1 // object.cc -- support for an object file for linking in gold
3 // Copyright 2006, 2007, 2008 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.
29 #include "libiberty.h"
31 #include "target-select.h"
32 #include "dwarf_reader.h"
45 // Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX
46 // section and read it in. SYMTAB_SHNDX is the index of the symbol
47 // table we care about.
49 template<int size
, bool big_endian
>
51 Xindex::initialize_symtab_xindex(Object
* object
, unsigned int symtab_shndx
)
53 if (!this->symtab_xindex_
.empty())
56 gold_assert(symtab_shndx
!= 0);
58 // Look through the sections in reverse order, on the theory that it
59 // is more likely to be near the end than the beginning.
60 unsigned int i
= object
->shnum();
64 if (object
->section_type(i
) == elfcpp::SHT_SYMTAB_SHNDX
65 && this->adjust_shndx(object
->section_link(i
)) == symtab_shndx
)
67 this->read_symtab_xindex
<size
, big_endian
>(object
, i
, NULL
);
72 object
->error(_("missing SHT_SYMTAB_SHNDX section"));
75 // Read in the symtab_xindex_ array, given the section index of the
76 // SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the
79 template<int size
, bool big_endian
>
81 Xindex::read_symtab_xindex(Object
* object
, unsigned int xindex_shndx
,
82 const unsigned char* pshdrs
)
84 section_size_type bytecount
;
85 const unsigned char* contents
;
87 contents
= object
->section_contents(xindex_shndx
, &bytecount
, false);
90 const unsigned char* p
= (pshdrs
92 * elfcpp::Elf_sizes
<size
>::shdr_size
));
93 typename
elfcpp::Shdr
<size
, big_endian
> shdr(p
);
94 bytecount
= convert_to_section_size_type(shdr
.get_sh_size());
95 contents
= object
->get_view(shdr
.get_sh_offset(), bytecount
, true, false);
98 gold_assert(this->symtab_xindex_
.empty());
99 this->symtab_xindex_
.reserve(bytecount
/ 4);
100 for (section_size_type i
= 0; i
< bytecount
; i
+= 4)
102 unsigned int shndx
= elfcpp::Swap
<32, big_endian
>::readval(contents
+ i
);
103 // We preadjust the section indexes we save.
104 this->symtab_xindex_
.push_back(this->adjust_shndx(shndx
));
108 // Symbol symndx has a section of SHN_XINDEX; return the real section
112 Xindex::sym_xindex_to_shndx(Object
* object
, unsigned int symndx
)
114 if (symndx
>= this->symtab_xindex_
.size())
116 object
->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
118 return elfcpp::SHN_UNDEF
;
120 unsigned int shndx
= this->symtab_xindex_
[symndx
];
121 if (shndx
< elfcpp::SHN_LORESERVE
|| shndx
>= object
->shnum())
123 object
->error(_("extended index for symbol %u out of range: %u"),
125 return elfcpp::SHN_UNDEF
;
132 // Set the target based on fields in the ELF file header.
135 Object::set_target(int machine
, int size
, bool big_endian
, int osabi
,
138 Target
* target
= select_target(machine
, size
, big_endian
, osabi
, abiversion
);
140 gold_fatal(_("%s: unsupported ELF machine number %d"),
141 this->name().c_str(), machine
);
142 this->target_
= target
;
145 // Report an error for this object file. This is used by the
146 // elfcpp::Elf_file interface, and also called by the Object code
150 Object::error(const char* format
, ...) const
153 va_start(args
, format
);
155 if (vasprintf(&buf
, format
, args
) < 0)
158 gold_error(_("%s: %s"), this->name().c_str(), buf
);
162 // Return a view of the contents of a section.
165 Object::section_contents(unsigned int shndx
, section_size_type
* plen
,
168 Location
loc(this->do_section_contents(shndx
));
169 *plen
= convert_to_section_size_type(loc
.data_size
);
170 return this->get_view(loc
.file_offset
, *plen
, true, cache
);
173 // Read the section data into SD. This is code common to Sized_relobj
174 // and Sized_dynobj, so we put it into Object.
176 template<int size
, bool big_endian
>
178 Object::read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>* elf_file
,
179 Read_symbols_data
* sd
)
181 const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
183 // Read the section headers.
184 const off_t shoff
= elf_file
->shoff();
185 const unsigned int shnum
= this->shnum();
186 sd
->section_headers
= this->get_lasting_view(shoff
, shnum
* shdr_size
,
189 // Read the section names.
190 const unsigned char* pshdrs
= sd
->section_headers
->data();
191 const unsigned char* pshdrnames
= pshdrs
+ elf_file
->shstrndx() * shdr_size
;
192 typename
elfcpp::Shdr
<size
, big_endian
> shdrnames(pshdrnames
);
194 if (shdrnames
.get_sh_type() != elfcpp::SHT_STRTAB
)
195 this->error(_("section name section has wrong type: %u"),
196 static_cast<unsigned int>(shdrnames
.get_sh_type()));
198 sd
->section_names_size
=
199 convert_to_section_size_type(shdrnames
.get_sh_size());
200 sd
->section_names
= this->get_lasting_view(shdrnames
.get_sh_offset(),
201 sd
->section_names_size
, false,
205 // If NAME is the name of a special .gnu.warning section, arrange for
206 // the warning to be issued. SHNDX is the section index. Return
207 // whether it is a warning section.
210 Object::handle_gnu_warning_section(const char* name
, unsigned int shndx
,
211 Symbol_table
* symtab
)
213 const char warn_prefix
[] = ".gnu.warning.";
214 const int warn_prefix_len
= sizeof warn_prefix
- 1;
215 if (strncmp(name
, warn_prefix
, warn_prefix_len
) == 0)
217 // Read the section contents to get the warning text. It would
218 // be nicer if we only did this if we have to actually issue a
219 // warning. Unfortunately, warnings are issued as we relocate
220 // sections. That means that we can not lock the object then,
221 // as we might try to issue the same warning multiple times
223 section_size_type len
;
224 const unsigned char* contents
= this->section_contents(shndx
, &len
,
226 std::string
warning(reinterpret_cast<const char*>(contents
), len
);
227 symtab
->add_warning(name
+ warn_prefix_len
, this, warning
);
233 // Class Sized_relobj.
235 template<int size
, bool big_endian
>
236 Sized_relobj
<size
, big_endian
>::Sized_relobj(
237 const std::string
& name
,
238 Input_file
* input_file
,
240 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
241 : Relobj(name
, input_file
, offset
),
242 elf_file_(this, ehdr
),
244 local_symbol_count_(0),
245 output_local_symbol_count_(0),
246 output_local_dynsym_count_(0),
248 local_symbol_offset_(0),
249 local_dynsym_offset_(0),
251 local_got_offsets_(),
252 kept_comdat_sections_(),
258 template<int size
, bool big_endian
>
259 Sized_relobj
<size
, big_endian
>::~Sized_relobj()
263 // Set up an object file based on the file header. This sets up the
264 // target and reads the section information.
