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"
43 // Set the target based on fields in the ELF file header.
46 Object::set_target(int machine
, int size
, bool big_endian
, int osabi
,
49 Target
* target
= select_target(machine
, size
, big_endian
, osabi
, abiversion
);
51 gold_fatal(_("%s: unsupported ELF machine number %d"),
52 this->name().c_str(), machine
);
53 this->target_
= target
;
56 // Report an error for this object file. This is used by the
57 // elfcpp::Elf_file interface, and also called by the Object code
61 Object::error(const char* format
, ...) const
64 va_start(args
, format
);
66 if (vasprintf(&buf
, format
, args
) < 0)
69 gold_error(_("%s: %s"), this->name().c_str(), buf
);
73 // Return a view of the contents of a section.
76 Object::section_contents(unsigned int shndx
, off_t
* plen
, bool cache
)
78 Location
loc(this->do_section_contents(shndx
));
79 *plen
= loc
.data_size
;
80 return this->get_view(loc
.file_offset
, loc
.data_size
, cache
);
83 // Read the section data into SD. This is code common to Sized_relobj
84 // and Sized_dynobj, so we put it into Object.
86 template<int size
, bool big_endian
>
88 Object::read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>* elf_file
,
89 Read_symbols_data
* sd
)
91 const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
93 // Read the section headers.
94 const off_t shoff
= elf_file
->shoff();
95 const unsigned int shnum
= this->shnum();
96 sd
->section_headers
= this->get_lasting_view(shoff
, shnum
* shdr_size
, true);
98 // Read the section names.
99 const unsigned char* pshdrs
= sd
->section_headers
->data();
100 const unsigned char* pshdrnames
= pshdrs
+ elf_file
->shstrndx() * shdr_size
;
101 typename
elfcpp::Shdr
<size
, big_endian
> shdrnames(pshdrnames
);
103 if (shdrnames
.get_sh_type() != elfcpp::SHT_STRTAB
)
104 this->error(_("section name section has wrong type: %u"),
105 static_cast<unsigned int>(shdrnames
.get_sh_type()));
107 sd
->section_names_size
= shdrnames
.get_sh_size();
108 sd
->section_names
= this->get_lasting_view(shdrnames
.get_sh_offset(),
109 sd
->section_names_size
, false);
112 // If NAME is the name of a special .gnu.warning section, arrange for
113 // the warning to be issued. SHNDX is the section index. Return
114 // whether it is a warning section.
117 Object::handle_gnu_warning_section(const char* name
, unsigned int shndx
,
118 Symbol_table
* symtab
)
120 const char warn_prefix
[] = ".gnu.warning.";
121 const int warn_prefix_len
= sizeof warn_prefix
- 1;
122 if (strncmp(name
, warn_prefix
, warn_prefix_len
) == 0)
124 symtab
->add_warning(name
+ warn_prefix_len
, this, shndx
);
130 // Class Sized_relobj.
132 template<int size
, bool big_endian
>
133 Sized_relobj
<size
, big_endian
>::Sized_relobj(
134 const std::string
& name
,
135 Input_file
* input_file
,
137 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
138 : Relobj(name
, input_file
, offset
),
139 elf_file_(this, ehdr
),
141 local_symbol_count_(0),
142 output_local_symbol_count_(0),
144 local_symbol_offset_(0),
146 local_got_offsets_(),
151 template<int size
, bool big_endian
>
152 Sized_relobj
<size
, big_endian
>::~Sized_relobj()
156 // Set up an object file based on the file header. This sets up the
157 // target and reads the section information.
159 template<int size
, bool big_endian
>
161 Sized_relobj
<size
, big_endian
>::setup(
162 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
164 this->set_target(ehdr
.get_e_machine(), size
, big_endian
,
165 ehdr
.get_e_ident()[elfcpp::EI_OSABI
],
166 ehdr
.get_e_ident()[elfcpp::EI_ABIVERSION
]);
168 const unsigned int shnum
= this->elf_file_
.shnum();
169 this->set_shnum(shnum
);
172 // Find the SHT_SYMTAB section, given the section headers. The ELF
173 // standard says that maybe in the future there can be more than one
174 // SHT_SYMTAB section. Until somebody figures out how that could
175 // work, we assume there is only one.
177 template<int size
, bool big_endian
>
179 Sized_relobj
<size
, big_endian
>::find_symtab(const unsigned char* pshdrs
)
181 const unsigned int shnum
= this->shnum();
182 this->symtab_shndx_
= 0;
185 // Look through the sections in reverse order, since gas tends
186 // to put the symbol table at the end.
187 const unsigned char* p
= pshdrs
+ shnum
* This::shdr_size
;
188 unsigned int i
= shnum
;
192 p
-= This::shdr_size
;
193 typename
This::Shdr
shdr(p
);
194 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB
)
196 this->symtab_shndx_
= i
;
203 // Return whether SHDR has the right type and flags to be a GNU
204 // .eh_frame section.
