1 // object.cc -- support for an object file for linking in gold
3 // Copyright 2006, 2007 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 // Set the target based on fields in the ELF file header.
48 Object::set_target(int machine
, int size
, bool big_endian
, int osabi
,
51 Target
* target
= select_target(machine
, size
, big_endian
, osabi
, abiversion
);
53 gold_fatal(_("%s: unsupported ELF machine number %d"),
54 this->name().c_str(), machine
);
55 this->target_
= target
;
58 // Report an error for this object file. This is used by the
59 // elfcpp::Elf_file interface, and also called by the Object code
63 Object::error(const char* format
, ...) const
66 va_start(args
, format
);
68 if (vasprintf(&buf
, format
, args
) < 0)
71 gold_error(_("%s: %s"), this->name().c_str(), buf
);
75 // Return a view of the contents of a section.
78 Object::section_contents(unsigned int shndx
, section_size_type
* plen
,
81 Location
loc(this->do_section_contents(shndx
));
82 *plen
= convert_to_section_size_type(loc
.data_size
);
83 return this->get_view(loc
.file_offset
, *plen
, cache
);
86 // Read the section data into SD. This is code common to Sized_relobj
87 // and Sized_dynobj, so we put it into Object.
89 template<int size
, bool big_endian
>
91 Object::read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>* elf_file
,
92 Read_symbols_data
* sd
)
94 const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
96 // Read the section headers.
97 const off_t shoff
= elf_file
->shoff();
98 const unsigned int shnum
= this->shnum();
99 sd
->section_headers
= this->get_lasting_view(shoff
, shnum
* shdr_size
, true);
101 // Read the section names.
102 const unsigned char* pshdrs
= sd
->section_headers
->data();
103 const unsigned char* pshdrnames
= pshdrs
+ elf_file
->shstrndx() * shdr_size
;
104 typename
elfcpp::Shdr
<size
, big_endian
> shdrnames(pshdrnames
);
106 if (shdrnames
.get_sh_type() != elfcpp::SHT_STRTAB
)
107 this->error(_("section name section has wrong type: %u"),
108 static_cast<unsigned int>(shdrnames
.get_sh_type()));
110 sd
->section_names_size
=
111 convert_to_section_size_type(shdrnames
.get_sh_size());
112 sd
->section_names
= this->get_lasting_view(shdrnames
.get_sh_offset(),
113 sd
->section_names_size
, false);
116 // If NAME is the name of a special .gnu.warning section, arrange for
117 // the warning to be issued. SHNDX is the section index. Return
118 // whether it is a warning section.
121 Object::handle_gnu_warning_section(const char* name
, unsigned int shndx
,
122 Symbol_table
* symtab
)
124 const char warn_prefix
[] = ".gnu.warning.";
125 const int warn_prefix_len
= sizeof warn_prefix
- 1;
126 if (strncmp(name
, warn_prefix
, warn_prefix_len
) == 0)
128 symtab
->add_warning(name
+ warn_prefix_len
, this, shndx
);
134 // Class Sized_relobj.
136 template<int size
, bool big_endian
>
137 Sized_relobj
<size
, big_endian
>::Sized_relobj(
138 const std::string
& name
,
139 Input_file
* input_file
,
141 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
142 : Relobj(name
, input_file
, offset
),
143 elf_file_(this, ehdr
),
145 local_symbol_count_(0),
146 output_local_symbol_count_(0),
147 output_local_dynsym_count_(0),
149 local_symbol_offset_(0),
150 local_dynsym_offset_(0),
152 local_got_offsets_(),
157 template<int size
, bool big_endian
>
158 Sized_relobj
<size
, big_endian
>::~Sized_relobj()
162 // Set up an object file based on the file header. This sets up the
163 // target and reads the section information.
165 template<int size
, bool big_endian
>
167 Sized_relobj
<size
, big_endian
>::setup(
168 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
170 this->set_target(ehdr
.get_e_machine(), size
, big_endian
,
171 ehdr
.get_e_ident()[elfcpp::EI_OSABI
],
172 ehdr
.get_e_ident()[elfcpp::EI_ABIVERSION
]);
174 const unsigned int shnum
= this->elf_file_
.shnum();
175 this->set_shnum(shnum
);
178 // Find the SHT_SYMTAB section, given the section headers. The ELF
179 // standard says that maybe in the future there can be more than one
180 // SHT_SYMTAB section. Until somebody figures out how that could
181 // work, we assume there is only one.
183 template<int size
, bool big_endian
>
185 Sized_relobj
<size
, big_endian
>::find_symtab(const unsigned char* pshdrs
)
187 const unsigned int shnum
= this->shnum();
188 this->symtab_shndx_
= 0;
191 // Look through the sections in reverse order, since gas tends
192 // to put the symbol table at the end.
193 const unsigned char* p
= pshdrs
+ shnum
* This::shdr_size
;
194 unsigned int i
= shnum
;
198 p
-= This::shdr_size
;
199 typename
This::Shdr
shdr(p
);
200 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB
)
202 this->symtab_shndx_
= i
;
209 // Return whether SHDR has the right type and flags to be a GNU
210 // .eh_frame section.
212 template<int size
, bool big_endian
>
214 Sized_relobj
<size
, big_endian
>::check_eh_frame_flags(
215 const elfcpp::Shdr
<size
, big_endian
>* shdr
) const
217 return (shdr
->get_sh_size() > 0
218 && shdr
->get_sh_type() == elfcpp::SHT_PROGBITS
219 && shdr
->get_sh_flags() == elfcpp::SHF_ALLOC
);
222 // Return whether there is a GNU .eh_frame section, given the section
223 // headers and the section names.
