Merge branch 'vendor/GCC50'
[dragonfly.git] / contrib / binutils-2.24 / gold / object.h
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f40e693d
JM
1// object.h -- support for an object file for linking in gold -*- C++ -*-
2
3// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
4// Free Software Foundation, Inc.
5// Written by Ian Lance Taylor <iant@google.com>.
6
7// This file is part of gold.
8
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.
13
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.
18
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.
23
24#ifndef GOLD_OBJECT_H
25#define GOLD_OBJECT_H
26
27#include <string>
28#include <vector>
29
30#include "elfcpp.h"
31#include "elfcpp_file.h"
32#include "fileread.h"
33#include "target.h"
34#include "archive.h"
35
36namespace gold
37{
38
39class General_options;
40class Task;
41class Cref;
42class Layout;
43class Output_data;
44class Output_section;
45class Output_file;
46class Output_symtab_xindex;
47class Pluginobj;
48class Dynobj;
49class Object_merge_map;
50class Relocatable_relocs;
51struct Symbols_data;
52
53template<typename Stringpool_char>
54class Stringpool_template;
55
56// Data to pass from read_symbols() to add_symbols().
57
58struct Read_symbols_data
59{
60 Read_symbols_data()
61 : section_headers(NULL), section_names(NULL), symbols(NULL),
62 symbol_names(NULL), versym(NULL), verdef(NULL), verneed(NULL)
63 { }
64
65 ~Read_symbols_data();
66
67 // Section headers.
68 File_view* section_headers;
69 // Section names.
70 File_view* section_names;
71 // Size of section name data in bytes.
72 section_size_type section_names_size;
73 // Symbol data.
74 File_view* symbols;
75 // Size of symbol data in bytes.
76 section_size_type symbols_size;
77 // Offset of external symbols within symbol data. This structure
78 // sometimes contains only external symbols, in which case this will
79 // be zero. Sometimes it contains all symbols.
80 section_offset_type external_symbols_offset;
81 // Symbol names.
82 File_view* symbol_names;
83 // Size of symbol name data in bytes.
84 section_size_type symbol_names_size;
85
86 // Version information. This is only used on dynamic objects.
87 // Version symbol data (from SHT_GNU_versym section).
88 File_view* versym;
89 section_size_type versym_size;
90 // Version definition data (from SHT_GNU_verdef section).
91 File_view* verdef;
92 section_size_type verdef_size;
93 unsigned int verdef_info;
94 // Needed version data (from SHT_GNU_verneed section).
95 File_view* verneed;
96 section_size_type verneed_size;
97 unsigned int verneed_info;
98};
99
100// Information used to print error messages.
101
102struct Symbol_location_info
103{
104 std::string source_file;
105 std::string enclosing_symbol_name;
106 elfcpp::STT enclosing_symbol_type;
107};
108
109// Data about a single relocation section. This is read in
110// read_relocs and processed in scan_relocs.
111
112struct Section_relocs
113{
114 Section_relocs()
115 : contents(NULL)
116 { }
117
118 ~Section_relocs()
119 { delete this->contents; }
120
121 // Index of reloc section.
122 unsigned int reloc_shndx;
123 // Index of section that relocs apply to.
124 unsigned int data_shndx;
125 // Contents of reloc section.
126 File_view* contents;
127 // Reloc section type.
128 unsigned int sh_type;
129 // Number of reloc entries.
130 size_t reloc_count;
131 // Output section.
132 Output_section* output_section;
133 // Whether this section has special handling for offsets.
134 bool needs_special_offset_handling;
135 // Whether the data section is allocated (has the SHF_ALLOC flag set).
136 bool is_data_section_allocated;
137};
138
139// Relocations in an object file. This is read in read_relocs and
140// processed in scan_relocs.
141
142struct Read_relocs_data
143{
144 Read_relocs_data()
145 : local_symbols(NULL)
146 { }
147
148 ~Read_relocs_data()
149 { delete this->local_symbols; }
150
151 typedef std::vector<Section_relocs> Relocs_list;
152 // The relocations.
153 Relocs_list relocs;
154 // The local symbols.
155 File_view* local_symbols;
156};
157
158// The Xindex class manages section indexes for objects with more than
159// 0xff00 sections.
160
161class Xindex
162{
163 public:
164 Xindex(int large_shndx_offset)
165 : large_shndx_offset_(large_shndx_offset), symtab_xindex_()
166 { }
167
168 // Initialize the symtab_xindex_ array, given the object and the
169 // section index of the symbol table to use.
170 template<int size, bool big_endian>
171 void
172 initialize_symtab_xindex(Object*, unsigned int symtab_shndx);
173
174 // Read in the symtab_xindex_ array, given its section index.
175 // PSHDRS may optionally point to the section headers.
176 template<int size, bool big_endian>
177 void
178 read_symtab_xindex(Object*, unsigned int xindex_shndx,
179 const unsigned char* pshdrs);
180
181 // Symbol SYMNDX in OBJECT has a section of SHN_XINDEX; return the
182 // real section index.
183 unsigned int
184 sym_xindex_to_shndx(Object* object, unsigned int symndx);
185
186 private:
187 // The type of the array giving the real section index for symbols
188 // whose st_shndx field holds SHN_XINDEX.
189 typedef std::vector<unsigned int> Symtab_xindex;
190
191 // Adjust a section index if necessary. This should only be called
192 // for ordinary section indexes.
193 unsigned int
194 adjust_shndx(unsigned int shndx)
195 {
196 if (shndx >= elfcpp::SHN_LORESERVE)
197 shndx += this->large_shndx_offset_;
198 return shndx;
199 }
200
201 // Adjust to apply to large section indexes.
202 int large_shndx_offset_;
203 // The data from the SHT_SYMTAB_SHNDX section.
204 Symtab_xindex symtab_xindex_;
205};
206
207// A GOT offset list. A symbol may have more than one GOT offset
208// (e.g., when mixing modules compiled with two different TLS models),
209// but will usually have at most one. GOT_TYPE identifies the type of
210// GOT entry; its values are specific to each target.
211
212class Got_offset_list
213{
214 public:
215 Got_offset_list()
216 : got_type_(-1U), got_offset_(0), got_next_(NULL)
217 { }
218
219 Got_offset_list(unsigned int got_type, unsigned int got_offset)
220 : got_type_(got_type), got_offset_(got_offset), got_next_(NULL)
221 { }
222
223 ~Got_offset_list()
224 {
225 if (this->got_next_ != NULL)
226 {
227 delete this->got_next_;
228 this->got_next_ = NULL;
229 }
230 }
231
232 // Initialize the fields to their default values.
233 void
234 init()
235 {
236 this->got_type_ = -1U;
237 this->got_offset_ = 0;
238 this->got_next_ = NULL;
239 }
240
241 // Set the offset for the GOT entry of type GOT_TYPE.
242 void
243 set_offset(unsigned int got_type, unsigned int got_offset)
244 {
245 if (this->got_type_ == -1U)
246 {
247 this->got_type_ = got_type;
248 this->got_offset_ = got_offset;
249 }
250 else
251 {
252 for (Got_offset_list* g = this; g != NULL; g = g->got_next_)
253 {
254 if (g->got_type_ == got_type)
255 {
256 g->got_offset_ = got_offset;
257 return;
258 }
259 }
260 Got_offset_list* g = new Got_offset_list(got_type, got_offset);
261 g->got_next_ = this->got_next_;
262 this->got_next_ = g;
263 }
264 }
265
266 // Return the offset for a GOT entry of type GOT_TYPE.
267 unsigned int
268 get_offset(unsigned int got_type) const
269 {
270 for (const Got_offset_list* g = this; g != NULL; g = g->got_next_)
271 {
272 if (g->got_type_ == got_type)
273 return g->got_offset_;
274 }
275 return -1U;
276 }
277
278 // Return a pointer to the list, or NULL if the list is empty.
279 const Got_offset_list*
280 get_list() const
281 {
282 if (this->got_type_ == -1U)
283 return NULL;
284 return this;
285 }
286
287 // Abstract visitor class for iterating over GOT offsets.
288 class Visitor
289 {
290 public:
291 Visitor()
292 { }
293
294 virtual
295 ~Visitor()
296 { }
297
298 virtual void
299 visit(unsigned int, unsigned int) = 0;
300 };
301
302 // Loop over all GOT offset entries, calling a visitor class V for each.
303 void
304 for_all_got_offsets(Visitor* v) const
305 {
306 if (this->got_type_ == -1U)
307 return;
308 for (const Got_offset_list* g = this; g != NULL; g = g->got_next_)
309 v->visit(g->got_type_, g->got_offset_);
310 }
311
312 private:
313 unsigned int got_type_;
314 unsigned int got_offset_;
315 Got_offset_list* got_next_;
316};
317
318// Object is an abstract base class which represents either a 32-bit
319// or a 64-bit input object. This can be a regular object file
320// (ET_REL) or a shared object (ET_DYN).
321
322class Object
323{
324 public:
325 typedef std::vector<Symbol*> Symbols;
326
327 // NAME is the name of the object as we would report it to the user
328 // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is
329 // used to read the file. OFFSET is the offset within the input
330 // file--0 for a .o or .so file, something else for a .a file.
331 Object(const std::string& name, Input_file* input_file, bool is_dynamic,
332 off_t offset = 0)
333 : name_(name), input_file_(input_file), offset_(offset), shnum_(-1U),
334 is_dynamic_(is_dynamic), is_needed_(false), uses_split_stack_(false),
335 has_no_split_stack_(false), no_export_(false),
336 is_in_system_directory_(false), as_needed_(false), xindex_(NULL)
337 {
338 if (input_file != NULL)
339 {
340 input_file->file().add_object();
341 this->is_in_system_directory_ = input_file->is_in_system_directory();
342 this->as_needed_ = input_file->options().as_needed();
343 }
344 }
345
346 virtual ~Object()
347 {
348 if (this->input_file_ != NULL)
349 this->input_file_->file().remove_object();
350 }
351
352 // Return the name of the object as we would report it to the user.
353 const std::string&
354 name() const
355 { return this->name_; }
356
357 // Get the offset into the file.
358 off_t
359 offset() const
360 { return this->offset_; }
361
362 // Return whether this is a dynamic object.
363 bool
364 is_dynamic() const
365 { return this->is_dynamic_; }
366
367 // Return whether this object is needed--true if it is a dynamic
368 // object which defines some symbol referenced by a regular object.
369 // We keep the flag here rather than in Dynobj for convenience when
370 // setting it.
371 bool
372 is_needed() const
373 { return this->is_needed_; }
374
375 // Record that this object is needed.
376 void
377 set_is_needed()
378 { this->is_needed_ = true; }
379
380 // Return whether this object was compiled with -fsplit-stack.
381 bool
382 uses_split_stack() const
383 { return this->uses_split_stack_; }
384
385 // Return whether this object contains any functions compiled with
386 // the no_split_stack attribute.
387 bool
388 has_no_split_stack() const
389 { return this->has_no_split_stack_; }
390
391 // Returns NULL for Objects that are not dynamic objects. This method
392 // is overridden in the Dynobj class.
393 Dynobj*
394 dynobj()
395 { return this->do_dynobj(); }
396
397 // Returns NULL for Objects that are not plugin objects. This method
398 // is overridden in the Pluginobj class.
399 Pluginobj*
400 pluginobj()
401 { return this->do_pluginobj(); }
402
403 // Get the file. We pass on const-ness.
404 Input_file*
405 input_file()
406 {
407 gold_assert(this->input_file_ != NULL);
408 return this->input_file_;
409 }
410
411 const Input_file*
412 input_file() const
413 {
414 gold_assert(this->input_file_ != NULL);
415 return this->input_file_;
416 }
417
418 // Lock the underlying file.
419 void
420 lock(const Task* t)
421 {
422 if (this->input_file_ != NULL)
423 this->input_file_->file().lock(t);
424 }
425
426 // Unlock the underlying file.
427 void
428 unlock(const Task* t)
429 {
430 if (this->input_file_ != NULL)
431 this->input_file()->file().unlock(t);
432 }
433
434 // Return whether the underlying file is locked.
435 bool
436 is_locked() const
437 { return this->input_file_ != NULL && this->input_file_->file().is_locked(); }
438
439 // Return the token, so that the task can be queued.
440 Task_token*
441 token()
442 {
443 if (this->input_file_ == NULL)
444 return NULL;
445 return this->input_file()->file().token();
446 }
447
448 // Release the underlying file.