266 template<int size
, bool big_endian
>
268 Sized_relobj
<size
, big_endian
>::setup(
269 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
271 this->set_target(ehdr
.get_e_machine(), size
, big_endian
,
272 ehdr
.get_e_ident()[elfcpp::EI_OSABI
],
273 ehdr
.get_e_ident()[elfcpp::EI_ABIVERSION
]);
275 const unsigned int shnum
= this->elf_file_
.shnum();
276 this->set_shnum(shnum
);
279 // Find the SHT_SYMTAB section, given the section headers. The ELF
280 // standard says that maybe in the future there can be more than one
281 // SHT_SYMTAB section. Until somebody figures out how that could
282 // work, we assume there is only one.
284 template<int size
, bool big_endian
>
286 Sized_relobj
<size
, big_endian
>::find_symtab(const unsigned char* pshdrs
)
288 const unsigned int shnum
= this->shnum();
289 this->symtab_shndx_
= 0;
292 // Look through the sections in reverse order, since gas tends
293 // to put the symbol table at the end.
294 const unsigned char* p
= pshdrs
+ shnum
* This::shdr_size
;
295 unsigned int i
= shnum
;
296 unsigned int xindex_shndx
= 0;
297 unsigned int xindex_link
= 0;
301 p
-= This::shdr_size
;
302 typename
This::Shdr
shdr(p
);
303 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB
)
305 this->symtab_shndx_
= i
;
306 if (xindex_shndx
> 0 && xindex_link
== i
)
309 new Xindex(this->elf_file_
.large_shndx_offset());
310 xindex
->read_symtab_xindex
<size
, big_endian
>(this,
313 this->set_xindex(xindex
);
318 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
319 // one. This will work if it follows the SHT_SYMTAB
321 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX
)
324 xindex_link
= this->adjust_shndx(shdr
.get_sh_link());
330 // Return the Xindex structure to use for object with lots of
333 template<int size
, bool big_endian
>
335 Sized_relobj
<size
, big_endian
>::do_initialize_xindex()
337 gold_assert(this->symtab_shndx_
!= -1U);
338 Xindex
* xindex
= new Xindex(this->elf_file_
.large_shndx_offset());
339 xindex
->initialize_symtab_xindex
<size
, big_endian
>(this, this->symtab_shndx_
);
343 // Return whether SHDR has the right type and flags to be a GNU
344 // .eh_frame section.
346 template<int size
, bool big_endian
>
348 Sized_relobj
<size
, big_endian
>::check_eh_frame_flags(
349 const elfcpp::Shdr
<size
, big_endian
>* shdr
) const
351 return (shdr
->get_sh_type() == elfcpp::SHT_PROGBITS
352 && (shdr
->get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
355 // Return whether there is a GNU .eh_frame section, given the section
356 // headers and the section names.
358 template<int size
, bool big_endian
>
360 Sized_relobj
<size
, big_endian
>::find_eh_frame(
361 const unsigned char* pshdrs
,
363 section_size_type names_size
) const
365 const unsigned int shnum
= this->shnum();
366 const unsigned char* p
= pshdrs
+ This::shdr_size
;
367 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
369 typename
This::Shdr
shdr(p
);
370 if (this->check_eh_frame_flags(&shdr
))
372 if (shdr
.get_sh_name() >= names_size
)
374 this->error(_("bad section name offset for section %u: %lu"),
375 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
379 const char* name
= names
+ shdr
.get_sh_name();
380 if (strcmp(name
, ".eh_frame") == 0)
387 // Read the sections and symbols from an object file.
389 template<int size
, bool big_endian
>
391 Sized_relobj
<size
, big_endian
>::do_read_symbols(Read_symbols_data
* sd
)
393 this->read_section_data(&this->elf_file_
, sd
);
395 const unsigned char* const pshdrs
= sd
->section_headers
->data();
397 this->find_symtab(pshdrs
);
399 const unsigned char* namesu
= sd
->section_names
->data();
400 const char* names
= reinterpret_cast<const char*>(namesu
);
401 if (memmem(names
, sd
->section_names_size
, ".eh_frame", 10) != NULL
)
403 if (this->find_eh_frame(pshdrs
, names
, sd
->section_names_size
))
404 this->has_eh_frame_
= true;
408 sd
->symbols_size
= 0;
409 sd
->external_symbols_offset
= 0;
410 sd
->symbol_names
= NULL
;
411 sd
->symbol_names_size
= 0;
413 if (this->symtab_shndx_
== 0)
415 // No symbol table. Weird but legal.
419 // Get the symbol table section header.
420 typename
This::Shdr
symtabshdr(pshdrs
421 + this->symtab_shndx_
* This::shdr_size
);
422 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
424 // If this object has a .eh_frame section, we need all the symbols.
425 // Otherwise we only need the external symbols. While it would be
426 // simpler to just always read all the symbols, I've seen object
427 // files with well over 2000 local symbols, which for a 64-bit
428 // object file format is over 5 pages that we don't need to read
431 const int sym_size
= This::sym_size
;
432 const unsigned int loccount
= symtabshdr
.get_sh_info();
433 this->local_symbol_count_
= loccount
;
434 this->local_values_
.resize(loccount
);
435 section_offset_type locsize
= loccount
* sym_size
;
436 off_t dataoff
= symtabshdr
.get_sh_offset();
437 section_size_type datasize
=
438 convert_to_section_size_type(symtabshdr
.get_sh_size());
439 off_t extoff
= dataoff
+ locsize
;
440 section_size_type extsize
= datasize
- locsize
;
442 off_t readoff
= this->has_eh_frame_
? dataoff
: extoff
;
443 section_size_type readsize
= this->has_eh_frame_
? datasize
: extsize
;
447 // No external symbols. Also weird but also legal.
451 File_view
* fvsymtab
= this->get_lasting_view(readoff
, readsize
, true, false);
453 // Read the section header for the symbol names.
454 unsigned int strtab_shndx
= this->adjust_shndx(symtabshdr
.get_sh_link());
455 if (strtab_shndx
>= this->shnum())
457 this->error(_("invalid symbol table name index: %u"), strtab_shndx
);
460 typename
This::Shdr
strtabshdr(pshdrs
+ strtab_shndx
* This::shdr_size
);
461 if (strtabshdr
.get_sh_type() != elfcpp::SHT_STRTAB
)
463 this->error(_("symbol table name section has wrong type: %u"),
464 static_cast<unsigned int>(strtabshdr
.get_sh_type()));
468 // Read the symbol names.
469 File_view
* fvstrtab
= this->get_lasting_view(strtabshdr
.get_sh_offset(),
470 strtabshdr
.get_sh_size(),
473 sd
->symbols
= fvsymtab
;
474 sd
->symbols_size
= readsize
;
475 sd
->external_symbols_offset
= this->has_eh_frame_
? locsize
: 0;
476 sd
->symbol_names
= fvstrtab
;
477 sd
->symbol_names_size
=
478 convert_to_section_size_type(strtabshdr
.get_sh_size());
481 // Return the section index of symbol SYM. Set *VALUE to its value in
482 // the object file. Set *IS_ORDINARY if this is an ordinary section
483 // index. not a special cod between SHN_LORESERVE and SHN_HIRESERVE.
484 // Note that for a symbol which is not defined in this object file,
485 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
486 // the final value of the symbol in the link.
488 template<int size
, bool big_endian
>
490 Sized_relobj
<size
, big_endian
>::symbol_section_and_value(unsigned int sym
,
494 section_size_type symbols_size
;
495 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
499 const size_t count
= symbols_size
/ This::sym_size
;
500 gold_assert(sym
< count
);
502 elfcpp::Sym
<size
, big_endian
> elfsym(symbols
+ sym
* This::sym_size
);
503 *value
= elfsym
.get_st_value();
505 return this->adjust_sym_shndx(sym
, elfsym
.get_st_shndx(), is_ordinary
);
508 // Return whether to include a section group in the link. LAYOUT is
509 // used to keep track of which section groups we have already seen.