225 template<int size
, bool big_endian
>
227 Sized_relobj
<size
, big_endian
>::find_eh_frame(
228 const unsigned char* pshdrs
,
230 section_size_type names_size
) const
232 const unsigned int shnum
= this->shnum();
233 const unsigned char* p
= pshdrs
+ This::shdr_size
;
234 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
236 typename
This::Shdr
shdr(p
);
237 if (this->check_eh_frame_flags(&shdr
))
239 if (shdr
.get_sh_name() >= names_size
)
241 this->error(_("bad section name offset for section %u: %lu"),
242 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
246 const char* name
= names
+ shdr
.get_sh_name();
247 if (strcmp(name
, ".eh_frame") == 0)
254 // Read the sections and symbols from an object file.
256 template<int size
, bool big_endian
>
258 Sized_relobj
<size
, big_endian
>::do_read_symbols(Read_symbols_data
* sd
)
260 this->read_section_data(&this->elf_file_
, sd
);
262 const unsigned char* const pshdrs
= sd
->section_headers
->data();
264 this->find_symtab(pshdrs
);
266 const unsigned char* namesu
= sd
->section_names
->data();
267 const char* names
= reinterpret_cast<const char*>(namesu
);
268 if (this->find_eh_frame(pshdrs
, names
, sd
->section_names_size
))
269 this->has_eh_frame_
= true;
272 sd
->symbols_size
= 0;
273 sd
->external_symbols_offset
= 0;
274 sd
->symbol_names
= NULL
;
275 sd
->symbol_names_size
= 0;
277 if (this->symtab_shndx_
== 0)
279 // No symbol table. Weird but legal.
283 // Get the symbol table section header.
284 typename
This::Shdr
symtabshdr(pshdrs
285 + this->symtab_shndx_
* This::shdr_size
);
286 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
288 // If this object has a .eh_frame section, we need all the symbols.
289 // Otherwise we only need the external symbols. While it would be
290 // simpler to just always read all the symbols, I've seen object
291 // files with well over 2000 local symbols, which for a 64-bit
292 // object file format is over 5 pages that we don't need to read
295 const int sym_size
= This::sym_size
;
296 const unsigned int loccount
= symtabshdr
.get_sh_info();
297 this->local_symbol_count_
= loccount
;
298 this->local_values_
.resize(loccount
);
299 section_offset_type locsize
= loccount
* sym_size
;
300 off_t dataoff
= symtabshdr
.get_sh_offset();
301 section_size_type datasize
=
302 convert_to_section_size_type(symtabshdr
.get_sh_size());
303 off_t extoff
= dataoff
+ locsize
;
304 section_size_type extsize
= datasize
- locsize
;
306 off_t readoff
= this->has_eh_frame_
? dataoff
: extoff
;
307 section_size_type readsize
= this->has_eh_frame_
? datasize
: extsize
;
309 File_view
* fvsymtab
= this->get_lasting_view(readoff
, readsize
, false);
311 // Read the section header for the symbol names.
312 unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
313 if (strtab_shndx
>= this->shnum())
315 this->error(_("invalid symbol table name index: %u"), strtab_shndx
);
318 typename
This::Shdr
strtabshdr(pshdrs
+ strtab_shndx
* This::shdr_size
);
319 if (strtabshdr
.get_sh_type() != elfcpp::SHT_STRTAB
)
321 this->error(_("symbol table name section has wrong type: %u"),
322 static_cast<unsigned int>(strtabshdr
.get_sh_type()));
326 // Read the symbol names.
327 File_view
* fvstrtab
= this->get_lasting_view(strtabshdr
.get_sh_offset(),
328 strtabshdr
.get_sh_size(), true);
330 sd
->symbols
= fvsymtab
;
331 sd
->symbols_size
= readsize
;
332 sd
->external_symbols_offset
= this->has_eh_frame_
? locsize
: 0;
333 sd
->symbol_names
= fvstrtab
;
334 sd
->symbol_names_size
=
335 convert_to_section_size_type(strtabshdr
.get_sh_size());
338 // Return the section index of symbol SYM. Set *VALUE to its value in
339 // the object file. Note that for a symbol which is not defined in
340 // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
341 // it will not return the final value of the symbol in the link.
343 template<int size
, bool big_endian
>
345 Sized_relobj
<size
, big_endian
>::symbol_section_and_value(unsigned int sym
,
348 section_size_type symbols_size
;
349 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
353 const size_t count
= symbols_size
/ This::sym_size
;
354 gold_assert(sym
< count
);
356 elfcpp::Sym
<size
, big_endian
> elfsym(symbols
+ sym
* This::sym_size
);
357 *value
= elfsym
.get_st_value();
358 // FIXME: Handle SHN_XINDEX.
359 return elfsym
.get_st_shndx();
362 // Return whether to include a section group in the link. LAYOUT is
363 // used to keep track of which section groups we have already seen.
364 // INDEX is the index of the section group and SHDR is the section
365 // header. If we do not want to include this group, we set bits in
366 // OMIT for each section which should be discarded.
368 template<int size
, bool big_endian
>
370 Sized_relobj
<size
, big_endian
>::include_section_group(
373 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
374 std::vector
<bool>* omit
)
376 // Read the section contents.
377 const unsigned char* pcon
= this->get_view(shdr
.get_sh_offset(),
378 shdr
.get_sh_size(), false);
379 const elfcpp::Elf_Word
* pword
=
380 reinterpret_cast<const elfcpp::Elf_Word
*>(pcon
);
382 // The first word contains flags. We only care about COMDAT section
383 // groups. Other section groups are always included in the link
384 // just like ordinary sections.
