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 "target-select.h"
30 #include "dwarf_reader.h"
42 // Set the target based on fields in the ELF file header.
45 Object::set_target(int machine
, int size
, bool big_endian
, int osabi
,
48 Target
* target
= select_target(machine
, size
, big_endian
, osabi
, abiversion
);
50 gold_fatal(_("%s: unsupported ELF machine number %d"),
51 this->name().c_str(), machine
);
52 this->target_
= target
;
55 // Report an error for this object file. This is used by the
56 // elfcpp::Elf_file interface, and also called by the Object code
60 Object::error(const char* format
, ...) const
63 va_start(args
, format
);
65 if (vasprintf(&buf
, format
, args
) < 0)
68 gold_error(_("%s: %s"), this->name().c_str(), buf
);
72 // Return a view of the contents of a section.
75 Object::section_contents(unsigned int shndx
, off_t
* plen
, bool cache
)
77 Location
loc(this->do_section_contents(shndx
));
78 *plen
= loc
.data_size
;
79 return this->get_view(loc
.file_offset
, loc
.data_size
, cache
);
82 // Read the section data into SD. This is code common to Sized_relobj
83 // and Sized_dynobj, so we put it into Object.
85 template<int size
, bool big_endian
>
87 Object::read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>* elf_file
,
88 Read_symbols_data
* sd
)
90 const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
92 // Read the section headers.
93 const off_t shoff
= elf_file
->shoff();
94 const unsigned int shnum
= this->shnum();
95 sd
->section_headers
= this->get_lasting_view(shoff
, shnum
* shdr_size
, true);
97 // Read the section names.
98 const unsigned char* pshdrs
= sd
->section_headers
->data();
99 const unsigned char* pshdrnames
= pshdrs
+ elf_file
->shstrndx() * shdr_size
;
100 typename
elfcpp::Shdr
<size
, big_endian
> shdrnames(pshdrnames
);
102 if (shdrnames
.get_sh_type() != elfcpp::SHT_STRTAB
)
103 this->error(_("section name section has wrong type: %u"),
104 static_cast<unsigned int>(shdrnames
.get_sh_type()));
106 sd
->section_names_size
= shdrnames
.get_sh_size();
107 sd
->section_names
= this->get_lasting_view(shdrnames
.get_sh_offset(),
108 sd
->section_names_size
, false);
111 // If NAME is the name of a special .gnu.warning section, arrange for
112 // the warning to be issued. SHNDX is the section index. Return
113 // whether it is a warning section.
116 Object::handle_gnu_warning_section(const char* name
, unsigned int shndx
,
117 Symbol_table
* symtab
)
119 const char warn_prefix
[] = ".gnu.warning.";
120 const int warn_prefix_len
= sizeof warn_prefix
- 1;
121 if (strncmp(name
, warn_prefix
, warn_prefix_len
) == 0)
123 symtab
->add_warning(name
+ warn_prefix_len
, this, shndx
);
129 // Class Sized_relobj.
131 template<int size
, bool big_endian
>
132 Sized_relobj
<size
, big_endian
>::Sized_relobj(
133 const std::string
& name
,
134 Input_file
* input_file
,
136 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
137 : Relobj(name
, input_file
, offset
),
138 elf_file_(this, ehdr
),
140 local_symbol_count_(0),
141 output_local_symbol_count_(0),
143 local_symbol_offset_(0),
145 local_got_offsets_(),
150 template<int size
, bool big_endian
>
151 Sized_relobj
<size
, big_endian
>::~Sized_relobj()
155 // Set up an object file based on the file header. This sets up the
156 // target and reads the section information.
158 template<int size
, bool big_endian
>
160 Sized_relobj
<size
, big_endian
>::setup(
161 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
163 this->set_target(ehdr
.get_e_machine(), size
, big_endian
,
164 ehdr
.get_e_ident()[elfcpp::EI_OSABI
],
165 ehdr
.get_e_ident()[elfcpp::EI_ABIVERSION
]);
167 const unsigned int shnum
= this->elf_file_
.shnum();
168 this->set_shnum(shnum
);
171 // Find the SHT_SYMTAB section, given the section headers. The ELF
172 // standard says that maybe in the future there can be more than one
173 // SHT_SYMTAB section. Until somebody figures out how that could
174 // work, we assume there is only one.
176 template<int size
, bool big_endian
>
178 Sized_relobj
<size
, big_endian
>::find_symtab(const unsigned char* pshdrs
)
180 const unsigned int shnum
= this->shnum();
181 this->symtab_shndx_
= 0;
184 // Look through the sections in reverse order, since gas tends
185 // to put the symbol table at the end.
186 const unsigned char* p
= pshdrs
+ shnum
* This::shdr_size
;
187 unsigned int i
= shnum
;
191 p
-= This::shdr_size
;
192 typename
This::Shdr
shdr(p
);
193 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB
)
195 this->symtab_shndx_
= i
;
202 // Return whether SHDR has the right type and flags to be a GNU
203 // .eh_frame section.