449 void
450 release()
451 {
452 if (this->input_file_ != NULL)
453 this->input_file()->file().release();
454 }
455
456 // Return whether we should just read symbols from this file.
457 bool
458 just_symbols() const
459 { return this->input_file()->just_symbols(); }
460
461 // Return whether this is an incremental object.
462 bool
463 is_incremental() const
464 { return this->do_is_incremental(); }
465
466 // Return the last modified time of the file.
467 Timespec
468 get_mtime()
469 { return this->do_get_mtime(); }
470
471 // Get the number of sections.
472 unsigned int
473 shnum() const
474 { return this->shnum_; }
475
476 // Return a view of the contents of a section. Set *PLEN to the
477 // size. CACHE is a hint as in File_read::get_view.
478 const unsigned char*
479 section_contents(unsigned int shndx, section_size_type* plen, bool cache);
480
481 // Adjust a symbol's section index as needed. SYMNDX is the index
482 // of the symbol and SHNDX is the symbol's section from
483 // get_st_shndx. This returns the section index. It sets
484 // *IS_ORDINARY to indicate whether this is a normal section index,
485 // rather than a special code between SHN_LORESERVE and
486 // SHN_HIRESERVE.
487 unsigned int
488 adjust_sym_shndx(unsigned int symndx, unsigned int shndx, bool* is_ordinary)
489 {
490 if (shndx < elfcpp::SHN_LORESERVE)
491 *is_ordinary = true;
492 else if (shndx == elfcpp::SHN_XINDEX)
493 {
494 if (this->xindex_ == NULL)
495 this->xindex_ = this->do_initialize_xindex();
496 shndx = this->xindex_->sym_xindex_to_shndx(this, symndx);
497 *is_ordinary = true;
498 }
499 else
500 *is_ordinary = false;
501 return shndx;
502 }
503
504 // Return the size of a section given a section index.
505 uint64_t
506 section_size(unsigned int shndx)
507 { return this->do_section_size(shndx); }
508
509 // Return the name of a section given a section index.
510 std::string
511 section_name(unsigned int shndx)
512 { return this->do_section_name(shndx); }
513
514 // Return the section flags given a section index.
515 uint64_t
516 section_flags(unsigned int shndx)
517 { return this->do_section_flags(shndx); }
518
519 // Return the section entsize given a section index.
520 uint64_t
521 section_entsize(unsigned int shndx)
522 { return this->do_section_entsize(shndx); }
523
524 // Return the section address given a section index.
525 uint64_t
526 section_address(unsigned int shndx)
527 { return this->do_section_address(shndx); }
528
529 // Return the section type given a section index.
530 unsigned int
531 section_type(unsigned int shndx)
532 { return this->do_section_type(shndx); }
533
534 // Return the section link field given a section index.
535 unsigned int
536 section_link(unsigned int shndx)
537 { return this->do_section_link(shndx); }
538
539 // Return the section info field given a section index.
540 unsigned int
541 section_info(unsigned int shndx)
542 { return this->do_section_info(shndx); }
543
544 // Return the required section alignment given a section index.
545 uint64_t
546 section_addralign(unsigned int shndx)
547 { return this->do_section_addralign(shndx); }
548
549 // Return the output section given a section index.
550 Output_section*
551 output_section(unsigned int shndx) const
552 { return this->do_output_section(shndx); }
553
554 // Given a section index, return its address.
555 // The return value will be -1U if the section is specially mapped,
556 // such as a merge section.
557 uint64_t
558 output_section_address(unsigned int shndx)
559 { return this->do_output_section_address(shndx); }
560
561 // Given a section index, return the offset in the Output_section.
562 // The return value will be -1U if the section is specially mapped,
563 // such as a merge section.
564 uint64_t
565 output_section_offset(unsigned int shndx) const
566 { return this->do_output_section_offset(shndx); }
567
568 // Read the symbol information.
569 void
570 read_symbols(Read_symbols_data* sd)
571 { return this->do_read_symbols(sd); }
572
573 // Pass sections which should be included in the link to the Layout
574 // object, and record where the sections go in the output file.
575 void
576 layout(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd)
577 { this->do_layout(symtab, layout, sd); }
578
579 // Add symbol information to the global symbol table.
580 void
581 add_symbols(Symbol_table* symtab, Read_symbols_data* sd, Layout *layout)
582 { this->do_add_symbols(symtab, sd, layout); }
583
584 // Add symbol information to the global symbol table.
585 Archive::Should_include
586 should_include_member(Symbol_table* symtab, Layout* layout,
587 Read_symbols_data* sd, std::string* why)
588 { return this->do_should_include_member(symtab, layout, sd, why); }
589
590 // Iterate over global symbols, calling a visitor class V for each.
591 void
592 for_all_global_symbols(Read_symbols_data* sd,
593 Library_base::Symbol_visitor_base* v)
594 { return this->do_for_all_global_symbols(sd, v); }
595
596 // Iterate over local symbols, calling a visitor class V for each GOT offset
597 // associated with a local symbol.
598 void
599 for_all_local_got_entries(Got_offset_list::Visitor* v) const
600 { this->do_for_all_local_got_entries(v); }
601
602 // Functions and types for the elfcpp::Elf_file interface. This
603 // permit us to use Object as the File template parameter for
604 // elfcpp::Elf_file.
605
606 // The View class is returned by view. It must support a single
607 // method, data(). This is trivial, because get_view does what we
608 // need.
609 class View
610 {
611 public:
612 View(const unsigned char* p)
613 : p_(p)
614 { }
615
616 const unsigned char*
617 data() const
618 { return this->p_; }
619
620 private:
621 const unsigned char* p_;
622 };
623
624 // Return a View.
625 View
626 view(off_t file_offset, section_size_type data_size)
627 { return View(this->get_view(file_offset, data_size, true, true)); }
628
629 // Report an error.
630 void
631 error(const char* format, ...) const ATTRIBUTE_PRINTF_2;
632
633 // A location in the file.
634 struct Location
635 {
636 off_t file_offset;
637 off_t data_size;
638
639 Location(off_t fo, section_size_type ds)
640 : file_offset(fo), data_size(ds)
641 { }
642 };
643
644 // Get a View given a Location.
645 View view(Location loc)
646 { return View(this->get_view(loc.file_offset, loc.data_size, true, true)); }
647
648 // Get a view into the underlying file.
649 const unsigned char*
650 get_view(off_t start, section_size_type size, bool aligned, bool cache)
651 {
652 return this->input_file()->file().get_view(this->offset_, start, size,
653 aligned, cache);
654 }
655
656 // Get a lasting view into the underlying file.
657 File_view*
658 get_lasting_view(off_t start, section_size_type size, bool aligned,
659 bool cache)
660 {
661 return this->input_file()->file().get_lasting_view(this->offset_, start,
662 size, aligned, cache);
663 }
664
665 // Read data from the underlying file.
666 void
667 read(off_t start, section_size_type size, void* p)
668 { this->input_file()->file().read(start + this->offset_, size, p); }
669
670 // Read multiple data from the underlying file.
671 void
672 read_multiple(const File_read::Read_multiple& rm)
673 { this->input_file()->file().read_multiple(this->offset_, rm); }
674
675 // Stop caching views in the underlying file.
676 void
677 clear_view_cache_marks()
678 {
679 if (this->input_file_ != NULL)
680 this->input_file_->file().clear_view_cache_marks();
681 }
682
683 // Get the number of global symbols defined by this object, and the
684 // number of the symbols whose final definition came from this
685 // object.
686 void
687 get_global_symbol_counts(const Symbol_table* symtab, size_t* defined,
688 size_t* used) const
689 { this->do_get_global_symbol_counts(symtab, defined, used); }
690
691 // Get the symbols defined in this object.
692 const Symbols*
693 get_global_symbols() const
694 { return this->do_get_global_symbols(); }
695
696 // Set flag that this object was found in a system directory.
697 void
698 set_is_in_system_directory()
699 { this->is_in_system_directory_ = true; }
700
701 // Return whether this object was found in a system directory.
702 bool
703 is_in_system_directory() const
704 { return this->is_in_system_directory_; }
705
706 // Set flag that this object was linked with --as-needed.
707 void
708 set_as_needed()
709 { this->as_needed_ = true; }
710
711 // Return whether this object was linked with --as-needed.
712 bool
713 as_needed() const
714 { return this->as_needed_; }
715
716 // Return whether we found this object by searching a directory.
717 bool
718 searched_for() const
719 { return this->input_file()->will_search_for(); }
720
721 bool
722 no_export() const
723 { return this->no_export_; }
724
725 void
726 set_no_export(bool value)
727 { this->no_export_ = value; }
728
729 // Return TRUE if the section is a compressed debug section, and set
730 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
731 bool
732 section_is_compressed(unsigned int shndx,
733 section_size_type* uncompressed_size) const
734 { return this->do_section_is_compressed(shndx, uncompressed_size); }
735
736 // Return a view of the decompressed contents of a section. Set *PLEN
737 // to the size. Set *IS_NEW to true if the contents need to be freed
738 // by the caller.
739 const unsigned char*
740 decompressed_section_contents(unsigned int shndx, section_size_type* plen,
741 bool* is_cached)
742 { return this->do_decompressed_section_contents(shndx, plen, is_cached); }
743
744 // Discard any buffers of decompressed sections. This is done
745 // at the end of the Add_symbols task.
746 void
747 discard_decompressed_sections()
748 { this->do_discard_decompressed_sections(); }
749
750 // Return the index of the first incremental relocation for symbol SYMNDX.
751 unsigned int
752 get_incremental_reloc_base(unsigned int symndx) const
753 { return this->do_get_incremental_reloc_base(symndx); }
754
755 // Return the number of incremental relocations for symbol SYMNDX.
756 unsigned int
757 get_incremental_reloc_count(unsigned int symndx) const
758 { return this->do_get_incremental_reloc_count(symndx); }
759
760 protected:
761 // Returns NULL for Objects that are not dynamic objects. This method
762 // is overridden in the Dynobj class.
763 virtual Dynobj*
764 do_dynobj()
765 { return NULL; }
766
767 // Returns NULL for Objects that are not plugin objects. This method
768 // is overridden in the Pluginobj class.
769 virtual Pluginobj*
770 do_pluginobj()
771 { return NULL; }
772
773 // Return TRUE if this is an incremental (unchanged) input file.
774 // We return FALSE by default; the incremental object classes
775 // override this method.
776 virtual bool
777 do_is_incremental() const
778 { return false; }
779
780 // Return the last modified time of the file. This method may be
781 // overridden for subclasses that don't use an actual file (e.g.,
782 // Incremental objects).
783 virtual Timespec
784 do_get_mtime()
785 { return this->input_file()->file().get_mtime(); }
786
787 // Read the symbols--implemented by child class.
788 virtual void
789 do_read_symbols(Read_symbols_data*) = 0;
790
791 // Lay out sections--implemented by child class.
792 virtual void
793 do_layout(Symbol_table*, Layout*, Read_symbols_data*) = 0;
794
795 // Add symbol information to the global symbol table--implemented by
796 // child class.
797 virtual void
798 do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*) = 0;
799
800 virtual Archive::Should_include
801 do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
802 std::string* why) = 0;
803
804 // Iterate over global symbols, calling a visitor class V for each.
805 virtual void
806 do_for_all_global_symbols(Read_symbols_data* sd,
807 Library_base::Symbol_visitor_base* v) = 0;
808
809 // Iterate over local symbols, calling a visitor class V for each GOT offset
810 // associated with a local symbol.
811 virtual void
812 do_for_all_local_got_entries(Got_offset_list::Visitor* v) const = 0;
813
814 // Return the location of the contents of a section. Implemented by
815 // child class.
816 virtual const unsigned char*
817 do_section_contents(unsigned int shndx, section_size_type* plen,
818 bool cache) = 0;
819
820 // Get the size of a section--implemented by child class.
821 virtual uint64_t
822 do_section_size(unsigned int shndx) = 0;
823
824 // Get the name of a section--implemented by child class.
825 virtual std::string
826 do_section_name(unsigned int shndx) = 0;
827
828 // Get section flags--implemented by child class.
829 virtual uint64_t
830 do_section_flags(unsigned int shndx) = 0;
831
832 // Get section entsize--implemented by child class.
833 virtual uint64_t
834 do_section_entsize(unsigned int shndx) = 0;
835
836 // Get section address--implemented by child class.
837 virtual uint64_t
838 do_section_address(unsigned int shndx) = 0;
839
840 // Get section type--implemented by child class.