385 elfcpp::Elf_Word flags
= elfcpp::Swap
<32, big_endian
>::readval(pword
);
386 if ((flags
& elfcpp::GRP_COMDAT
) == 0)
389 // Look up the group signature, which is the name of a symbol. This
390 // is a lot of effort to go to to read a string. Why didn't they
391 // just use the name of the SHT_GROUP section as the group
394 // Get the appropriate symbol table header (this will normally be
395 // the single SHT_SYMTAB section, but in principle it need not be).
396 const unsigned int link
= shdr
.get_sh_link();
397 typename
This::Shdr
symshdr(this, this->elf_file_
.section_header(link
));
399 // Read the symbol table entry.
400 if (shdr
.get_sh_info() >= symshdr
.get_sh_size() / This::sym_size
)
402 this->error(_("section group %u info %u out of range"),
403 index
, shdr
.get_sh_info());
406 off_t symoff
= symshdr
.get_sh_offset() + shdr
.get_sh_info() * This::sym_size
;
407 const unsigned char* psym
= this->get_view(symoff
, This::sym_size
, true);
408 elfcpp::Sym
<size
, big_endian
> sym(psym
);
410 // Read the symbol table names.
411 section_size_type symnamelen
;
412 const unsigned char* psymnamesu
;
413 psymnamesu
= this->section_contents(symshdr
.get_sh_link(), &symnamelen
,
415 const char* psymnames
= reinterpret_cast<const char*>(psymnamesu
);
417 // Get the section group signature.
418 if (sym
.get_st_name() >= symnamelen
)
420 this->error(_("symbol %u name offset %u out of range"),
421 shdr
.get_sh_info(), sym
.get_st_name());
425 const char* signature
= psymnames
+ sym
.get_st_name();
427 // It seems that some versions of gas will create a section group
428 // associated with a section symbol, and then fail to give a name to
429 // the section symbol. In such a case, use the name of the section.
432 if (signature
[0] == '\0' && sym
.get_st_type() == elfcpp::STT_SECTION
)
434 secname
= this->section_name(sym
.get_st_shndx());
435 signature
= secname
.c_str();
438 // Record this section group, and see whether we've already seen one
439 // with the same signature.
440 if (layout
->add_comdat(signature
, true))
443 // This is a duplicate. We want to discard the sections in this
445 size_t count
= shdr
.get_sh_size() / sizeof(elfcpp::Elf_Word
);
446 for (size_t i
= 1; i
< count
; ++i
)
448 elfcpp::Elf_Word secnum
=
449 elfcpp::Swap
<32, big_endian
>::readval(pword
+ i
);
450 if (secnum
>= this->shnum())
452 this->error(_("section %u in section group %u out of range"),
456 (*omit
)[secnum
] = true;
462 // Whether to include a linkonce section in the link. NAME is the
463 // name of the section and SHDR is the section header.
465 // Linkonce sections are a GNU extension implemented in the original
466 // GNU linker before section groups were defined. The semantics are
467 // that we only include one linkonce section with a given name. The
468 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
469 // where T is the type of section and SYMNAME is the name of a symbol.
470 // In an attempt to make linkonce sections interact well with section
471 // groups, we try to identify SYMNAME and use it like a section group
472 // signature. We want to block section groups with that signature,
473 // but not other linkonce sections with that signature. We also use
474 // the full name of the linkonce section as a normal section group
477 template<int size
, bool big_endian
>
479 Sized_relobj
<size
, big_endian
>::include_linkonce_section(
482 const elfcpp::Shdr
<size
, big_endian
>&)
484 // In general the symbol name we want will be the string following
485 // the last '.'. However, we have to handle the case of
486 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
487 // some versions of gcc. So we use a heuristic: if the name starts
488 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
489 // we look for the last '.'. We can't always simply skip
490 // ".gnu.linkonce.X", because we have to deal with cases like
491 // ".gnu.linkonce.d.rel.ro.local".
492 const char* const linkonce_t
= ".gnu.linkonce.t.";
494 if (strncmp(name
, linkonce_t
, strlen(linkonce_t
)) == 0)
495 symname
= name
+ strlen(linkonce_t
);
497 symname
= strrchr(name
, '.') + 1;
498 bool include1
= layout
->add_comdat(symname
, false);
499 bool include2
= layout
->add_comdat(name
, true);
500 return include1
&& include2
;
503 // Lay out the input sections. We walk through the sections and check
504 // whether they should be included in the link. If they should, we
505 // pass them to the Layout object, which will return an output section
508 template<int size
, bool big_endian
>
510 Sized_relobj
<size
, big_endian
>::do_layout(Symbol_table
* symtab
,
512 Read_symbols_data
* sd
)
514 const unsigned int shnum
= this->shnum();
518 // Get the section headers.
519 const unsigned char* pshdrs
= sd
->section_headers
->data();
521 // Get the section names.
522 const unsigned char* pnamesu
= sd
->section_names
->data();
523 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
525 // For each section, record the index of the reloc section if any.
526 // Use 0 to mean that there is no reloc section, -1U to mean that
527 // there is more than one.
528 std::vector
<unsigned int> reloc_shndx(shnum
, 0);
529 std::vector
<unsigned int> reloc_type(shnum
, elfcpp::SHT_NULL
);
530 // Skip the first, dummy, section.