205 template<int size
, bool big_endian
>
207 Sized_relobj
<size
, big_endian
>::check_eh_frame_flags(
208 const elfcpp::Shdr
<size
, big_endian
>* shdr
) const
210 return (shdr
->get_sh_size() > 0
211 && shdr
->get_sh_type() == elfcpp::SHT_PROGBITS
212 && shdr
->get_sh_flags() == elfcpp::SHF_ALLOC
);
215 // Return whether there is a GNU .eh_frame section, given the section
216 // headers and the section names.
218 template<int size
, bool big_endian
>
220 Sized_relobj
<size
, big_endian
>::find_eh_frame(const unsigned char* pshdrs
,
222 off_t names_size
) const
224 const unsigned int shnum
= this->shnum();
225 const unsigned char* p
= pshdrs
+ This::shdr_size
;
226 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
228 typename
This::Shdr
shdr(p
);
229 if (this->check_eh_frame_flags(&shdr
))
231 if (shdr
.get_sh_name() >= names_size
)
233 this->error(_("bad section name offset for section %u: %lu"),
234 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
238 const char* name
= names
+ shdr
.get_sh_name();
239 if (strcmp(name
, ".eh_frame") == 0)
246 // Read the sections and symbols from an object file.
248 template<int size
, bool big_endian
>
250 Sized_relobj
<size
, big_endian
>::do_read_symbols(Read_symbols_data
* sd
)
252 this->read_section_data(&this->elf_file_
, sd
);
254 const unsigned char* const pshdrs
= sd
->section_headers
->data();
256 this->find_symtab(pshdrs
);
258 const unsigned char* namesu
= sd
->section_names
->data();
259 const char* names
= reinterpret_cast<const char*>(namesu
);
260 if (this->find_eh_frame(pshdrs
, names
, sd
->section_names_size
))
261 this->has_eh_frame_
= true;
264 sd
->symbols_size
= 0;
265 sd
->external_symbols_offset
= 0;
266 sd
->symbol_names
= NULL
;
267 sd
->symbol_names_size
= 0;
269 if (this->symtab_shndx_
== 0)
271 // No symbol table. Weird but legal.
275 // Get the symbol table section header.
276 typename
This::Shdr
symtabshdr(pshdrs
277 + this->symtab_shndx_
* This::shdr_size
);
278 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
280 // If this object has a .eh_frame section, we need all the symbols.
281 // Otherwise we only need the external symbols. While it would be
282 // simpler to just always read all the symbols, I've seen object
283 // files with well over 2000 local symbols, which for a 64-bit
284 // object file format is over 5 pages that we don't need to read
287 const int sym_size
= This::sym_size
;
288 const unsigned int loccount
= symtabshdr
.get_sh_info();
289 this->local_symbol_count_
= loccount
;
290 off_t locsize
= loccount
* sym_size
;
291 off_t dataoff
= symtabshdr
.get_sh_offset();
292 off_t datasize
= symtabshdr
.get_sh_size();
293 off_t extoff
= dataoff
+ locsize
;
294 off_t extsize
= datasize
- locsize
;
296 off_t readoff
= this->has_eh_frame_
? dataoff
: extoff
;
297 off_t readsize
= this->has_eh_frame_
? datasize
: extsize
;
299 File_view
* fvsymtab
= this->get_lasting_view(readoff
, readsize
, false);
301 // Read the section header for the symbol names.
302 unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
303 if (strtab_shndx
>= this->shnum())
305 this->error(_("invalid symbol table name index: %u"), strtab_shndx
);
308 typename
This::Shdr
strtabshdr(pshdrs
+ strtab_shndx
* This::shdr_size
);
309 if (strtabshdr
.get_sh_type() != elfcpp::SHT_STRTAB
)
311 this->error(_("symbol table name section has wrong type: %u"),
312 static_cast<unsigned int>(strtabshdr
.get_sh_type()));
316 // Read the symbol names.
317 File_view
* fvstrtab
= this->get_lasting_view(strtabshdr
.get_sh_offset(),
318 strtabshdr
.get_sh_size(), true);
320 sd
->symbols
= fvsymtab
;
321 sd
->symbols_size
= readsize
;
322 sd
->external_symbols_offset
= this->has_eh_frame_
? locsize
: 0;
323 sd
->symbol_names
= fvstrtab
;
324 sd
->symbol_names_size
= strtabshdr
.get_sh_size();
327 // Return the section index of symbol SYM. Set *VALUE to its value in
328 // the object file. Note that for a symbol which is not defined in
329 // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
330 // it will not return the final value of the symbol in the link.