841 virtual unsigned int
842 do_section_type(unsigned int shndx) = 0;
843
844 // Get section link field--implemented by child class.
845 virtual unsigned int
846 do_section_link(unsigned int shndx) = 0;
847
848 // Get section info field--implemented by child class.
849 virtual unsigned int
850 do_section_info(unsigned int shndx) = 0;
851
852 // Get section alignment--implemented by child class.
853 virtual uint64_t
854 do_section_addralign(unsigned int shndx) = 0;
855
856 // Return the output section given a section index--implemented
857 // by child class.
858 virtual Output_section*
859 do_output_section(unsigned int) const
860 { gold_unreachable(); }
861
862 // Get the address of a section--implemented by child class.
863 virtual uint64_t
864 do_output_section_address(unsigned int)
865 { gold_unreachable(); }
866
867 // Get the offset of a section--implemented by child class.
868 virtual uint64_t
869 do_output_section_offset(unsigned int) const
870 { gold_unreachable(); }
871
872 // Return the Xindex structure to use.
873 virtual Xindex*
874 do_initialize_xindex() = 0;
875
876 // Implement get_global_symbol_counts--implemented by child class.
877 virtual void
878 do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const = 0;
879
880 virtual const Symbols*
881 do_get_global_symbols() const = 0;
882
883 // Set the number of sections.
884 void
885 set_shnum(int shnum)
886 { this->shnum_ = shnum; }
887
888 // Functions used by both Sized_relobj_file and Sized_dynobj.
889
890 // Read the section data into a Read_symbols_data object.
891 template<int size, bool big_endian>
892 void
893 read_section_data(elfcpp::Elf_file<size, big_endian, Object>*,
894 Read_symbols_data*);
895
896 // Find the section header with the given NAME. If HDR is non-NULL
897 // then it is a section header returned from a previous call to this
898 // function and the next section header with the same name will be
899 // returned.
900 template<int size, bool big_endian>
901 const unsigned char*
902 find_shdr(const unsigned char* pshdrs, const char* name,
903 const char* names, section_size_type names_size,
904 const unsigned char* hdr) const;
905
906 // Let the child class initialize the xindex object directly.
907 void
908 set_xindex(Xindex* xindex)
909 {
910 gold_assert(this->xindex_ == NULL);
911 this->xindex_ = xindex;
912 }
913
914 // If NAME is the name of a special .gnu.warning section, arrange
915 // for the warning to be issued. SHNDX is the section index.
916 // Return whether it is a warning section.
917 bool
918 handle_gnu_warning_section(const char* name, unsigned int shndx,
919 Symbol_table*);
920
921 // If NAME is the name of the special section which indicates that
922 // this object was compiled with -fsplit-stack, mark it accordingly,
923 // and return true. Otherwise return false.
924 bool
925 handle_split_stack_section(const char* name);
926
927 // Return TRUE if the section is a compressed debug section, and set
928 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
929 virtual bool
930 do_section_is_compressed(unsigned int, section_size_type*) const
931 { return false; }
932
933 // Return a view of the decompressed contents of a section. Set *PLEN
934 // to the size. This default implementation simply returns the
935 // raw section contents and sets *IS_NEW to false to indicate
936 // that the contents do not need to be freed by the caller.
937 // This function must be overridden for any types of object files
938 // that might contain compressed sections.
939 virtual const unsigned char*
940 do_decompressed_section_contents(unsigned int shndx,
941 section_size_type* plen,
942 bool* is_new)
943 {
944 *is_new = false;
945 return this->do_section_contents(shndx, plen, false);
946 }
947
948 // Discard any buffers of decompressed sections. This is done
949 // at the end of the Add_symbols task.
950 virtual void
951 do_discard_decompressed_sections()
952 { }
953
954 // Return the index of the first incremental relocation for symbol SYMNDX--
955 // implemented by child class.
956 virtual unsigned int
957 do_get_incremental_reloc_base(unsigned int) const
958 { gold_unreachable(); }
959
960 // Return the number of incremental relocations for symbol SYMNDX--
961 // implemented by child class.
962 virtual unsigned int
963 do_get_incremental_reloc_count(unsigned int) const
964 { gold_unreachable(); }
965
966 private:
967 // This class may not be copied.
968 Object(const Object&);
969 Object& operator=(const Object&);
970
971 // Name of object as printed to user.
972 std::string name_;
973 // For reading the file.
974 Input_file* input_file_;
975 // Offset within the file--0 for an object file, non-0 for an
976 // archive.
977 off_t offset_;
978 // Number of input sections.
979 unsigned int shnum_;
980 // Whether this is a dynamic object.
981 bool is_dynamic_ : 1;
982 // Whether this object is needed. This is only set for dynamic
983 // objects, and means that the object defined a symbol which was
984 // used by a reference from a regular object.
985 bool is_needed_ : 1;
986 // Whether this object was compiled with -fsplit-stack.
987 bool uses_split_stack_ : 1;
988 // Whether this object contains any functions compiled with the
989 // no_split_stack attribute.
990 bool has_no_split_stack_ : 1;
991 // True if exclude this object from automatic symbol export.
992 // This is used only for archive objects.
993 bool no_export_ : 1;
994 // True if the object was found in a system directory.
995 bool is_in_system_directory_ : 1;
996 // True if the object was linked with --as-needed.
997 bool as_needed_ : 1;
998 // Many sections for objects with more than SHN_LORESERVE sections.
999 Xindex* xindex_;
1000};
1001
1002// A regular object (ET_REL). This is an abstract base class itself.
1003// The implementation is the template class Sized_relobj_file.
1004
1005class Relobj : public Object
1006{
1007 public:
1008 Relobj(const std::string& name, Input_file* input_file, off_t offset = 0)
1009 : Object(name, input_file, false, offset),
1010 output_sections_(),
1011 map_to_relocatable_relocs_(NULL),
1012 object_merge_map_(NULL),
1013 relocs_must_follow_section_writes_(false),
1014 sd_(NULL),
1015 reloc_counts_(NULL),
1016 reloc_bases_(NULL),
1017 first_dyn_reloc_(0),
1018 dyn_reloc_count_(0)
1019 { }
1020
1021 // During garbage collection, the Read_symbols_data pass for
1022 // each object is stored as layout needs to be done after
1023 // reloc processing.
1024 Symbols_data*
1025 get_symbols_data()
1026 { return this->sd_; }
1027
1028 // Decides which section names have to be included in the worklist
1029 // as roots.
1030 bool
1031 is_section_name_included(const char* name);
1032
1033 void
1034 copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
1035 unsigned int section_header_size);
1036
1037 void
1038 set_symbols_data(Symbols_data* sd)
1039 { this->sd_ = sd; }
1040
1041 // During garbage collection, the Read_relocs pass for all objects
1042 // is done before scanning the relocs. In that case, this->rd_ is
1043 // used to store the information from Read_relocs for each object.
1044 // This data is also used to compute the list of relevant sections.
1045 Read_relocs_data*
1046 get_relocs_data()
1047 { return this->rd_; }
1048
1049 void
1050 set_relocs_data(Read_relocs_data* rd)
1051 { this->rd_ = rd; }
1052
1053 virtual bool
1054 is_output_section_offset_invalid(unsigned int shndx) const = 0;
1055
1056 // Read the relocs.
1057 void
1058 read_relocs(Read_relocs_data* rd)
1059 { return this->do_read_relocs(rd); }
1060
1061 // Process the relocs, during garbage collection only.
1062 void
1063 gc_process_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd)
1064 { return this->do_gc_process_relocs(symtab, layout, rd); }
1065
1066 // Scan the relocs and adjust the symbol table.
1067 void
1068 scan_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd)
1069 { return this->do_scan_relocs(symtab, layout, rd); }
1070
1071 // Return the value of the local symbol whose index is SYMNDX, plus
1072 // ADDEND. ADDEND is passed in so that we can correctly handle the
1073 // section symbol for a merge section.
1074 uint64_t
1075 local_symbol_value(unsigned int symndx, uint64_t addend) const
1076 { return this->do_local_symbol_value(symndx, addend); }
1077
1078 // Return the PLT offset for a local symbol. It is an error to call
1079 // this if it doesn't have one.
1080 unsigned int
1081 local_plt_offset(unsigned int symndx) const
1082 { return this->do_local_plt_offset(symndx); }
1083
1084 // Return whether the local symbol SYMNDX has a GOT offset of type
1085 // GOT_TYPE.
1086 bool
1087 local_has_got_offset(unsigned int symndx, unsigned int got_type) const
1088 { return this->do_local_has_got_offset(symndx, got_type); }
1089
1090 // Return the GOT offset of type GOT_TYPE of the local symbol
1091 // SYMNDX. It is an error to call this if the symbol does not have
1092 // a GOT offset of the specified type.
1093 unsigned int
1094 local_got_offset(unsigned int symndx, unsigned int got_type) const
1095 { return this->do_local_got_offset(symndx, got_type); }
1096
1097 // Set the GOT offset with type GOT_TYPE of the local symbol SYMNDX
1098 // to GOT_OFFSET.
1099 void
1100 set_local_got_offset(unsigned int symndx, unsigned int got_type,
1101 unsigned int got_offset)
1102 { this->do_set_local_got_offset(symndx, got_type, got_offset); }
1103
1104 // Return whether the local symbol SYMNDX is a TLS symbol.
1105 bool
1106 local_is_tls(unsigned int symndx) const
1107 { return this->do_local_is_tls(symndx); }
1108
1109 // The number of local symbols in the input symbol table.
1110 virtual unsigned int
1111 local_symbol_count() const
1112 { return this->do_local_symbol_count(); }
1113
1114 // The number of local symbols in the output symbol table.
1115 virtual unsigned int
1116 output_local_symbol_count() const
1117 { return this->do_output_local_symbol_count(); }
1118
1119 // The file offset for local symbols in the output symbol table.
1120 virtual off_t
1121 local_symbol_offset() const
1122 { return this->do_local_symbol_offset(); }
1123
1124 // Initial local symbol processing: count the number of local symbols
1125 // in the output symbol table and dynamic symbol table; add local symbol
1126 // names to *POOL and *DYNPOOL.
1127 void
1128 count_local_symbols(Stringpool_template<char>* pool,
1129 Stringpool_template<char>* dynpool)
1130 { return this->do_count_local_symbols(pool, dynpool); }
1131
1132 // Set the values of the local symbols, set the output symbol table
1133 // indexes for the local variables, and set the offset where local
1134 // symbol information will be stored. Returns the new local symbol index.
1135 unsigned int
1136 finalize_local_symbols(unsigned int index, off_t off, Symbol_table* symtab)
1137 { return this->do_finalize_local_symbols(index, off, symtab); }
1138
1139 // Set the output dynamic symbol table indexes for the local variables.
1140 unsigned int
1141 set_local_dynsym_indexes(unsigned int index)
1142 { return this->do_set_local_dynsym_indexes(index); }
1143
1144 // Set the offset where local dynamic symbol information will be stored.
1145 unsigned int
1146 set_local_dynsym_offset(off_t off)
1147 { return this->do_set_local_dynsym_offset(off); }
1148
1149 // Record a dynamic relocation against an input section from this object.
1150 void
1151 add_dyn_reloc(unsigned int index)
1152 {
1153 if (this->dyn_reloc_count_ == 0)
1154 this->first_dyn_reloc_ = index;
1155 ++this->dyn_reloc_count_;
1156 }
1157
1158 // Return the index of the first dynamic relocation.
1159 unsigned int
1160 first_dyn_reloc() const
1161 { return this->first_dyn_reloc_; }
1162
1163 // Return the count of dynamic relocations.
1164 unsigned int
1165 dyn_reloc_count() const
1166 { return this->dyn_reloc_count_; }
1167
1168 // Relocate the input sections and write out the local symbols.
1169 void
1170 relocate(const Symbol_table* symtab, const Layout* layout, Output_file* of)
1171 { return this->do_relocate(symtab, layout, of); }
1172
1173 // Return whether an input section is being included in the link.
1174 bool
1175 is_section_included(unsigned int shndx) const
1176 {
1177 gold_assert(shndx < this->output_sections_.size());
1178 return this->output_sections_[shndx] != NULL;
1179 }
1180
1181 // The output section of the input section with index SHNDX.
1182 // This is only used currently to remove a section from the link in
1183 // relaxation.