531 pshdrs
+= This::shdr_size
;
532 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
534 typename
This::Shdr
shdr(pshdrs
);
536 unsigned int sh_type
= shdr
.get_sh_type();
537 if (sh_type
== elfcpp::SHT_REL
|| sh_type
== elfcpp::SHT_RELA
)
539 unsigned int target_shndx
= shdr
.get_sh_info();
540 if (target_shndx
== 0 || target_shndx
>= shnum
)
542 this->error(_("relocation section %u has bad info %u"),
547 if (reloc_shndx
[target_shndx
] != 0)
548 reloc_shndx
[target_shndx
] = -1U;
551 reloc_shndx
[target_shndx
] = i
;
552 reloc_type
[target_shndx
] = sh_type
;
557 std::vector
<Map_to_output
>& map_sections(this->map_to_output());
558 map_sections
.resize(shnum
);
560 // Whether we've seen a .note.GNU-stack section.
561 bool seen_gnu_stack
= false;
562 // The flags of a .note.GNU-stack section.
563 uint64_t gnu_stack_flags
= 0;
565 // Keep track of which sections to omit.
566 std::vector
<bool> omit(shnum
, false);
568 // Keep track of .eh_frame sections.
569 std::vector
<unsigned int> eh_frame_sections
;
571 // Skip the first, dummy, section.
572 pshdrs
= sd
->section_headers
->data() + This::shdr_size
;
573 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
575 typename
This::Shdr
shdr(pshdrs
);
577 if (shdr
.get_sh_name() >= sd
->section_names_size
)
579 this->error(_("bad section name offset for section %u: %lu"),
580 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
584 const char* name
= pnames
+ shdr
.get_sh_name();
586 if (this->handle_gnu_warning_section(name
, i
, symtab
))
588 if (!parameters
->output_is_object())
592 // The .note.GNU-stack section is special. It gives the
593 // protection flags that this object file requires for the stack
595 if (strcmp(name
, ".note.GNU-stack") == 0)
597 seen_gnu_stack
= true;
598 gnu_stack_flags
|= shdr
.get_sh_flags();
602 bool discard
= omit
[i
];
605 if (shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
607 if (!this->include_section_group(layout
, i
, shdr
, &omit
))
610 else if ((shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) == 0
611 && Layout::is_linkonce(name
))
613 if (!this->include_linkonce_section(layout
, name
, shdr
))
620 // Do not include this section in the link.
621 map_sections
[i
].output_section
= NULL
;
625 // The .eh_frame section is special. It holds exception frame
626 // information that we need to read in order to generate the
627 // exception frame header. We process these after all the other
628 // sections so that the exception frame reader can reliably
629 // determine which sections are being discarded, and discard the
630 // corresponding information.
631 if (!parameters
->output_is_object()
632 && strcmp(name
, ".eh_frame") == 0
633 && this->check_eh_frame_flags(&shdr
))
635 eh_frame_sections
.push_back(i
);
640 Output_section
* os
= layout
->layout(this, i
, name
, shdr
,
641 reloc_shndx
[i
], reloc_type
[i
],
644 map_sections
[i
].output_section
= os
;
645 map_sections
[i
].offset
= offset
;
647 // If this section requires special handling, and if there are
648 // relocs that apply to it, then we must do the special handling
649 // before we apply the relocs.
650 if (offset
== -1 && reloc_shndx
[i
] != 0)
651 this->set_relocs_must_follow_section_writes();
654 layout
->layout_gnu_stack(seen_gnu_stack
, gnu_stack_flags
);
656 // Handle the .eh_frame sections at the end.
657 for (std::vector
<unsigned int>::const_iterator p
= eh_frame_sections
.begin();
658 p
!= eh_frame_sections
.end();
661 gold_assert(this->has_eh_frame_
);
662 gold_assert(sd
->external_symbols_offset
!= 0);
665 const unsigned char *pshdr
;
666 pshdr
= sd
->section_headers
->data() + i
* This::shdr_size
;
667 typename
This::Shdr
shdr(pshdr
);
670 Output_section
* os
= layout
->layout_eh_frame(this,
673 sd
->symbol_names
->data(),
674 sd
->symbol_names_size
,
679 map_sections
[i
].output_section
= os
;
680 map_sections
[i
].offset
= offset
;
682 // If this section requires special handling, and if there are
683 // relocs that apply to it, then we must do the special handling
684 // before we apply the relocs.
685 if (offset
== -1 && reloc_shndx
[i
] != 0)
686 this->set_relocs_must_follow_section_writes();
689 delete sd
->section_headers
;
690 sd
->section_headers
= NULL
;
691 delete sd
->section_names
;
692 sd
->section_names
= NULL
;
695 // Add the symbols to the symbol table.
697 template<int size
, bool big_endian
>
699 Sized_relobj
<size
, big_endian
>::do_add_symbols(Symbol_table
* symtab
,
700 Read_symbols_data
* sd
)
702 if (sd
->symbols
== NULL
)
704 gold_assert(sd
->symbol_names
== NULL
);
708 const int sym_size
= This::sym_size
;
709 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
711 if (symcount
* sym_size
!= sd
->symbols_size
- sd
->external_symbols_offset
)
713 this->error(_("size of symbols is not multiple of symbol size"));
717 this->symbols_
.resize(symcount
);
719 const char* sym_names
=
720 reinterpret_cast<const char*>(sd
->symbol_names
->data());
721 symtab
->add_from_relobj(this,
722 sd
->symbols
->data() + sd
->external_symbols_offset
,
723 symcount
, sym_names
, sd
->symbol_names_size
,
728 delete sd
->symbol_names
;
729 sd
->symbol_names
= NULL
;
732 // Finalize the local symbols. Here we add their names to *POOL and
733 // *DYNPOOL, and we add their values to THIS->LOCAL_VALUES_. This
734 // function is always called from a singleton thread. The actual
735 // output of the local symbols will occur in a separate task.