206 template<int size
, bool big_endian
>
208 Sized_relobj
<size
, big_endian
>::check_eh_frame_flags(
209 const elfcpp::Shdr
<size
, big_endian
>* shdr
) const
211 return (shdr
->get_sh_size() > 0
212 && shdr
->get_sh_type() == elfcpp::SHT_PROGBITS
213 && shdr
->get_sh_flags() == elfcpp::SHF_ALLOC
);
216 // Return whether there is a GNU .eh_frame section, given the section
217 // headers and the section names.
219 template<int size
, bool big_endian
>
221 Sized_relobj
<size
, big_endian
>::find_eh_frame(const unsigned char* pshdrs
,
223 off_t names_size
) const
225 const unsigned int shnum
= this->shnum();
226 const unsigned char* p
= pshdrs
+ This::shdr_size
;
227 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
229 typename
This::Shdr
shdr(p
);
230 if (this->check_eh_frame_flags(&shdr
))
232 if (shdr
.get_sh_name() >= names_size
)
234 this->error(_("bad section name offset for section %u: %lu"),
235 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
239 const char* name
= names
+ shdr
.get_sh_name();
240 if (strcmp(name
, ".eh_frame") == 0)
247 // Read the sections and symbols from an object file.
249 template<int size
, bool big_endian
>
251 Sized_relobj
<size
, big_endian
>::do_read_symbols(Read_symbols_data
* sd
)
253 this->read_section_data(&this->elf_file_
, sd
);
255 const unsigned char* const pshdrs
= sd
->section_headers
->data();
257 this->find_symtab(pshdrs
);
259 const unsigned char* namesu
= sd
->section_names
->data();
260 const char* names
= reinterpret_cast<const char*>(namesu
);
261 if (this->find_eh_frame(pshdrs
, names
, sd
->section_names_size
))
262 this->has_eh_frame_
= true;
265 sd
->symbols_size
= 0;
266 sd
->external_symbols_offset
= 0;
267 sd
->symbol_names
= NULL
;
268 sd
->symbol_names_size
= 0;
270 if (this->symtab_shndx_
== 0)
272 // No symbol table. Weird but legal.
276 // Get the symbol table section header.
277 typename
This::Shdr
symtabshdr(pshdrs
278 + this->symtab_shndx_
* This::shdr_size
);
279 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
281 // If this object has a .eh_frame section, we need all the symbols.
282 // Otherwise we only need the external symbols. While it would be
283 // simpler to just always read all the symbols, I've seen object
284 // files with well over 2000 local symbols, which for a 64-bit
285 // object file format is over 5 pages that we don't need to read
288 const int sym_size
= This::sym_size
;
289 const unsigned int loccount
= symtabshdr
.get_sh_info();
290 this->local_symbol_count_
= loccount
;
291 off_t locsize
= loccount
* sym_size
;
292 off_t dataoff
= symtabshdr
.get_sh_offset();
293 off_t datasize
= symtabshdr
.get_sh_size();
294 off_t extoff
= dataoff
+ locsize
;
295 off_t extsize
= datasize
- locsize
;
297 off_t readoff
= this->has_eh_frame_
? dataoff
: extoff
;
298 off_t readsize
= this->has_eh_frame_
? datasize
: extsize
;
300 File_view
* fvsymtab
= this->get_lasting_view(readoff
, readsize
, false);
302 // Read the section header for the symbol names.
303 unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
304 if (strtab_shndx
>= this->shnum())
306 this->error(_("invalid symbol table name index: %u"), strtab_shndx
);
309 typename
This::Shdr
strtabshdr(pshdrs
+ strtab_shndx
* This::shdr_size
);
310 if (strtabshdr
.get_sh_type() != elfcpp::SHT_STRTAB
)
312 this->error(_("symbol table name section has wrong type: %u"),
313 static_cast<unsigned int>(strtabshdr
.get_sh_type()));
317 // Read the symbol names.
318 File_view
* fvstrtab
= this->get_lasting_view(strtabshdr
.get_sh_offset(),
319 strtabshdr
.get_sh_size(), true);
321 sd
->symbols
= fvsymtab
;
322 sd
->symbols_size
= readsize
;
323 sd
->external_symbols_offset
= this->has_eh_frame_
? locsize
: 0;
324 sd
->symbol_names
= fvstrtab
;
325 sd
->symbol_names_size
= strtabshdr
.get_sh_size();
328 // Return the section index of symbol SYM. Set *VALUE to its value in
329 // the object file. Note that for a symbol which is not defined in
330 // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
331 // it will not return the final value of the symbol in the link.