510 // INDEX is the index of the section group and SHDR is the section
511 // header. If we do not want to include this group, we set bits in
512 // OMIT for each section which should be discarded.
514 template<int size
, bool big_endian
>
516 Sized_relobj
<size
, big_endian
>::include_section_group(
517 Symbol_table
* symtab
,
521 const unsigned char* shdrs
,
522 const char* section_names
,
523 section_size_type section_names_size
,
524 std::vector
<bool>* omit
)
526 // Read the section contents.
527 typename
This::Shdr
shdr(shdrs
+ index
* This::shdr_size
);
528 const unsigned char* pcon
= this->get_view(shdr
.get_sh_offset(),
529 shdr
.get_sh_size(), true, false);
530 const elfcpp::Elf_Word
* pword
=
531 reinterpret_cast<const elfcpp::Elf_Word
*>(pcon
);
533 // The first word contains flags. We only care about COMDAT section
534 // groups. Other section groups are always included in the link
535 // just like ordinary sections.
536 elfcpp::Elf_Word flags
= elfcpp::Swap
<32, big_endian
>::readval(pword
);
538 // Look up the group signature, which is the name of a symbol. This
539 // is a lot of effort to go to to read a string. Why didn't they
540 // just have the group signature point into the string table, rather
541 // than indirect through a symbol?
543 // Get the appropriate symbol table header (this will normally be
544 // the single SHT_SYMTAB section, but in principle it need not be).
545 const unsigned int link
= this->adjust_shndx(shdr
.get_sh_link());
546 typename
This::Shdr
symshdr(this, this->elf_file_
.section_header(link
));
548 // Read the symbol table entry.
549 unsigned int symndx
= shdr
.get_sh_info();
550 if (symndx
>= symshdr
.get_sh_size() / This::sym_size
)
552 this->error(_("section group %u info %u out of range"),
556 off_t symoff
= symshdr
.get_sh_offset() + symndx
* This::sym_size
;
557 const unsigned char* psym
= this->get_view(symoff
, This::sym_size
, true,
559 elfcpp::Sym
<size
, big_endian
> sym(psym
);
561 // Read the symbol table names.
562 section_size_type symnamelen
;
563 const unsigned char* psymnamesu
;
564 psymnamesu
= this->section_contents(this->adjust_shndx(symshdr
.get_sh_link()),
566 const char* psymnames
= reinterpret_cast<const char*>(psymnamesu
);
568 // Get the section group signature.
569 if (sym
.get_st_name() >= symnamelen
)
571 this->error(_("symbol %u name offset %u out of range"),
572 symndx
, sym
.get_st_name());
576 std::string
signature(psymnames
+ sym
.get_st_name());
578 // It seems that some versions of gas will create a section group
579 // associated with a section symbol, and then fail to give a name to
580 // the section symbol. In such a case, use the name of the section.
581 if (signature
[0] == '\0' && sym
.get_st_type() == elfcpp::STT_SECTION
)
584 unsigned int sym_shndx
= this->adjust_sym_shndx(symndx
,
587 if (!is_ordinary
|| sym_shndx
>= this->shnum())
589 this->error(_("symbol %u invalid section index %u"),
593 typename
This::Shdr
member_shdr(shdrs
+ sym_shndx
* This::shdr_size
);
594 if (member_shdr
.get_sh_name() < section_names_size
)
595 signature
= section_names
+ member_shdr
.get_sh_name();
598 // Record this section group in the layout, and see whether we've already
599 // seen one with the same signature.
600 bool include_group
= ((flags
& elfcpp::GRP_COMDAT
) == 0
601 || layout
->add_comdat(this, index
, signature
, true));
603 Sized_relobj
<size
, big_endian
>* kept_object
= NULL
;
604 Comdat_group
* kept_group
= NULL
;
608 // This group is being discarded. Find the object and group
609 // that was kept in its place.
610 unsigned int kept_group_index
= 0;
611 Relobj
* kept_relobj
= layout
->find_kept_object(signature
,
613 kept_object
= static_cast<Sized_relobj
<size
, big_endian
>*>(kept_relobj
);
614 if (kept_object
!= NULL
)
615 kept_group
= kept_object
->find_comdat_group(kept_group_index
);
617 else if (flags
& elfcpp::GRP_COMDAT
)
619 // This group is being kept. Create the table to map section names
620 // to section indexes and add it to the table of groups.
621 kept_group
= new Comdat_group();
622 this->add_comdat_group(index
, kept_group
);
625 size_t count
= shdr
.get_sh_size() / sizeof(elfcpp::Elf_Word
);
627 std::vector
<unsigned int> shndxes
;
628 bool relocate_group
= include_group
&& parameters
->options().relocatable();
630 shndxes
.reserve(count
- 1);
632 for (size_t i
= 1; i
< count
; ++i
)
634 elfcpp::Elf_Word secnum
=
635 this->adjust_shndx(elfcpp::Swap
<32, big_endian
>::readval(pword
+ i
));
638 shndxes
.push_back(secnum
);
640 if (secnum
>= this->shnum())
642 this->error(_("section %u in section group %u out of range"),
647 // Check for an earlier section number, since we're going to get
648 // it wrong--we may have already decided to include the section.
650 this->error(_("invalid section group %u refers to earlier section %u"),
653 // Get the name of the member section.
654 typename
This::Shdr
member_shdr(shdrs
+ secnum
* This::shdr_size
);
655 if (member_shdr
.get_sh_name() >= section_names_size
)
657 // This is an error, but it will be diagnosed eventually
658 // in do_layout, so we don't need to do anything here but
662 std::string
mname(section_names
+ member_shdr
.get_sh_name());
666 (*omit
)[secnum
] = true;
667 if (kept_group
!= NULL
)
669 // Find the corresponding kept section, and store that info
670 // in the discarded section table.
671 Comdat_group::const_iterator p
= kept_group
->find(mname
);
672 if (p
!= kept_group
->end())
674 Kept_comdat_section
* kept
=
675 new Kept_comdat_section(kept_object
, p
->second
);
676 this->set_kept_comdat_section(secnum
, kept
);
680 else if (flags
& elfcpp::GRP_COMDAT
)
682 // Add the section to the kept group table.
683 gold_assert(kept_group
!= NULL
);
684 kept_group
->insert(std::make_pair(mname
, secnum
));
689 layout
->layout_group(symtab
, this, index
, name
, signature
.c_str(),
690 shdr
, flags
, &shndxes
);
692 return include_group
;
695 // Whether to include a linkonce section in the link. NAME is the
696 // name of the section and SHDR is the section header.
698 // Linkonce sections are a GNU extension implemented in the original
699 // GNU linker before section groups were defined. The semantics are
700 // that we only include one linkonce section with a given name. The
701 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
702 // where T is the type of section and SYMNAME is the name of a symbol.