737 template<int size
, bool big_endian
>
739 Sized_relobj
<size
, big_endian
>::do_count_local_symbols(Stringpool
* pool
,
742 gold_assert(this->symtab_shndx_
!= -1U);
743 if (this->symtab_shndx_
== 0)
745 // This object has no symbols. Weird but legal.
749 // Read the symbol table section header.
750 const unsigned int symtab_shndx
= this->symtab_shndx_
;
751 typename
This::Shdr
symtabshdr(this,
752 this->elf_file_
.section_header(symtab_shndx
));
753 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
755 // Read the local symbols.
756 const int sym_size
= This::sym_size
;
757 const unsigned int loccount
= this->local_symbol_count_
;
758 gold_assert(loccount
== symtabshdr
.get_sh_info());
759 off_t locsize
= loccount
* sym_size
;
760 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
763 // Read the symbol names.
764 const unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
765 section_size_type strtab_size
;
766 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
769 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
771 // Loop over the local symbols.
773 const std::vector
<Map_to_output
>& mo(this->map_to_output());
774 unsigned int shnum
= this->shnum();
775 unsigned int count
= 0;
776 unsigned int dyncount
= 0;
777 // Skip the first, dummy, symbol.
779 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
781 elfcpp::Sym
<size
, big_endian
> sym(psyms
);
783 Symbol_value
<size
>& lv(this->local_values_
[i
]);
785 unsigned int shndx
= sym
.get_st_shndx();
786 lv
.set_input_shndx(shndx
);
788 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
789 lv
.set_is_section_symbol();
790 else if (sym
.get_st_type() == elfcpp::STT_TLS
)
791 lv
.set_is_tls_symbol();
793 // Save the input symbol value for use in do_finalize_local_symbols().
794 lv
.set_input_value(sym
.get_st_value());
796 // Decide whether this symbol should go into the output file.
798 if (shndx
< shnum
&& mo
[shndx
].output_section
== NULL
)
800 lv
.set_no_output_symtab_entry();
804 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
806 lv
.set_no_output_symtab_entry();
810 if (sym
.get_st_name() >= strtab_size
)
812 this->error(_("local symbol %u section name out of range: %u >= %u"),
813 i
, sym
.get_st_name(),
814 static_cast<unsigned int>(strtab_size
));
815 lv
.set_no_output_symtab_entry();
819 // Add the symbol to the symbol table string pool.
820 const char* name
= pnames
+ sym
.get_st_name();
821 pool
->add(name
, true, NULL
);
824 // If needed, add the symbol to the dynamic symbol table string pool.
825 if (lv
.needs_output_dynsym_entry())
827 dynpool
->add(name
, true, NULL
);
832 this->output_local_symbol_count_
= count
;
833 this->output_local_dynsym_count_
= dyncount
;
836 // Finalize the local symbols. Here we add their values to
837 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
838 // This function is always called from a singleton thread. The actual
839 // output of the local symbols will occur in a separate task.
841 template<int size
, bool big_endian
>
843 Sized_relobj
<size
, big_endian
>::do_finalize_local_symbols(unsigned int index
,
846 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
848 const unsigned int loccount
= this->local_symbol_count_
;
849 this->local_symbol_offset_
= off
;
851 const std::vector
<Map_to_output
>& mo(this->map_to_output());
852 unsigned int shnum
= this->shnum();
854 for (unsigned int i
= 1; i
< loccount
; ++i
)
856 Symbol_value
<size
>& lv(this->local_values_
[i
]);
858 unsigned int shndx
= lv
.input_shndx();
860 // Set the output symbol value.
862 if (shndx
>= elfcpp::SHN_LORESERVE
)
864 if (shndx
== elfcpp::SHN_ABS
)
865 lv
.set_output_value(lv
.input_value());
868 // FIXME: Handle SHN_XINDEX.
869 this->error(_("unknown section index %u for local symbol %u"),
871 lv
.set_output_value(0);
878 this->error(_("local symbol %u section index %u out of range"),
883 Output_section
* os
= mo
[shndx
].output_section
;
887 lv
.set_output_value(0);
890 else if (mo
[shndx
].offset
== -1)
892 // Leave the input value in place for SHF_MERGE sections.
894 else if (lv
.is_tls_symbol())
895 lv
.set_output_value(mo
[shndx
].output_section
->tls_offset()
899 lv
.set_output_value(mo
[shndx
].output_section
->address()
904 if (lv
.needs_output_symtab_entry())
906 lv
.set_output_symtab_index(index
);
913 // Set the output dynamic symbol table indexes for the local variables.
915 template<int size
, bool big_endian
>
917 Sized_relobj
<size
, big_endian
>::do_set_local_dynsym_indexes(unsigned int index
)
919 const unsigned int loccount
= this->local_symbol_count_
;
920 for (unsigned int i
= 1; i
< loccount
; ++i
)
922 Symbol_value
<size
>& lv(this->local_values_
[i
]);
923 if (lv
.needs_output_dynsym_entry())
925 lv
.set_output_dynsym_index(index
);
932 // Set the offset where local dynamic symbol information will be stored.
933 // Returns the count of local symbols contributed to the symbol table by
936 template<int size
, bool big_endian
>
938 Sized_relobj
<size
, big_endian
>::do_set_local_dynsym_offset(off_t off
)
940 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
941 this->local_dynsym_offset_
= off
;
942 return this->output_local_dynsym_count_
;
945 // Return the value of the local symbol symndx.