1184 void
1185 set_output_section(unsigned int shndx, Output_section* os)
1186 {
1187 gold_assert(shndx < this->output_sections_.size());
1188 this->output_sections_[shndx] = os;
1189 }
1190
1191 // Set the offset of an input section within its output section.
1192 void
1193 set_section_offset(unsigned int shndx, uint64_t off)
1194 { this->do_set_section_offset(shndx, off); }
1195
1196 // Return true if we need to wait for output sections to be written
1197 // before we can apply relocations. This is true if the object has
1198 // any relocations for sections which require special handling, such
1199 // as the exception frame section.
1200 bool
1201 relocs_must_follow_section_writes() const
1202 { return this->relocs_must_follow_section_writes_; }
1203
1204 // Return the object merge map.
1205 Object_merge_map*
1206 merge_map() const
1207 { return this->object_merge_map_; }
1208
1209 // Set the object merge map.
1210 void
1211 set_merge_map(Object_merge_map* object_merge_map)
1212 {
1213 gold_assert(this->object_merge_map_ == NULL);
1214 this->object_merge_map_ = object_merge_map;
1215 }
1216
1217 // Record the relocatable reloc info for an input reloc section.
1218 void
1219 set_relocatable_relocs(unsigned int reloc_shndx, Relocatable_relocs* rr)
1220 {
1221 gold_assert(reloc_shndx < this->shnum());
1222 (*this->map_to_relocatable_relocs_)[reloc_shndx] = rr;
1223 }
1224
1225 // Get the relocatable reloc info for an input reloc section.
1226 Relocatable_relocs*
1227 relocatable_relocs(unsigned int reloc_shndx)
1228 {
1229 gold_assert(reloc_shndx < this->shnum());
1230 return (*this->map_to_relocatable_relocs_)[reloc_shndx];
1231 }
1232
1233 // Layout sections whose layout was deferred while waiting for
1234 // input files from a plugin.
1235 void
1236 layout_deferred_sections(Layout* layout)
1237 { this->do_layout_deferred_sections(layout); }
1238
1239 // Return the index of the first incremental relocation for symbol SYMNDX.
1240 virtual unsigned int
1241 do_get_incremental_reloc_base(unsigned int symndx) const
1242 { return this->reloc_bases_[symndx]; }
1243
1244 // Return the number of incremental relocations for symbol SYMNDX.
1245 virtual unsigned int
1246 do_get_incremental_reloc_count(unsigned int symndx) const
1247 { return this->reloc_counts_[symndx]; }
1248
1249 // Return the word size of the object file.
1250 int
1251 elfsize() const
1252 { return this->do_elfsize(); }
1253
1254 // Return TRUE if this is a big-endian object file.
1255 bool
1256 is_big_endian() const
1257 { return this->do_is_big_endian(); }
1258
1259 protected:
1260 // The output section to be used for each input section, indexed by
1261 // the input section number. The output section is NULL if the
1262 // input section is to be discarded.
1263 typedef std::vector<Output_section*> Output_sections;
1264
1265 // Read the relocs--implemented by child class.
1266 virtual void
1267 do_read_relocs(Read_relocs_data*) = 0;
1268
1269 // Process the relocs--implemented by child class.
1270 virtual void
1271 do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0;
1272
1273 // Scan the relocs--implemented by child class.
1274 virtual void
1275 do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0;
1276
1277 // Return the value of a local symbol.
1278 virtual uint64_t
1279 do_local_symbol_value(unsigned int symndx, uint64_t addend) const = 0;
1280
1281 // Return the PLT offset of a local symbol.
1282 virtual unsigned int
1283 do_local_plt_offset(unsigned int symndx) const = 0;
1284
1285 // Return whether a local symbol has a GOT offset of a given type.
1286 virtual bool
1287 do_local_has_got_offset(unsigned int symndx,
1288 unsigned int got_type) const = 0;
1289
1290 // Return the GOT offset of a given type of a local symbol.
1291 virtual unsigned int
1292 do_local_got_offset(unsigned int symndx, unsigned int got_type) const = 0;
1293
1294 // Set the GOT offset with a given type for a local symbol.
1295 virtual void
1296 do_set_local_got_offset(unsigned int symndx, unsigned int got_type,
1297 unsigned int got_offset) = 0;
1298
1299 // Return whether local symbol SYMNDX is a TLS symbol.
1300 virtual bool
1301 do_local_is_tls(unsigned int symndx) const = 0;
1302
1303 // Return the number of local symbols--implemented by child class.
1304 virtual unsigned int
1305 do_local_symbol_count() const = 0;
1306
1307 // Return the number of output local symbols--implemented by child class.
1308 virtual unsigned int
1309 do_output_local_symbol_count() const = 0;
1310
1311 // Return the file offset for local symbols--implemented by child class.
1312 virtual off_t
1313 do_local_symbol_offset() const = 0;
1314
1315 // Count local symbols--implemented by child class.
1316 virtual void
1317 do_count_local_symbols(Stringpool_template<char>*,
1318 Stringpool_template<char>*) = 0;
1319
1320 // Finalize the local symbols. Set the output symbol table indexes
1321 // for the local variables, and set the offset where local symbol
1322 // information will be stored.
1323 virtual unsigned int
1324 do_finalize_local_symbols(unsigned int, off_t, Symbol_table*) = 0;
1325
1326 // Set the output dynamic symbol table indexes for the local variables.
1327 virtual unsigned int
1328 do_set_local_dynsym_indexes(unsigned int) = 0;
1329
1330 // Set the offset where local dynamic symbol information will be stored.
1331 virtual unsigned int
1332 do_set_local_dynsym_offset(off_t) = 0;
1333
1334 // Relocate the input sections and write out the local
1335 // symbols--implemented by child class.
1336 virtual void
1337 do_relocate(const Symbol_table* symtab, const Layout*, Output_file* of) = 0;
1338
1339 // Set the offset of a section--implemented by child class.
1340 virtual void
1341 do_set_section_offset(unsigned int shndx, uint64_t off) = 0;
1342
1343 // Layout sections whose layout was deferred while waiting for
1344 // input files from a plugin--implemented by child class.
1345 virtual void
1346 do_layout_deferred_sections(Layout*) = 0;
1347
1348 // Given a section index, return the corresponding Output_section.
1349 // The return value will be NULL if the section is not included in
1350 // the link.
1351 Output_section*
1352 do_output_section(unsigned int shndx) const
1353 {
1354 gold_assert(shndx < this->output_sections_.size());
1355 return this->output_sections_[shndx];
1356 }
1357
1358 // Return the vector mapping input sections to output sections.
1359 Output_sections&
1360 output_sections()
1361 { return this->output_sections_; }
1362
1363 const Output_sections&
1364 output_sections() const
1365 { return this->output_sections_; }
1366
1367 // Set the size of the relocatable relocs array.
1368 void
1369 size_relocatable_relocs()
1370 {
1371 this->map_to_relocatable_relocs_ =
1372 new std::vector<Relocatable_relocs*>(this->shnum());
1373 }
1374
1375 // Record that we must wait for the output sections to be written
1376 // before applying relocations.
1377 void
1378 set_relocs_must_follow_section_writes()
1379 { this->relocs_must_follow_section_writes_ = true; }
1380
1381 // Allocate the array for counting incremental relocations.
1382 void
1383 allocate_incremental_reloc_counts()
1384 {
1385 unsigned int nsyms = this->do_get_global_symbols()->size();
1386 this->reloc_counts_ = new unsigned int[nsyms];
1387 gold_assert(this->reloc_counts_ != NULL);
1388 memset(this->reloc_counts_, 0, nsyms * sizeof(unsigned int));
1389 }
1390
1391 // Record a relocation in this object referencing global symbol SYMNDX.
1392 // Used for tracking incremental link information.
1393 void
1394 count_incremental_reloc(unsigned int symndx)
1395 {
1396 unsigned int nsyms = this->do_get_global_symbols()->size();
1397 gold_assert(symndx < nsyms);
1398 gold_assert(this->reloc_counts_ != NULL);
1399 ++this->reloc_counts_[symndx];
1400 }
1401
1402 // Finalize the incremental relocation information.
1403 void
1404 finalize_incremental_relocs(Layout* layout, bool clear_counts);
1405
1406 // Return the index of the next relocation to be written for global symbol
1407 // SYMNDX. Only valid after finalize_incremental_relocs() has been called.
1408 unsigned int
1409 next_incremental_reloc_index(unsigned int symndx)
1410 {
1411 unsigned int nsyms = this->do_get_global_symbols()->size();
1412
1413 gold_assert(this->reloc_counts_ != NULL);
1414 gold_assert(this->reloc_bases_ != NULL);
1415 gold_assert(symndx < nsyms);
1416
1417 unsigned int counter = this->reloc_counts_[symndx]++;
1418 return this->reloc_bases_[symndx] + counter;
1419 }
1420
1421 // Return the word size of the object file--
1422 // implemented by child class.
1423 virtual int
1424 do_elfsize() const = 0;
1425
1426 // Return TRUE if this is a big-endian object file--
1427 // implemented by child class.
1428 virtual bool
1429 do_is_big_endian() const = 0;
1430
1431 private:
1432 // Mapping from input sections to output section.
1433 Output_sections output_sections_;
1434 // Mapping from input section index to the information recorded for
1435 // the relocations. This is only used for a relocatable link.
1436 std::vector<Relocatable_relocs*>* map_to_relocatable_relocs_;
1437 // Mappings for merge sections. This is managed by the code in the
1438 // Merge_map class.
1439 Object_merge_map* object_merge_map_;
1440 // Whether we need to wait for output sections to be written before
1441 // we can apply relocations.
1442 bool relocs_must_follow_section_writes_;
1443 // Used to store the relocs data computed by the Read_relocs pass.
1444 // Used during garbage collection of unused sections.
1445 Read_relocs_data* rd_;
1446 // Used to store the symbols data computed by the Read_symbols pass.
1447 // Again used during garbage collection when laying out referenced
1448 // sections.
1449 gold::Symbols_data* sd_;
1450 // Per-symbol counts of relocations, for incremental links.
1451 unsigned int* reloc_counts_;
1452 // Per-symbol base indexes of relocations, for incremental links.
1453 unsigned int* reloc_bases_;
1454 // Index of the first dynamic relocation for this object.
1455 unsigned int first_dyn_reloc_;
1456 // Count of dynamic relocations for this object.
1457 unsigned int dyn_reloc_count_;
1458};
1459
1460// This class is used to handle relocations against a section symbol
1461// in an SHF_MERGE section. For such a symbol, we need to know the
1462// addend of the relocation before we can determine the final value.
1463// The addend gives us the location in the input section, and we can
1464// determine how it is mapped to the output section. For a
1465// non-section symbol, we apply the addend to the final value of the
1466// symbol; that is done in finalize_local_symbols, and does not use
1467// this class.
1468
1469template<int size>
1470class Merged_symbol_value
1471{
1472 public:
1473 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;
1474
1475 // We use a hash table to map offsets in the input section to output
1476 // addresses.
1477 typedef Unordered_map<section_offset_type, Value> Output_addresses;
1478
1479 Merged_symbol_value(Value input_value, Value output_start_address)
1480 : input_value_(input_value), output_start_address_(output_start_address),
1481 output_addresses_()
1482 { }
1483
1484 // Initialize the hash table.
1485 void
1486 initialize_input_to_output_map(const Relobj*, unsigned int input_shndx);
1487
1488 // Release the hash table to save space.
1489 void
1490 free_input_to_output_map()
1491 { this->output_addresses_.clear(); }
1492
1493 // Get the output value corresponding to an addend. The object and
1494 // input section index are passed in because the caller will have
1495 // them; otherwise we could store them here.
1496 Value
1497 value(const Relobj* object, unsigned int input_shndx, Value addend) const
1498 {
1499 // This is a relocation against a section symbol. ADDEND is the
1500 // offset in the section. The result should be the start of some
1501 // merge area. If the object file wants something else, it should
1502 // use a regular symbol rather than a section symbol.
1503 // Unfortunately, PR 6658 shows a case in which the object file
1504 // refers to the section symbol, but uses a negative ADDEND to
1505 // compensate for a PC relative reloc. We can't handle the
1506 // general case. However, we can handle the special case of a
1507 // negative addend, by assuming that it refers to the start of the
1508 // section. Of course, that means that we have to guess when
1509 // ADDEND is negative. It is normal to see a 32-bit value here
1510 // even when the template parameter size is 64, as 64-bit object
1511 // file formats have 32-bit relocations. We know this is a merge
1512 // section, so we know it has to fit into memory. So we assume
1513 // that we won't see a value larger than a large 32-bit unsigned
1514 // value. This will break objects with very very large merge
1515 // sections; they probably break in other ways anyhow.
