2011-12-05 Tristan Gingold <gingold@adacore.com>
[binutils.git] / gold / object.h
bloba389c54a1fb0d14b0936f307da0545da0809a940
1 // object.h -- support for an object file for linking in gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 #ifndef GOLD_OBJECT_H
24 #define GOLD_OBJECT_H
26 #include <string>
27 #include <vector>
29 #include "elfcpp.h"
30 #include "elfcpp_file.h"
31 #include "fileread.h"
32 #include "target.h"
33 #include "archive.h"
35 namespace gold
38 class General_options;
39 class Task;
40 class Cref;
41 class Layout;
42 class Output_data;
43 class Output_section;
44 class Output_file;
45 class Output_symtab_xindex;
46 class Pluginobj;
47 class Dynobj;
48 class Object_merge_map;
49 class Relocatable_relocs;
50 class Symbols_data;
52 template<typename Stringpool_char>
53 class Stringpool_template;
55 // Data to pass from read_symbols() to add_symbols().
57 struct Read_symbols_data
59 Read_symbols_data()
60 : section_headers(NULL), section_names(NULL), symbols(NULL),
61 symbol_names(NULL), versym(NULL), verdef(NULL), verneed(NULL)
62 { }
64 ~Read_symbols_data();
66 // Section headers.
67 File_view* section_headers;
68 // Section names.
69 File_view* section_names;
70 // Size of section name data in bytes.
71 section_size_type section_names_size;
72 // Symbol data.
73 File_view* symbols;
74 // Size of symbol data in bytes.
75 section_size_type symbols_size;
76 // Offset of external symbols within symbol data. This structure
77 // sometimes contains only external symbols, in which case this will
78 // be zero. Sometimes it contains all symbols.
79 section_offset_type external_symbols_offset;
80 // Symbol names.
81 File_view* symbol_names;
82 // Size of symbol name data in bytes.
83 section_size_type symbol_names_size;
85 // Version information. This is only used on dynamic objects.
86 // Version symbol data (from SHT_GNU_versym section).
87 File_view* versym;
88 section_size_type versym_size;
89 // Version definition data (from SHT_GNU_verdef section).
90 File_view* verdef;
91 section_size_type verdef_size;
92 unsigned int verdef_info;
93 // Needed version data (from SHT_GNU_verneed section).
94 File_view* verneed;
95 section_size_type verneed_size;
96 unsigned int verneed_info;
99 // Information used to print error messages.
101 struct Symbol_location_info
103 std::string source_file;
104 std::string enclosing_symbol_name;
105 int line_number;
108 // Data about a single relocation section. This is read in
109 // read_relocs and processed in scan_relocs.
111 struct Section_relocs
113 Section_relocs()
114 : contents(NULL)
117 ~Section_relocs()
118 { delete this->contents; }
120 // Index of reloc section.
121 unsigned int reloc_shndx;
122 // Index of section that relocs apply to.
123 unsigned int data_shndx;
124 // Contents of reloc section.
125 File_view* contents;
126 // Reloc section type.
127 unsigned int sh_type;
128 // Number of reloc entries.
129 size_t reloc_count;
130 // Output section.
131 Output_section* output_section;
132 // Whether this section has special handling for offsets.
133 bool needs_special_offset_handling;
134 // Whether the data section is allocated (has the SHF_ALLOC flag set).
135 bool is_data_section_allocated;
138 // Relocations in an object file. This is read in read_relocs and
139 // processed in scan_relocs.
141 struct Read_relocs_data
143 Read_relocs_data()
144 : local_symbols(NULL)
147 ~Read_relocs_data()
148 { delete this->local_symbols; }
150 typedef std::vector<Section_relocs> Relocs_list;
151 // The relocations.
152 Relocs_list relocs;
153 // The local symbols.
154 File_view* local_symbols;
157 // The Xindex class manages section indexes for objects with more than
158 // 0xff00 sections.
160 class Xindex
162 public:
163 Xindex(int large_shndx_offset)
164 : large_shndx_offset_(large_shndx_offset), symtab_xindex_()
167 // Initialize the symtab_xindex_ array, given the object and the
168 // section index of the symbol table to use.
169 template<int size, bool big_endian>
170 void
171 initialize_symtab_xindex(Object*, unsigned int symtab_shndx);
173 // Read in the symtab_xindex_ array, given its section index.
174 // PSHDRS may optionally point to the section headers.
175 template<int size, bool big_endian>
176 void
177 read_symtab_xindex(Object*, unsigned int xindex_shndx,
178 const unsigned char* pshdrs);
180 // Symbol SYMNDX in OBJECT has a section of SHN_XINDEX; return the
181 // real section index.
182 unsigned int
183 sym_xindex_to_shndx(Object* object, unsigned int symndx);
185 private:
186 // The type of the array giving the real section index for symbols
187 // whose st_shndx field holds SHN_XINDEX.
188 typedef std::vector<unsigned int> Symtab_xindex;
190 // Adjust a section index if necessary. This should only be called
191 // for ordinary section indexes.
192 unsigned int
193 adjust_shndx(unsigned int shndx)
195 if (shndx >= elfcpp::SHN_LORESERVE)
196 shndx += this->large_shndx_offset_;
197 return shndx;
200 // Adjust to apply to large section indexes.
201 int large_shndx_offset_;
202 // The data from the SHT_SYMTAB_SHNDX section.
203 Symtab_xindex symtab_xindex_;
206 // A GOT offset list. A symbol may have more than one GOT offset
207 // (e.g., when mixing modules compiled with two different TLS models),
208 // but will usually have at most one. GOT_TYPE identifies the type of
209 // GOT entry; its values are specific to each target.
211 class Got_offset_list
213 public:
214 Got_offset_list()
215 : got_type_(-1U), got_offset_(0), got_next_(NULL)
218 Got_offset_list(unsigned int got_type, unsigned int got_offset)
219 : got_type_(got_type), got_offset_(got_offset), got_next_(NULL)
222 ~Got_offset_list()
224 if (this->got_next_ != NULL)
226 delete this->got_next_;
227 this->got_next_ = NULL;
231 // Initialize the fields to their default values.
232 void
233 init()
235 this->got_type_ = -1U;
236 this->got_offset_ = 0;
237 this->got_next_ = NULL;
240 // Set the offset for the GOT entry of type GOT_TYPE.
241 void
242 set_offset(unsigned int got_type, unsigned int got_offset)
244 if (this->got_type_ == -1U)
246 this->got_type_ = got_type;
247 this->got_offset_ = got_offset;
249 else
251 for (Got_offset_list* g = this; g != NULL; g = g->got_next_)
253 if (g->got_type_ == got_type)
255 g->got_offset_ = got_offset;
256 return;
259 Got_offset_list* g = new Got_offset_list(got_type, got_offset);
260 g->got_next_ = this->got_next_;
261 this->got_next_ = g;
265 // Return the offset for a GOT entry of type GOT_TYPE.
266 unsigned int
267 get_offset(unsigned int got_type) const
269 for (const Got_offset_list* g = this; g != NULL; g = g->got_next_)
271 if (g->got_type_ == got_type)
272 return g->got_offset_;
274 return -1U;
277 // Return a pointer to the list, or NULL if the list is empty.
278 const Got_offset_list*
279 get_list() const
281 if (this->got_type_ == -1U)
282 return NULL;
283 return this;
286 // Abstract visitor class for iterating over GOT offsets.
287 class Visitor
289 public:
290 Visitor()
293 virtual
294 ~Visitor()
297 virtual void
298 visit(unsigned int, unsigned int) = 0;
301 // Loop over all GOT offset entries, calling a visitor class V for each.
302 void
303 for_all_got_offsets(Visitor* v) const
305 if (this->got_type_ == -1U)
306 return;
307 for (const Got_offset_list* g = this; g != NULL; g = g->got_next_)
308 v->visit(g->got_type_, g->got_offset_);
311 private:
312 unsigned int got_type_;
313 unsigned int got_offset_;
314 Got_offset_list* got_next_;
317 // Object is an abstract base class which represents either a 32-bit
318 // or a 64-bit input object. This can be a regular object file
319 // (ET_REL) or a shared object (ET_DYN).
321 class Object
323 public:
324 typedef std::vector<Symbol*> Symbols;
326 // NAME is the name of the object as we would report it to the user
327 // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is
328 // used to read the file. OFFSET is the offset within the input
329 // file--0 for a .o or .so file, something else for a .a file.
330 Object(const std::string& name, Input_file* input_file, bool is_dynamic,
331 off_t offset = 0)
332 : name_(name), input_file_(input_file), offset_(offset), shnum_(-1U),
333 is_dynamic_(is_dynamic), is_needed_(false), uses_split_stack_(false),
334 has_no_split_stack_(false), no_export_(false),
335 is_in_system_directory_(false), as_needed_(false), xindex_(NULL)
337 if (input_file != NULL)
339 input_file->file().add_object();
340 this->is_in_system_directory_ = input_file->is_in_system_directory();
341 this->as_needed_ = input_file->options().as_needed();
345 virtual ~Object()
347 if (this->input_file_ != NULL)
348 this->input_file_->file().remove_object();
351 // Return the name of the object as we would report it to the tuser.
352 const std::string&
353 name() const
354 { return this->name_; }
356 // Get the offset into the file.
357 off_t
358 offset() const
359 { return this->offset_; }
361 // Return whether this is a dynamic object.
362 bool
363 is_dynamic() const
364 { return this->is_dynamic_; }
366 // Return whether this object is needed--true if it is a dynamic
367 // object which defines some symbol referenced by a regular object.
368 // We keep the flag here rather than in Dynobj for convenience when
369 // setting it.
370 bool
371 is_needed() const
372 { return this->is_needed_; }
374 // Record that this object is needed.
375 void
376 set_is_needed()
377 { this->is_needed_ = true; }
379 // Return whether this object was compiled with -fsplit-stack.
380 bool
381 uses_split_stack() const
382 { return this->uses_split_stack_; }
384 // Return whether this object contains any functions compiled with
385 // the no_split_stack attribute.
386 bool
387 has_no_split_stack() const
388 { return this->has_no_split_stack_; }
390 // Returns NULL for Objects that are not dynamic objects. This method
391 // is overridden in the Dynobj class.
392 Dynobj*
393 dynobj()
394 { return this->do_dynobj(); }
396 // Returns NULL for Objects that are not plugin objects. This method
397 // is overridden in the Pluginobj class.
398 Pluginobj*
399 pluginobj()
400 { return this->do_pluginobj(); }
402 // Get the file. We pass on const-ness.
403 Input_file*
404 input_file()
406 gold_assert(this->input_file_ != NULL);
407 return this->input_file_;
410 const Input_file*
411 input_file() const
413 gold_assert(this->input_file_ != NULL);
414 return this->input_file_;
417 // Lock the underlying file.
418 void
419 lock(const Task* t)
421 if (this->input_file_ != NULL)
422 this->input_file_->file().lock(t);
425 // Unlock the underlying file.