333 template<int size
, bool big_endian
>
335 Sized_relobj
<size
, big_endian
>::symbol_section_and_value(unsigned int sym
,
339 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
343 const size_t count
= symbols_size
/ This::sym_size
;
344 gold_assert(sym
< count
);
346 elfcpp::Sym
<size
, big_endian
> elfsym(symbols
+ sym
* This::sym_size
);
347 *value
= elfsym
.get_st_value();
348 // FIXME: Handle SHN_XINDEX.
349 return elfsym
.get_st_shndx();
352 // Return whether to include a section group in the link. LAYOUT is
353 // used to keep track of which section groups we have already seen.
354 // INDEX is the index of the section group and SHDR is the section
355 // header. If we do not want to include this group, we set bits in
356 // OMIT for each section which should be discarded.
358 template<int size
, bool big_endian
>
360 Sized_relobj
<size
, big_endian
>::include_section_group(
363 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
364 std::vector
<bool>* omit
)
366 // Read the section contents.
367 const unsigned char* pcon
= this->get_view(shdr
.get_sh_offset(),
368 shdr
.get_sh_size(), false);
369 const elfcpp::Elf_Word
* pword
=
370 reinterpret_cast<const elfcpp::Elf_Word
*>(pcon
);
372 // The first word contains flags. We only care about COMDAT section
373 // groups. Other section groups are always included in the link
374 // just like ordinary sections.
375 elfcpp::Elf_Word flags
= elfcpp::Swap
<32, big_endian
>::readval(pword
);
376 if ((flags
& elfcpp::GRP_COMDAT
) == 0)
379 // Look up the group signature, which is the name of a symbol. This
380 // is a lot of effort to go to to read a string. Why didn't they
381 // just use the name of the SHT_GROUP section as the group
384 // Get the appropriate symbol table header (this will normally be
385 // the single SHT_SYMTAB section, but in principle it need not be).
386 const unsigned int link
= shdr
.get_sh_link();
387 typename
This::Shdr
symshdr(this, this->elf_file_
.section_header(link
));
389 // Read the symbol table entry.
390 if (shdr
.get_sh_info() >= symshdr
.get_sh_size() / This::sym_size
)
392 this->error(_("section group %u info %u out of range"),
393 index
, shdr
.get_sh_info());
396 off_t symoff
= symshdr
.get_sh_offset() + shdr
.get_sh_info() * This::sym_size
;
397 const unsigned char* psym
= this->get_view(symoff
, This::sym_size
, true);
398 elfcpp::Sym
<size
, big_endian
> sym(psym
);
400 // Read the symbol table names.
402 const unsigned char* psymnamesu
;
403 psymnamesu
= this->section_contents(symshdr
.get_sh_link(), &symnamelen
,
405 const char* psymnames
= reinterpret_cast<const char*>(psymnamesu
);
407 // Get the section group signature.
408 if (sym
.get_st_name() >= symnamelen
)
410 this->error(_("symbol %u name offset %u out of range"),
411 shdr
.get_sh_info(), sym
.get_st_name());
415 const char* signature
= psymnames
+ sym
.get_st_name();
417 // It seems that some versions of gas will create a section group
418 // associated with a section symbol, and then fail to give a name to
419 // the section symbol. In such a case, use the name of the section.
422 if (signature
[0] == '\0' && sym
.get_st_type() == elfcpp::STT_SECTION
)
424 secname
= this->section_name(sym
.get_st_shndx());
425 signature
= secname
.c_str();
428 // Record this section group, and see whether we've already seen one
429 // with the same signature.
430 if (layout
->add_comdat(signature
, true))
433 // This is a duplicate. We want to discard the sections in this
435 size_t count
= shdr
.get_sh_size() / sizeof(elfcpp::Elf_Word
);
436 for (size_t i
= 1; i
< count
; ++i
)
438 elfcpp::Elf_Word secnum
=
439 elfcpp::Swap
<32, big_endian
>::readval(pword
+ i
);
440 if (secnum
>= this->shnum())
442 this->error(_("section %u in section group %u out of range"),
446 (*omit
)[secnum
] = true;
452 // Whether to include a linkonce section in the link. NAME is the
453 // name of the section and SHDR is the section header.
455 // Linkonce sections are a GNU extension implemented in the original
456 // GNU linker before section groups were defined. The semantics are
457 // that we only include one linkonce section with a given name. The
458 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
459 // where T is the type of section and SYMNAME is the name of a symbol.
460 // In an attempt to make linkonce sections interact well with section
461 // groups, we try to identify SYMNAME and use it like a section group
462 // signature. We want to block section groups with that signature,
463 // but not other linkonce sections with that signature. We also use
464 // the full name of the linkonce section as a normal section group
467 template<int size
, bool big_endian
>
469 Sized_relobj
<size
, big_endian
>::include_linkonce_section(
472 const elfcpp::Shdr
<size
, big_endian
>&)
474 // In general the symbol name we want will be the string following
475 // the last '.'. However, we have to handle the case of
476 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
477 // some versions of gcc. So we use a heuristic: if the name starts
478 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
479 // we look for the last '.'. We can't always simply skip
480 // ".gnu.linkonce.X", because we have to deal with cases like
481 // ".gnu.linkonce.d.rel.ro.local".
