Kept_section> Signatures;
1315
1316 // Mapping from input section name/type/flags to output section. We
1317 // use canonicalized strings here.
1318
1319 typedef std::pair<Stringpool::Key,
1320 std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
1321
1322 struct Hash_key
1323 {
1324 size_t
1325 operator()(const Key& k) const;
1326 };
1327
1328 typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
1329
1330 // A comparison class for segments.
1331
1332 class Compare_segments
1333 {
1334 public:
1335 Compare_segments(Layout* layout)
1336 : layout_(layout)
1337 { }
1338
1339 bool
1340 operator()(const Output_segment* seg1, const Output_segment* seg2)
1341 { return this->layout_->segment_precedes(seg1, seg2); }
1342
1343 private:
1344 Layout* layout_;
1345 };
1346
1347 typedef std::vector<Output_section_data*> Output_section_data_list;
1348
1349 // Debug checker class.
1350 class Relaxation_debug_check
1351 {
1352 public:
1353 Relaxation_debug_check()
1354 : section_infos_()
1355 { }
1356
1357 // Check that sections and special data are in reset states.
1358 void
1359 check_output_data_for_reset_values(const Layout::Section_list&,
1360 const Layout::Data_list& special_outputs,
1361 const Layout::Data_list& relax_outputs);
1362
1363 // Record information of a section list.
1364 void
1365 read_sections(const Layout::Section_list&);
1366
1367 // Verify a section list with recorded information.
1368 void
1369 verify_sections(const Layout::Section_list&);
1370
1371 private:
1372 // Information we care about a section.
1373 struct Section_info
1374 {
1375 // Output section described by this.
1376 Output_section* output_section;
1377 // Load address.
1378 uint64_t address;
1379 // Data size.
1380 off_t data_size;
1381 // File offset.
1382 off_t offset;
1383 };
1384
1385 // Section information.
1386 std::vector<Section_info> section_infos_;
1387 };
1388
1389 // Program properties from .note.gnu.property sections.
1390 struct Gnu_property
1391 {
1392 size_t pr_datasz;
1393 unsigned char* pr_data;
1394 };
1395 typedef std::map<unsigned int, Gnu_property> Gnu_properties;
1396
1397 // The number of input files, for sizing tables.
1398 int number_of_input_files_;
1399 // Information set by scripts or by command line options.
1400 Script_options* script_options_;
1401 // The output section names.
1402 Stringpool namepool_;
1403 // The output symbol names.
1404 Stringpool sympool_;
1405 // The dynamic strings, if needed.
1406 Stringpool dynpool_;
1407 // The list of group sections and linkonce sections which we have seen.
1408 Signatures signatures_;
1409 // The mapping from input section name/type/flags to output sections.
1410 Section_name_map section_name_map_;
1411 // The list of output segments.
1412 Segment_list segment_list_;
1413 // The list of output sections.
1414 Section_list section_list_;
1415 // The list of output sections which are not attached to any output
1416 // segment.
1417 Section_list unattached_section_list_;
1418 // The list of unattached Output_data objects which require special
1419 // handling because they are not Output_sections.
1420 Data_list special_output_list_;
1421 // Like special_output_list_, but cleared and recreated on each
1422 // iteration of relaxation.
1423 Data_list relax_output_list_;
1424 // The section headers.
1425 Output_section_headers* section_headers_;
1426 // A pointer to the PT_TLS segment if there is one.
1427 Output_segment* tls_segment_;
1428 // A pointer to the PT_GNU_RELRO segment if there is one.
1429 Output_segment* relro_segment_;
1430 // A pointer to the PT_INTERP segment if there is one.
1431 Output_segment* interp_segment_;
1432 // A backend may increase the size of the PT_GNU_RELRO segment if
1433 // there is one. This is the amount to increase it by.
1434 unsigned int increase_relro_;
1435 // The SHT_SYMTAB output section.
1436 Output_section* symtab_section_;
1437 // The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
1438 Output_symtab_xindex* symtab_xindex_;
1439 // The SHT_DYNSYM output section if there is one.
1440 Output_section* dynsym_section_;
1441 // The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
1442 Output_symtab_xindex* dynsym_xindex_;
1443 // The SHT_DYNAMIC output section if there is one.
1444 Output_section* dynamic_section_;
1445 // The _DYNAMIC symbol if there is one.
1446 Symbol* dynamic_symbol_;
1447 // The dynamic data which goes into dynamic_section_.
1448 Output_data_dynamic* dynamic_data_;
1449 // The exception frame output section if there is one.
1450 Output_section* eh_frame_section_;
1451 // The exception frame data for eh_frame_section_.
1452 Eh_frame* eh_frame_data_;
1453 // Whether we have added eh_frame_data_ to the .eh_frame section.
1454 bool added_eh_frame_data_;
1455 // The exception frame header output section if there is one.