1516 Value input_offset = this->input_value_;
1517 if (addend < 0xffffff00)
1518 {
1519 input_offset += addend;
1520 addend = 0;
1521 }
1522 typename Output_addresses::const_iterator p =
1523 this->output_addresses_.find(input_offset);
1524 if (p != this->output_addresses_.end())
1525 return p->second + addend;
1526
1527 return (this->value_from_output_section(object, input_shndx, input_offset)
1528 + addend);
1529 }
1530
1531 private:
1532 // Get the output value for an input offset if we couldn't find it
1533 // in the hash table.
1534 Value
1535 value_from_output_section(const Relobj*, unsigned int input_shndx,
1536 Value input_offset) const;
1537
1538 // The value of the section symbol in the input file. This is
1539 // normally zero, but could in principle be something else.
1540 Value input_value_;
1541 // The start address of this merged section in the output file.
1542 Value output_start_address_;
1543 // A hash table which maps offsets in the input section to output
1544 // addresses. This only maps specific offsets, not all offsets.
1545 Output_addresses output_addresses_;
1546};
1547
1548// This POD class is holds the value of a symbol. This is used for
1549// local symbols, and for all symbols during relocation processing.
1550// For special sections, such as SHF_MERGE sections, this calls a
1551// function to get the final symbol value.
1552
1553template<int size>
1554class Symbol_value
1555{
1556 public:
1557 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;
1558
1559 Symbol_value()
1560 : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0),
1561 is_ordinary_shndx_(false), is_section_symbol_(false),
1562 is_tls_symbol_(false), is_ifunc_symbol_(false), has_output_value_(true)
1563 { this->u_.value = 0; }
1564
1565 ~Symbol_value()
1566 {
1567 if (!this->has_output_value_)
1568 delete this->u_.merged_symbol_value;
1569 }
1570
1571 // Get the value of this symbol. OBJECT is the object in which this
1572 // symbol is defined, and ADDEND is an addend to add to the value.
1573 template<bool big_endian>
1574 Value
1575 value(const Sized_relobj_file<size, big_endian>* object, Value addend) const
1576 {
1577 if (this->has_output_value_)
1578 return this->u_.value + addend;
1579 else
1580 {
1581 gold_assert(this->is_ordinary_shndx_);
1582 return this->u_.merged_symbol_value->value(object, this->input_shndx_,
1583 addend);
1584 }
1585 }
1586
1587 // Set the value of this symbol in the output symbol table.
1588 void
1589 set_output_value(Value value)
1590 { this->u_.value = value; }
1591
1592 // For a section symbol in a merged section, we need more
1593 // information.
1594 void
1595 set_merged_symbol_value(Merged_symbol_value<size>* msv)
1596 {
1597 gold_assert(this->is_section_symbol_);
1598 this->has_output_value_ = false;
1599 this->u_.merged_symbol_value = msv;
1600 }
1601
1602 // Initialize the input to output map for a section symbol in a
1603 // merged section. We also initialize the value of a non-section
1604 // symbol in a merged section.
1605 void
1606 initialize_input_to_output_map(const Relobj* object)
1607 {
1608 if (!this->has_output_value_)
1609 {
1610 gold_assert(this->is_section_symbol_ && this->is_ordinary_shndx_);
1611 Merged_symbol_value<size>* msv = this->u_.merged_symbol_value;
1612 msv->initialize_input_to_output_map(object, this->input_shndx_);
1613 }
1614 }
1615
1616 // Free the input to output map for a section symbol in a merged
1617 // section.
1618 void
1619 free_input_to_output_map()
1620 {
1621 if (!this->has_output_value_)
1622 this->u_.merged_symbol_value->free_input_to_output_map();
1623 }
1624
1625 // Set the value of the symbol from the input file. This is only
1626 // called by count_local_symbols, to communicate the value to
1627 // finalize_local_symbols.
1628 void
1629 set_input_value(Value value)
1630 { this->u_.value = value; }
1631
1632 // Return the input value. This is only called by
1633 // finalize_local_symbols and (in special cases) relocate_section.
1634 Value
1635 input_value() const
1636 { return this->u_.value; }
1637
1638 // Return whether we have set the index in the output symbol table
1639 // yet.
1640 bool
1641 is_output_symtab_index_set() const
1642 {
1643 return (this->output_symtab_index_ != 0
1644 && this->output_symtab_index_ != -2U);
1645 }
1646
1647 // Return whether this symbol may be discarded from the normal
1648 // symbol table.
1649 bool
1650 may_be_discarded_from_output_symtab() const
1651 {
1652 gold_assert(!this->is_output_symtab_index_set());
1653 return this->output_symtab_index_ != -2U;
1654 }
1655
1656 // Return whether this symbol has an entry in the output symbol
1657 // table.
1658 bool
1659 has_output_symtab_entry() const
1660 {
1661 gold_assert(this->is_output_symtab_index_set());
1662 return this->output_symtab_index_ != -1U;
1663 }
1664
1665 // Return the index in the output symbol table.
1666 unsigned int
1667 output_symtab_index() const
1668 {
1669 gold_assert(this->is_output_symtab_index_set()
1670 && this->output_symtab_index_ != -1U);
1671 return this->output_symtab_index_;
1672 }
1673
1674 // Set the index in the output symbol table.
1675 void
1676 set_output_symtab_index(unsigned int i)
1677 {
1678 gold_assert(!this->is_output_symtab_index_set());
1679 gold_assert(i != 0 && i != -1U && i != -2U);
1680 this->output_symtab_index_ = i;
1681 }
1682
1683 // Record that this symbol should not go into the output symbol
1684 // table.
1685 void
1686 set_no_output_symtab_entry()
1687 {
1688 gold_assert(this->output_symtab_index_ == 0);
1689 this->output_symtab_index_ = -1U;
1690 }
1691
1692 // Record that this symbol must go into the output symbol table,
1693 // because it there is a relocation that uses it.
1694 void
1695 set_must_have_output_symtab_entry()
1696 {
1697 gold_assert(!this->is_output_symtab_index_set());
1698 this->output_symtab_index_ = -2U;
1699 }
1700
1701 // Set the index in the output dynamic symbol table.
1702 void
1703 set_needs_output_dynsym_entry()
1704 {
1705 gold_assert(!this->is_section_symbol());
1706 this->output_dynsym_index_ = 0;
1707 }
1708
1709 // Return whether this symbol should go into the dynamic symbol
1710 // table.
1711 bool
1712 needs_output_dynsym_entry() const
1713 {
1714 return this->output_dynsym_index_ != -1U;
1715 }
1716
1717 // Return whether this symbol has an entry in the dynamic symbol
1718 // table.
1719 bool
1720 has_output_dynsym_entry() const
1721 {
1722 gold_assert(this->output_dynsym_index_ != 0);
1723 return this->output_dynsym_index_ != -1U;
1724 }
1725
1726 // Record that this symbol should go into the dynamic symbol table.
1727 void
1728 set_output_dynsym_index(unsigned int i)
1729 {
1730 gold_assert(this->output_dynsym_index_ == 0);
1731 gold_assert(i != 0 && i != -1U);
1732 this->output_dynsym_index_ = i;
1733 }
1734
1735 // Return the index in the output dynamic symbol table.
1736 unsigned int
1737 output_dynsym_index() const
1738 {
1739 gold_assert(this->output_dynsym_index_ != 0
1740 && this->output_dynsym_index_ != -1U);
1741 return this->output_dynsym_index_;
1742 }
1743
1744 // Set the index of the input section in the input file.
1745 void
1746 set_input_shndx(unsigned int i, bool is_ordinary)
1747 {
1748 this->input_shndx_ = i;
1749 // input_shndx_ field is a bitfield, so make sure that the value
1750 // fits.
1751 gold_assert(this->input_shndx_ == i);
1752 this->is_ordinary_shndx_ = is_ordinary;
1753 }
1754
1755 // Return the index of the input section in the input file.
1756 unsigned int
1757 input_shndx(bool* is_ordinary) const
1758 {
1759 *is_ordinary = this->is_ordinary_shndx_;
1760 return this->input_shndx_;
1761 }
1762
1763 // Whether this is a section symbol.
1764 bool
1765 is_section_symbol() const
1766 { return this->is_section_symbol_; }
1767
1768 // Record that this is a section symbol.
1769 void
1770 set_is_section_symbol()
1771 {
1772 gold_assert(!this->needs_output_dynsym_entry());
1773 this->is_section_symbol_ = true;
1774 }
1775
1776 // Record that this is a TLS symbol.
1777 void
1778 set_is_tls_symbol()
1779 { this->is_tls_symbol_ = true; }
1780
1781 // Return true if this is a TLS symbol.
1782 bool
1783 is_tls_symbol() const
1784 { return this->is_tls_symbol_; }
1785
1786 // Record that this is an IFUNC symbol.
1787 void
1788 set_is_ifunc_symbol()
1789 { this->is_ifunc_symbol_ = true; }
1790
1791 // Return true if this is an IFUNC symbol.
1792 bool
1793 is_ifunc_symbol() const
1794 { return this->is_ifunc_symbol_; }
1795
1796 // Return true if this has output value.
1797 bool
1798 has_output_value() const
1799 { return this->has_output_value_; }
1800
1801 private:
1802 // The index of this local symbol in the output symbol table. This
1803 // will be 0 if no value has been assigned yet, and the symbol may
1804 // be omitted. This will be -1U if the symbol should not go into
1805 // the symbol table. This will be -2U if the symbol must go into
1806 // the symbol table, but no index has been assigned yet.
1807 unsigned int output_symtab_index_;
1808 // The index of this local symbol in the dynamic symbol table. This
1809 // will be -1U if the symbol should not go into the symbol table.
1810 unsigned int output_dynsym_index_;
1811 // The section index in the input file in which this symbol is
1812 // defined.
1813 unsigned int input_shndx_ : 27;
1814 // Whether the section index is an ordinary index, not a special
1815 // value.
1816 bool is_ordinary_shndx_ : 1;
1817 // Whether this is a STT_SECTION symbol.
1818 bool is_section_symbol_ : 1;
1819 // Whether this is a STT_TLS symbol.
1820 bool is_tls_symbol_ : 1;
1821 // Whether this is a STT_GNU_IFUNC symbol.
1822 bool is_ifunc_symbol_ : 1;
1823 // Whether this symbol has a value for the output file. This is
1824 // normally set to true during Layout::finalize, by
1825 // finalize_local_symbols. It will be false for a section symbol in
1826 // a merge section, as for such symbols we can not determine the
1827 // value to use in a relocation until we see the addend.
1828 bool has_output_value_ : 1;
1829 union
1830 {
1831 // This is used if has_output_value_ is true. Between
1832 // count_local_symbols and finalize_local_symbols, this is the
1833 // value in the input file. After finalize_local_symbols, it is
1834 // the value in the output file.
1835 Value value;
1836 // This is used if has_output_value_ is false. It points to the
1837 // information we need to get the value for a merge section.
1838 Merged_symbol_value<size>* merged_symbol_value;
1839 } u_;
1840};
1841
1842// This type is used to modify relocations for -fsplit-stack. It is
1843// indexed by relocation index, and means that the relocation at that
1844// index should use the symbol from the vector, rather than the one
1845// indicated by the relocation.
1846
1847class Reloc_symbol_changes
1848{
1849 public:
1850 Reloc_symbol_changes(size_t count)
1851 : vec_(count, NULL)
1852 { }
1853
1854 void
1855 set(size_t i, Symbol* sym)
1856 { this->vec_[i] = sym; }
1857
1858 const Symbol*
1859 operator[](size_t i) const
1860 { return this->vec_[i]; }
1861
1862 private:
1863 std::vector<Symbol*> vec_;
1864};
1865
1866// Type for mapping section index to uncompressed size and contents.
1867
1868struct Compressed_section_info
1869{
1870 section_size_type size;
1871 const unsigned char* contents;
1872};
1873typedef std::map<unsigned int, Compressed_section_info> Compressed_section_map;
1874
1875// Abstract base class for a regular object file, either a real object file
1876// or an incremental (unchanged) object. This is size and endian specific.