482 const char* const linkonce_t
= ".gnu.linkonce.t.";
484 if (strncmp(name
, linkonce_t
, strlen(linkonce_t
)) == 0)
485 symname
= name
+ strlen(linkonce_t
);
487 symname
= strrchr(name
, '.') + 1;
488 bool include1
= layout
->add_comdat(symname
, false);
489 bool include2
= layout
->add_comdat(name
, true);
490 return include1
&& include2
;
493 // Lay out the input sections. We walk through the sections and check
494 // whether they should be included in the link. If they should, we
495 // pass them to the Layout object, which will return an output section
498 template<int size
, bool big_endian
>
500 Sized_relobj
<size
, big_endian
>::do_layout(Symbol_table
* symtab
,
502 Read_symbols_data
* sd
)
504 const unsigned int shnum
= this->shnum();
508 // Get the section headers.
509 const unsigned char* pshdrs
= sd
->section_headers
->data();
511 // Get the section names.
512 const unsigned char* pnamesu
= sd
->section_names
->data();
513 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
515 // For each section, record the index of the reloc section if any.
516 // Use 0 to mean that there is no reloc section, -1U to mean that
517 // there is more than one.
518 std::vector
<unsigned int> reloc_shndx(shnum
, 0);
519 std::vector
<unsigned int> reloc_type(shnum
, elfcpp::SHT_NULL
);
520 // Skip the first, dummy, section.
521 pshdrs
+= This::shdr_size
;
522 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
524 typename
This::Shdr
shdr(pshdrs
);
526 unsigned int sh_type
= shdr
.get_sh_type();
527 if (sh_type
== elfcpp::SHT_REL
|| sh_type
== elfcpp::SHT_RELA
)
529 unsigned int target_shndx
= shdr
.get_sh_info();
530 if (target_shndx
== 0 || target_shndx
>= shnum
)
532 this->error(_("relocation section %u has bad info %u"),
537 if (reloc_shndx
[target_shndx
] != 0)
538 reloc_shndx
[target_shndx
] = -1U;
541 reloc_shndx
[target_shndx
] = i
;
542 reloc_type
[target_shndx
] = sh_type
;
547 std::vector
<Map_to_output
>& map_sections(this->map_to_output());
548 map_sections
.resize(shnum
);
550 // Whether we've seen a .note.GNU-stack section.
551 bool seen_gnu_stack
= false;
552 // The flags of a .note.GNU-stack section.
553 uint64_t gnu_stack_flags
= 0;
555 // Keep track of which sections to omit.
556 std::vector
<bool> omit(shnum
, false);
558 // Keep track of .eh_frame sections.
559 std::vector
<unsigned int> eh_frame_sections
;
561 // Skip the first, dummy, section.
562 pshdrs
= sd
->section_headers
->data() + This::shdr_size
;
563 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
565 typename
This::Shdr
shdr(pshdrs
);
567 if (shdr
.get_sh_name() >= sd
->section_names_size
)
569 this->error(_("bad section name offset for section %u: %lu"),
570 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
574 const char* name
= pnames
+ shdr
.get_sh_name();
576 if (this->handle_gnu_warning_section(name
, i
, symtab
))
578 if (!parameters
->output_is_object())
582 // The .note.GNU-stack section is special. It gives the
583 // protection flags that this object file requires for the stack
585 if (strcmp(name
, ".note.GNU-stack") == 0)
587 seen_gnu_stack
= true;
588 gnu_stack_flags
|= shdr
.get_sh_flags();
592 bool discard
= omit
[i
];
595 if (shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
597 if (!this->include_section_group(layout
, i
, shdr
, &omit
))
600 else if ((shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) == 0
601 && Layout::is_linkonce(name
))
603 if (!this->include_linkonce_section(layout
, name
, shdr
))
610 // Do not include this section in the link.
611 map_sections
[i
].output_section
= NULL
;
615 // The .eh_frame section is special. It holds exception frame
616 // information that we need to read in order to generate the
617 // exception frame header. We process these after all the other
618 // sections so that the exception frame reader can reliably
619 // determine which sections are being discarded, and discard the
620 // corresponding information.
621 if (!parameters
->output_is_object()
622 && strcmp(name
, ".eh_frame") == 0
623 && this->check_eh_frame_flags(&shdr
))
625 eh_frame_sections
.push_back(i
);
630 Output_section
* os
= layout
->layout(this, i
, name
, shdr
,
631 reloc_shndx
[i
], reloc_type
[i
],
634 map_sections
[i
].output_section
= os
;
635 map_sections
[i
].offset
= offset
;
637 // If this section requires special handling, and if there are
638 // relocs that apply to it, then we must do the special handling
639 // before we apply the relocs.