426 void
427 unlock(const Task* t)
429 if (this->input_file_ != NULL)
430 this->input_file()->file().unlock(t);
433 // Return whether the underlying file is locked.
434 bool
435 is_locked() const
436 { return this->input_file_ != NULL && this->input_file_->file().is_locked(); }
438 // Return the token, so that the task can be queued.
439 Task_token*
440 token()
442 if (this->input_file_ == NULL)
443 return NULL;
444 return this->input_file()->file().token();
447 // Release the underlying file.
448 void
449 release()
451 if (this->input_file_ != NULL)
452 this->input_file()->file().release();
455 // Return whether we should just read symbols from this file.
456 bool
457 just_symbols() const
458 { return this->input_file()->just_symbols(); }
460 // Return whether this is an incremental object.
461 bool
462 is_incremental() const
463 { return this->do_is_incremental(); }
465 // Return the last modified time of the file.
466 Timespec
467 get_mtime()
468 { return this->do_get_mtime(); }
470 // Get the number of sections.
471 unsigned int
472 shnum() const
473 { return this->shnum_; }
475 // Return a view of the contents of a section. Set *PLEN to the
476 // size. CACHE is a hint as in File_read::get_view.
477 const unsigned char*
478 section_contents(unsigned int shndx, section_size_type* plen, bool cache);
480 // Adjust a symbol's section index as needed. SYMNDX is the index
481 // of the symbol and SHNDX is the symbol's section from
482 // get_st_shndx. This returns the section index. It sets
483 // *IS_ORDINARY to indicate whether this is a normal section index,
484 // rather than a special code between SHN_LORESERVE and
485 // SHN_HIRESERVE.
486 unsigned int
487 adjust_sym_shndx(unsigned int symndx, unsigned int shndx, bool* is_ordinary)
489 if (shndx < elfcpp::SHN_LORESERVE)
490 *is_ordinary = true;
491 else if (shndx == elfcpp::SHN_XINDEX)
493 if (this->xindex_ == NULL)
494 this->xindex_ = this->do_initialize_xindex();
495 shndx = this->xindex_->sym_xindex_to_shndx(this, symndx);
496 *is_ordinary = true;
498 else
499 *is_ordinary = false;
500 return shndx;
503 // Return the size of a section given a section index.
504 uint64_t
505 section_size(unsigned int shndx)
506 { return this->do_section_size(shndx); }
508 // Return the name of a section given a section index.
509 std::string
510 section_name(unsigned int shndx)
511 { return this->do_section_name(shndx); }
513 // Return the section flags given a section index.
514 uint64_t
515 section_flags(unsigned int shndx)
516 { return this->do_section_flags(shndx); }
518 // Return the section entsize given a section index.
519 uint64_t
520 section_entsize(unsigned int shndx)
521 { return this->do_section_entsize(shndx); }
523 // Return the section address given a section index.
524 uint64_t
525 section_address(unsigned int shndx)
526 { return this->do_section_address(shndx); }
528 // Return the section type given a section index.
529 unsigned int
530 section_type(unsigned int shndx)
531 { return this->do_section_type(shndx); }
533 // Return the section link field given a section index.
534 unsigned int
535 section_link(unsigned int shndx)
536 { return this->do_section_link(shndx); }
538 // Return the section info field given a section index.
539 unsigned int
540 section_info(unsigned int shndx)
541 { return this->do_section_info(shndx); }
543 // Return the required section alignment given a section index.
544 uint64_t
545 section_addralign(unsigned int shndx)
546 { return this->do_section_addralign(shndx); }
548 // Return the output section given a section index.
549 Output_section*
550 output_section(unsigned int shndx) const
551 { return this->do_output_section(shndx); }
553 // Given a section index, return the offset in the Output_section.
554 // The return value will be -1U if the section is specially mapped,
555 // such as a merge section.
556 uint64_t
557 output_section_offset(unsigned int shndx) const
558 { return this->do_output_section_offset(shndx); }
560 // Read the symbol information.
561 void
562 read_symbols(Read_symbols_data* sd)
563 { return this->do_read_symbols(sd); }
565 // Pass sections which should be included in the link to the Layout
566 // object, and record where the sections go in the output file.
567 void
568 layout(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd)
569 { this->do_layout(symtab, layout, sd); }
571 // Add symbol information to the global symbol table.
572 void
573 add_symbols(Symbol_table* symtab, Read_symbols_data* sd, Layout *layout)
574 { this->do_add_symbols(symtab, sd, layout); }
576 // Add symbol information to the global symbol table.
577 Archive::Should_include
578 should_include_member(Symbol_table* symtab, Layout* layout,
579 Read_symbols_data* sd, std::string* why)
580 { return this->do_should_include_member(symtab, layout, sd, why); }
582 // Iterate over global symbols, calling a visitor class V for each.
583 void
584 for_all_global_symbols(Read_symbols_data* sd,
585 Library_base::Symbol_visitor_base* v)
586 { return this->do_for_all_global_symbols(sd, v); }
588 // Iterate over local symbols, calling a visitor class V for each GOT offset
589 // associated with a local symbol.
590 void
591 for_all_local_got_entries(Got_offset_list::Visitor* v) const
592 { this->do_for_all_local_got_entries(v); }
594 // Functions and types for the elfcpp::Elf_file interface. This
595 // permit us to use Object as the File template parameter for
596 // elfcpp::Elf_file.
598 // The View class is returned by view. It must support a single
599 // method, data(). This is trivial, because get_view does what we
600 // need.
601 class View
603 public:
604 View(const unsigned char* p)
605 : p_(p)
608 const unsigned char*
609 data() const
610 { return this->p_; }
612 private:
613 const unsigned char* p_;
616 // Return a View.
617 View
618 view(off_t file_offset, section_size_type data_size)
619 { return View(this->get_view(file_offset, data_size, true, true)); }
621 // Report an error.
622 void
623 error(const char* format, ...) const ATTRIBUTE_PRINTF_2;
625 // A location in the file.
626 struct Location
628 off_t file_offset;
629 off_t data_size;
631 Location(off_t fo, section_size_type ds)
632 : file_offset(fo), data_size(ds)
636 // Get a View given a Location.
637 View view(Location loc)
638 { return View(this->get_view(loc.file_offset, loc.data_size, true, true)); }
640 // Get a view into the underlying file.
641 const unsigned char*
642 get_view(off_t start, section_size_type size, bool aligned, bool cache)
644 return this->input_file()->file().get_view(this->offset_, start, size,
645 aligned, cache);
648 // Get a lasting view into the underlying file.
649 File_view*
650 get_lasting_view(off_t start, section_size_type size, bool aligned,
651 bool cache)
653 return this->input_file()->file().get_lasting_view(this->offset_, start,
654 size, aligned, cache);
657 // Read data from the underlying file.
658 void
659 read(off_t start, section_size_type size, void* p)
660 { this->input_file()->file().read(start + this->offset_, size, p); }
662 // Read multiple data from the underlying file.
663 void
664 read_multiple(const File_read::Read_multiple& rm)
665 { this->input_file()->file().read_multiple(this->offset_, rm); }
667 // Stop caching views in the underlying file.
668 void
669 clear_view_cache_marks()
671 if (this->input_file_ != NULL)
672 this->input_file_->file().clear_view_cache_marks();
675 // Get the number of global symbols defined by this object, and the
676 // number of the symbols whose final definition came from this
677 // object.
678 void
679 get_global_symbol_counts(const Symbol_table* symtab, size_t* defined,
680 size_t* used) const
681 { this->do_get_global_symbol_counts(symtab, defined, used); }
683 // Get the symbols defined in this object.
684 const Symbols*
685 get_global_symbols() const
686 { return this->do_get_global_symbols(); }
688 // Set flag that this object was found in a system directory.
689 void
690 set_is_in_system_directory()
691 { this->is_in_system_directory_ = true; }
693 // Return whether this object was found in a system directory.
694 bool
695 is_in_system_directory() const
696 { return this->is_in_system_directory_; }
698 // Set flag that this object was linked with --as-needed.
699 void
700 set_as_needed()
701 { this->as_needed_ = true; }
703 // Return whether this object was linked with --as-needed.
704 bool
705 as_needed() const
706 { return this->as_needed_; }
708 // Return whether we found this object by searching a directory.
709 bool
710 searched_for() const
711 { return this->input_file()->will_search_for(); }
713 bool
714 no_export() const
715 { return this->no_export_; }
717 void
718 set_no_export(bool value)
719 { this->no_export_ = value; }
721 // Return TRUE if the section is a compressed debug section, and set
722 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
723 bool
724 section_is_compressed(unsigned int shndx,
725 section_size_type* uncompressed_size) const
726 { return this->do_section_is_compressed(shndx, uncompressed_size); }
728 // Return the index of the first incremental relocation for symbol SYMNDX.
729 unsigned int
730 get_incremental_reloc_base(unsigned int symndx) const
731 { return this->do_get_incremental_reloc_base(symndx); }
733 // Return the number of incremental relocations for symbol SYMNDX.
734 unsigned int
735 get_incremental_reloc_count(unsigned int symndx) const
736 { return this->do_get_incremental_reloc_count(symndx); }
738 protected:
739 // Returns NULL for Objects that are not dynamic objects. This method
740 // is overridden in the Dynobj class.
741 virtual Dynobj*
742 do_dynobj()
743 { return NULL; }
745 // Returns NULL for Objects that are not plugin objects. This method
746 // is overridden in the Pluginobj class.
747 virtual Pluginobj*
748 do_pluginobj()
749 { return NULL; }
751 // Return TRUE if this is an incremental (unchanged) input file.
752 // We return FALSE by default; the incremental object classes
753 // override this method.
754 virtual bool
755 do_is_incremental() const
756 { return false; }
758 // Return the last modified time of the file. This method may be
759 // overridden for subclasses that don't use an actual file (e.g.,
760 // Incremental objects).
761 virtual Timespec
762 do_get_mtime()
763 { return this->input_file()->file().get_mtime(); }
765 // Read the symbols--implemented by child class.
766 virtual void
767 do_read_symbols(Read_symbols_data*) = 0;
769 // Lay out sections--implemented by child class.
770 virtual void
771 do_layout(Symbol_table*, Layout*, Read_symbols_data*) = 0;
773 // Add symbol information to the global symbol table--implemented by
774 // child class.
775 virtual void
776 do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*) = 0;
778 virtual Archive::Should_include
779 do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
780 std::string* why) = 0;
782 // Iterate over global symbols, calling a visitor class V for each.
783 virtual void
784 do_for_all_global_symbols(Read_symbols_data* sd,
785 Library_base::Symbol_visitor_base* v) = 0;
787 // Iterate over local symbols, calling a visitor class V for each GOT offset
788 // associated with a local symbol.