332 template<int size
, bool big_endian
>
334 Sized_relobj
<size
, big_endian
>::symbol_section_and_value(unsigned int sym
,
338 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
342 const size_t count
= symbols_size
/ This::sym_size
;
343 gold_assert(sym
< count
);
345 elfcpp::Sym
<size
, big_endian
> elfsym(symbols
+ sym
* This::sym_size
);
346 *value
= elfsym
.get_st_value();
347 // FIXME: Handle SHN_XINDEX.
348 return elfsym
.get_st_shndx();
351 // Return whether to include a section group in the link. LAYOUT is
352 // used to keep track of which section groups we have already seen.
353 // INDEX is the index of the section group and SHDR is the section
354 // header. If we do not want to include this group, we set bits in
355 // OMIT for each section which should be discarded.
357 template<int size
, bool big_endian
>
359 Sized_relobj
<size
, big_endian
>::include_section_group(
362 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
363 std::vector
<bool>* omit
)
365 // Read the section contents.
366 const unsigned char* pcon
= this->get_view(shdr
.get_sh_offset(),
367 shdr
.get_sh_size(), false);
368 const elfcpp::Elf_Word
* pword
=
369 reinterpret_cast<const elfcpp::Elf_Word
*>(pcon
);
371 // The first word contains flags. We only care about COMDAT section
372 // groups. Other section groups are always included in the link
373 // just like ordinary sections.
374 elfcpp::Elf_Word flags
= elfcpp::Swap
<32, big_endian
>::readval(pword
);
375 if ((flags
& elfcpp::GRP_COMDAT
) == 0)
378 // Look up the group signature, which is the name of a symbol. This
379 // is a lot of effort to go to to read a string. Why didn't they
380 // just use the name of the SHT_GROUP section as the group
383 // Get the appropriate symbol table header (this will normally be
384 // the single SHT_SYMTAB section, but in principle it need not be).
385 const unsigned int link
= shdr
.get_sh_link();
386 typename
This::Shdr
symshdr(this, this->elf_file_
.section_header(link
));
388 // Read the symbol table entry.
389 if (shdr
.get_sh_info() >= symshdr
.get_sh_size() / This::sym_size
)
391 this->error(_("section group %u info %u out of range"),
392 index
, shdr
.get_sh_info());
395 off_t symoff
= symshdr
.get_sh_offset() + shdr
.get_sh_info() * This::sym_size
;
396 const unsigned char* psym
= this->get_view(symoff
, This::sym_size
, true);
397 elfcpp::Sym
<size
, big_endian
> sym(psym
);
399 // Read the symbol table names.
401 const unsigned char* psymnamesu
;
402 psymnamesu
= this->section_contents(symshdr
.get_sh_link(), &symnamelen
,
404 const char* psymnames
= reinterpret_cast<const char*>(psymnamesu
);
406 // Get the section group signature.
407 if (sym
.get_st_name() >= symnamelen
)
409 this->error(_("symbol %u name offset %u out of range"),
410 shdr
.get_sh_info(), sym
.get_st_name());
414 const char* signature
= psymnames
+ sym
.get_st_name();
416 // It seems that some versions of gas will create a section group
417 // associated with a section symbol, and then fail to give a name to
418 // the section symbol. In such a case, use the name of the section.
421 if (signature
[0] == '\0' && sym
.get_st_type() == elfcpp::STT_SECTION
)
423 secname
= this->section_name(sym
.get_st_shndx());
424 signature
= secname
.c_str();
427 // Record this section group, and see whether we've already seen one
428 // with the same signature.
429 if (layout
->add_comdat(signature
, true))
432 // This is a duplicate. We want to discard the sections in this
434 size_t count
= shdr
.get_sh_size() / sizeof(elfcpp::Elf_Word
);
435 for (size_t i
= 1; i
< count
; ++i
)
437 elfcpp::Elf_Word secnum
=
438 elfcpp::Swap
<32, big_endian
>::readval(pword
+ i
);
439 if (secnum
>= this->shnum())
441 this->error(_("section %u in section group %u out of range"),
445 (*omit
)[secnum
] = true;
451 // Whether to include a linkonce section in the link. NAME is the
452 // name of the section and SHDR is the section header.
454 // Linkonce sections are a GNU extension implemented in the original
455 // GNU linker before section groups were defined. The semantics are
456 // that we only include one linkonce section with a given name. The
457 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
458 // where T is the type of section and SYMNAME is the name of a symbol.
459 // In an attempt to make linkonce sections interact well with section
460 // groups, we try to identify SYMNAME and use it like a section group
461 // signature. We want to block section groups with that signature,
462 // but not other linkonce sections with that signature. We also use
463 // the full name of the linkonce section as a normal section group
466 template<int size
, bool big_endian
>
468 Sized_relobj
<size
, big_endian
>::include_linkonce_section(
471 const elfcpp::Shdr
<size
, big_endian
>&)
473 // In general the symbol name we want will be the string following
474 // the last '.'. However, we have to handle the case of
475 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
476 // some versions of gcc. So we use a heuristic: if the name starts
477 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
478 // we look for the last '.'. We can't always simply skip
479 // ".gnu.linkonce.X", because we have to deal with cases like
480 // ".gnu.linkonce.d.rel.ro.local".