640 if (offset
== -1 && reloc_shndx
[i
] != 0)
641 this->set_relocs_must_follow_section_writes();
644 layout
->layout_gnu_stack(seen_gnu_stack
, gnu_stack_flags
);
646 // Handle the .eh_frame sections at the end.
647 for (std::vector
<unsigned int>::const_iterator p
= eh_frame_sections
.begin();
648 p
!= eh_frame_sections
.end();
651 gold_assert(this->has_eh_frame_
);
652 gold_assert(sd
->external_symbols_offset
!= 0);
655 const unsigned char *pshdr
;
656 pshdr
= sd
->section_headers
->data() + i
* This::shdr_size
;
657 typename
This::Shdr
shdr(pshdr
);
660 Output_section
* os
= layout
->layout_eh_frame(this,
663 sd
->symbol_names
->data(),
664 sd
->symbol_names_size
,
669 map_sections
[i
].output_section
= os
;
670 map_sections
[i
].offset
= offset
;
672 // If this section requires special handling, and if there are
673 // relocs that apply to it, then we must do the special handling
674 // before we apply the relocs.
675 if (offset
== -1 && reloc_shndx
[i
] != 0)
676 this->set_relocs_must_follow_section_writes();
679 delete sd
->section_headers
;
680 sd
->section_headers
= NULL
;
681 delete sd
->section_names
;
682 sd
->section_names
= NULL
;
685 // Add the symbols to the symbol table.
687 template<int size
, bool big_endian
>
689 Sized_relobj
<size
, big_endian
>::do_add_symbols(Symbol_table
* symtab
,
690 Read_symbols_data
* sd
)
692 if (sd
->symbols
== NULL
)
694 gold_assert(sd
->symbol_names
== NULL
);
698 const int sym_size
= This::sym_size
;
699 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
701 if (static_cast<off_t
>(symcount
* sym_size
)
702 != sd
->symbols_size
- sd
->external_symbols_offset
)
704 this->error(_("size of symbols is not multiple of symbol size"));
708 this->symbols_
.resize(symcount
);
710 const char* sym_names
=
711 reinterpret_cast<const char*>(sd
->symbol_names
->data());
712 symtab
->add_from_relobj(this,
713 sd
->symbols
->data() + sd
->external_symbols_offset
,
714 symcount
, sym_names
, sd
->symbol_names_size
,
719 delete sd
->symbol_names
;
720 sd
->symbol_names
= NULL
;
723 // Finalize the local symbols. Here we record the file offset at
724 // which they should be output, we add their names to *POOL, and we
725 // add their values to THIS->LOCAL_VALUES_. Return the symbol index.
726 // This function is always called from the main thread. The actual
727 // output of the local symbols will occur in a separate task.
729 template<int size
, bool big_endian
>
731 Sized_relobj
<size
, big_endian
>::do_finalize_local_symbols(unsigned int index
,
735 gold_assert(this->symtab_shndx_
!= -1U);
736 if (this->symtab_shndx_
== 0)
738 // This object has no symbols. Weird but legal.
742 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
744 this->local_symbol_offset_
= off
;
746 // Read the symbol table section header.
747 const unsigned int symtab_shndx
= this->symtab_shndx_
;
748 typename
This::Shdr
symtabshdr(this,
749 this->elf_file_
.section_header(symtab_shndx
));
750 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
752 // Read the local symbols.
753 const int sym_size
= This::sym_size
;
754 const unsigned int loccount
= this->local_symbol_count_
;
755 gold_assert(loccount
== symtabshdr
.get_sh_info());
756 off_t locsize
= loccount
* sym_size
;
757 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
760 this->local_values_
.resize(loccount
);
762 // Read the symbol names.
763 const unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
765 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
768 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
770 // Loop over the local symbols.
772 const std::vector
<Map_to_output
>& mo(this->map_to_output());
773 unsigned int shnum
= this->shnum();
774 unsigned int count
= 0;
775 // Skip the first, dummy, symbol.
777 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
779 elfcpp::Sym
<size
, big_endian
> sym(psyms
);
781 Symbol_value
<size
>& lv(this->local_values_
[i
]);
783 unsigned int shndx
= sym
.get_st_shndx();
784 lv
.set_input_shndx(shndx
);
786 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
787 lv
.set_is_section_symbol();
789 if (shndx
>= elfcpp::SHN_LORESERVE
)
791 if (shndx
== elfcpp::SHN_ABS
)
792 lv
.set_output_value(sym
.get_st_value());
795 // FIXME: Handle SHN_XINDEX.
796 this->error(_("unknown section index %u for local symbol %u"),
798 lv
.set_output_value(0);
805 this->error(_("local symbol %u section index %u out of range"),
810 Output_section
* os
= mo
[shndx
].output_section
;
814 lv
.set_output_value(0);
815 lv
.set_no_output_symtab_entry();
819 if (mo
[shndx
].offset
== -1)
820 lv
.set_input_value(sym
.get_st_value());
822 lv
.set_output_value(mo
[shndx
].output_section
->address()
824 + sym
.get_st_value());
827 // Decide whether this symbol should go into the output file.