789 virtual void
790 do_for_all_local_got_entries(Got_offset_list::Visitor* v) const = 0;
792 // Return the location of the contents of a section. Implemented by
793 // child class.
794 virtual Location
795 do_section_contents(unsigned int shndx) = 0;
797 // Get the size of a section--implemented by child class.
798 virtual uint64_t
799 do_section_size(unsigned int shndx) = 0;
801 // Get the name of a section--implemented by child class.
802 virtual std::string
803 do_section_name(unsigned int shndx) = 0;
805 // Get section flags--implemented by child class.
806 virtual uint64_t
807 do_section_flags(unsigned int shndx) = 0;
809 // Get section entsize--implemented by child class.
810 virtual uint64_t
811 do_section_entsize(unsigned int shndx) = 0;
813 // Get section address--implemented by child class.
814 virtual uint64_t
815 do_section_address(unsigned int shndx) = 0;
817 // Get section type--implemented by child class.
818 virtual unsigned int
819 do_section_type(unsigned int shndx) = 0;
821 // Get section link field--implemented by child class.
822 virtual unsigned int
823 do_section_link(unsigned int shndx) = 0;
825 // Get section info field--implemented by child class.
826 virtual unsigned int
827 do_section_info(unsigned int shndx) = 0;
829 // Get section alignment--implemented by child class.
830 virtual uint64_t
831 do_section_addralign(unsigned int shndx) = 0;
833 // Return the output section given a section index--implemented
834 // by child class.
835 virtual Output_section*
836 do_output_section(unsigned int) const
837 { gold_unreachable(); }
839 // Get the offset of a section--implemented by child class.
840 virtual uint64_t
841 do_output_section_offset(unsigned int) const
842 { gold_unreachable(); }
844 // Return the Xindex structure to use.
845 virtual Xindex*
846 do_initialize_xindex() = 0;
848 // Implement get_global_symbol_counts--implemented by child class.
849 virtual void
850 do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const = 0;
852 virtual const Symbols*
853 do_get_global_symbols() const = 0;
855 // Set the number of sections.
856 void
857 set_shnum(int shnum)
858 { this->shnum_ = shnum; }
860 // Functions used by both Sized_relobj_file and Sized_dynobj.
862 // Read the section data into a Read_symbols_data object.
863 template<int size, bool big_endian>
864 void
865 read_section_data(elfcpp::Elf_file<size, big_endian, Object>*,
866 Read_symbols_data*);
868 // Let the child class initialize the xindex object directly.
869 void
870 set_xindex(Xindex* xindex)
872 gold_assert(this->xindex_ == NULL);
873 this->xindex_ = xindex;
876 // If NAME is the name of a special .gnu.warning section, arrange
877 // for the warning to be issued. SHNDX is the section index.
878 // Return whether it is a warning section.
879 bool
880 handle_gnu_warning_section(const char* name, unsigned int shndx,
881 Symbol_table*);
883 // If NAME is the name of the special section which indicates that
884 // this object was compiled with -fsplit-stack, mark it accordingly,
885 // and return true. Otherwise return false.
886 bool
887 handle_split_stack_section(const char* name);
889 // Return TRUE if the section is a compressed debug section, and set
890 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
891 virtual bool
892 do_section_is_compressed(unsigned int, section_size_type*) const
893 { return false; }
895 // Return the index of the first incremental relocation for symbol SYMNDX--
896 // implemented by child class.
897 virtual unsigned int
898 do_get_incremental_reloc_base(unsigned int) const
899 { gold_unreachable(); }
901 // Return the number of incremental relocations for symbol SYMNDX--
902 // implemented by child class.
903 virtual unsigned int
904 do_get_incremental_reloc_count(unsigned int) const
905 { gold_unreachable(); }
907 private:
908 // This class may not be copied.
909 Object(const Object&);
910 Object& operator=(const Object&);
912 // Name of object as printed to user.
913 std::string name_;
914 // For reading the file.
915 Input_file* input_file_;
916 // Offset within the file--0 for an object file, non-0 for an
917 // archive.
918 off_t offset_;
919 // Number of input sections.
920 unsigned int shnum_;
921 // Whether this is a dynamic object.
922 bool is_dynamic_ : 1;
923 // Whether this object is needed. This is only set for dynamic
924 // objects, and means that the object defined a symbol which was
925 // used by a reference from a regular object.
926 bool is_needed_ : 1;
927 // Whether this object was compiled with -fsplit-stack.
928 bool uses_split_stack_ : 1;
929 // Whether this object contains any functions compiled with the
930 // no_split_stack attribute.
931 bool has_no_split_stack_ : 1;
932 // True if exclude this object from automatic symbol export.
933 // This is used only for archive objects.
934 bool no_export_ : 1;
935 // True if the object was found in a system directory.
936 bool is_in_system_directory_ : 1;
937 // True if the object was linked with --as-needed.
938 bool as_needed_ : 1;
939 // Many sections for objects with more than SHN_LORESERVE sections.
940 Xindex* xindex_;
943 // A regular object (ET_REL). This is an abstract base class itself.
944 // The implementation is the template class Sized_relobj_file.
946 class Relobj : public Object
948 public:
949 Relobj(const std::string& name, Input_file* input_file, off_t offset = 0)
950 : Object(name, input_file, false, offset),
951 output_sections_(),
952 map_to_relocatable_relocs_(NULL),
953 object_merge_map_(NULL),
954 relocs_must_follow_section_writes_(false),
955 sd_(NULL),
956 reloc_counts_(NULL),
957 reloc_bases_(NULL),
958 first_dyn_reloc_(0),
959 dyn_reloc_count_(0)
962 // During garbage collection, the Read_symbols_data pass for
963 // each object is stored as layout needs to be done after
964 // reloc processing.
965 Symbols_data*
966 get_symbols_data()
967 { return this->sd_; }
969 // Decides which section names have to be included in the worklist
970 // as roots.
971 bool
972 is_section_name_included(const char* name);
974 void
975 copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
976 unsigned int section_header_size);
978 void
979 set_symbols_data(Symbols_data* sd)
980 { this->sd_ = sd; }
982 // During garbage collection, the Read_relocs pass for all objects
983 // is done before scanning the relocs. In that case, this->rd_ is
984 // used to store the information from Read_relocs for each object.
985 // This data is also used to compute the list of relevant sections.
986 Read_relocs_data*
987 get_relocs_data()
988 { return this->rd_; }
990 void
991 set_relocs_data(Read_relocs_data* rd)
992 { this->rd_ = rd; }
994 virtual bool
995 is_output_section_offset_invalid(unsigned int shndx) const = 0;
997 // Read the relocs.
998 void
999 read_relocs(Read_relocs_data* rd)
1000 { return this->do_read_relocs(rd); }
1002 // Process the relocs, during garbage collection only.
1003 void
1004 gc_process_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd)
1005 { return this->do_gc_process_relocs(symtab, layout, rd); }
1007 // Scan the relocs and adjust the symbol table.
1008 void
1009 scan_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd)
1010 { return this->do_scan_relocs(symtab, layout, rd); }
1012 // The number of local symbols in the input symbol table.
1013 virtual unsigned int
1014 local_symbol_count() const
1015 { return this->do_local_symbol_count(); }
1017 // The number of local symbols in the output symbol table.
1018 virtual unsigned int
1019 output_local_symbol_count() const
1020 { return this->do_output_local_symbol_count(); }
1022 // The file offset for local symbols in the output symbol table.
1023 virtual off_t
1024 local_symbol_offset() const
1025 { return this->do_local_symbol_offset(); }
1027 // Initial local symbol processing: count the number of local symbols
1028 // in the output symbol table and dynamic symbol table; add local symbol
1029 // names to *POOL and *DYNPOOL.
1030 void
1031 count_local_symbols(Stringpool_template<char>* pool,
1032 Stringpool_template<char>* dynpool)
1033 { return this->do_count_local_symbols(pool, dynpool); }
1035 // Set the values of the local symbols, set the output symbol table
1036 // indexes for the local variables, and set the offset where local
1037 // symbol information will be stored. Returns the new local symbol index.
1038 unsigned int
1039 finalize_local_symbols(unsigned int index, off_t off, Symbol_table* symtab)
1040 { return this->do_finalize_local_symbols(index, off, symtab); }
1042 // Set the output dynamic symbol table indexes for the local variables.
1043 unsigned int
1044 set_local_dynsym_indexes(unsigned int index)
1045 { return this->do_set_local_dynsym_indexes(index); }
1047 // Set the offset where local dynamic symbol information will be stored.
1048 unsigned int
1049 set_local_dynsym_offset(off_t off)
1050 { return this->do_set_local_dynsym_offset(off); }
1052 // Record a dynamic relocation against an input section from this object.
1053 void
1054 add_dyn_reloc(unsigned int index)
1056 if (this->dyn_reloc_count_ == 0)
1057 this->first_dyn_reloc_ = index;
1058 ++this->dyn_reloc_count_;
1061 // Return the index of the first dynamic relocation.
1062 unsigned int
1063 first_dyn_reloc() const
1064 { return this->first_dyn_reloc_; }
1066 // Return the count of dynamic relocations.
1067 unsigned int
1068 dyn_reloc_count() const
1069 { return this->dyn_reloc_count_; }
1071 // Relocate the input sections and write out the local symbols.
1072 void
1073 relocate(const Symbol_table* symtab, const Layout* layout, Output_file* of)
1074 { return this->do_relocate(symtab, layout, of); }
1076 // Return whether an input section is being included in the link.
1077 bool
1078 is_section_included(unsigned int shndx) const
1080 gold_assert(shndx < this->output_sections_.size());
1081 return this->output_sections_[shndx] != NULL;
1084 // The the output section of the input section with index SHNDX.
1085 // This is only used currently to remove a section from the link in
1086 // relaxation.
1087 void
1088 set_output_section(unsigned int shndx, Output_section* os)
1090 gold_assert(shndx < this->output_sections_.size());
1091 this->output_sections_[shndx] = os;
1094 // Set the offset of an input section within its output section.
1095 void
1096 set_section_offset(unsigned int shndx, uint64_t off)
1097 { this->do_set_section_offset(shndx, off); }
1099 // Return true if we need to wait for output sections to be written
1100 // before we can apply relocations. This is true if the object has
1101 // any relocations for sections which require special handling, such
1102 // as the exception frame section.
1103 bool
1104 relocs_must_follow_section_writes() const
1105 { return this->relocs_must_follow_section_writes_; }
1107 // Return the object merge map.
1108 Object_merge_map*
1109 merge_map() const
1110 { return this->object_merge_map_; }
1112 // Set the object merge map.
1113 void
1114 set_merge_map(Object_merge_map* object_merge_map)
1116 gold_assert(this->object_merge_map_ == NULL);
1117 this->object_merge_map_ = object_merge_map;
1120 // Record the relocatable reloc info for an input reloc section.