481 const char* const linkonce_t
= ".gnu.linkonce.t.";
483 if (strncmp(name
, linkonce_t
, strlen(linkonce_t
)) == 0)
484 symname
= name
+ strlen(linkonce_t
);
486 symname
= strrchr(name
, '.') + 1;
487 bool include1
= layout
->add_comdat(symname
, false);
488 bool include2
= layout
->add_comdat(name
, true);
489 return include1
&& include2
;
492 // Lay out the input sections. We walk through the sections and check
493 // whether they should be included in the link. If they should, we
494 // pass them to the Layout object, which will return an output section
497 template<int size
, bool big_endian
>
499 Sized_relobj
<size
, big_endian
>::do_layout(Symbol_table
* symtab
,
501 Read_symbols_data
* sd
)
503 const unsigned int shnum
= this->shnum();
507 // Get the section headers.
508 const unsigned char* pshdrs
= sd
->section_headers
->data();
510 // Get the section names.
511 const unsigned char* pnamesu
= sd
->section_names
->data();
512 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
514 // For each section, record the index of the reloc section if any.
515 // Use 0 to mean that there is no reloc section, -1U to mean that
516 // there is more than one.
517 std::vector
<unsigned int> reloc_shndx(shnum
, 0);
518 std::vector
<unsigned int> reloc_type(shnum
, elfcpp::SHT_NULL
);
519 // Skip the first, dummy, section.
520 pshdrs
+= This::shdr_size
;
521 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
523 typename
This::Shdr
shdr(pshdrs
);
525 unsigned int sh_type
= shdr
.get_sh_type();
526 if (sh_type
== elfcpp::SHT_REL
|| sh_type
== elfcpp::SHT_RELA
)
528 unsigned int target_shndx
= shdr
.get_sh_info();
529 if (target_shndx
== 0 || target_shndx
>= shnum
)
531 this->error(_("relocation section %u has bad info %u"),
536 if (reloc_shndx
[target_shndx
] != 0)
537 reloc_shndx
[target_shndx
] = -1U;
540 reloc_shndx
[target_shndx
] = i
;
541 reloc_type
[target_shndx
] = sh_type
;
546 std::vector
<Map_to_output
>& map_sections(this->map_to_output());
547 map_sections
.resize(shnum
);
549 // Whether we've seen a .note.GNU-stack section.
550 bool seen_gnu_stack
= false;
551 // The flags of a .note.GNU-stack section.
552 uint64_t gnu_stack_flags
= 0;
554 // Keep track of which sections to omit.
555 std::vector
<bool> omit(shnum
, false);
557 // Keep track of .eh_frame sections.
558 std::vector
<unsigned int> eh_frame_sections
;
560 // Skip the first, dummy, section.
561 pshdrs
= sd
->section_headers
->data() + This::shdr_size
;
562 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
564 typename
This::Shdr
shdr(pshdrs
);
566 if (shdr
.get_sh_name() >= sd
->section_names_size
)
568 this->error(_("bad section name offset for section %u: %lu"),
569 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
573 const char* name
= pnames
+ shdr
.get_sh_name();
575 if (this->handle_gnu_warning_section(name
, i
, symtab
))
577 if (!parameters
->output_is_object())
581 // The .note.GNU-stack section is special. It gives the
582 // protection flags that this object file requires for the stack
584 if (strcmp(name
, ".note.GNU-stack") == 0)
586 seen_gnu_stack
= true;
587 gnu_stack_flags
|= shdr
.get_sh_flags();
591 bool discard
= omit
[i
];
594 if (shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
596 if (!this->include_section_group(layout
, i
, shdr
, &omit
))
599 else if ((shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) == 0
600 && Layout::is_linkonce(name
))
602 if (!this->include_linkonce_section(layout
, name
, shdr
))
609 // Do not include this section in the link.
610 map_sections
[i
].output_section
= NULL
;
614 // The .eh_frame section is special. It holds exception frame
615 // information that we need to read in order to generate the
616 // exception frame header. We process these after all the other
617 // sections so that the exception frame reader can reliably
618 // determine which sections are being discarded, and discard the
619 // corresponding information.
620 if (!parameters
->output_is_object()
621 && strcmp(name
, ".eh_frame") == 0
622 && this->check_eh_frame_flags(&shdr
))
624 eh_frame_sections
.push_back(i
);
629 Output_section
* os
= layout
->layout(this, i
, name
, shdr
,
630 reloc_shndx
[i
], reloc_type
[i
],
633 map_sections
[i
].output_section
= os
;
634 map_sections
[i
].offset
= offset
;
636 // If this section requires special handling, and if there are
637 // relocs that apply to it, then we must do the special handling
638 // before we apply the relocs.