946 template<int size
, bool big_endian
>
947 typename
elfcpp::Elf_types
<size
>::Elf_Addr
948 Sized_relobj
<size
, big_endian
>::local_symbol_value(unsigned int symndx
) const
950 gold_assert(symndx
< this->local_symbol_count_
);
951 gold_assert(symndx
< this->local_values_
.size());
952 const Symbol_value
<size
>& lv(this->local_values_
[symndx
]);
953 return lv
.value(this, 0);
956 // Return the value of a local symbol defined in input section SHNDX,
957 // with value VALUE, adding addend ADDEND. IS_SECTION_SYMBOL
958 // indicates whether the symbol is a section symbol. This handles
959 // SHF_MERGE sections.
960 template<int size
, bool big_endian
>
961 typename
elfcpp::Elf_types
<size
>::Elf_Addr
962 Sized_relobj
<size
, big_endian
>::local_value(unsigned int shndx
,
964 bool is_section_symbol
,
965 Address addend
) const
967 const std::vector
<Map_to_output
>& mo(this->map_to_output());
968 Output_section
* os
= mo
[shndx
].output_section
;
971 gold_assert(mo
[shndx
].offset
== -1);
973 // Do the mapping required by the output section. If this is not a
974 // section symbol, then we want to map the symbol value, and then
975 // include the addend. If this is a section symbol, then we need to
976 // include the addend to figure out where in the section we are,
977 // before we do the mapping. This will do the right thing provided
978 // the assembler is careful to only convert a relocation in a merged
979 // section to a section symbol if there is a zero addend. If the
980 // assembler does not do this, then in general we can't know what to
981 // do, because we can't distinguish the addend for the instruction
982 // format from the addend for the section offset.
984 if (is_section_symbol
)
985 return os
->output_address(this, shndx
, value
+ addend
);
987 return addend
+ os
->output_address(this, shndx
, value
);
990 // Write out the local symbols.
992 template<int size
, bool big_endian
>
994 Sized_relobj
<size
, big_endian
>::write_local_symbols(
996 const Stringpool
* sympool
,
997 const Stringpool
* dynpool
)
999 if (parameters
->strip_all() && this->output_local_dynsym_count_
== 0)
1002 gold_assert(this->symtab_shndx_
!= -1U);
1003 if (this->symtab_shndx_
== 0)
1005 // This object has no symbols. Weird but legal.
1009 // Read the symbol table section header.
1010 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1011 typename
This::Shdr
symtabshdr(this,
1012 this->elf_file_
.section_header(symtab_shndx
));
1013 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1014 const unsigned int loccount
= this->local_symbol_count_
;
1015 gold_assert(loccount
== symtabshdr
.get_sh_info());
1017 // Read the local symbols.
1018 const int sym_size
= This::sym_size
;
1019 off_t locsize
= loccount
* sym_size
;
1020 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1023 // Read the symbol names.
1024 const unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
1025 section_size_type strtab_size
;
1026 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
1029 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
1031 // Get views into the output file for the portions of the symbol table
1032 // and the dynamic symbol table that we will be writing.
1033 off_t output_size
= this->output_local_symbol_count_
* sym_size
;
1034 unsigned char* oview
= NULL
;
1035 if (output_size
> 0)
1036 oview
= of
->get_output_view(this->local_symbol_offset_
, output_size
);
1038 off_t dyn_output_size
= this->output_local_dynsym_count_
* sym_size
;
1039 unsigned char* dyn_oview
= NULL
;
1040 if (dyn_output_size
> 0)
1041 dyn_oview
= of
->get_output_view(this->local_dynsym_offset_
,
1044 const std::vector
<Map_to_output
>& mo(this->map_to_output());
1046 gold_assert(this->local_values_
.size() == loccount
);
1048 unsigned char* ov
= oview
;
1049 unsigned char* dyn_ov
= dyn_oview
;
1051 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
1053 elfcpp::Sym
<size
, big_endian
> isym(psyms
);
1055 unsigned int st_shndx
= isym
.get_st_shndx();
1056 if (st_shndx
< elfcpp::SHN_LORESERVE
)
1058 gold_assert(st_shndx
< mo
.size());
1059 if (mo
[st_shndx
].output_section
== NULL
)
1061 st_shndx
= mo
[st_shndx
].output_section
->out_shndx();
1064 // Write the symbol to the output symbol table.
1065 if (!parameters
->strip_all()
1066 && this->local_values_
[i
].needs_output_symtab_entry())
1068 elfcpp::Sym_write
<size
, big_endian
> osym(ov
);
1070 gold_assert(isym
.get_st_name() < strtab_size
);
1071 const char* name
= pnames
+ isym
.get_st_name();
1072 osym
.put_st_name(sympool
->get_offset(name
));
1073 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
1074 osym
.put_st_size(isym
.get_st_size());
1075 osym
.put_st_info(isym
.get_st_info());
1076 osym
.put_st_other(isym
.get_st_other());
1077 osym
.put_st_shndx(st_shndx
);
1082 // Write the symbol to the output dynamic symbol table.