703 // In an attempt to make linkonce sections interact well with section
704 // groups, we try to identify SYMNAME and use it like a section group
705 // signature. We want to block section groups with that signature,
706 // but not other linkonce sections with that signature. We also use
707 // the full name of the linkonce section as a normal section group
710 template<int size
, bool big_endian
>
712 Sized_relobj
<size
, big_endian
>::include_linkonce_section(
716 const elfcpp::Shdr
<size
, big_endian
>&)
718 // In general the symbol name we want will be the string following
719 // the last '.'. However, we have to handle the case of
720 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
721 // some versions of gcc. So we use a heuristic: if the name starts
722 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
723 // we look for the last '.'. We can't always simply skip
724 // ".gnu.linkonce.X", because we have to deal with cases like
725 // ".gnu.linkonce.d.rel.ro.local".
726 const char* const linkonce_t
= ".gnu.linkonce.t.";
728 if (strncmp(name
, linkonce_t
, strlen(linkonce_t
)) == 0)
729 symname
= name
+ strlen(linkonce_t
);
731 symname
= strrchr(name
, '.') + 1;
732 std::string
sig1(symname
);
733 std::string
sig2(name
);
734 bool include1
= layout
->add_comdat(this, index
, sig1
, false);
735 bool include2
= layout
->add_comdat(this, index
, sig2
, true);
739 // The section is being discarded on the basis of its section
740 // name (i.e., the kept section was also a linkonce section).
741 // In this case, the section index stored with the layout object
742 // is the linkonce section that was kept.
743 unsigned int kept_group_index
= 0;
744 Relobj
* kept_relobj
= layout
->find_kept_object(sig2
, &kept_group_index
);
745 if (kept_relobj
!= NULL
)
747 Sized_relobj
<size
, big_endian
>* kept_object
748 = static_cast<Sized_relobj
<size
, big_endian
>*>(kept_relobj
);
749 Kept_comdat_section
* kept
=
750 new Kept_comdat_section(kept_object
, kept_group_index
);
751 this->set_kept_comdat_section(index
, kept
);
756 // The section is being discarded on the basis of its symbol
757 // name. This means that the corresponding kept section was
758 // part of a comdat group, and it will be difficult to identify
759 // the specific section within that group that corresponds to
760 // this linkonce section. We'll handle the simple case where
761 // the group has only one member section. Otherwise, it's not
763 unsigned int kept_group_index
= 0;
764 Relobj
* kept_relobj
= layout
->find_kept_object(sig1
, &kept_group_index
);
765 if (kept_relobj
!= NULL
)
767 Sized_relobj
<size
, big_endian
>* kept_object
=
768 static_cast<Sized_relobj
<size
, big_endian
>*>(kept_relobj
);
769 Comdat_group
* kept_group
=
770 kept_object
->find_comdat_group(kept_group_index
);
771 if (kept_group
!= NULL
&& kept_group
->size() == 1)
773 Comdat_group::const_iterator p
= kept_group
->begin();
774 gold_assert(p
!= kept_group
->end());
775 Kept_comdat_section
* kept
=
776 new Kept_comdat_section(kept_object
, p
->second
);
777 this->set_kept_comdat_section(index
, kept
);
782 return include1
&& include2
;
785 // Lay out the input sections. We walk through the sections and check
786 // whether they should be included in the link. If they should, we
787 // pass them to the Layout object, which will return an output section
790 template<int size
, bool big_endian
>
792 Sized_relobj
<size
, big_endian
>::do_layout(Symbol_table
* symtab
,
794 Read_symbols_data
* sd
)
796 const unsigned int shnum
= this->shnum();
800 // Get the section headers.
801 const unsigned char* shdrs
= sd
->section_headers
->data();
802 const unsigned char* pshdrs
;
804 // Get the section names.
805 const unsigned char* pnamesu
= sd
->section_names
->data();
806 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
808 // For each section, record the index of the reloc section if any.
809 // Use 0 to mean that there is no reloc section, -1U to mean that
810 // there is more than one.
811 std::vector
<unsigned int> reloc_shndx(shnum
, 0);
812 std::vector
<unsigned int> reloc_type(shnum
, elfcpp::SHT_NULL
);
813 // Skip the first, dummy, section.
814 pshdrs
= shdrs
+ This::shdr_size
;
815 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
817 typename
This::Shdr
shdr(pshdrs
);
819 unsigned int sh_type
= shdr
.get_sh_type();
820 if (sh_type
== elfcpp::SHT_REL
|| sh_type
== elfcpp::SHT_RELA
)
822 unsigned int target_shndx
= this->adjust_shndx(shdr
.get_sh_info());
823 if (target_shndx
== 0 || target_shndx
>= shnum
)
825 this->error(_("relocation section %u has bad info %u"),
830 if (reloc_shndx
[target_shndx
] != 0)
831 reloc_shndx
[target_shndx
] = -1U;
834 reloc_shndx
[target_shndx
] = i
;
835 reloc_type
[target_shndx
] = sh_type
;
840 Output_sections
& out_sections(this->output_sections());
841 std::vector
<Address
>& out_section_offsets(this->section_offsets_
);
843 out_sections
.resize(shnum
);
844 out_section_offsets
.resize(shnum
);
846 // If we are only linking for symbols, then there is nothing else to
848 if (this->input_file()->just_symbols())
850 delete sd
->section_headers
;
851 sd
->section_headers
= NULL
;
852 delete sd
->section_names
;
853 sd
->section_names
= NULL
;
857 // Whether we've seen a .note.GNU-stack section.
858 bool seen_gnu_stack
= false;
859 // The flags of a .note.GNU-stack section.
860 uint64_t gnu_stack_flags
= 0;
862 // Keep track of which sections to omit.
863 std::vector
<bool> omit(shnum
, false);
865 // Keep track of reloc sections when emitting relocations.
866 const bool relocatable
= parameters
->options().relocatable();
867 const bool emit_relocs
= (relocatable
868 || parameters
->options().emit_relocs());
869 std::vector
<unsigned int> reloc_sections
;
871 // Keep track of .eh_frame sections.
872 std::vector
<unsigned int> eh_frame_sections
;
874 // Skip the first, dummy, section.
875 pshdrs
= shdrs
+ This::shdr_size
;
876 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
878 typename
This::Shdr
shdr(pshdrs
);
880 if (shdr
.get_sh_name() >= sd
->section_names_size
)
882 this->error(_("bad section name offset for section %u: %lu"),
883 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
887 const char* name
= pnames
+ shdr
.get_sh_name();
889 if (this->handle_gnu_warning_section(name
, i
, symtab
))
895 // The .note.GNU-stack section is special. It gives the
896 // protection flags that this object file requires for the stack
898 if (strcmp(name
, ".note.GNU-stack") == 0)
900 seen_gnu_stack
= true;
901 gnu_stack_flags
|= shdr
.get_sh_flags();
905 bool discard
= omit
[i
];
908 if (shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
910 if (!this->include_section_group(symtab
, layout
, i
, name
, shdrs
,
911 pnames
, sd
->section_names_size
,
915 else if ((shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) == 0
916 && Layout::is_linkonce(name
))
918 if (!this->include_linkonce_section(layout
, i
, name
, shdr
))
925 // Do not include this section in the link.
926 out_sections
[i
] = NULL
;
927 out_section_offsets
[i
] = -1U;
931 // When doing a relocatable link we are going to copy input
932 // reloc sections into the output. We only want to copy the
933 // ones associated with sections which are not being discarded.
934 // However, we don't know that yet for all sections. So save
935 // reloc sections and process them later.