639 if (offset
== -1 && reloc_shndx
[i
] != 0)
640 this->set_relocs_must_follow_section_writes();
643 layout
->layout_gnu_stack(seen_gnu_stack
, gnu_stack_flags
);
645 // Handle the .eh_frame sections at the end.
646 for (std::vector
<unsigned int>::const_iterator p
= eh_frame_sections
.begin();
647 p
!= eh_frame_sections
.end();
650 gold_assert(this->has_eh_frame_
);
651 gold_assert(sd
->external_symbols_offset
!= 0);
654 const unsigned char *pshdr
;
655 pshdr
= sd
->section_headers
->data() + i
* This::shdr_size
;
656 typename
This::Shdr
shdr(pshdr
);
659 Output_section
* os
= layout
->layout_eh_frame(this,
662 sd
->symbol_names
->data(),
663 sd
->symbol_names_size
,
668 map_sections
[i
].output_section
= os
;
669 map_sections
[i
].offset
= offset
;
671 // If this section requires special handling, and if there are
672 // relocs that apply to it, then we must do the special handling
673 // before we apply the relocs.
674 if (offset
== -1 && reloc_shndx
[i
] != 0)
675 this->set_relocs_must_follow_section_writes();
678 delete sd
->section_headers
;
679 sd
->section_headers
= NULL
;
680 delete sd
->section_names
;
681 sd
->section_names
= NULL
;
684 // Add the symbols to the symbol table.
686 template<int size
, bool big_endian
>
688 Sized_relobj
<size
, big_endian
>::do_add_symbols(Symbol_table
* symtab
,
689 Read_symbols_data
* sd
)
691 if (sd
->symbols
== NULL
)
693 gold_assert(sd
->symbol_names
== NULL
);
697 const int sym_size
= This::sym_size
;
698 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
700 if (static_cast<off_t
>(symcount
* sym_size
)
701 != sd
->symbols_size
- sd
->external_symbols_offset
)
703 this->error(_("size of symbols is not multiple of symbol size"));
707 this->symbols_
.resize(symcount
);
709 const char* sym_names
=
710 reinterpret_cast<const char*>(sd
->symbol_names
->data());
711 symtab
->add_from_relobj(this,
712 sd
->symbols
->data() + sd
->external_symbols_offset
,
713 symcount
, sym_names
, sd
->symbol_names_size
,
718 delete sd
->symbol_names
;
719 sd
->symbol_names
= NULL
;
722 // Finalize the local symbols. Here we record the file offset at
723 // which they should be output, we add their names to *POOL, and we
724 // add their values to THIS->LOCAL_VALUES_. Return the symbol index.
725 // This function is always called from the main thread. The actual
726 // output of the local symbols will occur in a separate task.
728 template<int size
, bool big_endian
>
730 Sized_relobj
<size
, big_endian
>::do_finalize_local_symbols(unsigned int index
,
734 gold_assert(this->symtab_shndx_
!= -1U);
735 if (this->symtab_shndx_
== 0)
737 // This object has no symbols. Weird but legal.
741 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
743 this->local_symbol_offset_
= off
;
745 // Read the symbol table section header.
746 const unsigned int symtab_shndx
= this->symtab_shndx_
;
747 typename
This::Shdr
symtabshdr(this,
748 this->elf_file_
.section_header(symtab_shndx
));
749 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
751 // Read the local symbols.
752 const int sym_size
= This::sym_size
;
753 const unsigned int loccount
= this->local_symbol_count_
;
754 gold_assert(loccount
== symtabshdr
.get_sh_info());
755 off_t locsize
= loccount
* sym_size
;
756 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
759 this->local_values_
.resize(loccount
);
761 // Read the symbol names.
762 const unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
764 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
767 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
769 // Loop over the local symbols.
771 const std::vector
<Map_to_output
>& mo(this->map_to_output());
772 unsigned int shnum
= this->shnum();
773 unsigned int count
= 0;
774 // Skip the first, dummy, symbol.
776 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
778 elfcpp::Sym
<size
, big_endian
> sym(psyms
);
780 Symbol_value
<size
>& lv(this->local_values_
[i
]);
782 unsigned int shndx
= sym
.get_st_shndx();
783 lv
.set_input_shndx(shndx
);
785 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
786 lv
.set_is_section_symbol();
788 if (shndx
>= elfcpp::SHN_LORESERVE
)
790 if (shndx
== elfcpp::SHN_ABS
)
791 lv
.set_output_value(sym
.get_st_value());
794 // FIXME: Handle SHN_XINDEX.
795 this->error(_("unknown section index %u for local symbol %u"),
797 lv
.set_output_value(0);
804 this->error(_("local symbol %u section index %u out of range"),
809 Output_section
* os
= mo
[shndx
].output_section
;
813 lv
.set_output_value(0);
814 lv
.set_no_output_symtab_entry();
818 if (mo
[shndx
].offset
== -1)
819 lv
.set_input_value(sym
.get_st_value());
821 lv
.set_output_value(mo
[shndx
].output_section
->address()
823 + sym
.get_st_value());
826 // Decide whether this symbol should go into the output file.