829 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
831 lv
.set_no_output_symtab_entry();
835 if (sym
.get_st_name() >= strtab_size
)
837 this->error(_("local symbol %u section name out of range: %u >= %u"),
838 i
, sym
.get_st_name(),
839 static_cast<unsigned int>(strtab_size
));
840 lv
.set_no_output_symtab_entry();
844 const char* name
= pnames
+ sym
.get_st_name();
845 pool
->add(name
, true, NULL
);
846 lv
.set_output_symtab_index(index
);
851 this->output_local_symbol_count_
= count
;
856 // Return the value of the local symbol symndx.
857 template<int size
, bool big_endian
>
858 typename
elfcpp::Elf_types
<size
>::Elf_Addr
859 Sized_relobj
<size
, big_endian
>::local_symbol_value(unsigned int symndx
) const
861 gold_assert(symndx
< this->local_symbol_count_
);
862 gold_assert(symndx
< this->local_values_
.size());
863 const Symbol_value
<size
>& lv(this->local_values_
[symndx
]);
864 return lv
.value(this, 0);
867 // Return the value of a local symbol defined in input section SHNDX,
868 // with value VALUE, adding addend ADDEND. IS_SECTION_SYMBOL
869 // indicates whether the symbol is a section symbol. This handles
870 // SHF_MERGE sections.
871 template<int size
, bool big_endian
>
872 typename
elfcpp::Elf_types
<size
>::Elf_Addr
873 Sized_relobj
<size
, big_endian
>::local_value(unsigned int shndx
,
875 bool is_section_symbol
,
876 Address addend
) const
878 const std::vector
<Map_to_output
>& mo(this->map_to_output());
879 Output_section
* os
= mo
[shndx
].output_section
;
882 gold_assert(mo
[shndx
].offset
== -1);
884 // Do the mapping required by the output section. If this is not a
885 // section symbol, then we want to map the symbol value, and then
886 // include the addend. If this is a section symbol, then we need to
887 // include the addend to figure out where in the section we are,
888 // before we do the mapping. This will do the right thing provided
889 // the assembler is careful to only convert a relocation in a merged
890 // section to a section symbol if there is a zero addend. If the
891 // assembler does not do this, then in general we can't know what to
892 // do, because we can't distinguish the addend for the instruction
893 // format from the addend for the section offset.
895 if (is_section_symbol
)
896 return os
->output_address(this, shndx
, value
+ addend
);
898 return addend
+ os
->output_address(this, shndx
, value
);
901 // Write out the local symbols.
903 template<int size
, bool big_endian
>
905 Sized_relobj
<size
, big_endian
>::write_local_symbols(Output_file
* of
,
906 const Stringpool
* sympool
)
908 if (parameters
->strip_all())
911 gold_assert(this->symtab_shndx_
!= -1U);
912 if (this->symtab_shndx_
== 0)
914 // This object has no symbols. Weird but legal.
918 // Read the symbol table section header.
919 const unsigned int symtab_shndx
= this->symtab_shndx_
;
920 typename
This::Shdr
symtabshdr(this,
921 this->elf_file_
.section_header(symtab_shndx
));
922 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
923 const unsigned int loccount
= this->local_symbol_count_
;
924 gold_assert(loccount
== symtabshdr
.get_sh_info());
926 // Read the local symbols.
927 const int sym_size
= This::sym_size
;
928 off_t locsize
= loccount
* sym_size
;
929 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
932 // Read the symbol names.
933 const unsigned int strtab_shndx
= symtabshdr
.get_sh_link();
935 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
938 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
940 // Get a view into the output file.