937 && (shdr
.get_sh_type() == elfcpp::SHT_REL
938 || shdr
.get_sh_type() == elfcpp::SHT_RELA
))
940 reloc_sections
.push_back(i
);
944 if (relocatable
&& shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
947 // The .eh_frame section is special. It holds exception frame
948 // information that we need to read in order to generate the
949 // exception frame header. We process these after all the other
950 // sections so that the exception frame reader can reliably
951 // determine which sections are being discarded, and discard the
952 // corresponding information.
954 && strcmp(name
, ".eh_frame") == 0
955 && this->check_eh_frame_flags(&shdr
))
957 eh_frame_sections
.push_back(i
);
962 Output_section
* os
= layout
->layout(this, i
, name
, shdr
,
963 reloc_shndx
[i
], reloc_type
[i
],
966 out_sections
[i
] = os
;
968 out_section_offsets
[i
] = -1U;
970 out_section_offsets
[i
] = convert_types
<Address
, off_t
>(offset
);
972 // If this section requires special handling, and if there are
973 // relocs that apply to it, then we must do the special handling
974 // before we apply the relocs.
975 if (offset
== -1 && reloc_shndx
[i
] != 0)
976 this->set_relocs_must_follow_section_writes();
979 layout
->layout_gnu_stack(seen_gnu_stack
, gnu_stack_flags
);
981 // When doing a relocatable link handle the reloc sections at the
984 this->size_relocatable_relocs();
985 for (std::vector
<unsigned int>::const_iterator p
= reloc_sections
.begin();
986 p
!= reloc_sections
.end();
990 const unsigned char* pshdr
;
991 pshdr
= sd
->section_headers
->data() + i
* This::shdr_size
;
992 typename
This::Shdr
shdr(pshdr
);
994 unsigned int data_shndx
= this->adjust_shndx(shdr
.get_sh_info());
995 if (data_shndx
>= shnum
)
997 // We already warned about this above.
1001 Output_section
* data_section
= out_sections
[data_shndx
];
1002 if (data_section
== NULL
)
1004 out_sections
[i
] = NULL
;
1005 out_section_offsets
[i
] = -1U;
1009 Relocatable_relocs
* rr
= new Relocatable_relocs();
1010 this->set_relocatable_relocs(i
, rr
);
1012 Output_section
* os
= layout
->layout_reloc(this, i
, shdr
, data_section
,
1014 out_sections
[i
] = os
;
1015 out_section_offsets
[i
] = -1U;
1018 // Handle the .eh_frame sections at the end.
1019 for (std::vector
<unsigned int>::const_iterator p
= eh_frame_sections
.begin();
1020 p
!= eh_frame_sections
.end();
1023 gold_assert(this->has_eh_frame_
);
1024 gold_assert(sd
->external_symbols_offset
!= 0);
1026 unsigned int i
= *p
;
1027 const unsigned char *pshdr
;
1028 pshdr
= sd
->section_headers
->data() + i
* This::shdr_size
;
1029 typename
This::Shdr
shdr(pshdr
);
1032 Output_section
* os
= layout
->layout_eh_frame(this,
1033 sd
->symbols
->data(),
1035 sd
->symbol_names
->data(),
1036 sd
->symbol_names_size
,
1041 out_sections
[i
] = os
;
1043 out_section_offsets
[i
] = -1U;
1045 out_section_offsets
[i
] = convert_types
<Address
, off_t
>(offset
);
1047 // If this section requires special handling, and if there are
1048 // relocs that apply to it, then we must do the special handling
1049 // before we apply the relocs.
1050 if (offset
== -1 && reloc_shndx
[i
] != 0)
1051 this->set_relocs_must_follow_section_writes();
1054 delete sd
->section_headers
;
1055 sd
->section_headers
= NULL
;
1056 delete sd
->section_names
;
1057 sd
->section_names
= NULL
;
1060 // Add the symbols to the symbol table.
1062 template<int size
, bool big_endian
>
1064 Sized_relobj
<size
, big_endian
>::do_add_symbols(Symbol_table
* symtab
,
1065 Read_symbols_data
* sd
)
1067 if (sd
->symbols
== NULL
)
1069 gold_assert(sd
->symbol_names
== NULL
);
1073 const int sym_size
= This::sym_size
;
1074 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
1076 if (symcount
* sym_size
!= sd
->symbols_size
- sd
->external_symbols_offset
)
1078 this->error(_("size of symbols is not multiple of symbol size"));
1082 this->symbols_
.resize(symcount
);
1084 const char* sym_names
=
1085 reinterpret_cast<const char*>(sd
->symbol_names
->data());
1086 symtab
->add_from_relobj(this,
1087 sd
->symbols
->data() + sd
->external_symbols_offset
,
1088 symcount
, this->local_symbol_count_
,
1089 sym_names
, sd
->symbol_names_size
,
1094 delete sd
->symbol_names
;
1095 sd
->symbol_names
= NULL
;
1098 // First pass over the local symbols. Here we add their names to
1099 // *POOL and *DYNPOOL, and we store the symbol value in
1100 // THIS->LOCAL_VALUES_. This function is always called from a
1101 // singleton thread. This is followed by a call to
1102 // finalize_local_symbols.
1104 template<int size
, bool big_endian
>
1106 Sized_relobj
<size
, big_endian
>::do_count_local_symbols(Stringpool
* pool
,
1107 Stringpool
* dynpool
)
1109 gold_assert(this->symtab_shndx_
!= -1U);
1110 if (this->symtab_shndx_
== 0)
1112 // This object has no symbols. Weird but legal.
1116 // Read the symbol table section header.
1117 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1118 typename
This::Shdr
symtabshdr(this,
1119 this->elf_file_
.section_header(symtab_shndx
));
1120 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1122 // Read the local symbols.
1123 const int sym_size
= This::sym_size
;
1124 const unsigned int loccount
= this->local_symbol_count_
;
1125 gold_assert(loccount
== symtabshdr
.get_sh_info());
1126 off_t locsize
= loccount
* sym_size
;
1127 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1128 locsize
, true, true);
1130 // Read the symbol names.
1131 const unsigned int strtab_shndx
=
1132 this->adjust_shndx(symtabshdr
.get_sh_link());
1133 section_size_type strtab_size
;
1134 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
1137 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
1139 // Loop over the local symbols.
1141 const Output_sections
& out_sections(this->output_sections());
1142 unsigned int shnum
= this->shnum();
1143 unsigned int count
= 0;
1144 unsigned int dyncount
= 0;
1145 // Skip the first, dummy, symbol.
1147 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
1149 elfcpp::Sym
<size
, big_endian
> sym(psyms
);
1151 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1154 unsigned int shndx
= this->adjust_sym_shndx(i
, sym
.get_st_shndx(),
1156 lv
.set_input_shndx(shndx
, is_ordinary
);
1158 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
1159 lv
.set_is_section_symbol();
1160 else if (sym
.get_st_type() == elfcpp::STT_TLS
)
1161 lv
.set_is_tls_symbol();
1163 // Save the input symbol value for use in do_finalize_local_symbols().
1164 lv
.set_input_value(sym
.get_st_value());
1166 // Decide whether this symbol should go into the output file.