1121 void
1122 set_relocatable_relocs(unsigned int reloc_shndx, Relocatable_relocs* rr)
1124 gold_assert(reloc_shndx < this->shnum());
1125 (*this->map_to_relocatable_relocs_)[reloc_shndx] = rr;
1128 // Get the relocatable reloc info for an input reloc section.
1129 Relocatable_relocs*
1130 relocatable_relocs(unsigned int reloc_shndx)
1132 gold_assert(reloc_shndx < this->shnum());
1133 return (*this->map_to_relocatable_relocs_)[reloc_shndx];
1136 // Layout sections whose layout was deferred while waiting for
1137 // input files from a plugin.
1138 void
1139 layout_deferred_sections(Layout* layout)
1140 { this->do_layout_deferred_sections(layout); }
1142 // Return the index of the first incremental relocation for symbol SYMNDX.
1143 virtual unsigned int
1144 do_get_incremental_reloc_base(unsigned int symndx) const
1145 { return this->reloc_bases_[symndx]; }
1147 // Return the number of incremental relocations for symbol SYMNDX.
1148 virtual unsigned int
1149 do_get_incremental_reloc_count(unsigned int symndx) const
1150 { return this->reloc_counts_[symndx]; }
1152 protected:
1153 // The output section to be used for each input section, indexed by
1154 // the input section number. The output section is NULL if the
1155 // input section is to be discarded.
1156 typedef std::vector<Output_section*> Output_sections;
1158 // Read the relocs--implemented by child class.
1159 virtual void
1160 do_read_relocs(Read_relocs_data*) = 0;
1162 // Process the relocs--implemented by child class.
1163 virtual void
1164 do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0;
1166 // Scan the relocs--implemented by child class.
1167 virtual void
1168 do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0;
1170 // Return the number of local symbols--implemented by child class.
1171 virtual unsigned int
1172 do_local_symbol_count() const = 0;
1174 // Return the number of output local symbols--implemented by child class.
1175 virtual unsigned int
1176 do_output_local_symbol_count() const = 0;
1178 // Return the file offset for local symbols--implemented by child class.
1179 virtual off_t
1180 do_local_symbol_offset() const = 0;
1182 // Count local symbols--implemented by child class.
1183 virtual void
1184 do_count_local_symbols(Stringpool_template<char>*,
1185 Stringpool_template<char>*) = 0;
1187 // Finalize the local symbols. Set the output symbol table indexes
1188 // for the local variables, and set the offset where local symbol
1189 // information will be stored.
1190 virtual unsigned int
1191 do_finalize_local_symbols(unsigned int, off_t, Symbol_table*) = 0;
1193 // Set the output dynamic symbol table indexes for the local variables.
1194 virtual unsigned int
1195 do_set_local_dynsym_indexes(unsigned int) = 0;
1197 // Set the offset where local dynamic symbol information will be stored.
1198 virtual unsigned int
1199 do_set_local_dynsym_offset(off_t) = 0;
1201 // Relocate the input sections and write out the local
1202 // symbols--implemented by child class.
1203 virtual void
1204 do_relocate(const Symbol_table* symtab, const Layout*, Output_file* of) = 0;
1206 // Set the offset of a section--implemented by child class.
1207 virtual void
1208 do_set_section_offset(unsigned int shndx, uint64_t off) = 0;
1210 // Layout sections whose layout was deferred while waiting for
1211 // input files from a plugin--implemented by child class.
1212 virtual void
1213 do_layout_deferred_sections(Layout*) = 0;
1215 // Given a section index, return the corresponding Output_section.
1216 // The return value will be NULL if the section is not included in
1217 // the link.
1218 Output_section*
1219 do_output_section(unsigned int shndx) const
1221 gold_assert(shndx < this->output_sections_.size());
1222 return this->output_sections_[shndx];
1225 // Return the vector mapping input sections to output sections.
1226 Output_sections&
1227 output_sections()
1228 { return this->output_sections_; }
1230 const Output_sections&
1231 output_sections() const
1232 { return this->output_sections_; }
1234 // Set the size of the relocatable relocs array.
1235 void
1236 size_relocatable_relocs()
1238 this->map_to_relocatable_relocs_ =
1239 new std::vector<Relocatable_relocs*>(this->shnum());
1242 // Record that we must wait for the output sections to be written
1243 // before applying relocations.
1244 void
1245 set_relocs_must_follow_section_writes()
1246 { this->relocs_must_follow_section_writes_ = true; }
1248 // Allocate the array for counting incremental relocations.
1249 void
1250 allocate_incremental_reloc_counts()
1252 unsigned int nsyms = this->do_get_global_symbols()->size();
1253 this->reloc_counts_ = new unsigned int[nsyms];
1254 gold_assert(this->reloc_counts_ != NULL);
1255 memset(this->reloc_counts_, 0, nsyms * sizeof(unsigned int));
1258 // Record a relocation in this object referencing global symbol SYMNDX.
1259 // Used for tracking incremental link information.
1260 void
1261 count_incremental_reloc(unsigned int symndx)
1263 unsigned int nsyms = this->do_get_global_symbols()->size();
1264 gold_assert(symndx < nsyms);
1265 gold_assert(this->reloc_counts_ != NULL);
1266 ++this->reloc_counts_[symndx];
1269 // Finalize the incremental relocation information.
1270 void
1271 finalize_incremental_relocs(Layout* layout, bool clear_counts);
1273 // Return the index of the next relocation to be written for global symbol
1274 // SYMNDX. Only valid after finalize_incremental_relocs() has been called.
1275 unsigned int
1276 next_incremental_reloc_index(unsigned int symndx)
1278 unsigned int nsyms = this->do_get_global_symbols()->size();
1280 gold_assert(this->reloc_counts_ != NULL);
1281 gold_assert(this->reloc_bases_ != NULL);
1282 gold_assert(symndx < nsyms);
1284 unsigned int counter = this->reloc_counts_[symndx]++;
1285 return this->reloc_bases_[symndx] + counter;
1288 private:
1289 // Mapping from input sections to output section.
1290 Output_sections output_sections_;
1291 // Mapping from input section index to the information recorded for
1292 // the relocations. This is only used for a relocatable link.
1293 std::vector<Relocatable_relocs*>* map_to_relocatable_relocs_;
1294 // Mappings for merge sections. This is managed by the code in the
1295 // Merge_map class.
1296 Object_merge_map* object_merge_map_;
1297 // Whether we need to wait for output sections to be written before
1298 // we can apply relocations.
1299 bool relocs_must_follow_section_writes_;
1300 // Used to store the relocs data computed by the Read_relocs pass.
1301 // Used during garbage collection of unused sections.
1302 Read_relocs_data* rd_;
1303 // Used to store the symbols data computed by the Read_symbols pass.
1304 // Again used during garbage collection when laying out referenced
1305 // sections.
1306 gold::Symbols_data* sd_;
1307 // Per-symbol counts of relocations, for incremental links.
1308 unsigned int* reloc_counts_;
1309 // Per-symbol base indexes of relocations, for incremental links.
1310 unsigned int* reloc_bases_;
1311 // Index of the first dynamic relocation for this object.
1312 unsigned int first_dyn_reloc_;
1313 // Count of dynamic relocations for this object.
1314 unsigned int dyn_reloc_count_;
1317 // This class is used to handle relocations against a section symbol
1318 // in an SHF_MERGE section. For such a symbol, we need to know the
1319 // addend of the relocation before we can determine the final value.
1320 // The addend gives us the location in the input section, and we can
1321 // determine how it is mapped to the output section. For a
1322 // non-section symbol, we apply the addend to the final value of the
1323 // symbol; that is done in finalize_local_symbols, and does not use
1324 // this class.
1326 template<int size>
1327 class Merged_symbol_value
1329 public:
1330 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;
1332 // We use a hash table to map offsets in the input section to output
1333 // addresses.
1334 typedef Unordered_map<section_offset_type, Value> Output_addresses;
1336 Merged_symbol_value(Value input_value, Value output_start_address)
1337 : input_value_(input_value), output_start_address_(output_start_address),
1338 output_addresses_()
1341 // Initialize the hash table.
1342 void
1343 initialize_input_to_output_map(const Relobj*, unsigned int input_shndx);
1345 // Release the hash table to save space.
1346 void
1347 free_input_to_output_map()
1348 { this->output_addresses_.clear(); }
1350 // Get the output value corresponding to an addend. The object and
1351 // input section index are passed in because the caller will have
1352 // them; otherwise we could store them here.
1353 Value
1354 value(const Relobj* object, unsigned int input_shndx, Value addend) const
1356 // This is a relocation against a section symbol. ADDEND is the
1357 // offset in the section. The result should be the start of some
1358 // merge area. If the object file wants something else, it should
1359 // use a regular symbol rather than a section symbol.
1360 // Unfortunately, PR 6658 shows a case in which the object file
1361 // refers to the section symbol, but uses a negative ADDEND to
1362 // compensate for a PC relative reloc. We can't handle the
1363 // general case. However, we can handle the special case of a
1364 // negative addend, by assuming that it refers to the start of the
1365 // section. Of course, that means that we have to guess when
1366 // ADDEND is negative. It is normal to see a 32-bit value here
1367 // even when the template parameter size is 64, as 64-bit object
1368 // file formats have 32-bit relocations. We know this is a merge
1369 // section, so we know it has to fit into memory. So we assume
1370 // that we won't see a value larger than a large 32-bit unsigned
1371 // value. This will break objects with very very large merge
1372 // sections; they probably break in other ways anyhow.
1373 Value input_offset = this->input_value_;
1374 if (addend < 0xffffff00)
1376 input_offset += addend;
1377 addend = 0;
1379 typename Output_addresses::const_iterator p =
1380 this->output_addresses_.find(input_offset);
1381 if (p != this->output_addresses_.end())
1382 return p->second + addend;
1384 return (this->value_from_output_section(object, input_shndx, input_offset)
1385 + addend);
1388 private:
1389 // Get the output value for an input offset if we couldn't find it
1390 // in the hash table.
1391 Value
1392 value_from_output_section(const Relobj*, unsigned int input_shndx,
1393 Value input_offset) const;
1395 // The value of the section symbol in the input file. This is
1396 // normally zero, but could in principle be something else.
1397 Value input_value_;
1398 // The start address of this merged section in the output file.
1399 Value output_start_address_;
1400 // A hash table which maps offsets in the input section to output
1401 // addresses. This only maps specific offsets, not all offsets.
1402 Output_addresses output_addresses_;
1405 // This POD class is holds the value of a symbol. This is used for
1406 // local symbols, and for all symbols during relocation processing.
1407 // For special sections, such as SHF_MERGE sections, this calls a
1408 // function to get the final symbol value.
1410 template<int size>
1411 class Symbol_value
1413 public:
1414 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;
1416 Symbol_value()
1417 : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0),
1418 is_ordinary_shndx_(false), is_section_symbol_(false),
1419 is_tls_symbol_(false), is_ifunc_symbol_(false), has_output_value_(true)
1420 { this->u_.value = 0; }
1422 ~Symbol_value()
1424 if (!this->has_output_value_)
1425 delete this->u_.merged_symbol_value;
1428 // Get the value of this symbol. OBJECT is the object in which this
1429 // symbol is defined, and ADDEND is an addend to add to the value.