1877
1878template<int size, bool big_endian>
1879class Sized_relobj : public Relobj
1880{
1881 public:
1882 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
1883 typedef Relobj::Symbols Symbols;
1884
1885 static const Address invalid_address = static_cast<Address>(0) - 1;
1886
1887 Sized_relobj(const std::string& name, Input_file* input_file)
1888 : Relobj(name, input_file), local_got_offsets_(), section_offsets_()
1889 { }
1890
1891 Sized_relobj(const std::string& name, Input_file* input_file,
1892 off_t offset)
1893 : Relobj(name, input_file, offset), local_got_offsets_(), section_offsets_()
1894 { }
1895
1896 ~Sized_relobj()
1897 { }
1898
1899 // If this is a regular object, return a pointer to the Sized_relobj_file
1900 // object. Otherwise, return NULL.
1901 virtual Sized_relobj_file<size, big_endian>*
1902 sized_relobj()
1903 { return NULL; }
1904
1905 const virtual Sized_relobj_file<size, big_endian>*
1906 sized_relobj() const
1907 { return NULL; }
1908
1909 // Checks if the offset of input section SHNDX within its output
1910 // section is invalid.
1911 bool
1912 is_output_section_offset_invalid(unsigned int shndx) const
1913 { return this->get_output_section_offset(shndx) == invalid_address; }
1914
1915 // Get the offset of input section SHNDX within its output section.
1916 // This is -1 if the input section requires a special mapping, such
1917 // as a merge section. The output section can be found in the
1918 // output_sections_ field of the parent class Relobj.
1919 Address
1920 get_output_section_offset(unsigned int shndx) const
1921 {
1922 gold_assert(shndx < this->section_offsets_.size());
1923 return this->section_offsets_[shndx];
1924 }
1925
1926 // Iterate over local symbols, calling a visitor class V for each GOT offset
1927 // associated with a local symbol.
1928 void
1929 do_for_all_local_got_entries(Got_offset_list::Visitor* v) const;
1930
1931 protected:
1932 typedef Relobj::Output_sections Output_sections;
1933
1934 // Clear the local symbol information.
1935 void
1936 clear_got_offsets()
1937 { this->local_got_offsets_.clear(); }
1938
1939 // Return the vector of section offsets.
1940 std::vector<Address>&
1941 section_offsets()
1942 { return this->section_offsets_; }
1943
1944 // Get the address of an output section.
1945 uint64_t
1946 do_output_section_address(unsigned int shndx);
1947
1948 // Get the offset of a section.
1949 uint64_t
1950 do_output_section_offset(unsigned int shndx) const
1951 {
1952 Address off = this->get_output_section_offset(shndx);
1953 if (off == invalid_address)
1954 return -1ULL;
1955 return off;
1956 }
1957
1958 // Set the offset of a section.
1959 void
1960 do_set_section_offset(unsigned int shndx, uint64_t off)
1961 {
1962 gold_assert(shndx < this->section_offsets_.size());
1963 this->section_offsets_[shndx] =
1964 (off == static_cast<uint64_t>(-1)
1965 ? invalid_address
1966 : convert_types<Address, uint64_t>(off));
1967 }
1968
1969 // Return whether the local symbol SYMNDX has a GOT offset of type
1970 // GOT_TYPE.
1971 bool
1972 do_local_has_got_offset(unsigned int symndx, unsigned int got_type) const
1973 {
1974 Local_got_offsets::const_iterator p =
1975 this->local_got_offsets_.find(symndx);
1976 return (p != this->local_got_offsets_.end()
1977 && p->second->get_offset(got_type) != -1U);
1978 }
1979
1980 // Return the GOT offset of type GOT_TYPE of the local symbol
1981 // SYMNDX.
1982 unsigned int
1983 do_local_got_offset(unsigned int symndx, unsigned int got_type) const
1984 {
1985 Local_got_offsets::const_iterator p =
1986 this->local_got_offsets_.find(symndx);
1987 gold_assert(p != this->local_got_offsets_.end());
1988 unsigned int off = p->second->get_offset(got_type);
1989 gold_assert(off != -1U);
1990 return off;
1991 }
1992
1993 // Set the GOT offset with type GOT_TYPE of the local symbol SYMNDX
1994 // to GOT_OFFSET.
1995 void
1996 do_set_local_got_offset(unsigned int symndx, unsigned int got_type,
1997 unsigned int got_offset)
1998 {
1999 Local_got_offsets::const_iterator p =
2000 this->local_got_offsets_.find(symndx);
2001 if (p != this->local_got_offsets_.end())
2002 p->second->set_offset(got_type, got_offset);
2003 else
2004 {
2005 Got_offset_list* g = new Got_offset_list(got_type, got_offset);
2006 std::pair<Local_got_offsets::iterator, bool> ins =
2007 this->local_got_offsets_.insert(std::make_pair(symndx, g));
2008 gold_assert(ins.second);
2009 }
2010 }
2011
2012 // Return the word size of the object file.
2013 virtual int
2014 do_elfsize() const
2015 { return size; }
2016
2017 // Return TRUE if this is a big-endian object file.
2018 virtual bool
2019 do_is_big_endian() const
2020 { return big_endian; }
2021
2022 private:
2023 // The GOT offsets of local symbols. This map also stores GOT offsets
2024 // for tp-relative offsets for TLS symbols.
2025 typedef Unordered_map<unsigned int, Got_offset_list*> Local_got_offsets;
2026
2027 // GOT offsets for local non-TLS symbols, and tp-relative offsets
2028 // for TLS symbols, indexed by symbol number.
2029 Local_got_offsets local_got_offsets_;
2030 // For each input section, the offset of the input section in its
2031 // output section. This is INVALID_ADDRESS if the input section requires a
2032 // special mapping.
2033 std::vector<Address> section_offsets_;
2034};
2035
2036// A regular object file. This is size and endian specific.
2037
2038template<int size, bool big_endian>
2039class Sized_relobj_file : public Sized_relobj<size, big_endian>
2040{
2041 public:
2042 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
2043 typedef typename Sized_relobj<size, big_endian>::Symbols Symbols;
2044 typedef std::vector<Symbol_value<size> > Local_values;
2045
2046 static const Address invalid_address = static_cast<Address>(0) - 1;
2047
2048 enum Compute_final_local_value_status
2049 {
2050 // No error.
2051 CFLV_OK,
2052 // An error occurred.
2053 CFLV_ERROR,
2054 // The local symbol has no output section.
2055 CFLV_DISCARDED
2056 };
2057
2058 Sized_relobj_file(const std::string& name,
2059 Input_file* input_file,
2060 off_t offset,
2061 const typename elfcpp::Ehdr<size, big_endian>&);
2062
2063 ~Sized_relobj_file();
2064
2065 // Set up the object file based on TARGET.
2066 void
2067 setup()
2068 { this->do_setup(); }
2069
2070 // Return a pointer to the Sized_relobj_file object.
2071 Sized_relobj_file<size, big_endian>*
2072 sized_relobj()
2073 { return this; }
2074
2075 const Sized_relobj_file<size, big_endian>*
2076 sized_relobj() const
2077 { return this; }
2078
2079 // Return the ELF file type.
2080 int
2081 e_type() const
2082 { return this->e_type_; }
2083
2084 // Return the number of symbols. This is only valid after
2085 // Object::add_symbols has been called.
2086 unsigned int
2087 symbol_count() const
2088 { return this->local_symbol_count_ + this->symbols_.size(); }
2089
2090 // If SYM is the index of a global symbol in the object file's
2091 // symbol table, return the Symbol object. Otherwise, return NULL.
2092 Symbol*
2093 global_symbol(unsigned int sym) const
2094 {
2095 if (sym >= this->local_symbol_count_)
2096 {
2097 gold_assert(sym - this->local_symbol_count_ < this->symbols_.size());
2098 return this->symbols_[sym - this->local_symbol_count_];
2099 }
2100 return NULL;
2101 }
2102
2103 // Return the section index of symbol SYM. Set *VALUE to its value
2104 // in the object file. Set *IS_ORDINARY if this is an ordinary
2105 // section index, not a special code between SHN_LORESERVE and
2106 // SHN_HIRESERVE. Note that for a symbol which is not defined in
2107 // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
2108 // it will not return the final value of the symbol in the link.
2109 unsigned int
2110 symbol_section_and_value(unsigned int sym, Address* value, bool* is_ordinary);
2111
2112 // Return a pointer to the Symbol_value structure which holds the
2113 // value of a local symbol.
2114 const Symbol_value<size>*
2115 local_symbol(unsigned int sym) const
2116 {
2117 gold_assert(sym < this->local_values_.size());
2118 return &this->local_values_[sym];
2119 }
2120
2121 // Return the index of local symbol SYM in the ordinary symbol
2122 // table. A value of -1U means that the symbol is not being output.
2123 unsigned int
2124 symtab_index(unsigned int sym) const
2125 {
2126 gold_assert(sym < this->local_values_.size());
2127 return this->local_values_[sym].output_symtab_index();
2128 }
2129
2130 // Return the index of local symbol SYM in the dynamic symbol
2131 // table. A value of -1U means that the symbol is not being output.
2132 unsigned int
2133 dynsym_index(unsigned int sym) const
2134 {
2135 gold_assert(sym < this->local_values_.size());
2136 return this->local_values_[sym].output_dynsym_index();
2137 }
2138
2139 // Return the input section index of local symbol SYM.
2140 unsigned int
2141 local_symbol_input_shndx(unsigned int sym, bool* is_ordinary) const
2142 {
2143 gold_assert(sym < this->local_values_.size());
2144 return this->local_values_[sym].input_shndx(is_ordinary);
2145 }
2146
2147 // Record that local symbol SYM must be in the output symbol table.
2148 void
2149 set_must_have_output_symtab_entry(unsigned int sym)
2150 {
2151 gold_assert(sym < this->local_values_.size());
2152 this->local_values_[sym].set_must_have_output_symtab_entry();
2153 }
2154
2155 // Record that local symbol SYM needs a dynamic symbol entry.
2156 void
2157 set_needs_output_dynsym_entry(unsigned int sym)
2158 {
2159 gold_assert(sym < this->local_values_.size());
2160 this->local_values_[sym].set_needs_output_dynsym_entry();
2161 }
2162
2163 // Return whether the local symbol SYMNDX has a PLT offset.
2164 bool
2165 local_has_plt_offset(unsigned int symndx) const;
2166
2167 // Set the PLT offset of the local symbol SYMNDX.
2168 void
2169 set_local_plt_offset(unsigned int symndx, unsigned int plt_offset);
2170
2171 // Adjust this local symbol value. Return false if the symbol
2172 // should be discarded from the output file.
2173 bool
2174 adjust_local_symbol(Symbol_value<size>* lv) const
2175 { return this->do_adjust_local_symbol(lv); }
2176
2177 // Return the name of the symbol that spans the given offset in the
2178 // specified section in this object. This is used only for error
2179 // messages and is not particularly efficient.
2180 bool
2181 get_symbol_location_info(unsigned int shndx, off_t offset,
2182 Symbol_location_info* info);
2183
2184 // Look for a kept section corresponding to the given discarded section,
2185 // and return its output address. This is used only for relocations in
2186 // debugging sections.
2187 Address
2188 map_to_kept_section(unsigned int shndx, bool* found) const;
2189
2190 // Compute final local symbol value. R_SYM is the local symbol index.
2191 // LV_IN points to a local symbol value containing the input value.
2192 // LV_OUT points to a local symbol value storing the final output value,
2193 // which must not be a merged symbol value since before calling this
2194 // method to avoid memory leak. SYMTAB points to a symbol table.
2195 //
2196 // The method returns a status code at return. If the return status is
2197 // CFLV_OK, *LV_OUT contains the final value. If the return status is
2198 // CFLV_ERROR, *LV_OUT is 0. If the return status is CFLV_DISCARDED,
2199 // *LV_OUT is not modified.
2200 Compute_final_local_value_status
2201 compute_final_local_value(unsigned int r_sym,
2202 const Symbol_value<size>* lv_in,
2203 Symbol_value<size>* lv_out,
2204 const Symbol_table* symtab);
2205
2206 protected:
2207 typedef typename Sized_relobj<size, big_endian>::Output_sections
2208 Output_sections;
2209
2210 // Set up.
2211 virtual void
2212 do_setup();
2213
2214 // Read the symbols.
2215 void
2216 do_read_symbols(Read_symbols_data*);
2217
2218 // Return the value of a local symbol.