1168 if (shndx
< shnum
&& out_sections
[shndx
] == NULL
)
1170 lv
.set_no_output_symtab_entry();
1171 gold_assert(!lv
.needs_output_dynsym_entry());
1175 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
1177 lv
.set_no_output_symtab_entry();
1178 gold_assert(!lv
.needs_output_dynsym_entry());
1182 if (sym
.get_st_name() >= strtab_size
)
1184 this->error(_("local symbol %u section name out of range: %u >= %u"),
1185 i
, sym
.get_st_name(),
1186 static_cast<unsigned int>(strtab_size
));
1187 lv
.set_no_output_symtab_entry();
1191 // Add the symbol to the symbol table string pool.
1192 const char* name
= pnames
+ sym
.get_st_name();
1193 pool
->add(name
, true, NULL
);
1196 // If needed, add the symbol to the dynamic symbol table string pool.
1197 if (lv
.needs_output_dynsym_entry())
1199 dynpool
->add(name
, true, NULL
);
1204 this->output_local_symbol_count_
= count
;
1205 this->output_local_dynsym_count_
= dyncount
;
1208 // Finalize the local symbols. Here we set the final value in
1209 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
1210 // This function is always called from a singleton thread. The actual
1211 // output of the local symbols will occur in a separate task.
1213 template<int size
, bool big_endian
>
1215 Sized_relobj
<size
, big_endian
>::do_finalize_local_symbols(unsigned int index
,
1218 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
1220 const unsigned int loccount
= this->local_symbol_count_
;
1221 this->local_symbol_offset_
= off
;
1223 const Output_sections
& out_sections(this->output_sections());
1224 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
1225 unsigned int shnum
= this->shnum();
1227 for (unsigned int i
= 1; i
< loccount
; ++i
)
1229 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1232 unsigned int shndx
= lv
.input_shndx(&is_ordinary
);
1234 // Set the output symbol value.
1238 if (shndx
== elfcpp::SHN_ABS
|| shndx
== elfcpp::SHN_COMMON
)
1239 lv
.set_output_value(lv
.input_value());
1242 this->error(_("unknown section index %u for local symbol %u"),
1244 lv
.set_output_value(0);
1251 this->error(_("local symbol %u section index %u out of range"),
1256 Output_section
* os
= out_sections
[shndx
];
1260 // This local symbol belongs to a section we are discarding.
1261 // In some cases when applying relocations later, we will
1262 // attempt to match it to the corresponding kept section,
1263 // so we leave the input value unchanged here.
1266 else if (out_offsets
[shndx
] == -1U)
1268 // This is a SHF_MERGE section or one which otherwise
1269 // requires special handling. We get the output address
1270 // of the start of the merged section. If this is not a
1271 // section symbol, we can then determine the final
1272 // value. If it is a section symbol, we can not, as in
1273 // that case we have to consider the addend to determine
1274 // the value to use in a relocation.
1275 if (!lv
.is_section_symbol())
1276 lv
.set_output_value(os
->output_address(this, shndx
,
1280 section_offset_type start
=
1281 os
->starting_output_address(this, shndx
);
1282 Merged_symbol_value
<size
>* msv
=
1283 new Merged_symbol_value
<size
>(lv
.input_value(), start
);
1284 lv
.set_merged_symbol_value(msv
);
1287 else if (lv
.is_tls_symbol())
1288 lv
.set_output_value(os
->tls_offset()
1289 + out_offsets
[shndx
]
1290 + lv
.input_value());
1292 lv
.set_output_value(os
->address()
1293 + out_offsets
[shndx
]
1294 + lv
.input_value());
1297 if (lv
.needs_output_symtab_entry())
1299 lv
.set_output_symtab_index(index
);
1306 // Set the output dynamic symbol table indexes for the local variables.
1308 template<int size
, bool big_endian
>
1310 Sized_relobj
<size
, big_endian
>::do_set_local_dynsym_indexes(unsigned int index
)
1312 const unsigned int loccount
= this->local_symbol_count_
;
1313 for (unsigned int i
= 1; i
< loccount
; ++i
)
1315 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1316 if (lv
.needs_output_dynsym_entry())
1318 lv
.set_output_dynsym_index(index
);
1325 // Set the offset where local dynamic symbol information will be stored.
1326 // Returns the count of local symbols contributed to the symbol table by
1329 template<int size
, bool big_endian
>
1331 Sized_relobj
<size
, big_endian
>::do_set_local_dynsym_offset(off_t off
)
1333 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
1334 this->local_dynsym_offset_
= off
;
1335 return this->output_local_dynsym_count_
;
1338 // Write out the local symbols.
1340 template<int size
, bool big_endian
>
1342 Sized_relobj
<size
, big_endian
>::write_local_symbols(
1344 const Stringpool
* sympool
,
1345 const Stringpool
* dynpool
,
1346 Output_symtab_xindex
* symtab_xindex
,
1347 Output_symtab_xindex
* dynsym_xindex
)
1349 if (parameters
->options().strip_all()
1350 && this->output_local_dynsym_count_
== 0)
1353 gold_assert(this->symtab_shndx_
!= -1U);
1354 if (this->symtab_shndx_
== 0)
1356 // This object has no symbols. Weird but legal.
1360 // Read the symbol table section header.
1361 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1362 typename
This::Shdr
symtabshdr(this,
1363 this->elf_file_
.section_header(symtab_shndx
));
1364 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1365 const unsigned int loccount
= this->local_symbol_count_
;
1366 gold_assert(loccount
== symtabshdr
.get_sh_info());
1368 // Read the local symbols.
1369 const int sym_size
= This::sym_size
;
1370 off_t locsize
= loccount
* sym_size
;
1371 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1372 locsize
, true, false);
1374 // Read the symbol names.
1375 const unsigned int strtab_shndx
=
1376 this->adjust_shndx(symtabshdr
.get_sh_link());
1377 section_size_type strtab_size
;
1378 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
1381 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
1383 // Get views into the output file for the portions of the symbol table
1384 // and the dynamic symbol table that we will be writing.
1385 off_t output_size
= this->output_local_symbol_count_
* sym_size
;
1386 unsigned char* oview
= NULL
;
1387 if (output_size
> 0)
1388 oview
= of
->get_output_view(this->local_symbol_offset_
, output_size
);
1390 off_t dyn_output_size
= this->output_local_dynsym_count_
* sym_size
;
1391 unsigned char* dyn_oview
= NULL
;
1392 if (dyn_output_size
> 0)
1393 dyn_oview
= of
->get_output_view(this->local_dynsym_offset_
,
1396 const Output_sections
out_sections(this->output_sections());
1398 gold_assert(this->local_values_
.size() == loccount
);
1400 unsigned char* ov
= oview
;
1401 unsigned char* dyn_ov
= dyn_oview
;
1403 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
1405 elfcpp::Sym
<size
, big_endian
> isym(psyms
);
1407 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1410 unsigned int st_shndx
= this->adjust_sym_shndx(i
, isym
.get_st_shndx(),
1414 gold_assert(st_shndx
< out_sections
.size());
1415 if (out_sections
[st_shndx
] == NULL
)
1417 st_shndx
= out_sections
[st_shndx
]->out_shndx();
1418 if (st_shndx
>= elfcpp::SHN_LORESERVE
)
1420 if (lv
.needs_output_symtab_entry())
1421 symtab_xindex
->add(lv
.output_symtab_index(), st_shndx
);
1422 if (lv
.needs_output_dynsym_entry())
1423 dynsym_xindex
->add(lv
.output_dynsym_index(), st_shndx
);
1424 st_shndx
= elfcpp::SHN_XINDEX
;
1428 // Write the symbol to the output symbol table.