1430 template<bool big_endian>
1431 Value
1432 value(const Sized_relobj_file<size, big_endian>* object, Value addend) const
1434 if (this->has_output_value_)
1435 return this->u_.value + addend;
1436 else
1438 gold_assert(this->is_ordinary_shndx_);
1439 return this->u_.merged_symbol_value->value(object, this->input_shndx_,
1440 addend);
1444 // Set the value of this symbol in the output symbol table.
1445 void
1446 set_output_value(Value value)
1447 { this->u_.value = value; }
1449 // For a section symbol in a merged section, we need more
1450 // information.
1451 void
1452 set_merged_symbol_value(Merged_symbol_value<size>* msv)
1454 gold_assert(this->is_section_symbol_);
1455 this->has_output_value_ = false;
1456 this->u_.merged_symbol_value = msv;
1459 // Initialize the input to output map for a section symbol in a
1460 // merged section. We also initialize the value of a non-section
1461 // symbol in a merged section.
1462 void
1463 initialize_input_to_output_map(const Relobj* object)
1465 if (!this->has_output_value_)
1467 gold_assert(this->is_section_symbol_ && this->is_ordinary_shndx_);
1468 Merged_symbol_value<size>* msv = this->u_.merged_symbol_value;
1469 msv->initialize_input_to_output_map(object, this->input_shndx_);
1473 // Free the input to output map for a section symbol in a merged
1474 // section.
1475 void
1476 free_input_to_output_map()
1478 if (!this->has_output_value_)
1479 this->u_.merged_symbol_value->free_input_to_output_map();
1482 // Set the value of the symbol from the input file. This is only
1483 // called by count_local_symbols, to communicate the value to
1484 // finalize_local_symbols.
1485 void
1486 set_input_value(Value value)
1487 { this->u_.value = value; }
1489 // Return the input value. This is only called by
1490 // finalize_local_symbols and (in special cases) relocate_section.
1491 Value
1492 input_value() const
1493 { return this->u_.value; }
1495 // Return whether we have set the index in the output symbol table
1496 // yet.
1497 bool
1498 is_output_symtab_index_set() const
1500 return (this->output_symtab_index_ != 0
1501 && this->output_symtab_index_ != -2U);
1504 // Return whether this symbol may be discarded from the normal
1505 // symbol table.
1506 bool
1507 may_be_discarded_from_output_symtab() const
1509 gold_assert(!this->is_output_symtab_index_set());
1510 return this->output_symtab_index_ != -2U;
1513 // Return whether this symbol has an entry in the output symbol
1514 // table.
1515 bool
1516 has_output_symtab_entry() const
1518 gold_assert(this->is_output_symtab_index_set());
1519 return this->output_symtab_index_ != -1U;
1522 // Return the index in the output symbol table.
1523 unsigned int
1524 output_symtab_index() const
1526 gold_assert(this->is_output_symtab_index_set()
1527 && this->output_symtab_index_ != -1U);
1528 return this->output_symtab_index_;
1531 // Set the index in the output symbol table.
1532 void
1533 set_output_symtab_index(unsigned int i)
1535 gold_assert(!this->is_output_symtab_index_set());
1536 gold_assert(i != 0 && i != -1U && i != -2U);
1537 this->output_symtab_index_ = i;
1540 // Record that this symbol should not go into the output symbol
1541 // table.
1542 void
1543 set_no_output_symtab_entry()
1545 gold_assert(this->output_symtab_index_ == 0);
1546 this->output_symtab_index_ = -1U;
1549 // Record that this symbol must go into the output symbol table,
1550 // because it there is a relocation that uses it.
1551 void
1552 set_must_have_output_symtab_entry()
1554 gold_assert(!this->is_output_symtab_index_set());
1555 this->output_symtab_index_ = -2U;
1558 // Set the index in the output dynamic symbol table.
1559 void
1560 set_needs_output_dynsym_entry()
1562 gold_assert(!this->is_section_symbol());
1563 this->output_dynsym_index_ = 0;
1566 // Return whether this symbol should go into the dynamic symbol
1567 // table.
1568 bool
1569 needs_output_dynsym_entry() const
1571 return this->output_dynsym_index_ != -1U;
1574 // Return whether this symbol has an entry in the dynamic symbol
1575 // table.
1576 bool
1577 has_output_dynsym_entry() const
1579 gold_assert(this->output_dynsym_index_ != 0);
1580 return this->output_dynsym_index_ != -1U;
1583 // Record that this symbol should go into the dynamic symbol table.
1584 void
1585 set_output_dynsym_index(unsigned int i)
1587 gold_assert(this->output_dynsym_index_ == 0);
1588 gold_assert(i != 0 && i != -1U);
1589 this->output_dynsym_index_ = i;
1592 // Return the index in the output dynamic symbol table.
1593 unsigned int
1594 output_dynsym_index() const
1596 gold_assert(this->output_dynsym_index_ != 0
1597 && this->output_dynsym_index_ != -1U);
1598 return this->output_dynsym_index_;
1601 // Set the index of the input section in the input file.
1602 void
1603 set_input_shndx(unsigned int i, bool is_ordinary)
1605 this->input_shndx_ = i;
1606 // input_shndx_ field is a bitfield, so make sure that the value
1607 // fits.
1608 gold_assert(this->input_shndx_ == i);
1609 this->is_ordinary_shndx_ = is_ordinary;
1612 // Return the index of the input section in the input file.
1613 unsigned int
1614 input_shndx(bool* is_ordinary) const
1616 *is_ordinary = this->is_ordinary_shndx_;
1617 return this->input_shndx_;
1620 // Whether this is a section symbol.
1621 bool
1622 is_section_symbol() const
1623 { return this->is_section_symbol_; }
1625 // Record that this is a section symbol.
1626 void
1627 set_is_section_symbol()
1629 gold_assert(!this->needs_output_dynsym_entry());
1630 this->is_section_symbol_ = true;
1633 // Record that this is a TLS symbol.
1634 void
1635 set_is_tls_symbol()
1636 { this->is_tls_symbol_ = true; }
1638 // Return true if this is a TLS symbol.
1639 bool
1640 is_tls_symbol() const
1641 { return this->is_tls_symbol_; }
1643 // Record that this is an IFUNC symbol.
1644 void
1645 set_is_ifunc_symbol()
1646 { this->is_ifunc_symbol_ = true; }
1648 // Return true if this is an IFUNC symbol.
1649 bool
1650 is_ifunc_symbol() const
1651 { return this->is_ifunc_symbol_; }
1653 // Return true if this has output value.
1654 bool
1655 has_output_value() const
1656 { return this->has_output_value_; }
1658 private:
1659 // The index of this local symbol in the output symbol table. This
1660 // will be 0 if no value has been assigned yet, and the symbol may
1661 // be omitted. This will be -1U if the symbol should not go into
1662 // the symbol table. This will be -2U if the symbol must go into
1663 // the symbol table, but no index has been assigned yet.
1664 unsigned int output_symtab_index_;
1665 // The index of this local symbol in the dynamic symbol table. This
1666 // will be -1U if the symbol should not go into the symbol table.
1667 unsigned int output_dynsym_index_;
1668 // The section index in the input file in which this symbol is
1669 // defined.
1670 unsigned int input_shndx_ : 27;
1671 // Whether the section index is an ordinary index, not a special
1672 // value.
1673 bool is_ordinary_shndx_ : 1;
1674 // Whether this is a STT_SECTION symbol.
1675 bool is_section_symbol_ : 1;
1676 // Whether this is a STT_TLS symbol.
1677 bool is_tls_symbol_ : 1;
1678 // Whether this is a STT_GNU_IFUNC symbol.
1679 bool is_ifunc_symbol_ : 1;
1680 // Whether this symbol has a value for the output file. This is
1681 // normally set to true during Layout::finalize, by
1682 // finalize_local_symbols. It will be false for a section symbol in
1683 // a merge section, as for such symbols we can not determine the
1684 // value to use in a relocation until we see the addend.
1685 bool has_output_value_ : 1;
1686 union
1688 // This is used if has_output_value_ is true. Between
1689 // count_local_symbols and finalize_local_symbols, this is the
1690 // value in the input file. After finalize_local_symbols, it is
1691 // the value in the output file.
1692 Value value;
1693 // This is used if has_output_value_ is false. It points to the
1694 // information we need to get the value for a merge section.
1695 Merged_symbol_value<size>* merged_symbol_value;
1696 } u_;
1699 // This type is used to modify relocations for -fsplit-stack. It is
1700 // indexed by relocation index, and means that the relocation at that
1701 // index should use the symbol from the vector, rather than the one
1702 // indicated by the relocation.
1704 class Reloc_symbol_changes
1706 public:
1707 Reloc_symbol_changes(size_t count)
1708 : vec_(count, NULL)
1711 void
1712 set(size_t i, Symbol* sym)
1713 { this->vec_[i] = sym; }
1715 const Symbol*
1716 operator[](size_t i) const
1717 { return this->vec_[i]; }
1719 private:
1720 std::vector<Symbol*> vec_;
1723 // Type for mapping section index to uncompressed size.
1725 typedef std::map<unsigned int, section_size_type> Compressed_section_map;
1727 // Abstract base class for a regular object file, either a real object file
1728 // or an incremental (unchanged) object. This is size and endian specific.
1730 template<int size, bool big_endian>
1731 class Sized_relobj : public Relobj
1733 public:
1734 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
1735 typedef Relobj::Symbols Symbols;
1737 static const Address invalid_address = static_cast<Address>(0) - 1;
1739 Sized_relobj(const std::string& name, Input_file* input_file)
1740 : Relobj(name, input_file), local_got_offsets_(), section_offsets_()
1743 Sized_relobj(const std::string& name, Input_file* input_file,
1744 off_t offset)
1745 : Relobj(name, input_file, offset), local_got_offsets_(), section_offsets_()
1748 ~Sized_relobj()
1751 // If this is a regular object, return a pointer to the Sized_relobj_file
1752 // object. Otherwise, return NULL.
1753 virtual Sized_relobj_file<size, big_endian>*
1754 sized_relobj()
1755 { return NULL; }
1757 const virtual Sized_relobj_file<size, big_endian>*
1758 sized_relobj() const
1759 { return NULL; }
1761 // Checks if the offset of input section SHNDX within its output
1762 // section is invalid.
1763 bool
1764 is_output_section_offset_invalid(unsigned int shndx) const
1765 { return this->get_output_section_offset(shndx) == invalid_address; }
1767 // Get the offset of input section SHNDX within its output section.
1768 // This is -1 if the input section requires a special mapping, such
1769 // as a merge section. The output section can be found in the
1770 // output_sections_ field of the parent class Relobj.