828 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
830 lv
.set_no_output_symtab_entry();
834 if (sym
.get_st_name() >= strtab_size
)
836 this->error(_("local symbol %u section name out of range: %u >= %u"),
837 i
, sym
.get_st_name(),
838 static_cast<unsigned int>(strtab_size
));
839 lv
.set_no_output_symtab_entry();
843 const char* name
= pnames
+ sym
.get_st_name();
844 pool
->add(name
, true, NULL
);
845 lv
.set_output_symtab_index(index
);
850 this->output_local_symbol_count_
= count
;
855 // Return the value of the local symbol symndx.
856 template<int size
, bool big_endian
>
857 typename
elfcpp::Elf_types
<size
>::Elf_Addr
858 Sized_relobj
<size
, big_endian
>::local_symbol_value(unsigned int symndx
) const
860 gold_assert(symndx
< this->local_symbol_count_
);
861 gold_assert(symndx
< this->local_values_
.size());
862 const Symbol_value
<size
>& lv(this->local_values_
[symndx
]);
863 return lv
.value(this, 0);
866 // Return the value of a local symbol defined in input section SHNDX,
867 // with value VALUE, adding addend ADDEND. IS_SECTION_SYMBOL
868 // indicates whether the symbol is a section symbol. This handles
869 // SHF_MERGE sections.
870 template<int size
, bool big_endian
>
871 typename
elfcpp::Elf_types
<size
>::Elf_Addr
872 Sized_relobj
<size
, big_endian
>::local_value(unsigned int shndx
,
874 bool is_section_symbol
,
875 Address addend
) const
877 const std::vector
<Map_to_output
>& mo(this->map_to_output());
878 Output_section
* os
= mo
[shndx
].output_section
;
881 gold_assert(mo
[shndx
].offset
== -1);
883 // Do the mapping required by the output section. If this is not a
884 // section symbol, then we want to map the symbol value, and then
885 // include the addend. If this is a section symbol, then we need to
886 // include the addend to figure out where in the section we are,
887 // before we do the mapping. This will do the right thing provided
888 // the assembler is careful to only convert a relocation in a merged
889 // section to a section symbol if there is a zero addend. If the
890 // assembler does not do this, then in general we can't know what to
891 // do, because we can't distinguish the addend for the instruction
892 // format from the addend for the section offset.
894 if (is_section_symbol
)
895 return os
->output_address(this, shndx
, value
+ addend
);
897 return addend
+ os
->output_address(this, shndx
, value
);
900 // Write out the local symbols.
902 template<int size
, bool big_endian
>
904 Sized_relobj
<size
, big_endian
>::write_local_symbols(Output_file
* of
,
905 const Stringpool
* sympool
)
907 if (parameters
->strip_all())
910 gold_assert(this->symtab_shndx_
!= -1U);
911 if (this->symtab_shndx_
== 0)
913 // This object has no symbols. Weird but legal.
917 // Read the symbol table section header.
918 const unsigned int symtab_shndx
= this->symtab_shndx_
;
919 typename
This::Shdr
symtabshdr(this,
920 this->elf_file_
.section_header(symtab_shndx
));
921 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
922 const unsigned int loccount
= this->local_symbol_count_
;
923 gold_assert(loccount
== symtabshdr
.get_sh_info());
925 // Read the local symbols.
926 const int sym_size
= This::sym_size
;
927 off_t locsize
= loccount
* sym_size
;
928 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
931 // Read the symbol names.
932 const unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
934 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
937 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
939 // Get a view into the output file.