1083 if (this->local_values_
[i
].needs_output_dynsym_entry())
1085 gold_assert(dyn_ov
< dyn_oview
+ dyn_output_size
);
1086 elfcpp::Sym_write
<size
, big_endian
> osym(dyn_ov
);
1088 gold_assert(isym
.get_st_name() < strtab_size
);
1089 const char* name
= pnames
+ isym
.get_st_name();
1090 osym
.put_st_name(dynpool
->get_offset(name
));
1091 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
1092 osym
.put_st_size(isym
.get_st_size());
1093 osym
.put_st_info(isym
.get_st_info());
1094 osym
.put_st_other(isym
.get_st_other());
1095 osym
.put_st_shndx(st_shndx
);
1102 if (output_size
> 0)
1104 gold_assert(ov
- oview
== output_size
);
1105 of
->write_output_view(this->local_symbol_offset_
, output_size
, oview
);
1108 if (dyn_output_size
> 0)
1110 gold_assert(dyn_ov
- dyn_oview
== dyn_output_size
);
1111 of
->write_output_view(this->local_dynsym_offset_
, dyn_output_size
,
1116 // Set *INFO to symbolic information about the offset OFFSET in the
1117 // section SHNDX. Return true if we found something, false if we
1120 template<int size
, bool big_endian
>
1122 Sized_relobj
<size
, big_endian
>::get_symbol_location_info(
1125 Symbol_location_info
* info
)
1127 if (this->symtab_shndx_
== 0)
1130 section_size_type symbols_size
;
1131 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
1135 unsigned int symbol_names_shndx
= this->section_link(this->symtab_shndx_
);
1136 section_size_type names_size
;
1137 const unsigned char* symbol_names_u
=
1138 this->section_contents(symbol_names_shndx
, &names_size
, false);
1139 const char* symbol_names
= reinterpret_cast<const char*>(symbol_names_u
);
1141 const int sym_size
= This::sym_size
;
1142 const size_t count
= symbols_size
/ sym_size
;
1144 const unsigned char* p
= symbols
;
1145 for (size_t i
= 0; i
< count
; ++i
, p
+= sym_size
)
1147 elfcpp::Sym
<size
, big_endian
> sym(p
);
1149 if (sym
.get_st_type() == elfcpp::STT_FILE
)
1151 if (sym
.get_st_name() >= names_size
)
1152 info
->source_file
= "(invalid)";
1154 info
->source_file
= symbol_names
+ sym
.get_st_name();
1156 else if (sym
.get_st_shndx() == shndx
1157 && static_cast<off_t
>(sym
.get_st_value()) <= offset
1158 && (static_cast<off_t
>(sym
.get_st_value() + sym
.get_st_size())
1161 if (sym
.get_st_name() > names_size
)
1162 info
->enclosing_symbol_name
= "(invalid)";
1165 info
->enclosing_symbol_name
= symbol_names
+ sym
.get_st_name();
1166 if (parameters
->demangle())
1168 char* demangled_name
= cplus_demangle(
1169 info
->enclosing_symbol_name
.c_str(),
1170 DMGL_ANSI
| DMGL_PARAMS
);
1171 if (demangled_name
!= NULL
)
1173 info
->enclosing_symbol_name
.assign(demangled_name
);
1174 free(demangled_name
);
1185 // Input_objects methods.
1187 // Add a regular relocatable object to the list. Return false if this
1188 // object should be ignored.
1191 Input_objects::add_object(Object
* obj
)
1193 Target
* target
= obj
->target();
1194 if (this->target_
== NULL
)
1195 this->target_
= target
;
1196 else if (this->target_
!= target
)
1198 gold_error(_("%s: incompatible target"), obj
->name().c_str());
1202 if (!obj
->is_dynamic())
1203 this->relobj_list_
.push_back(static_cast<Relobj
*>(obj
));
1206 // See if this is a duplicate SONAME.
1207 Dynobj
* dynobj
= static_cast<Dynobj
*>(obj
);
1208 const char* soname
= dynobj
->soname();
1210 std::pair
<Unordered_set
<std::string
>::iterator
, bool> ins
=
1211 this->sonames_
.insert(soname
);
1214 // We have already seen a dynamic object with this soname.
1218 this->dynobj_list_
.push_back(dynobj
);
1220 // If this is -lc, remember the directory in which we found it.
1221 // We use this when issuing warnings about undefined symbols: as
1222 // a heuristic, we don't warn about system libraries found in
1223 // the same directory as -lc.
1224 if (strncmp(soname
, "libc.so", 7) == 0)
1226 const char* object_name
= dynobj
->name().c_str();
1227 const char* base
= lbasename(object_name
);
1228 if (base
!= object_name
)
1229 this->system_library_directory_
.assign(object_name
,
1230 base
- 1 - object_name
);
1234 set_parameters_target(target
);
1239 // Return whether an object was found in the system library directory.
1242 Input_objects::found_in_system_library_directory(const Object
* object
) const
1244 return (!this->system_library_directory_
.empty()
1245 && object
->name().compare(0,
1246 this->system_library_directory_
.size(),
1247 this->system_library_directory_
) == 0);
1250 // For each dynamic object, record whether we've seen all of its
1251 // explicit dependencies.
1254 Input_objects::check_dynamic_dependencies() const
1256 for (Dynobj_list::const_iterator p
= this->dynobj_list_
.begin();
1257 p
!= this->dynobj_list_
.end();
1260 const Dynobj::Needed
& needed((*p
)->needed());
1261 bool found_all
= true;
1262 for (Dynobj::Needed::const_iterator pneeded
= needed
.begin();
1263 pneeded
!= needed
.end();
1266 if (this->sonames_
.find(*pneeded
) == this->sonames_
.end())
1272 (*p
)->set_has_unknown_needed_entries(!found_all
);
1276 // Relocate_info methods.
1278 // Return a string describing the location of a relocation. This is
1279 // only used in error messages.
1281 template<int size
, bool big_endian
>
1283 Relocate_info
<size
, big_endian
>::location(size_t, off_t offset
) const
1285 // See if we can get line-number information from debugging sections.
1286 std::string filename
;
1287 std::string file_and_lineno
; // Better than filename-only, if available.
1289 Sized_dwarf_line_info
<size
, big_endian
> line_info(this->object
);
1290 // This will be "" if we failed to parse the debug info for any reason.