1771 Address
1772 get_output_section_offset(unsigned int shndx) const
1774 gold_assert(shndx < this->section_offsets_.size());
1775 return this->section_offsets_[shndx];
1778 // Return whether the local symbol SYMNDX has a GOT offset.
1779 // For TLS symbols, the GOT entry will hold its tp-relative offset.
1780 bool
1781 local_has_got_offset(unsigned int symndx, unsigned int got_type) const
1783 Local_got_offsets::const_iterator p =
1784 this->local_got_offsets_.find(symndx);
1785 return (p != this->local_got_offsets_.end()
1786 && p->second->get_offset(got_type) != -1U);
1789 // Return the GOT offset of the local symbol SYMNDX.
1790 unsigned int
1791 local_got_offset(unsigned int symndx, unsigned int got_type) const
1793 Local_got_offsets::const_iterator p =
1794 this->local_got_offsets_.find(symndx);
1795 gold_assert(p != this->local_got_offsets_.end());
1796 unsigned int off = p->second->get_offset(got_type);
1797 gold_assert(off != -1U);
1798 return off;
1801 // Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET.
1802 void
1803 set_local_got_offset(unsigned int symndx, unsigned int got_type,
1804 unsigned int got_offset)
1806 Local_got_offsets::const_iterator p =
1807 this->local_got_offsets_.find(symndx);
1808 if (p != this->local_got_offsets_.end())
1809 p->second->set_offset(got_type, got_offset);
1810 else
1812 Got_offset_list* g = new Got_offset_list(got_type, got_offset);
1813 std::pair<Local_got_offsets::iterator, bool> ins =
1814 this->local_got_offsets_.insert(std::make_pair(symndx, g));
1815 gold_assert(ins.second);
1819 // Iterate over local symbols, calling a visitor class V for each GOT offset
1820 // associated with a local symbol.
1821 void
1822 do_for_all_local_got_entries(Got_offset_list::Visitor* v) const;
1824 protected:
1825 typedef Relobj::Output_sections Output_sections;
1827 // Clear the local symbol information.
1828 void
1829 clear_got_offsets()
1830 { this->local_got_offsets_.clear(); }
1832 // Return the vector of section offsets.
1833 std::vector<Address>&
1834 section_offsets()
1835 { return this->section_offsets_; }
1837 // Get the offset of a section.
1838 uint64_t
1839 do_output_section_offset(unsigned int shndx) const
1841 Address off = this->get_output_section_offset(shndx);
1842 if (off == invalid_address)
1843 return -1ULL;
1844 return off;
1847 // Set the offset of a section.
1848 void
1849 do_set_section_offset(unsigned int shndx, uint64_t off)
1851 gold_assert(shndx < this->section_offsets_.size());
1852 this->section_offsets_[shndx] =
1853 (off == static_cast<uint64_t>(-1)
1854 ? invalid_address
1855 : convert_types<Address, uint64_t>(off));
1858 private:
1859 // The GOT offsets of local symbols. This map also stores GOT offsets
1860 // for tp-relative offsets for TLS symbols.
1861 typedef Unordered_map<unsigned int, Got_offset_list*> Local_got_offsets;
1863 // GOT offsets for local non-TLS symbols, and tp-relative offsets
1864 // for TLS symbols, indexed by symbol number.
1865 Local_got_offsets local_got_offsets_;
1866 // For each input section, the offset of the input section in its
1867 // output section. This is INVALID_ADDRESS if the input section requires a
1868 // special mapping.
1869 std::vector<Address> section_offsets_;
1872 // A regular object file. This is size and endian specific.
1874 template<int size, bool big_endian>
1875 class Sized_relobj_file : public Sized_relobj<size, big_endian>
1877 public:
1878 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
1879 typedef typename Sized_relobj<size, big_endian>::Symbols Symbols;
1880 typedef std::vector<Symbol_value<size> > Local_values;
1882 static const Address invalid_address = static_cast<Address>(0) - 1;
1884 enum Compute_final_local_value_status
1886 // No error.
1887 CFLV_OK,
1888 // An error occurred.
1889 CFLV_ERROR,
1890 // The local symbol has no output section.
1891 CFLV_DISCARDED
1894 Sized_relobj_file(const std::string& name,
1895 Input_file* input_file,
1896 off_t offset,
1897 const typename elfcpp::Ehdr<size, big_endian>&);
1899 ~Sized_relobj_file();
1901 // Set up the object file based on TARGET.
1902 void
1903 setup()
1904 { this->do_setup(); }
1906 // Return a pointer to the Sized_relobj_file object.
1907 Sized_relobj_file<size, big_endian>*
1908 sized_relobj()
1909 { return this; }
1911 const Sized_relobj_file<size, big_endian>*
1912 sized_relobj() const
1913 { return this; }
1915 // Return the ELF file type.
1917 e_type() const
1918 { return this->e_type_; }
1920 // Return the number of symbols. This is only valid after
1921 // Object::add_symbols has been called.
1922 unsigned int
1923 symbol_count() const
1924 { return this->local_symbol_count_ + this->symbols_.size(); }
1926 // If SYM is the index of a global symbol in the object file's
1927 // symbol table, return the Symbol object. Otherwise, return NULL.
1928 Symbol*
1929 global_symbol(unsigned int sym) const
1931 if (sym >= this->local_symbol_count_)
1933 gold_assert(sym - this->local_symbol_count_ < this->symbols_.size());
1934 return this->symbols_[sym - this->local_symbol_count_];
1936 return NULL;
1939 // Return the section index of symbol SYM. Set *VALUE to its value
1940 // in the object file. Set *IS_ORDINARY if this is an ordinary
1941 // section index, not a special code between SHN_LORESERVE and
1942 // SHN_HIRESERVE. Note that for a symbol which is not defined in
1943 // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
1944 // it will not return the final value of the symbol in the link.
1945 unsigned int
1946 symbol_section_and_value(unsigned int sym, Address* value, bool* is_ordinary);
1948 // Return a pointer to the Symbol_value structure which holds the
1949 // value of a local symbol.
1950 const Symbol_value<size>*
1951 local_symbol(unsigned int sym) const
1953 gold_assert(sym < this->local_values_.size());
1954 return &this->local_values_[sym];
1957 // Return the index of local symbol SYM in the ordinary symbol
1958 // table. A value of -1U means that the symbol is not being output.
1959 unsigned int
1960 symtab_index(unsigned int sym) const
1962 gold_assert(sym < this->local_values_.size());
1963 return this->local_values_[sym].output_symtab_index();
1966 // Return the index of local symbol SYM in the dynamic symbol
1967 // table. A value of -1U means that the symbol is not being output.
1968 unsigned int
1969 dynsym_index(unsigned int sym) const
1971 gold_assert(sym < this->local_values_.size());
1972 return this->local_values_[sym].output_dynsym_index();
1975 // Return the input section index of local symbol SYM.
1976 unsigned int
1977 local_symbol_input_shndx(unsigned int sym, bool* is_ordinary) const
1979 gold_assert(sym < this->local_values_.size());
1980 return this->local_values_[sym].input_shndx(is_ordinary);
1983 // Record that local symbol SYM must be in the output symbol table.
1984 void
1985 set_must_have_output_symtab_entry(unsigned int sym)
1987 gold_assert(sym < this->local_values_.size());
1988 this->local_values_[sym].set_must_have_output_symtab_entry();
1991 // Record that local symbol SYM needs a dynamic symbol entry.
1992 void
1993 set_needs_output_dynsym_entry(unsigned int sym)
1995 gold_assert(sym < this->local_values_.size());
1996 this->local_values_[sym].set_needs_output_dynsym_entry();
1999 // Return whether the local symbol SYMNDX has a PLT offset.
2000 bool
2001 local_has_plt_offset(unsigned int symndx) const;
2003 // Return the PLT offset for a local symbol. It is an error to call
2004 // this if it doesn't have one.
2005 unsigned int
2006 local_plt_offset(unsigned int symndx) const;
2008 // Set the PLT offset of the local symbol SYMNDX.
2009 void
2010 set_local_plt_offset(unsigned int symndx, unsigned int plt_offset);
2012 // Return the name of the symbol that spans the given offset in the
2013 // specified section in this object. This is used only for error
2014 // messages and is not particularly efficient.
2015 bool
2016 get_symbol_location_info(unsigned int shndx, off_t offset,
2017 Symbol_location_info* info);
2019 // Look for a kept section corresponding to the given discarded section,
2020 // and return its output address. This is used only for relocations in
2021 // debugging sections.
2022 Address
2023 map_to_kept_section(unsigned int shndx, bool* found) const;
2025 // Compute final local symbol value. R_SYM is the local symbol index.
2026 // LV_IN points to a local symbol value containing the input value.
2027 // LV_OUT points to a local symbol value storing the final output value,
2028 // which must not be a merged symbol value since before calling this
2029 // method to avoid memory leak. SYMTAB points to a symbol table.
2031 // The method returns a status code at return. If the return status is
2032 // CFLV_OK, *LV_OUT contains the final value. If the return status is
2033 // CFLV_ERROR, *LV_OUT is 0. If the return status is CFLV_DISCARDED,
2034 // *LV_OUT is not modified.
2035 Compute_final_local_value_status
2036 compute_final_local_value(unsigned int r_sym,
2037 const Symbol_value<size>* lv_in,
2038 Symbol_value<size>* lv_out,
2039 const Symbol_table* symtab);
2041 protected:
2042 typedef typename Sized_relobj<size, big_endian>::Output_sections
2043 Output_sections;
2045 // Set up.
2046 virtual void
2047 do_setup();
2049 // Read the symbols.
2050 void
2051 do_read_symbols(Read_symbols_data*);
2053 // Return the number of local symbols.
2054 unsigned int
2055 do_local_symbol_count() const
2056 { return this->local_symbol_count_; }
2058 // Return the number of local symbols in the output symbol table.
2059 unsigned int
2060 do_output_local_symbol_count() const
2061 { return this->output_local_symbol_count_; }
2063 // Return the number of local symbols in the output symbol table.
2064 off_t
2065 do_local_symbol_offset() const
2066 { return this->local_symbol_offset_; }
2068 // Lay out the input sections.
2069 void
2070 do_layout(Symbol_table*, Layout*, Read_symbols_data*);
2072 // Layout sections whose layout was deferred while waiting for
2073 // input files from a plugin.
2074 void
2075 do_layout_deferred_sections(Layout*);
2077 // Add the symbols to the symbol table.
2078 void
2079 do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
2081 Archive::Should_include
2082 do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
2083 std::string* why);
2085 // Iterate over global symbols, calling a visitor class V for each.
2086 void
2087 do_for_all_global_symbols(Read_symbols_data* sd,
2088 Library_base::Symbol_visitor_base* v);
2090 // Read the relocs.
2091 void
2092 do_read_relocs(Read_relocs_data*);
2094 // Process the relocs to find list of referenced sections. Used only
2095 // during garbage collection.