941 off_t output_size
= this->output_local_symbol_count_
* sym_size
;
942 unsigned char* oview
= of
->get_output_view(this->local_symbol_offset_
,
945 const std::vector
<Map_to_output
>& mo(this->map_to_output());
947 gold_assert(this->local_values_
.size() == loccount
);
949 unsigned char* ov
= oview
;
951 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
953 elfcpp::Sym
<size
, big_endian
> isym(psyms
);
955 if (!this->local_values_
[i
].needs_output_symtab_entry())
958 unsigned int st_shndx
= isym
.get_st_shndx();
959 if (st_shndx
< elfcpp::SHN_LORESERVE
)
961 gold_assert(st_shndx
< mo
.size());
962 if (mo
[st_shndx
].output_section
== NULL
)
964 st_shndx
= mo
[st_shndx
].output_section
->out_shndx();
967 elfcpp::Sym_write
<size
, big_endian
> osym(ov
);
969 gold_assert(isym
.get_st_name() < strtab_size
);
970 const char* name
= pnames
+ isym
.get_st_name();
971 osym
.put_st_name(sympool
->get_offset(name
));
972 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
973 osym
.put_st_size(isym
.get_st_size());
974 osym
.put_st_info(isym
.get_st_info());
975 osym
.put_st_other(isym
.get_st_other());
976 osym
.put_st_shndx(st_shndx
);
981 gold_assert(ov
- oview
== output_size
);
983 of
->write_output_view(this->local_symbol_offset_
, output_size
, oview
);
986 // Set *INFO to symbolic information about the offset OFFSET in the
987 // section SHNDX. Return true if we found something, false if we
990 template<int size
, bool big_endian
>
992 Sized_relobj
<size
, big_endian
>::get_symbol_location_info(
995 Symbol_location_info
* info
)
997 if (this->symtab_shndx_
== 0)
1001 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
1005 unsigned int symbol_names_shndx
= this->section_link(this->symtab_shndx_
);
1007 const unsigned char* symbol_names_u
=
1008 this->section_contents(symbol_names_shndx
, &names_size
, false);
1009 const char* symbol_names
= reinterpret_cast<const char*>(symbol_names_u
);
1011 const int sym_size
= This::sym_size
;
1012 const size_t count
= symbols_size
/ sym_size
;
1014 const unsigned char* p
= symbols
;
1015 for (size_t i
= 0; i
< count
; ++i
, p
+= sym_size
)
1017 elfcpp::Sym
<size
, big_endian
> sym(p
);
1019 if (sym
.get_st_type() == elfcpp::STT_FILE
)
1021 if (sym
.get_st_name() >= names_size
)
1022 info
->source_file
= "(invalid)";
1024 info
->source_file
= symbol_names
+ sym
.get_st_name();
1026 else if (sym
.get_st_shndx() == shndx
1027 && static_cast<off_t
>(sym
.get_st_value()) <= offset
1028 && (static_cast<off_t
>(sym
.get_st_value() + sym
.get_st_size())
1031 if (sym
.get_st_name() > names_size
)
1032 info
->enclosing_symbol_name
= "(invalid)";
1034 info
->enclosing_symbol_name
= symbol_names
+ sym
.get_st_name();
1042 // Input_objects methods.
1044 // Add a regular relocatable object to the list. Return false if this
1045 // object should be ignored.
1048 Input_objects::add_object(Object
* obj
)
1050 Target
* target
= obj
->target();
1051 if (this->target_
== NULL
)
1052 this->target_
= target
;
1053 else if (this->target_
!= target
)
1055 gold_error(_("%s: incompatible target"), obj
->name().c_str());
1059 if (!obj
->is_dynamic())
1060 this->relobj_list_
.push_back(static_cast<Relobj
*>(obj
));
1063 // See if this is a duplicate SONAME.
1064 Dynobj
* dynobj
= static_cast<Dynobj
*>(obj
);
1066 std::pair
<Unordered_set
<std::string
>::iterator
, bool> ins
=
1067 this->sonames_
.insert(dynobj
->soname());
1070 // We have already seen a dynamic object with this soname.
1074 this->dynobj_list_
.push_back(dynobj
);
1077 set_parameters_size_and_endianness(target
->get_size(),
1078 target
->is_big_endian());
1083 // Relocate_info methods.
1085 // Return a string describing the location of a relocation. This is
1086 // only used in error messages.
1088 template<int size
, bool big_endian
>
1090 Relocate_info
<size
, big_endian
>::location(size_t, off_t offset
) const
1092 // See if we can get line-number information from debugging sections.
1093 std::string filename
;
1094 std::string file_and_lineno
; // Better than filename-only, if available.
1096 Dwarf_line_info
<size
, big_endian
> line_info(this->object
);
1097 // This will be "" if we failed to parse the debug info for any reason.
1098 file_and_lineno
= line_info
.addr2line(this->data_shndx
, offset
);
1100 std::string
ret(this->object
->name());
1102 Symbol_location_info info
;
1103 if (this->object
->get_symbol_location_info(this->data_shndx
, offset
, &info
))
1105 ret
+= " in function ";
1106 // We could demangle this name before printing, but we don't
1107 // bother because gcc runs linker output through a demangle
1108 // filter itself. The only advantage to demangling here is if
1109 // someone might call ld directly, rather than via gcc. If we
1110 // did want to demangle, cplus_demangle() is in libiberty.
1111 ret
+= info
.enclosing_symbol_name
;
1113 filename
= info
.source_file
;
1116 if (!file_and_lineno
.empty())
1117 ret
+= file_and_lineno
;
1120 if (!filename
.empty())
1123 ret
+= this->object
->section_name(this->data_shndx
);
1125 // Offsets into sections have to be positive.
1126 snprintf(buf
, sizeof(buf
), "+0x%lx", static_cast<long>(offset
));
1133 } // End namespace gold.