2219 uint64_t
2220 do_local_symbol_value(unsigned int symndx, uint64_t addend) const
2221 {
2222 const Symbol_value<size>* symval = this->local_symbol(symndx);
2223 return symval->value(this, addend);
2224 }
2225
2226 // Return the PLT offset for a local symbol. It is an error to call
2227 // this if it doesn't have one.
2228 unsigned int
2229 do_local_plt_offset(unsigned int symndx) const;
2230
2231 // Return whether local symbol SYMNDX is a TLS symbol.
2232 bool
2233 do_local_is_tls(unsigned int symndx) const
2234 { return this->local_symbol(symndx)->is_tls_symbol(); }
2235
2236 // Return the number of local symbols.
2237 unsigned int
2238 do_local_symbol_count() const
2239 { return this->local_symbol_count_; }
2240
2241 // Return the number of local symbols in the output symbol table.
2242 unsigned int
2243 do_output_local_symbol_count() const
2244 { return this->output_local_symbol_count_; }
2245
2246 // Return the number of local symbols in the output symbol table.
2247 off_t
2248 do_local_symbol_offset() const
2249 { return this->local_symbol_offset_; }
2250
2251 // Lay out the input sections.
2252 void
2253 do_layout(Symbol_table*, Layout*, Read_symbols_data*);
2254
2255 // Layout sections whose layout was deferred while waiting for
2256 // input files from a plugin.
2257 void
2258 do_layout_deferred_sections(Layout*);
2259
2260 // Add the symbols to the symbol table.
2261 void
2262 do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
2263
2264 Archive::Should_include
2265 do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
2266 std::string* why);
2267
2268 // Iterate over global symbols, calling a visitor class V for each.
2269 void
2270 do_for_all_global_symbols(Read_symbols_data* sd,
2271 Library_base::Symbol_visitor_base* v);
2272
2273 // Read the relocs.
2274 void
2275 do_read_relocs(Read_relocs_data*);
2276
2277 // Process the relocs to find list of referenced sections. Used only
2278 // during garbage collection.
2279 void
2280 do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*);
2281
2282 // Scan the relocs and adjust the symbol table.
2283 void
2284 do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*);
2285
2286 // Count the local symbols.
2287 void
2288 do_count_local_symbols(Stringpool_template<char>*,
2289 Stringpool_template<char>*);
2290
2291 // Finalize the local symbols.
2292 unsigned int
2293 do_finalize_local_symbols(unsigned int, off_t, Symbol_table*);
2294
2295 // Set the offset where local dynamic symbol information will be stored.
2296 unsigned int
2297 do_set_local_dynsym_indexes(unsigned int);
2298
2299 // Set the offset where local dynamic symbol information will be stored.
2300 unsigned int
2301 do_set_local_dynsym_offset(off_t);
2302
2303 // Relocate the input sections and write out the local symbols.
2304 void
2305 do_relocate(const Symbol_table* symtab, const Layout*, Output_file* of);
2306
2307 // Get the size of a section.
2308 uint64_t
2309 do_section_size(unsigned int shndx)
2310 { return this->elf_file_.section_size(shndx); }
2311
2312 // Get the name of a section.
2313 std::string
2314 do_section_name(unsigned int shndx)
2315 { return this->elf_file_.section_name(shndx); }
2316
2317 // Return the location of the contents of a section.
2318 const unsigned char*
2319 do_section_contents(unsigned int shndx, section_size_type* plen,
2320 bool cache)
2321 {
2322 Object::Location loc(this->elf_file_.section_contents(shndx));
2323 *plen = convert_to_section_size_type(loc.data_size);
2324 if (*plen == 0)
2325 {
2326 static const unsigned char empty[1] = { '\0' };
2327 return empty;
2328 }
2329 return this->get_view(loc.file_offset, *plen, true, cache);
2330 }
2331
2332 // Return section flags.
2333 uint64_t
2334 do_section_flags(unsigned int shndx);
2335
2336 // Return section entsize.
2337 uint64_t
2338 do_section_entsize(unsigned int shndx);
2339
2340 // Return section address.
2341 uint64_t
2342 do_section_address(unsigned int shndx)
2343 { return this->elf_file_.section_addr(shndx); }
2344
2345 // Return section type.
2346 unsigned int
2347 do_section_type(unsigned int shndx)
2348 { return this->elf_file_.section_type(shndx); }
2349
2350 // Return the section link field.
2351 unsigned int
2352 do_section_link(unsigned int shndx)
2353 { return this->elf_file_.section_link(shndx); }
2354
2355 // Return the section info field.
2356 unsigned int
2357 do_section_info(unsigned int shndx)
2358 { return this->elf_file_.section_info(shndx); }
2359
2360 // Return the section alignment.
2361 uint64_t
2362 do_section_addralign(unsigned int shndx)
2363 { return this->elf_file_.section_addralign(shndx); }
2364
2365 // Return the Xindex structure to use.
2366 Xindex*
2367 do_initialize_xindex();
2368
2369 // Get symbol counts.
2370 void
2371 do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
2372
2373 // Get the global symbols.
2374 const Symbols*
2375 do_get_global_symbols() const
2376 { return &this->symbols_; }
2377
2378 // Adjust a section index if necessary.
2379 unsigned int
2380 adjust_shndx(unsigned int shndx)
2381 {
2382 if (shndx >= elfcpp::SHN_LORESERVE)
2383 shndx += this->elf_file_.large_shndx_offset();
2384 return shndx;
2385 }
2386
2387 // Initialize input to output maps for section symbols in merged
2388 // sections.
2389 void
2390 initialize_input_to_output_maps();
2391
2392 // Free the input to output maps for section symbols in merged
2393 // sections.
2394 void
2395 free_input_to_output_maps();
2396
2397 // Return symbol table section index.
2398 unsigned int
2399 symtab_shndx() const
2400 { return this->symtab_shndx_; }
2401
2402 // Allow a child class to access the ELF file.
2403 elfcpp::Elf_file<size, big_endian, Object>*
2404 elf_file()
2405 { return &this->elf_file_; }
2406
2407 // Allow a child class to access the local values.
2408 Local_values*
2409 local_values()
2410 { return &this->local_values_; }
2411
2412 // Views and sizes when relocating.
2413 struct View_size
2414 {
2415 unsigned char* view;
2416 typename elfcpp::Elf_types<size>::Elf_Addr address;
2417 off_t offset;
2418 section_size_type view_size;
2419 bool is_input_output_view;
2420 bool is_postprocessing_view;
2421 bool is_ctors_reverse_view;
2422 };
2423
2424 typedef std::vector<View_size> Views;
2425
2426 // Stash away info for a number of special sections.
2427 // Return true if any of the sections found require local symbols to be read.
2428 virtual bool
2429 do_find_special_sections(Read_symbols_data* sd);
2430
2431 // This may be overriden by a child class.
2432 virtual void
2433 do_relocate_sections(const Symbol_table* symtab, const Layout* layout,
2434 const unsigned char* pshdrs, Output_file* of,
2435 Views* pviews);
2436
2437 // Adjust this local symbol value. Return false if the symbol
2438 // should be discarded from the output file.
2439 virtual bool
2440 do_adjust_local_symbol(Symbol_value<size>*) const
2441 { return true; }
2442
2443 // Allow a child to set output local symbol count.
2444 void
2445 set_output_local_symbol_count(unsigned int value)
2446 { this->output_local_symbol_count_ = value; }
2447
2448 // Return TRUE if the section is a compressed debug section, and set
2449 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
2450 bool
2451 do_section_is_compressed(unsigned int shndx,
2452 section_size_type* uncompressed_size) const
2453 {
2454 if (this->compressed_sections_ == NULL)
2455 return false;
2456 Compressed_section_map::const_iterator p =
2457 this->compressed_sections_->find(shndx);
2458 if (p != this->compressed_sections_->end())
2459 {
2460 if (uncompressed_size != NULL)
2461 *uncompressed_size = p->second.size;
2462 return true;
2463 }
2464 return false;
2465 }
2466
2467 // Return a view of the uncompressed contents of a section. Set *PLEN
2468 // to the size. Set *IS_NEW to true if the contents need to be deleted
2469 // by the caller.
2470 const unsigned char*
2471 do_decompressed_section_contents(unsigned int shndx,
2472 section_size_type* plen,
2473 bool* is_new);
2474
2475 // Discard any buffers of decompressed sections. This is done
2476 // at the end of the Add_symbols task.
2477 void
2478 do_discard_decompressed_sections();
2479
2480 private:
2481 // For convenience.
2482 typedef Sized_relobj_file<size, big_endian> This;
2483 static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
2484 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
2485 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2486 typedef elfcpp::Shdr<size, big_endian> Shdr;
2487
2488 // To keep track of discarded comdat sections, we need to map a member
2489 // section index to the object and section index of the corresponding
2490 // kept section.
2491 struct Kept_comdat_section
2492 {
2493 Kept_comdat_section(Relobj* a_object, unsigned int a_shndx)
2494 : object(a_object), shndx(a_shndx)
2495 { }
2496 Relobj* object;
2497 unsigned int shndx;
2498 };
2499 typedef std::map<unsigned int, Kept_comdat_section>
2500 Kept_comdat_section_table;
2501
2502 // Find the SHT_SYMTAB section, given the section headers.
2503 void
2504 find_symtab(const unsigned char* pshdrs);
2505
2506 // Return whether SHDR has the right flags for a GNU style exception
2507 // frame section.
2508 bool
2509 check_eh_frame_flags(const elfcpp::Shdr<size, big_endian>* shdr) const;
2510
2511 // Return whether there is a section named .eh_frame which might be
2512 // a GNU style exception frame section.
2513 bool
2514 find_eh_frame(const unsigned char* pshdrs, const char* names,
2515 section_size_type names_size) const;
2516
2517 // Whether to include a section group in the link.
2518 bool
2519 include_section_group(Symbol_table*, Layout*, unsigned int, const char*,
2520 const unsigned char*, const char*, section_size_type,
2521 std::vector<bool>*);
2522
2523 // Whether to include a linkonce section in the link.
2524 bool
2525 include_linkonce_section(Layout*, unsigned int, const char*,
2526 const elfcpp::Shdr<size, big_endian>&);
2527
2528 // Layout an input section.
2529 void
2530 layout_section(Layout* layout, unsigned int shndx, const char* name,
2531 const typename This::Shdr& shdr, unsigned int reloc_shndx,
2532 unsigned int reloc_type);
2533
2534 // Layout an input .eh_frame section.
2535 void
2536 layout_eh_frame_section(Layout* layout, const unsigned char* symbols_data,
2537 section_size_type symbols_size,
2538 const unsigned char* symbol_names_data,
2539 section_size_type symbol_names_size,
2540 unsigned int shndx, const typename This::Shdr&,
2541 unsigned int reloc_shndx, unsigned int reloc_type);
2542
2543 // Write section data to the output file. Record the views and
2544 // sizes in VIEWS for use when relocating.
2545 void
2546 write_sections(const Layout*, const unsigned char* pshdrs, Output_file*,
2547 Views*);
2548
2549 // Relocate the sections in the output file.
2550 void
2551 relocate_sections(const Symbol_table* symtab, const Layout* layout,
2552 const unsigned char* pshdrs, Output_file* of,
2553 Views* pviews)
2554 { this->do_relocate_sections(symtab, layout, pshdrs, of, pviews); }
2555
2556 // Reverse the words in a section. Used for .ctors sections mapped
2557 // to .init_array sections.
2558 void
2559 reverse_words(unsigned char*, section_size_type);
2560
2561 // Scan the input relocations for --emit-relocs.
2562 void
2563 emit_relocs_scan(Symbol_table*, Layout*, const unsigned char* plocal_syms,
2564 const Read_relocs_data::Relocs_list::iterator&);
2565
2566 // Scan the input relocations for --emit-relocs, templatized on the
2567 // type of the relocation section.
2568 template<int sh_type>
2569 void
2570 emit_relocs_scan_reltype(Symbol_table*, Layout*,
2571 const unsigned char* plocal_syms,
2572 const Read_relocs_data::Relocs_list::iterator&,
2573 Relocatable_relocs*);
2574
2575 // Scan the input relocations for --incremental.
2576 void
2577 incremental_relocs_scan(const Read_relocs_data::Relocs_list::iterator&);
2578
2579 // Scan the input relocations for --incremental, templatized on the
2580 // type of the relocation section.