1456 Output_section* eh_frame_hdr_section_;
1457 // The data for the .gdb_index section.
1458 Gdb_index* gdb_index_data_;
1459 // The space for the build ID checksum if there is one.
1460 Output_section_data* build_id_note_;
1461 // The space for the package metadata JSON if there is one.
1462 Output_section_data* package_metadata_note_;
1463 // The output section containing dwarf abbreviations
1464 Output_reduced_debug_abbrev_section* debug_abbrev_;
1465 // The output section containing the dwarf debug info tree
1466 Output_reduced_debug_info_section* debug_info_;
1467 // A list of group sections and their signatures.
1468 Group_signatures group_signatures_;
1469 // The size of the output file.
1470 off_t output_file_size_;
1471 // Whether we have added an input section to an output section.
1472 bool have_added_input_section_;
1473 // Whether we have attached the sections to the segments.
1474 bool sections_are_attached_;
1475 // Whether we have seen an object file marked to require an
1476 // executable stack.
1477 bool input_requires_executable_stack_;
1478 // Whether we have seen at least one object file with an executable
1479 // stack marker.
1480 bool input_with_gnu_stack_note_;
1481 // Whether we have seen at least one object file without an
1482 // executable stack marker.
1483 bool input_without_gnu_stack_note_;
1484 // Whether we have seen an object file that uses the static TLS model.
1485 bool has_static_tls_;
1486 // Whether any sections require postprocessing.
1487 bool any_postprocessing_sections_;
1488 // Whether we have resized the signatures_ hash table.
1489 bool resized_signatures_;
1490 // Whether we have created a .stab*str output section.
1491 bool have_stabstr_section_;
1492 // True if the input sections in the output sections should be sorted
1493 // as specified in a section ordering file.
1494 bool section_ordering_specified_;
1495 // True if some input sections need to be mapped to a unique segment,
1496 // after being mapped to a unique Output_section.
1497 bool unique_segment_for_sections_specified_;
1498 // In incremental build, holds information check the inputs and build the
1499 // .gnu_incremental_inputs section.
1500 Incremental_inputs* incremental_inputs_;
1501 // Whether we record output section data created in script
1502 bool record_output_section_data_from_script_;
1503 // Set if this is a slim LTO object not loaded with a compiler plugin
1504 bool lto_slim_object_;
1505 // List of output data that needs to be removed at relaxation clean up.
1506 Output_section_data_list script_output_section_data_list_;
1507 // Structure to save segment states before entering the relaxation loop.
1508 Segment_states* segment_states_;
1509 // A relaxation debug checker. We only create one when in debugging mode.
1510 Relaxation_debug_check* relaxation_debug_check_;
1511 // Plugins specify section_ordering using this map. This is set in
1512 // update_section_order in plugin.cc
1513 std::map<Section_id, unsigned int> section_order_map_;
1514 // This maps an input section to a unique segment. This is done by first
1515 // placing such input sections in unique output sections and then mapping
1516 // the output section to a unique segment. Unique_segment_info stores
1517 // any additional flags and alignment of the new segment.
1518 Section_segment_map section_segment_map_;
1519 // Hash a pattern to its position in the section ordering file.
1520 Unordered_map<std::string, unsigned int> input_section_position_;
1521 // Vector of glob only patterns in the section_ordering file.
1522 std::vector<std::string> input_section_glob_;
1523 // For incremental links, the base file to be modified.
1524 Incremental_binary* incremental_base_;
1525 // For incremental links, a list of free space within the file.
1526 Free_list free_list_;
1527 // Program properties.
1528 Gnu_properties gnu_properties_;
1529 };
1530
1531 // This task handles writing out data in output sections which is not
1532 // part of an input section, or which requires special handling. When
1533 // this is done, it unblocks both output_sections_blocker and
1534 // final_blocker.
1535
1536 class Write_sections_task : public Task
1537 {
1538 public:
1539 Write_sections_task(const Layout* layout, Output_file* of,
1540 Task_token* output_sections_blocker,
1541 Task_token* input_sections_blocker,
1542 Task_token* final_blocker)
1543 : layout_(layout), of_(of),
1544 output_sections_blocker_(output_sections_blocker),
1545 input_sections_blocker_(input_sections_blocker),
1546 final_blocker_(final_blocker)
1547 { }
1548
1549 // The standard Task methods.
1550
1551 Task_token*
1552 is_runnable();
1553
1554 void
1555 locks(Task_locker*);
1556
1557 void
1558 run(Workqueue*);
1559
1560 std::string
1561 get_name() const
1562 { return "Write_sections_task"; }
1563
1564 private:
1565 class Write_sections_locker;
1566
1567 const Layout* layout_;
1568 Output_file* of_;
1569 Task_token* output_sections_blocker_;
1570 Task_token* input_sections_blocker_;
1571 Task_token* final_blocker_;
1572 };
1573
1574 // This task handles writing out data which is not part of a section
1575 // or segment.