2096 void
2097 do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*);
2099 // Scan the relocs and adjust the symbol table.
2100 void
2101 do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*);
2103 // Count the local symbols.
2104 void
2105 do_count_local_symbols(Stringpool_template<char>*,
2106 Stringpool_template<char>*);
2108 // Finalize the local symbols.
2109 unsigned int
2110 do_finalize_local_symbols(unsigned int, off_t, Symbol_table*);
2112 // Set the offset where local dynamic symbol information will be stored.
2113 unsigned int
2114 do_set_local_dynsym_indexes(unsigned int);
2116 // Set the offset where local dynamic symbol information will be stored.
2117 unsigned int
2118 do_set_local_dynsym_offset(off_t);
2120 // Relocate the input sections and write out the local symbols.
2121 void
2122 do_relocate(const Symbol_table* symtab, const Layout*, Output_file* of);
2124 // Get the size of a section.
2125 uint64_t
2126 do_section_size(unsigned int shndx)
2127 { return this->elf_file_.section_size(shndx); }
2129 // Get the name of a section.
2130 std::string
2131 do_section_name(unsigned int shndx)
2132 { return this->elf_file_.section_name(shndx); }
2134 // Return the location of the contents of a section.
2135 Object::Location
2136 do_section_contents(unsigned int shndx)
2137 { return this->elf_file_.section_contents(shndx); }
2139 // Return section flags.
2140 uint64_t
2141 do_section_flags(unsigned int shndx);
2143 // Return section entsize.
2144 uint64_t
2145 do_section_entsize(unsigned int shndx);
2147 // Return section address.
2148 uint64_t
2149 do_section_address(unsigned int shndx)
2150 { return this->elf_file_.section_addr(shndx); }
2152 // Return section type.
2153 unsigned int
2154 do_section_type(unsigned int shndx)
2155 { return this->elf_file_.section_type(shndx); }
2157 // Return the section link field.
2158 unsigned int
2159 do_section_link(unsigned int shndx)
2160 { return this->elf_file_.section_link(shndx); }
2162 // Return the section info field.
2163 unsigned int
2164 do_section_info(unsigned int shndx)
2165 { return this->elf_file_.section_info(shndx); }
2167 // Return the section alignment.
2168 uint64_t
2169 do_section_addralign(unsigned int shndx)
2170 { return this->elf_file_.section_addralign(shndx); }
2172 // Return the Xindex structure to use.
2173 Xindex*
2174 do_initialize_xindex();
2176 // Get symbol counts.
2177 void
2178 do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
2180 // Get the global symbols.
2181 const Symbols*
2182 do_get_global_symbols() const
2183 { return &this->symbols_; }
2185 // Adjust a section index if necessary.
2186 unsigned int
2187 adjust_shndx(unsigned int shndx)
2189 if (shndx >= elfcpp::SHN_LORESERVE)
2190 shndx += this->elf_file_.large_shndx_offset();
2191 return shndx;
2194 // Initialize input to output maps for section symbols in merged
2195 // sections.
2196 void
2197 initialize_input_to_output_maps();
2199 // Free the input to output maps for section symbols in merged
2200 // sections.
2201 void
2202 free_input_to_output_maps();
2204 // Return symbol table section index.
2205 unsigned int
2206 symtab_shndx() const
2207 { return this->symtab_shndx_; }
2209 // Allow a child class to access the ELF file.
2210 elfcpp::Elf_file<size, big_endian, Object>*
2211 elf_file()
2212 { return &this->elf_file_; }
2214 // Allow a child class to access the local values.
2215 Local_values*
2216 local_values()
2217 { return &this->local_values_; }
2219 // Views and sizes when relocating.
2220 struct View_size
2222 unsigned char* view;
2223 typename elfcpp::Elf_types<size>::Elf_Addr address;
2224 off_t offset;
2225 section_size_type view_size;
2226 bool is_input_output_view;
2227 bool is_postprocessing_view;
2228 bool is_ctors_reverse_view;
2231 typedef std::vector<View_size> Views;
2233 // This may be overriden by a child class.
2234 virtual void
2235 do_relocate_sections(const Symbol_table* symtab, const Layout* layout,
2236 const unsigned char* pshdrs, Output_file* of,
2237 Views* pviews);
2239 // Allow a child to set output local symbol count.
2240 void
2241 set_output_local_symbol_count(unsigned int value)
2242 { this->output_local_symbol_count_ = value; }
2244 // Return TRUE if the section is a compressed debug section, and set
2245 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
2246 bool
2247 do_section_is_compressed(unsigned int shndx,
2248 section_size_type* uncompressed_size) const
2250 if (this->compressed_sections_ == NULL)
2251 return false;
2252 Compressed_section_map::const_iterator p =
2253 this->compressed_sections_->find(shndx);
2254 if (p != this->compressed_sections_->end())
2256 if (uncompressed_size != NULL)
2257 *uncompressed_size = p->second;
2258 return true;
2260 return false;
2263 private:
2264 // For convenience.
2265 typedef Sized_relobj_file<size, big_endian> This;
2266 static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
2267 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
2268 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2269 typedef elfcpp::Shdr<size, big_endian> Shdr;
2271 // To keep track of discarded comdat sections, we need to map a member
2272 // section index to the object and section index of the corresponding
2273 // kept section.
2274 struct Kept_comdat_section
2276 Kept_comdat_section(Relobj* a_object, unsigned int a_shndx)
2277 : object(a_object), shndx(a_shndx)
2279 Relobj* object;
2280 unsigned int shndx;
2282 typedef std::map<unsigned int, Kept_comdat_section>
2283 Kept_comdat_section_table;
2285 // Find the SHT_SYMTAB section, given the section headers.
2286 void
2287 find_symtab(const unsigned char* pshdrs);
2289 // Return whether SHDR has the right flags for a GNU style exception
2290 // frame section.
2291 bool
2292 check_eh_frame_flags(const elfcpp::Shdr<size, big_endian>* shdr) const;
2294 // Return whether there is a section named .eh_frame which might be
2295 // a GNU style exception frame section.
2296 bool
2297 find_eh_frame(const unsigned char* pshdrs, const char* names,
2298 section_size_type names_size) const;
2300 // Whether to include a section group in the link.
2301 bool
2302 include_section_group(Symbol_table*, Layout*, unsigned int, const char*,
2303 const unsigned char*, const char*, section_size_type,
2304 std::vector<bool>*);
2306 // Whether to include a linkonce section in the link.
2307 bool
2308 include_linkonce_section(Layout*, unsigned int, const char*,
2309 const elfcpp::Shdr<size, big_endian>&);
2311 // Layout an input section.
2312 void
2313 layout_section(Layout* layout, unsigned int shndx, const char* name,
2314 const typename This::Shdr& shdr, unsigned int reloc_shndx,
2315 unsigned int reloc_type);
2317 // Layout an input .eh_frame section.
2318 void
2319 layout_eh_frame_section(Layout* layout, const unsigned char* symbols_data,
2320 section_size_type symbols_size,
2321 const unsigned char* symbol_names_data,
2322 section_size_type symbol_names_size,
2323 unsigned int shndx, const typename This::Shdr&,
2324 unsigned int reloc_shndx, unsigned int reloc_type);
2326 // Write section data to the output file. Record the views and
2327 // sizes in VIEWS for use when relocating.
2328 void
2329 write_sections(const Layout*, const unsigned char* pshdrs, Output_file*,
2330 Views*);
2332 // Relocate the sections in the output file.
2333 void
2334 relocate_sections(const Symbol_table* symtab, const Layout* layout,
2335 const unsigned char* pshdrs, Output_file* of,
2336 Views* pviews)
2337 { this->do_relocate_sections(symtab, layout, pshdrs, of, pviews); }
2339 // Reverse the words in a section. Used for .ctors sections mapped
2340 // to .init_array sections.
2341 void
2342 reverse_words(unsigned char*, section_size_type);
2344 // Scan the input relocations for --emit-relocs.
2345 void
2346 emit_relocs_scan(Symbol_table*, Layout*, const unsigned char* plocal_syms,
2347 const Read_relocs_data::Relocs_list::iterator&);
2349 // Scan the input relocations for --emit-relocs, templatized on the
2350 // type of the relocation section.
2351 template<int sh_type>
2352 void
2353 emit_relocs_scan_reltype(Symbol_table*, Layout*,
2354 const unsigned char* plocal_syms,
2355 const Read_relocs_data::Relocs_list::iterator&,
2356 Relocatable_relocs*);
2358 // Emit the relocs for --emit-relocs.
2359 void
2360 emit_relocs(const Relocate_info<size, big_endian>*, unsigned int,
2361 unsigned int sh_type, const unsigned char* prelocs,
2362 size_t reloc_count, Output_section*, Address output_offset,
2363 unsigned char* view, Address address,
2364 section_size_type view_size,
2365 unsigned char* reloc_view, section_size_type reloc_view_size);
2367 // Emit the relocs for --emit-relocs, templatized on the type of the
2368 // relocation section.
2369 template<int sh_type>
2370 void
2371 emit_relocs_reltype(const Relocate_info<size, big_endian>*, unsigned int,
2372 const unsigned char* prelocs, size_t reloc_count,
2373 Output_section*, Address output_offset,
2374 unsigned char* view, Address address,
2375 section_size_type view_size,
2376 unsigned char* reloc_view,
2377 section_size_type reloc_view_size);
2379 // Scan the input relocations for --incremental.
2380 void
2381 incremental_relocs_scan(const Read_relocs_data::Relocs_list::iterator&);
2383 // Scan the input relocations for --incremental, templatized on the
2384 // type of the relocation section.
2385 template<int sh_type>
2386 void
2387 incremental_relocs_scan_reltype(
2388 const Read_relocs_data::Relocs_list::iterator&);
2390 void
2391 incremental_relocs_write(const Relocate_info<size, big_endian>*,
2392 unsigned int sh_type,
2393 const unsigned char* prelocs,
2394 size_t reloc_count,
2395 Output_section*,
2396 Address output_offset,
2397 Output_file*);
2399 template<int sh_type>
2400 void
2401 incremental_relocs_write_reltype(const Relocate_info<size, big_endian>*,
2402 const unsigned char* prelocs,
2403 size_t reloc_count,
2404 Output_section*,
2405 Address output_offset,
2406 Output_file*);
2408 // A type shared by split_stack_adjust_reltype and find_functions.
2409 typedef std::map<section_offset_type, section_size_type> Function_offsets;
2411 // Check for -fsplit-stack routines calling non-split-stack routines.