2581 template<int sh_type>
2582 void
2583 incremental_relocs_scan_reltype(
2584 const Read_relocs_data::Relocs_list::iterator&);
2585
2586 void
2587 incremental_relocs_write(const Relocate_info<size, big_endian>*,
2588 unsigned int sh_type,
2589 const unsigned char* prelocs,
2590 size_t reloc_count,
2591 Output_section*,
2592 Address output_offset,
2593 Output_file*);
2594
2595 template<int sh_type>
2596 void
2597 incremental_relocs_write_reltype(const Relocate_info<size, big_endian>*,
2598 const unsigned char* prelocs,
2599 size_t reloc_count,
2600 Output_section*,
2601 Address output_offset,
2602 Output_file*);
2603
2604 // A type shared by split_stack_adjust_reltype and find_functions.
2605 typedef std::map<section_offset_type, section_size_type> Function_offsets;
2606
2607 // Check for -fsplit-stack routines calling non-split-stack routines.
2608 void
2609 split_stack_adjust(const Symbol_table*, const unsigned char* pshdrs,
2610 unsigned int sh_type, unsigned int shndx,
2611 const unsigned char* prelocs, size_t reloc_count,
2612 unsigned char* view, section_size_type view_size,
2613 Reloc_symbol_changes** reloc_map);
2614
2615 template<int sh_type>
2616 void
2617 split_stack_adjust_reltype(const Symbol_table*, const unsigned char* pshdrs,
2618 unsigned int shndx, const unsigned char* prelocs,
2619 size_t reloc_count, unsigned char* view,
2620 section_size_type view_size,
2621 Reloc_symbol_changes** reloc_map);
2622
2623 // Find all functions in a section.
2624 void
2625 find_functions(const unsigned char* pshdrs, unsigned int shndx,
2626 Function_offsets*);
2627
2628 // Write out the local symbols.
2629 void
2630 write_local_symbols(Output_file*,
2631 const Stringpool_template<char>*,
2632 const Stringpool_template<char>*,
2633 Output_symtab_xindex*,
2634 Output_symtab_xindex*,
2635 off_t);
2636
2637 // Record a mapping from discarded section SHNDX to the corresponding
2638 // kept section.
2639 void
2640 set_kept_comdat_section(unsigned int shndx, Relobj* kept_object,
2641 unsigned int kept_shndx)
2642 {
2643 Kept_comdat_section kept(kept_object, kept_shndx);
2644 this->kept_comdat_sections_.insert(std::make_pair(shndx, kept));
2645 }
2646
2647 // Find the kept section corresponding to the discarded section
2648 // SHNDX. Return true if found.
2649 bool
2650 get_kept_comdat_section(unsigned int shndx, Relobj** kept_object,
2651 unsigned int* kept_shndx) const
2652 {
2653 typename Kept_comdat_section_table::const_iterator p =
2654 this->kept_comdat_sections_.find(shndx);
2655 if (p == this->kept_comdat_sections_.end())
2656 return false;
2657 *kept_object = p->second.object;
2658 *kept_shndx = p->second.shndx;
2659 return true;
2660 }
2661
2662 // Compute final local symbol value. R_SYM is the local symbol index.
2663 // LV_IN points to a local symbol value containing the input value.
2664 // LV_OUT points to a local symbol value storing the final output value,
2665 // which must not be a merged symbol value since before calling this
2666 // method to avoid memory leak. RELOCATABLE indicates whether we are
2667 // linking a relocatable output. OUT_SECTIONS is an array of output
2668 // sections. OUT_OFFSETS is an array of offsets of the sections. SYMTAB
2669 // points to a symbol table.
2670 //
2671 // The method returns a status code at return. If the return status is
2672 // CFLV_OK, *LV_OUT contains the final value. If the return status is
2673 // CFLV_ERROR, *LV_OUT is 0. If the return status is CFLV_DISCARDED,
2674 // *LV_OUT is not modified.
2675 inline Compute_final_local_value_status
2676 compute_final_local_value_internal(unsigned int r_sym,
2677 const Symbol_value<size>* lv_in,
2678 Symbol_value<size>* lv_out,
2679 bool relocatable,
2680 const Output_sections& out_sections,
2681 const std::vector<Address>& out_offsets,
2682 const Symbol_table* symtab);
2683
2684 // The PLT offsets of local symbols.
2685 typedef Unordered_map<unsigned int, unsigned int> Local_plt_offsets;
2686
2687 // Saved information for sections whose layout was deferred.
2688 struct Deferred_layout
2689 {
2690 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
2691 Deferred_layout(unsigned int shndx, const char* name,
2692 const unsigned char* pshdr,
2693 unsigned int reloc_shndx, unsigned int reloc_type)
2694 : shndx_(shndx), name_(name), reloc_shndx_(reloc_shndx),
2695 reloc_type_(reloc_type)
2696 {
2697 memcpy(this->shdr_data_, pshdr, shdr_size);
2698 }
2699 unsigned int shndx_;
2700 std::string name_;
2701 unsigned int reloc_shndx_;
2702 unsigned int reloc_type_;
2703 unsigned char shdr_data_[shdr_size];
2704 };
2705
2706 // General access to the ELF file.
2707 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
2708 // Type of ELF file (ET_REL or ET_EXEC). ET_EXEC files are allowed
2709 // as input files only for the --just-symbols option.
2710 int e_type_;
2711 // Index of SHT_SYMTAB section.
2712 unsigned int symtab_shndx_;
2713 // The number of local symbols.
2714 unsigned int local_symbol_count_;
2715 // The number of local symbols which go into the output file.
2716 unsigned int output_local_symbol_count_;
2717 // The number of local symbols which go into the output file's dynamic
2718 // symbol table.
2719 unsigned int output_local_dynsym_count_;
2720 // The entries in the symbol table for the external symbols.
2721 Symbols symbols_;
2722 // Number of symbols defined in object file itself.
2723 size_t defined_count_;
2724 // File offset for local symbols (relative to start of symbol table).
2725 off_t local_symbol_offset_;
2726 // File offset for local dynamic symbols (absolute).
2727 off_t local_dynsym_offset_;
2728 // Values of local symbols.
2729 Local_values local_values_;
2730 // PLT offsets for local symbols.
2731 Local_plt_offsets local_plt_offsets_;
2732 // Table mapping discarded comdat sections to corresponding kept sections.
2733 Kept_comdat_section_table kept_comdat_sections_;
2734 // Whether this object has a GNU style .eh_frame section.
2735 bool has_eh_frame_;
2736 // If this object has a GNU style .eh_frame section that is discarded in
2737 // output, record the index here. Otherwise it is -1U.
2738 unsigned int discarded_eh_frame_shndx_;
2739 // The list of sections whose layout was deferred.
2740 std::vector<Deferred_layout> deferred_layout_;
2741 // The list of relocation sections whose layout was deferred.
2742 std::vector<Deferred_layout> deferred_layout_relocs_;
2743 // For compressed debug sections, map section index to uncompressed size
2744 // and contents.
2745 Compressed_section_map* compressed_sections_;
2746};
2747
2748// A class to manage the list of all objects.
2749
2750class Input_objects
2751{
2752 public:
2753 Input_objects()
2754 : relobj_list_(), dynobj_list_(), sonames_(), cref_(NULL)
2755 { }
2756
2757 // The type of the list of input relocateable objects.
2758 typedef std::vector<Relobj*> Relobj_list;
2759 typedef Relobj_list::const_iterator Relobj_iterator;
2760
2761 // The type of the list of input dynamic objects.
2762 typedef std::vector<Dynobj*> Dynobj_list;
2763 typedef Dynobj_list::const_iterator Dynobj_iterator;
2764
2765 // Add an object to the list. Return true if all is well, or false
2766 // if this object should be ignored.
2767 bool
2768 add_object(Object*);
2769
2770 // Start processing an archive.
2771 void
2772 archive_start(Archive*);
2773
2774 // Stop processing an archive.
2775 void
2776 archive_stop(Archive*);
2777
2778 // For each dynamic object, check whether we've seen all of its
2779 // explicit dependencies.
2780 void
2781 check_dynamic_dependencies() const;
2782
2783 // Return whether an object was found in the system library
2784 // directory.
2785 bool
2786 found_in_system_library_directory(const Object*) const;
2787
2788 // Print symbol counts.
2789 void
2790 print_symbol_counts(const Symbol_table*) const;
2791
2792 // Print a cross reference table.
2793 void
2794 print_cref(const Symbol_table*, FILE*) const;
2795
2796 // Iterate over all regular objects.
2797
2798 Relobj_iterator
2799 relobj_begin() const
2800 { return this->relobj_list_.begin(); }
2801
2802 Relobj_iterator
2803 relobj_end() const
2804 { return this->relobj_list_.end(); }
2805
2806 // Iterate over all dynamic objects.
2807
2808 Dynobj_iterator
2809 dynobj_begin() const
2810 { return this->dynobj_list_.begin(); }
2811
2812 Dynobj_iterator
2813 dynobj_end() const
2814 { return this->dynobj_list_.end(); }
2815
2816 // Return whether we have seen any dynamic objects.
2817 bool
2818 any_dynamic() const
2819 { return !this->dynobj_list_.empty(); }
2820
2821 // Return the number of non dynamic objects.
2822 int
2823 number_of_relobjs() const
2824 { return this->relobj_list_.size(); }
2825
2826 // Return the number of input objects.
2827 int
2828 number_of_input_objects() const
2829 { return this->relobj_list_.size() + this->dynobj_list_.size(); }
2830
2831 private:
2832 Input_objects(const Input_objects&);
2833 Input_objects& operator=(const Input_objects&);
2834
2835 // The list of ordinary objects included in the link.
2836 Relobj_list relobj_list_;
2837 // The list of dynamic objects included in the link.
2838 Dynobj_list dynobj_list_;
2839 // SONAMEs that we have seen.
2840 Unordered_set<std::string> sonames_;
2841 // Manage cross-references if requested.
2842 Cref* cref_;
2843};
2844
2845// Some of the information we pass to the relocation routines. We
2846// group this together to avoid passing a dozen different arguments.
2847
2848template<int size, bool big_endian>
2849struct Relocate_info
2850{
2851 // Symbol table.
2852 const Symbol_table* symtab;
2853 // Layout.
2854 const Layout* layout;
2855 // Object being relocated.
2856 Sized_relobj_file<size, big_endian>* object;
2857 // Section index of relocation section.
2858 unsigned int reloc_shndx;
2859 // Section header of relocation section.
2860 const unsigned char* reloc_shdr;
2861 // Section index of section being relocated.
2862 unsigned int data_shndx;
2863 // Section header of data section.
2864 const unsigned char* data_shdr;
2865
2866 // Return a string showing the location of a relocation. This is
2867 // only used for error messages.
2868 std::string
2869 location(size_t relnum, off_t reloffset) const;
2870};
2871
2872// This is used to represent a section in an object and is used as the
2873// key type for various section maps.
2874typedef std::pair<Object*, unsigned int> Section_id;
2875
2876// This is similar to Section_id but is used when the section
2877// pointers are const.
2878typedef std::pair<const Object*, unsigned int> Const_section_id;
2879
2880// The hash value is based on the address of an object in memory during
2881// linking. It is okay to use this for looking up sections but never use
2882// this in an unordered container that we want to traverse in a repeatable
2883// manner.
2884
2885struct Section_id_hash
2886{
2887 size_t operator()(const Section_id& loc) const
2888 { return reinterpret_cast<uintptr_t>(loc.first) ^ loc.second; }
2889};
2890
2891struct Const_section_id_hash
2892{
2893 size_t operator()(const Const_section_id& loc) const
2894 { return reinterpret_cast<uintptr_t>(loc.first) ^ loc.second; }
2895};
2896
2897// Return whether INPUT_FILE contains an ELF object start at file
2898// offset OFFSET. This sets *START to point to a view of the start of
2899// the file. It sets *READ_SIZE to the number of bytes in the view.
2900
2901extern bool
2902is_elf_object(Input_file* input_file, off_t offset,
2903 const unsigned char** start, int* read_size);
2904
2905// Return an Object appropriate for the input file. P is BYTES long,
2906// and holds the ELF header. If PUNCONFIGURED is not NULL, then if
2907// this sees an object the linker is not configured to support, it
2908// sets *PUNCONFIGURED to true and returns NULL without giving an
2909// error message.
2910
2911extern Object*
2912make_elf_object(const std::string& name, Input_file*,
2913 off_t offset, const unsigned char* p,
2914 section_offset_type bytes, bool* punconfigured);
2915
2916} // end namespace gold
2917
2918#endif // !defined(GOLD_OBJECT_H)