1429 if (!parameters
->options().strip_all()
1430 && lv
.needs_output_symtab_entry())
1432 elfcpp::Sym_write
<size
, big_endian
> osym(ov
);
1434 gold_assert(isym
.get_st_name() < strtab_size
);
1435 const char* name
= pnames
+ isym
.get_st_name();
1436 osym
.put_st_name(sympool
->get_offset(name
));
1437 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
1438 osym
.put_st_size(isym
.get_st_size());
1439 osym
.put_st_info(isym
.get_st_info());
1440 osym
.put_st_other(isym
.get_st_other());
1441 osym
.put_st_shndx(st_shndx
);
1446 // Write the symbol to the output dynamic symbol table.
1447 if (lv
.needs_output_dynsym_entry())
1449 gold_assert(dyn_ov
< dyn_oview
+ dyn_output_size
);
1450 elfcpp::Sym_write
<size
, big_endian
> osym(dyn_ov
);
1452 gold_assert(isym
.get_st_name() < strtab_size
);
1453 const char* name
= pnames
+ isym
.get_st_name();
1454 osym
.put_st_name(dynpool
->get_offset(name
));
1455 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
1456 osym
.put_st_size(isym
.get_st_size());
1457 osym
.put_st_info(isym
.get_st_info());
1458 osym
.put_st_other(isym
.get_st_other());
1459 osym
.put_st_shndx(st_shndx
);
1466 if (output_size
> 0)
1468 gold_assert(ov
- oview
== output_size
);
1469 of
->write_output_view(this->local_symbol_offset_
, output_size
, oview
);
1472 if (dyn_output_size
> 0)
1474 gold_assert(dyn_ov
- dyn_oview
== dyn_output_size
);
1475 of
->write_output_view(this->local_dynsym_offset_
, dyn_output_size
,
1480 // Set *INFO to symbolic information about the offset OFFSET in the
1481 // section SHNDX. Return true if we found something, false if we
1484 template<int size
, bool big_endian
>
1486 Sized_relobj
<size
, big_endian
>::get_symbol_location_info(
1489 Symbol_location_info
* info
)
1491 if (this->symtab_shndx_
== 0)
1494 section_size_type symbols_size
;
1495 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
1499 unsigned int symbol_names_shndx
=
1500 this->adjust_shndx(this->section_link(this->symtab_shndx_
));
1501 section_size_type names_size
;
1502 const unsigned char* symbol_names_u
=
1503 this->section_contents(symbol_names_shndx
, &names_size
, false);
1504 const char* symbol_names
= reinterpret_cast<const char*>(symbol_names_u
);
1506 const int sym_size
= This::sym_size
;
1507 const size_t count
= symbols_size
/ sym_size
;
1509 const unsigned char* p
= symbols
;
1510 for (size_t i
= 0; i
< count
; ++i
, p
+= sym_size
)
1512 elfcpp::Sym
<size
, big_endian
> sym(p
);
1514 if (sym
.get_st_type() == elfcpp::STT_FILE
)
1516 if (sym
.get_st_name() >= names_size
)
1517 info
->source_file
= "(invalid)";
1519 info
->source_file
= symbol_names
+ sym
.get_st_name();
1524 unsigned int st_shndx
= this->adjust_sym_shndx(i
, sym
.get_st_shndx(),
1527 && st_shndx
== shndx
1528 && static_cast<off_t
>(sym
.get_st_value()) <= offset
1529 && (static_cast<off_t
>(sym
.get_st_value() + sym
.get_st_size())
1532 if (sym
.get_st_name() > names_size
)
1533 info
->enclosing_symbol_name
= "(invalid)";
1536 info
->enclosing_symbol_name
= symbol_names
+ sym
.get_st_name();
1537 if (parameters
->options().do_demangle())
1539 char* demangled_name
= cplus_demangle(
1540 info
->enclosing_symbol_name
.c_str(),
1541 DMGL_ANSI
| DMGL_PARAMS
);
1542 if (demangled_name
!= NULL
)
1544 info
->enclosing_symbol_name
.assign(demangled_name
);
1545 free(demangled_name
);
1556 // Look for a kept section corresponding to the given discarded section,
1557 // and return its output address. This is used only for relocations in
1558 // debugging sections. If we can't find the kept section, return 0.
1560 template<int size
, bool big_endian
>
1561 typename Sized_relobj
<size
, big_endian
>::Address
1562 Sized_relobj
<size
, big_endian
>::map_to_kept_section(
1566 Kept_comdat_section
*kept
= this->get_kept_comdat_section(shndx
);
1569 gold_assert(kept
->object_
!= NULL
);
1571 Output_section
* os
= kept
->object_
->output_section(kept
->shndx_
);
1572 Address offset
= kept
->object_
->get_output_section_offset(kept
->shndx_
);
1573 gold_assert(os
!= NULL
&& offset
!= -1U);
1574 return os
->address() + offset
;
1580 // Input_objects methods.
1582 // Add a regular relocatable object to the list. Return false if this
1583 // object should be ignored.
1586 Input_objects::add_object(Object
* obj
)
1588 // Set the global target from the first object file we recognize.
1589 Target
* target
= obj
->target();
1590 if (!parameters
->target_valid())
1591 set_parameters_target(target
);
1592 else if (target
!= ¶meters
->target())
1594 obj
->error(_("incompatible target"));
1598 // Print the filename if the -t/--trace option is selected.
1599 if (parameters
->options().trace())
1600 gold_info("%s", obj
->name().c_str());
1602 if (!obj
->is_dynamic())
1603 this->relobj_list_
.push_back(static_cast<Relobj
*>(obj
));
1606 // See if this is a duplicate SONAME.
1607 Dynobj
* dynobj
= static_cast<Dynobj
*>(obj
);
1608 const char* soname
= dynobj
->soname();
1610 std::pair
<Unordered_set
<std::string
>::iterator
, bool> ins
=
1611 this->sonames_
.insert(soname
);
1614 // We have already seen a dynamic object with this soname.
1618 this->dynobj_list_
.push_back(dynobj
);
1620 // If this is -lc, remember the directory in which we found it.
1621 // We use this when issuing warnings about undefined symbols: as
1622 // a heuristic, we don't warn about system libraries found in
1623 // the same directory as -lc.
1624 if (strncmp(soname
, "libc.so", 7) == 0)
1626 const char* object_name
= dynobj
->name().c_str();
1627 const char* base
= lbasename(object_name
);
1628 if (base
!= object_name
)
1629 this->system_library_directory_
.assign(object_name
,
1630 base
- 1 - object_name
);
1637 // Return whether an object was found in the system library directory.
1640 Input_objects::found_in_system_library_directory(const Object
* object
) const
1642 return (!this->system_library_directory_
.empty()
1643 && object
->name().compare(0,
1644 this->system_library_directory_
.size(),
1645 this->system_library_directory_
) == 0);
1648 // For each dynamic object, record whether we've seen all of its
1649 // explicit dependencies.