1138 using namespace gold
;
1140 // Read an ELF file with the header and return the appropriate
1141 // instance of Object.
1143 template<int size
, bool big_endian
>
1145 make_elf_sized_object(const std::string
& name
, Input_file
* input_file
,
1146 off_t offset
, const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
1148 int et
= ehdr
.get_e_type();
1149 if (et
== elfcpp::ET_REL
)
1151 Sized_relobj
<size
, big_endian
>* obj
=
1152 new Sized_relobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1156 else if (et
== elfcpp::ET_DYN
)
1158 Sized_dynobj
<size
, big_endian
>* obj
=
1159 new Sized_dynobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
1165 gold_error(_("%s: unsupported ELF file type %d"),
1171 } // End anonymous namespace.
1176 // Read an ELF file and return the appropriate instance of Object.
1179 make_elf_object(const std::string
& name
, Input_file
* input_file
, off_t offset
,
1180 const unsigned char* p
, off_t bytes
)
1182 if (bytes
< elfcpp::EI_NIDENT
)
1184 gold_error(_("%s: ELF file too short"), name
.c_str());
1188 int v
= p
[elfcpp::EI_VERSION
];
1189 if (v
!= elfcpp::EV_CURRENT
)
1191 if (v
== elfcpp::EV_NONE
)
1192 gold_error(_("%s: invalid ELF version 0"), name
.c_str());
1194 gold_error(_("%s: unsupported ELF version %d"), name
.c_str(), v
);
1198 int c
= p
[elfcpp::EI_CLASS
];
1199 if (c
== elfcpp::ELFCLASSNONE
)
1201 gold_error(_("%s: invalid ELF class 0"), name
.c_str());
1204 else if (c
!= elfcpp::ELFCLASS32
1205 && c
!= elfcpp::ELFCLASS64
)
1207 gold_error(_("%s: unsupported ELF class %d"), name
.c_str(), c
);
1211 int d
= p
[elfcpp::EI_DATA
];
1212 if (d
== elfcpp::ELFDATANONE
)
1214 gold_error(_("%s: invalid ELF data encoding"), name
.c_str());
1217 else if (d
!= elfcpp::ELFDATA2LSB
1218 && d
!= elfcpp::ELFDATA2MSB
)
1220 gold_error(_("%s: unsupported ELF data encoding %d"), name
.c_str(), d
);
1224 bool big_endian
= d
== elfcpp::ELFDATA2MSB
;
1226 if (c
== elfcpp::ELFCLASS32
)
1228 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
1230 gold_error(_("%s: ELF file too short"), name
.c_str());
1235 #ifdef HAVE_TARGET_32_BIG
1236 elfcpp::Ehdr
<32, true> ehdr(p
);
1237 return make_elf_sized_object
<32, true>(name
, input_file
,
1240 gold_error(_("%s: not configured to support "
1241 "32-bit big-endian object"),
1248 #ifdef HAVE_TARGET_32_LITTLE
1249 elfcpp::Ehdr
<32, false> ehdr(p
);
1250 return make_elf_sized_object
<32, false>(name
, input_file
,
1253 gold_error(_("%s: not configured to support "
1254 "32-bit little-endian object"),
1262 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
1264 gold_error(_("%s: ELF file too short"), name
.c_str());
1269 #ifdef HAVE_TARGET_64_BIG
1270 elfcpp::Ehdr
<64, true> ehdr(p
);
1271 return make_elf_sized_object
<64, true>(name
, input_file
,
1274 gold_error(_("%s: not configured to support "
1275 "64-bit big-endian object"),
1282 #ifdef HAVE_TARGET_64_LITTLE
1283 elfcpp::Ehdr
<64, false> ehdr(p
);
1284 return make_elf_sized_object
<64, false>(name
, input_file
,
1287 gold_error(_("%s: not configured to support "
1288 "64-bit little-endian object"),
1296 // Instantiate the templates we need. We could use the configure
1297 // script to restrict this to only the ones for implemented targets.
1299 #ifdef HAVE_TARGET_32_LITTLE
1301 class Sized_relobj
<32, false>;
1304 #ifdef HAVE_TARGET_32_BIG
1306 class Sized_relobj
<32, true>;
1309 #ifdef HAVE_TARGET_64_LITTLE
1311 class Sized_relobj
<64, false>;
1314 #ifdef HAVE_TARGET_64_BIG
1316 class Sized_relobj
<64, true>;
1319 #ifdef HAVE_TARGET_32_LITTLE
1321 struct Relocate_info
<32, false>;
1324 #ifdef HAVE_TARGET_32_BIG
1326 struct Relocate_info
<32, true>;
1329 #ifdef HAVE_TARGET_64_LITTLE
1331 struct Relocate_info
<64, false>;
1334 #ifdef HAVE_TARGET_64_BIG
1336 struct Relocate_info
<64, true>;
1339 } // End namespace gold.