940 off_t output_size
= this->output_local_symbol_count_
* sym_size
;
941 unsigned char* oview
= of
->get_output_view(this->local_symbol_offset_
,
944 const std::vector
<Map_to_output
>& mo(this->map_to_output());
946 gold_assert(this->local_values_
.size() == loccount
);
948 unsigned char* ov
= oview
;
950 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
952 elfcpp::Sym
<size
, big_endian
> isym(psyms
);
954 if (!this->local_values_
[i
].needs_output_symtab_entry())
957 unsigned int st_shndx
= isym
.get_st_shndx();
958 if (st_shndx
< elfcpp::SHN_LORESERVE
)
960 gold_assert(st_shndx
< mo
.size());
961 if (mo
[st_shndx
].output_section
== NULL
)
963 st_shndx
= mo
[st_shndx
].output_section
->out_shndx();
966 elfcpp::Sym_write
<size
, big_endian
> osym(ov
);
968 gold_assert(isym
.get_st_name() < strtab_size
);
969 const char* name
= pnames
+ isym
.get_st_name();
970 osym
.put_st_name(sympool
->get_offset(name
));
971 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
972 osym
.put_st_size(isym
.get_st_size());
973 osym
.put_st_info(isym
.get_st_info());
974 osym
.put_st_other(isym
.get_st_other());
975 osym
.put_st_shndx(st_shndx
);
980 gold_assert(ov
- oview
== output_size
);
982 of
->write_output_view(this->local_symbol_offset_
, output_size
, oview
);
985 // Set *INFO to symbolic information about the offset OFFSET in the
986 // section SHNDX. Return true if we found something, false if we
989 template<int size
, bool big_endian
>
991 Sized_relobj
<size
, big_endian
>::get_symbol_location_info(
994 Symbol_location_info
* info
)
996 if (this->symtab_shndx_
== 0)
1000 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
1004 unsigned int symbol_names_shndx
= this->section_link(this->symtab_shndx_
);
1006 const unsigned char* symbol_names_u
=
1007 this->section_contents(symbol_names_shndx
, &names_size
, false);
1008 const char* symbol_names
= reinterpret_cast<const char*>(symbol_names_u
);
1010 const int sym_size
= This::sym_size
;
1011 const size_t count
= symbols_size
/ sym_size
;
1013 const unsigned char* p
= symbols
;
1014 for (size_t i
= 0; i
< count
; ++i
, p
+= sym_size
)
1016 elfcpp::Sym
<size
, big_endian
> sym(p
);
1018 if (sym
.get_st_type() == elfcpp::STT_FILE
)
1020 if (sym
.get_st_name() >= names_size
)
1021 info
->source_file
= "(invalid)";
1023 info
->source_file
= symbol_names
+ sym
.get_st_name();
1025 else if (sym
.get_st_shndx() == shndx
1026 && static_cast<off_t
>(sym
.get_st_value()) <= offset
1027 && (static_cast<off_t
>(sym
.get_st_value() + sym
.get_st_size())
1030 if (sym
.get_st_name() > names_size
)
1031 info
->enclosing_symbol_name
= "(invalid)";
1033 info
->enclosing_symbol_name
= symbol_names
+ sym
.get_st_name();
1041 // Input_objects methods.
1043 // Add a regular relocatable object to the list. Return false if this
1044 // object should be ignored.
1047 Input_objects::add_object(Object
* obj
)
1049 Target
* target
= obj
->target();
1050 if (this->target_
== NULL
)
1051 this->target_
= target
;
1052 else if (this->target_
!= target
)
1054 gold_error(_("%s: incompatible target"), obj
->name().c_str());
1058 if (!obj
->is_dynamic())
1059 this->relobj_list_
.push_back(static_cast<Relobj
*>(obj
));
1062 // See if this is a duplicate SONAME.
1063 Dynobj
* dynobj
= static_cast<Dynobj
*>(obj
);
1065 std::pair
<Unordered_set
<std::string
>::iterator
, bool> ins
=
1066 this->sonames_
.insert(dynobj
->soname());
1069 // We have already seen a dynamic object with this soname.
1073 this->dynobj_list_
.push_back(dynobj
);
1076 set_parameters_size_and_endianness(target
->get_size(),
1077 target
->is_big_endian());
1082 // Relocate_info methods.
1084 // Return a string describing the location of a relocation. This is
1085 // only used in error messages.
1087 template<int size
, bool big_endian
>
1089 Relocate_info
<size
, big_endian
>::location(size_t, off_t offset
) const
1091 // See if we can get line-number information from debugging sections.
1092 std::string filename
;
1093 std::string file_and_lineno
; // Better than filename-only, if available.
1094 for (unsigned int shndx
= 0; shndx
< this->object
->shnum(); ++shndx
)
1095 if (this->object
->section_name(shndx
) == ".debug_line")
1097 off_t debuglines_size
;
1098 const unsigned char* debuglines
= this->object
->section_contents(
1099 shndx
, &debuglines_size
, false);
1102 Dwarf_line_info
<size
, big_endian
> line_info(debuglines
,
1104 line_info
.read_line_mappings();
1105 file_and_lineno
= line_info
.addr2line(this->data_shndx
, offset
);
1110 std::string
ret(this->object
->name());
1112 Symbol_location_info info
;
1113 if (this->object
->get_symbol_location_info(this->data_shndx
, offset
, &info
))
1115 ret
+= " in function ";
1116 // We could demangle this name before printing, but we don't
1117 // bother because gcc runs linker output through a demangle
1118 // filter itself. The only advantage to demangling here is if
1119 // someone might call ld directly, rather than via gcc. If we
1120 // did want to demangle, cplus_demangle() is in libiberty.
1121 ret
+= info
.enclosing_symbol_name
;
1123 filename
= info
.source_file
;
1126 if (!file_and_lineno
.empty())
1127 ret
+= file_and_lineno
;
1130 if (!filename
.empty())
1133 ret
+= this->object
->section_name(this->data_shndx
);
1135 // Offsets into sections have to be positive.
1136 snprintf(buf
, sizeof(buf
), "+0x%lx", static_cast<long>(offset
));
1143 } // End namespace gold.