1652 Input_objects::check_dynamic_dependencies() const
1654 for (Dynobj_list::const_iterator p
= this->dynobj_list_
.begin();
1655 p
!= this->dynobj_list_
.end();
1658 const Dynobj::Needed
& needed((*p
)->needed());
1659 bool found_all
= true;
1660 for (Dynobj::Needed::const_iterator pneeded
= needed
.begin();
1661 pneeded
!= needed
.end();
1664 if (this->sonames_
.find(*pneeded
) == this->sonames_
.end())
1670 (*p
)->set_has_unknown_needed_entries(!found_all
);
1674 // Relocate_info methods.
1676 // Return a string describing the location of a relocation. This is
1677 // only used in error messages.
1679 template<int size
, bool big_endian
>
1681 Relocate_info
<size
, big_endian
>::location(size_t, off_t offset
) const
1683 // See if we can get line-number information from debugging sections.
1684 std::string filename
;
1685 std::string file_and_lineno
; // Better than filename-only, if available.
1687 Sized_dwarf_line_info
<size
, big_endian
> line_info(this->object
);
1688 // This will be "" if we failed to parse the debug info for any reason.
1689 file_and_lineno
= line_info
.addr2line(this->data_shndx
, offset
);
1691 std::string
ret(this->object
->name());
1693 Symbol_location_info info
;
1694 if (this->object
->get_symbol_location_info(this->data_shndx
, offset
, &info
))
1696 ret
+= " in function ";
1697 ret
+= info
.enclosing_symbol_name
;
1699 filename
= info
.source_file
;
1702 if (!file_and_lineno
.empty())
1703 ret
+= file_and_lineno
;
1706 if (!filename
.empty())
1709 ret
+= this->object
->section_name(this->data_shndx
);
1711 // Offsets into sections have to be positive.
1712 snprintf(buf
, sizeof(buf
), "+0x%lx", static_cast<long>(offset
));
1719 } // End namespace gold.
1724 using namespace gold
;
1726 // Read an ELF file with the header and return the appropriate
1727 // instance of Object.
1729 template<int size
, bool big_endian
>
1731 make_elf_sized_object(const std::string
& name
, Input_file
* input_file
,
1732 off_t offset
, const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
1734 int et
= ehdr
.get_e_type();
1735 if (et
== elfcpp::ET_REL
)
1737 Sized_relobj
<size
, big_endian
>* obj
=
1738 new Sized_relobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1742 else if (et
== elfcpp::ET_DYN
)
1744 Sized_dynobj
<size
, big_endian
>* obj
=
1745 new Sized_dynobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1751 gold_error(_("%s: unsupported ELF file type %d"),
1757 } // End anonymous namespace.
1762 // Read an ELF file and return the appropriate instance of Object.
1765 make_elf_object(const std::string
& name
, Input_file
* input_file
, off_t offset
,
1766 const unsigned char* p
, section_offset_type bytes
)
1768 if (bytes
< elfcpp::EI_NIDENT
)
1770 gold_error(_("%s: ELF file too short"), name
.c_str());
1774 int v
= p
[elfcpp::EI_VERSION
];
1775 if (v
!= elfcpp::EV_CURRENT
)
1777 if (v
== elfcpp::EV_NONE
)
1778 gold_error(_("%s: invalid ELF version 0"), name
.c_str());
1780 gold_error(_("%s: unsupported ELF version %d"), name
.c_str(), v
);
1784 int c
= p
[elfcpp::EI_CLASS
];
1785 if (c
== elfcpp::ELFCLASSNONE
)
1787 gold_error(_("%s: invalid ELF class 0"), name
.c_str());
1790 else if (c
!= elfcpp::ELFCLASS32
1791 && c
!= elfcpp::ELFCLASS64
)
1793 gold_error(_("%s: unsupported ELF class %d"), name
.c_str(), c
);
1797 int d
= p
[elfcpp::EI_DATA
];
1798 if (d
== elfcpp::ELFDATANONE
)
1800 gold_error(_("%s: invalid ELF data encoding"), name
.c_str());
1803 else if (d
!= elfcpp::ELFDATA2LSB
1804 && d
!= elfcpp::ELFDATA2MSB
)
1806 gold_error(_("%s: unsupported ELF data encoding %d"), name
.c_str(), d
);
1810 bool big_endian
= d
== elfcpp::ELFDATA2MSB
;
1812 if (c
== elfcpp::ELFCLASS32
)
1814 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
1816 gold_error(_("%s: ELF file too short"), name
.c_str());
1821 #ifdef HAVE_TARGET_32_BIG
1822 elfcpp::Ehdr
<32, true> ehdr(p
);
1823 return make_elf_sized_object
<32, true>(name
, input_file
,
1826 gold_error(_("%s: not configured to support "
1827 "32-bit big-endian object"),
1834 #ifdef HAVE_TARGET_32_LITTLE
1835 elfcpp::Ehdr
<32, false> ehdr(p
);
1836 return make_elf_sized_object
<32, false>(name
, input_file
,
1839 gold_error(_("%s: not configured to support "
1840 "32-bit little-endian object"),
1848 if (bytes
< elfcpp::Elf_sizes
<64>::ehdr_size
)
1850 gold_error(_("%s: ELF file too short"), name
.c_str());
1855 #ifdef HAVE_TARGET_64_BIG
1856 elfcpp::Ehdr
<64, true> ehdr(p
);
1857 return make_elf_sized_object
<64, true>(name
, input_file
,
1860 gold_error(_("%s: not configured to support "
1861 "64-bit big-endian object"),
1868 #ifdef HAVE_TARGET_64_LITTLE
1869 elfcpp::Ehdr
<64, false> ehdr(p
);
1870 return make_elf_sized_object
<64, false>(name
, input_file
,
1873 gold_error(_("%s: not configured to support "
1874 "64-bit little-endian object"),
1882 // Instantiate the templates we need.
1884 #ifdef HAVE_TARGET_32_LITTLE
1887 Object::read_section_data
<32, false>(elfcpp::Elf_file
<32, false, Object
>*,
1888 Read_symbols_data
*);
1891 #ifdef HAVE_TARGET_32_BIG
1894 Object::read_section_data
<32, true>(elfcpp::Elf_file
<32, true, Object
>*,
1895 Read_symbols_data
*);
1898 #ifdef HAVE_TARGET_64_LITTLE
1901 Object::read_section_data
<64, false>(elfcpp::Elf_file
<64, false, Object
>*,
1902 Read_symbols_data
*);
1905 #ifdef HAVE_TARGET_64_BIG
1908 Object::read_section_data
<64, true>(elfcpp::Elf_file
<64, true, Object
>*,
1909 Read_symbols_data
*);
1912 #ifdef HAVE_TARGET_32_LITTLE
1914 class Sized_relobj
<32, false>;
1917 #ifdef HAVE_TARGET_32_BIG
1919 class Sized_relobj
<32, true>;
1922 #ifdef HAVE_TARGET_64_LITTLE
1924 class Sized_relobj
<64, false>;
1927 #ifdef HAVE_TARGET_64_BIG
1929 class Sized_relobj
<64, true>;
1932 #ifdef HAVE_TARGET_32_LITTLE
1934 struct Relocate_info
<32, false>;
1937 #ifdef HAVE_TARGET_32_BIG
1939 struct Relocate_info
<32, true>;
1942 #ifdef HAVE_TARGET_64_LITTLE
1944 struct Relocate_info
<64, false>;
1947 #ifdef HAVE_TARGET_64_BIG
1949 struct Relocate_info
<64, true>;
1952 } // End namespace gold.