1576
1577 class Write_data_task : public Task
1578 {
1579 public:
1580 Write_data_task(const Layout* layout, const Symbol_table* symtab,
1581 Output_file* of, Task_token* final_blocker)
1582 : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
1583 { }
1584
1585 // The standard Task methods.
1586
1587 Task_token*
1588 is_runnable();
1589
1590 void
1591 locks(Task_locker*);
1592
1593 void
1594 run(Workqueue*);
1595
1596 std::string
1597 get_name() const
1598 { return "Write_data_task"; }
1599
1600 private:
1601 const Layout* layout_;
1602 const Symbol_table* symtab_;
1603 Output_file* of_;
1604 Task_token* final_blocker_;
1605 };
1606
1607 // This task handles writing out the global symbols.
1608
1609 class Write_symbols_task : public Task
1610 {
1611 public:
1612 Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
1613 const Input_objects* /*input_objects*/,
1614 const Stringpool* sympool, const Stringpool* dynpool,
1615 Output_file* of, Task_token* final_blocker)
1616 : layout_(layout), symtab_(symtab),
1617 sympool_(sympool), dynpool_(dynpool), of_(of),
1618 final_blocker_(final_blocker)
1619 { }
1620
1621 // The standard Task methods.
1622
1623 Task_token*
1624 is_runnable();
1625
1626 void
1627 locks(Task_locker*);
1628
1629 void
1630 run(Workqueue*);
1631
1632 std::string
1633 get_name() const
1634 { return "Write_symbols_task"; }
1635
1636 private:
1637 const Layout* layout_;
1638 const Symbol_table* symtab_;
1639 const Stringpool* sympool_;
1640 const Stringpool* dynpool_;
1641 Output_file* of_;
1642 Task_token* final_blocker_;
1643 };
1644
1645 // This task handles writing out data in output sections which can't
1646 // be written out until all the input sections have been handled.
1647 // This is for sections whose contents is based on the contents of
1648 // other output sections.
1649
1650 class Write_after_input_sections_task : public Task
1651 {
1652 public:
1653 Write_after_input_sections_task(Layout* layout, Output_file* of,
1654 Task_token* input_sections_blocker,
1655 Task_token* final_blocker)
1656 : layout_(layout), of_(of),
1657 input_sections_blocker_(input_sections_blocker),
1658 final_blocker_(final_blocker)
1659 { }
1660
1661 // The standard Task methods.
1662
1663 Task_token*
1664 is_runnable();
1665
1666 void
1667 locks(Task_locker*);
1668
1669 void
1670 run(Workqueue*);
1671
1672 std::string
1673 get_name() const
1674 { return "Write_after_input_sections_task"; }
1675
1676 private:
1677 Layout* layout_;
1678 Output_file* of_;
1679 Task_token* input_sections_blocker_;
1680 Task_token* final_blocker_;
1681 };
1682
1683 // This task function handles computation of the build id.
1684 // When using --build-id=tree, it schedules the tasks that
1685 // compute the hashes for each chunk of the file. This task
1686 // cannot run until we have finalized the size of the output
1687 // file, after the completion of Write_after_input_sections_task.
1688
1689 class Build_id_task_runner : public Task_function_runner
1690 {
1691 public:
1692 Build_id_task_runner(const General_options* options, const Layout* layout,
1693 Output_file* of)
1694 : options_(options), layout_(layout), of_(of)
1695 { }
1696
1697 // Run the operation.
1698 void
1699 run(Workqueue*, const Task*);
1700
1701 private:
1702 const General_options* options_;
1703 const Layout* layout_;
1704 Output_file* of_;
1705 };
1706
1707 // This task function handles closing the file.
1708
1709 class Close_task_runner : public Task_function_runner
1710 {
1711 public:
1712 Close_task_runner(const General_options* options, const Layout* layout,
1713 Output_file* of, unsigned char* array_of_hashes,
1714 size_t size_of_hashes)
1715 : options_(options), layout_(layout), of_(of),
1716 array_of_hashes_(array_of_hashes), size_of_hashes_(size_of_hashes)
1717 { }
1718
1719 // Run the operation.
1720 void
1721 run(Workqueue*, const Task*);
1722
1723 private:
1724 const General_options* options_;
1725 const Layout* layout_;
1726 Output_file* of_;
1727 unsigned char* const array_of_hashes_;
1728 const size_t size_of_hashes_;
1729 };
1730
1731 // A small helper function to align an address.
1732
1733 inline uint64_t
1734 align_address(uint64_t address, uint64_t addralign)
1735 {
1736 if (addralign != 0)
1737 address = (address + addralign - 1) &~ (addralign - 1);
1738 return address;
1739 }
1740
1741 } // End namespace gold.
1742
1743 #endif // !defined(GOLD_LAYOUT_H)