1148 using namespace gold
;
1150 // Read an ELF file with the header and return the appropriate
1151 // instance of Object.
1153 template<int size
, bool big_endian
>
1155 make_elf_sized_object(const std::string
& name
, Input_file
* input_file
,
1156 off_t offset
, const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
1158 int et
= ehdr
.get_e_type();
1159 if (et
== elfcpp::ET_REL
)
1161 Sized_relobj
<size
, big_endian
>* obj
=
1162 new Sized_relobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1166 else if (et
== elfcpp::ET_DYN
)
1168 Sized_dynobj
<size
, big_endian
>* obj
=
1169 new Sized_dynobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1175 gold_error(_("%s: unsupported ELF file type %d"),
1181 } // End anonymous namespace.
1186 // Read an ELF file and return the appropriate instance of Object.
1189 make_elf_object(const std::string
& name
, Input_file
* input_file
, off_t offset
,
1190 const unsigned char* p
, off_t bytes
)
1192 if (bytes
< elfcpp::EI_NIDENT
)
1194 gold_error(_("%s: ELF file too short"), name
.c_str());
1198 int v
= p
[elfcpp::EI_VERSION
];
1199 if (v
!= elfcpp::EV_CURRENT
)
1201 if (v
== elfcpp::EV_NONE
)
1202 gold_error(_("%s: invalid ELF version 0"), name
.c_str());
1204 gold_error(_("%s: unsupported ELF version %d"), name
.c_str(), v
);
1208 int c
= p
[elfcpp::EI_CLASS
];
1209 if (c
== elfcpp::ELFCLASSNONE
)
1211 gold_error(_("%s: invalid ELF class 0"), name
.c_str());
1214 else if (c
!= elfcpp::ELFCLASS32
1215 && c
!= elfcpp::ELFCLASS64
)
1217 gold_error(_("%s: unsupported ELF class %d"), name
.c_str(), c
);
1221 int d
= p
[elfcpp::EI_DATA
];
1222 if (d
== elfcpp::ELFDATANONE
)
1224 gold_error(_("%s: invalid ELF data encoding"), name
.c_str());
1227 else if (d
!= elfcpp::ELFDATA2LSB
1228 && d
!= elfcpp::ELFDATA2MSB
)
1230 gold_error(_("%s: unsupported ELF data encoding %d"), name
.c_str(), d
);
1234 bool big_endian
= d
== elfcpp::ELFDATA2MSB
;
1236 if (c
== elfcpp::ELFCLASS32
)
1238 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
1240 gold_error(_("%s: ELF file too short"), name
.c_str());
1245 #ifdef HAVE_TARGET_32_BIG
1246 elfcpp::Ehdr
<32, true> ehdr(p
);
1247 return make_elf_sized_object
<32, true>(name
, input_file
,
1250 gold_error(_("%s: not configured to support "
1251 "32-bit big-endian object"),
1258 #ifdef HAVE_TARGET_32_LITTLE
1259 elfcpp::Ehdr
<32, false> ehdr(p
);
1260 return make_elf_sized_object
<32, false>(name
, input_file
,
1263 gold_error(_("%s: not configured to support "
1264 "32-bit little-endian object"),
1272 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
1274 gold_error(_("%s: ELF file too short"), name
.c_str());
1279 #ifdef HAVE_TARGET_64_BIG
1280 elfcpp::Ehdr
<64, true> ehdr(p
);
1281 return make_elf_sized_object
<64, true>(name
, input_file
,
1284 gold_error(_("%s: not configured to support "
1285 "64-bit big-endian object"),
1292 #ifdef HAVE_TARGET_64_LITTLE
1293 elfcpp::Ehdr
<64, false> ehdr(p
);
1294 return make_elf_sized_object
<64, false>(name
, input_file
,
1297 gold_error(_("%s: not configured to support "
1298 "64-bit little-endian object"),
1306 // Instantiate the templates we need. We could use the configure
1307 // script to restrict this to only the ones for implemented targets.
1309 #ifdef HAVE_TARGET_32_LITTLE
1311 class Sized_relobj
<32, false>;
1314 #ifdef HAVE_TARGET_32_BIG
1316 class Sized_relobj
<32, true>;
1319 #ifdef HAVE_TARGET_64_LITTLE
1321 class Sized_relobj
<64, false>;
1324 #ifdef HAVE_TARGET_64_BIG
1326 class Sized_relobj
<64, true>;
1329 #ifdef HAVE_TARGET_32_LITTLE
1331 struct Relocate_info
<32, false>;
1334 #ifdef HAVE_TARGET_32_BIG
1336 struct Relocate_info
<32, true>;
1339 #ifdef HAVE_TARGET_64_LITTLE
1341 struct Relocate_info
<64, false>;
1344 #ifdef HAVE_TARGET_64_BIG
1346 struct Relocate_info
<64, true>;
1349 } // End namespace gold.