2412 void
2413 split_stack_adjust(const Symbol_table*, const unsigned char* pshdrs,
2414 unsigned int sh_type, unsigned int shndx,
2415 const unsigned char* prelocs, size_t reloc_count,
2416 unsigned char* view, section_size_type view_size,
2417 Reloc_symbol_changes** reloc_map);
2419 template<int sh_type>
2420 void
2421 split_stack_adjust_reltype(const Symbol_table*, const unsigned char* pshdrs,
2422 unsigned int shndx, const unsigned char* prelocs,
2423 size_t reloc_count, unsigned char* view,
2424 section_size_type view_size,
2425 Reloc_symbol_changes** reloc_map);
2427 // Find all functions in a section.
2428 void
2429 find_functions(const unsigned char* pshdrs, unsigned int shndx,
2430 Function_offsets*);
2432 // Write out the local symbols.
2433 void
2434 write_local_symbols(Output_file*,
2435 const Stringpool_template<char>*,
2436 const Stringpool_template<char>*,
2437 Output_symtab_xindex*,
2438 Output_symtab_xindex*,
2439 off_t);
2441 // Record a mapping from discarded section SHNDX to the corresponding
2442 // kept section.
2443 void
2444 set_kept_comdat_section(unsigned int shndx, Relobj* kept_object,
2445 unsigned int kept_shndx)
2447 Kept_comdat_section kept(kept_object, kept_shndx);
2448 this->kept_comdat_sections_.insert(std::make_pair(shndx, kept));
2451 // Find the kept section corresponding to the discarded section
2452 // SHNDX. Return true if found.
2453 bool
2454 get_kept_comdat_section(unsigned int shndx, Relobj** kept_object,
2455 unsigned int* kept_shndx) const
2457 typename Kept_comdat_section_table::const_iterator p =
2458 this->kept_comdat_sections_.find(shndx);
2459 if (p == this->kept_comdat_sections_.end())
2460 return false;
2461 *kept_object = p->second.object;
2462 *kept_shndx = p->second.shndx;
2463 return true;
2466 // Compute final local symbol value. R_SYM is the local symbol index.
2467 // LV_IN points to a local symbol value containing the input value.
2468 // LV_OUT points to a local symbol value storing the final output value,
2469 // which must not be a merged symbol value since before calling this
2470 // method to avoid memory leak. RELOCATABLE indicates whether we are
2471 // linking a relocatable output. OUT_SECTIONS is an array of output
2472 // sections. OUT_OFFSETS is an array of offsets of the sections. SYMTAB
2473 // points to a symbol table.
2475 // The method returns a status code at return. If the return status is
2476 // CFLV_OK, *LV_OUT contains the final value. If the return status is
2477 // CFLV_ERROR, *LV_OUT is 0. If the return status is CFLV_DISCARDED,
2478 // *LV_OUT is not modified.
2479 inline Compute_final_local_value_status
2480 compute_final_local_value_internal(unsigned int r_sym,
2481 const Symbol_value<size>* lv_in,
2482 Symbol_value<size>* lv_out,
2483 bool relocatable,
2484 const Output_sections& out_sections,
2485 const std::vector<Address>& out_offsets,
2486 const Symbol_table* symtab);
2488 // The PLT offsets of local symbols.
2489 typedef Unordered_map<unsigned int, unsigned int> Local_plt_offsets;
2491 // Saved information for sections whose layout was deferred.
2492 struct Deferred_layout
2494 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
2495 Deferred_layout(unsigned int shndx, const char* name,
2496 const unsigned char* pshdr,
2497 unsigned int reloc_shndx, unsigned int reloc_type)
2498 : shndx_(shndx), name_(name), reloc_shndx_(reloc_shndx),
2499 reloc_type_(reloc_type)
2501 memcpy(this->shdr_data_, pshdr, shdr_size);
2503 unsigned int shndx_;
2504 std::string name_;
2505 unsigned int reloc_shndx_;
2506 unsigned int reloc_type_;
2507 unsigned char shdr_data_[shdr_size];
2510 // General access to the ELF file.
2511 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
2512 // Type of ELF file (ET_REL or ET_EXEC). ET_EXEC files are allowed
2513 // as input files only for the --just-symbols option.
2514 int e_type_;
2515 // Index of SHT_SYMTAB section.
2516 unsigned int symtab_shndx_;
2517 // The number of local symbols.
2518 unsigned int local_symbol_count_;
2519 // The number of local symbols which go into the output file.
2520 unsigned int output_local_symbol_count_;
2521 // The number of local symbols which go into the output file's dynamic
2522 // symbol table.
2523 unsigned int output_local_dynsym_count_;
2524 // The entries in the symbol table for the external symbols.
2525 Symbols symbols_;
2526 // Number of symbols defined in object file itself.
2527 size_t defined_count_;
2528 // File offset for local symbols (relative to start of symbol table).
2529 off_t local_symbol_offset_;
2530 // File offset for local dynamic symbols (absolute).
2531 off_t local_dynsym_offset_;
2532 // Values of local symbols.
2533 Local_values local_values_;
2534 // PLT offsets for local symbols.
2535 Local_plt_offsets local_plt_offsets_;
2536 // Table mapping discarded comdat sections to corresponding kept sections.
2537 Kept_comdat_section_table kept_comdat_sections_;
2538 // Whether this object has a GNU style .eh_frame section.
2539 bool has_eh_frame_;
2540 // If this object has a GNU style .eh_frame section that is discarded in
2541 // output, record the index here. Otherwise it is -1U.
2542 unsigned int discarded_eh_frame_shndx_;
2543 // The list of sections whose layout was deferred.
2544 std::vector<Deferred_layout> deferred_layout_;
2545 // The list of relocation sections whose layout was deferred.
2546 std::vector<Deferred_layout> deferred_layout_relocs_;
2547 // For compressed debug sections, map section index to uncompressed size.
2548 Compressed_section_map* compressed_sections_;
2551 // A class to manage the list of all objects.
2553 class Input_objects
2555 public:
2556 Input_objects()
2557 : relobj_list_(), dynobj_list_(), sonames_(), cref_(NULL)
2560 // The type of the list of input relocateable objects.
2561 typedef std::vector<Relobj*> Relobj_list;
2562 typedef Relobj_list::const_iterator Relobj_iterator;
2564 // The type of the list of input dynamic objects.
2565 typedef std::vector<Dynobj*> Dynobj_list;
2566 typedef Dynobj_list::const_iterator Dynobj_iterator;
2568 // Add an object to the list. Return true if all is well, or false
2569 // if this object should be ignored.
2570 bool
2571 add_object(Object*);
2573 // Start processing an archive.
2574 void
2575 archive_start(Archive*);
2577 // Stop processing an archive.
2578 void
2579 archive_stop(Archive*);
2581 // For each dynamic object, check whether we've seen all of its
2582 // explicit dependencies.
2583 void
2584 check_dynamic_dependencies() const;
2586 // Return whether an object was found in the system library
2587 // directory.
2588 bool
2589 found_in_system_library_directory(const Object*) const;
2591 // Print symbol counts.
2592 void
2593 print_symbol_counts(const Symbol_table*) const;
2595 // Print a cross reference table.
2596 void
2597 print_cref(const Symbol_table*, FILE*) const;
2599 // Iterate over all regular objects.
2601 Relobj_iterator
2602 relobj_begin() const
2603 { return this->relobj_list_.begin(); }
2605 Relobj_iterator
2606 relobj_end() const
2607 { return this->relobj_list_.end(); }
2609 // Iterate over all dynamic objects.
2611 Dynobj_iterator
2612 dynobj_begin() const
2613 { return this->dynobj_list_.begin(); }
2615 Dynobj_iterator
2616 dynobj_end() const
2617 { return this->dynobj_list_.end(); }
2619 // Return whether we have seen any dynamic objects.
2620 bool
2621 any_dynamic() const
2622 { return !this->dynobj_list_.empty(); }
2624 // Return the number of non dynamic objects.
2626 number_of_relobjs() const
2627 { return this->relobj_list_.size(); }
2629 // Return the number of input objects.
2631 number_of_input_objects() const
2632 { return this->relobj_list_.size() + this->dynobj_list_.size(); }
2634 private:
2635 Input_objects(const Input_objects&);
2636 Input_objects& operator=(const Input_objects&);
2638 // The list of ordinary objects included in the link.
2639 Relobj_list relobj_list_;
2640 // The list of dynamic objects included in the link.
2641 Dynobj_list dynobj_list_;
2642 // SONAMEs that we have seen.
2643 Unordered_set<std::string> sonames_;
2644 // Manage cross-references if requested.
2645 Cref* cref_;
2648 // Some of the information we pass to the relocation routines. We
2649 // group this together to avoid passing a dozen different arguments.
2651 template<int size, bool big_endian>
2652 struct Relocate_info
2654 // Symbol table.
2655 const Symbol_table* symtab;
2656 // Layout.
2657 const Layout* layout;
2658 // Object being relocated.
2659 Sized_relobj_file<size, big_endian>* object;
2660 // Section index of relocation section.
2661 unsigned int reloc_shndx;
2662 // Section header of relocation section.
2663 const unsigned char* reloc_shdr;
2664 // Section index of section being relocated.
2665 unsigned int data_shndx;
2666 // Section header of data section.
2667 const unsigned char* data_shdr;
2669 // Return a string showing the location of a relocation. This is
2670 // only used for error messages.
2671 std::string
2672 location(size_t relnum, off_t reloffset) const;
2675 // This is used to represent a section in an object and is used as the
2676 // key type for various section maps.
2677 typedef std::pair<Object*, unsigned int> Section_id;
2679 // This is similar to Section_id but is used when the section
2680 // pointers are const.
2681 typedef std::pair<const Object*, unsigned int> Const_section_id;
2683 // The hash value is based on the address of an object in memory during
2684 // linking. It is okay to use this for looking up sections but never use
2685 // this in an unordered container that we want to traverse in a repeatable
2686 // manner.
2688 struct Section_id_hash
2690 size_t operator()(const Section_id& loc) const
2691 { return reinterpret_cast<uintptr_t>(loc.first) ^ loc.second; }
2694 struct Const_section_id_hash
2696 size_t operator()(const Const_section_id& loc) const
2697 { return reinterpret_cast<uintptr_t>(loc.first) ^ loc.second; }
2700 // Return whether INPUT_FILE contains an ELF object start at file
2701 // offset OFFSET. This sets *START to point to a view of the start of
2702 // the file. It sets *READ_SIZE to the number of bytes in the view.
2704 extern bool
2705 is_elf_object(Input_file* input_file, off_t offset,
2706 const unsigned char** start, int* read_size);
2708 // Return an Object appropriate for the input file. P is BYTES long,
2709 // and holds the ELF header. If PUNCONFIGURED is not NULL, then if
2710 // this sees an object the linker is not configured to support, it
2711 // sets *PUNCONFIGURED to true and returns NULL without giving an
2712 // error message.
2714 extern Object*
2715 make_elf_object(const std::string& name, Input_file*,
2716 off_t offset, const unsigned char* p,
2717 section_offset_type bytes, bool* punconfigured);
2719 } // end namespace gold
2721 #endif // !defined(GOLD_OBJECT_H)