1291 file_and_lineno
= line_info
.addr2line(this->data_shndx
, offset
);
1293 std::string
ret(this->object
->name());
1295 Symbol_location_info info
;
1296 if (this->object
->get_symbol_location_info(this->data_shndx
, offset
, &info
))
1298 ret
+= " in function ";
1299 ret
+= info
.enclosing_symbol_name
;
1301 filename
= info
.source_file
;
1304 if (!file_and_lineno
.empty())
1305 ret
+= file_and_lineno
;
1308 if (!filename
.empty())
1311 ret
+= this->object
->section_name(this->data_shndx
);
1313 // Offsets into sections have to be positive.
1314 snprintf(buf
, sizeof(buf
), "+0x%lx", static_cast<long>(offset
));
1321 } // End namespace gold.
1326 using namespace gold
;
1328 // Read an ELF file with the header and return the appropriate
1329 // instance of Object.
1331 template<int size
, bool big_endian
>
1333 make_elf_sized_object(const std::string
& name
, Input_file
* input_file
,
1334 off_t offset
, const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
1336 int et
= ehdr
.get_e_type();
1337 if (et
== elfcpp::ET_REL
)
1339 Sized_relobj
<size
, big_endian
>* obj
=
1340 new Sized_relobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1344 else if (et
== elfcpp::ET_DYN
)
1346 Sized_dynobj
<size
, big_endian
>* obj
=
1347 new Sized_dynobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1353 gold_error(_("%s: unsupported ELF file type %d"),
1359 } // End anonymous namespace.
1364 // Read an ELF file and return the appropriate instance of Object.
1367 make_elf_object(const std::string
& name
, Input_file
* input_file
, off_t offset
,
1368 const unsigned char* p
, section_offset_type bytes
)
1370 if (bytes
< elfcpp::EI_NIDENT
)
1372 gold_error(_("%s: ELF file too short"), name
.c_str());
1376 int v
= p
[elfcpp::EI_VERSION
];
1377 if (v
!= elfcpp::EV_CURRENT
)
1379 if (v
== elfcpp::EV_NONE
)
1380 gold_error(_("%s: invalid ELF version 0"), name
.c_str());
1382 gold_error(_("%s: unsupported ELF version %d"), name
.c_str(), v
);
1386 int c
= p
[elfcpp::EI_CLASS
];
1387 if (c
== elfcpp::ELFCLASSNONE
)
1389 gold_error(_("%s: invalid ELF class 0"), name
.c_str());
1392 else if (c
!= elfcpp::ELFCLASS32
1393 && c
!= elfcpp::ELFCLASS64
)
1395 gold_error(_("%s: unsupported ELF class %d"), name
.c_str(), c
);
1399 int d
= p
[elfcpp::EI_DATA
];
1400 if (d
== elfcpp::ELFDATANONE
)
1402 gold_error(_("%s: invalid ELF data encoding"), name
.c_str());
1405 else if (d
!= elfcpp::ELFDATA2LSB
1406 && d
!= elfcpp::ELFDATA2MSB
)
1408 gold_error(_("%s: unsupported ELF data encoding %d"), name
.c_str(), d
);
1412 bool big_endian
= d
== elfcpp::ELFDATA2MSB
;
1414 if (c
== elfcpp::ELFCLASS32
)
1416 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
1418 gold_error(_("%s: ELF file too short"), name
.c_str());
1423 #ifdef HAVE_TARGET_32_BIG
1424 elfcpp::Ehdr
<32, true> ehdr(p
);
1425 return make_elf_sized_object
<32, true>(name
, input_file
,
1428 gold_error(_("%s: not configured to support "
1429 "32-bit big-endian object"),
1436 #ifdef HAVE_TARGET_32_LITTLE
1437 elfcpp::Ehdr
<32, false> ehdr(p
);
1438 return make_elf_sized_object
<32, false>(name
, input_file
,
1441 gold_error(_("%s: not configured to support "
1442 "32-bit little-endian object"),
1450 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
1452 gold_error(_("%s: ELF file too short"), name
.c_str());
1457 #ifdef HAVE_TARGET_64_BIG
1458 elfcpp::Ehdr
<64, true> ehdr(p
);
1459 return make_elf_sized_object
<64, true>(name
, input_file
,
1462 gold_error(_("%s: not configured to support "
1463 "64-bit big-endian object"),
1470 #ifdef HAVE_TARGET_64_LITTLE
1471 elfcpp::Ehdr
<64, false> ehdr(p
);
1472 return make_elf_sized_object
<64, false>(name
, input_file
,
1475 gold_error(_("%s: not configured to support "
1476 "64-bit little-endian object"),
1484 // Instantiate the templates we need. We could use the configure
1485 // script to restrict this to only the ones for implemented targets.
1487 #ifdef HAVE_TARGET_32_LITTLE
1489 class Sized_relobj
<32, false>;
1492 #ifdef HAVE_TARGET_32_BIG
1494 class Sized_relobj
<32, true>;
1497 #ifdef HAVE_TARGET_64_LITTLE
1499 class Sized_relobj
<64, false>;
1502 #ifdef HAVE_TARGET_64_BIG
1504 class Sized_relobj
<64, true>;
1507 #ifdef HAVE_TARGET_32_LITTLE
1509 struct Relocate_info
<32, false>;
1512 #ifdef HAVE_TARGET_32_BIG
1514 struct Relocate_info
<32, true>;
1517 #ifdef HAVE_TARGET_64_LITTLE
1519 struct Relocate_info
<64, false>;
1522 #ifdef HAVE_TARGET_64_BIG
1524 struct Relocate_info
<64, true>;
1527 } // End namespace gold.