1 // object.cc -- support for an object file for linking in gold
3 // Copyright 2006, 2007, 2008, 2009 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"
32 #include "target-select.h"
33 #include "dwarf_reader.h"
48 // Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX
49 // section and read it in. SYMTAB_SHNDX is the index of the symbol
50 // table we care about.
52 template<int size
, bool big_endian
>
54 Xindex::initialize_symtab_xindex(Object
* object
, unsigned int symtab_shndx
)
56 if (!this->symtab_xindex_
.empty())
59 gold_assert(symtab_shndx
!= 0);
61 // Look through the sections in reverse order, on the theory that it
62 // is more likely to be near the end than the beginning.
63 unsigned int i
= object
->shnum();
67 if (object
->section_type(i
) == elfcpp::SHT_SYMTAB_SHNDX
68 && this->adjust_shndx(object
->section_link(i
)) == symtab_shndx
)
70 this->read_symtab_xindex
<size
, big_endian
>(object
, i
, NULL
);
75 object
->error(_("missing SHT_SYMTAB_SHNDX section"));
78 // Read in the symtab_xindex_ array, given the section index of the
79 // SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the
82 template<int size
, bool big_endian
>
84 Xindex::read_symtab_xindex(Object
* object
, unsigned int xindex_shndx
,
85 const unsigned char* pshdrs
)
87 section_size_type bytecount
;
88 const unsigned char* contents
;
90 contents
= object
->section_contents(xindex_shndx
, &bytecount
, false);
93 const unsigned char* p
= (pshdrs
95 * elfcpp::Elf_sizes
<size
>::shdr_size
));
96 typename
elfcpp::Shdr
<size
, big_endian
> shdr(p
);
97 bytecount
= convert_to_section_size_type(shdr
.get_sh_size());
98 contents
= object
->get_view(shdr
.get_sh_offset(), bytecount
, true, false);
101 gold_assert(this->symtab_xindex_
.empty());
102 this->symtab_xindex_
.reserve(bytecount
/ 4);
103 for (section_size_type i
= 0; i
< bytecount
; i
+= 4)
105 unsigned int shndx
= elfcpp::Swap
<32, big_endian
>::readval(contents
+ i
);
106 // We preadjust the section indexes we save.
107 this->symtab_xindex_
.push_back(this->adjust_shndx(shndx
));
111 // Symbol symndx has a section of SHN_XINDEX; return the real section
115 Xindex::sym_xindex_to_shndx(Object
* object
, unsigned int symndx
)
117 if (symndx
>= this->symtab_xindex_
.size())
119 object
->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
121 return elfcpp::SHN_UNDEF
;
123 unsigned int shndx
= this->symtab_xindex_
[symndx
];
124 if (shndx
< elfcpp::SHN_LORESERVE
|| shndx
>= object
->shnum())
126 object
->error(_("extended index for symbol %u out of range: %u"),
128 return elfcpp::SHN_UNDEF
;
135 // Set the target based on fields in the ELF file header.
138 Object::set_target(int machine
, int size
, bool big_endian
, int osabi
,
141 Target
* target
= select_target(machine
, size
, big_endian
, osabi
, abiversion
);
143 gold_fatal(_("%s: unsupported ELF machine number %d"),
144 this->name().c_str(), machine
);
145 this->target_
= target
;
148 // Report an error for this object file. This is used by the
149 // elfcpp::Elf_file interface, and also called by the Object code
153 Object::error(const char* format
, ...) const
156 va_start(args
, format
);
158 if (vasprintf(&buf
, format
, args
) < 0)
161 gold_error(_("%s: %s"), this->name().c_str(), buf
);
165 // Return a view of the contents of a section.
168 Object::section_contents(unsigned int shndx
, section_size_type
* plen
,
171 Location
loc(this->do_section_contents(shndx
));
172 *plen
= convert_to_section_size_type(loc
.data_size
);
173 return this->get_view(loc
.file_offset
, *plen
, true, cache
);
176 // Read the section data into SD. This is code common to Sized_relobj
177 // and Sized_dynobj, so we put it into Object.
179 template<int size
, bool big_endian
>
181 Object::read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>* elf_file
,
182 Read_symbols_data
* sd
)
184 const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
186 // Read the section headers.
187 const off_t shoff
= elf_file
->shoff();
188 const unsigned int shnum
= this->shnum();
189 sd
->section_headers
= this->get_lasting_view(shoff
, shnum
* shdr_size
,
192 // Read the section names.
193 const unsigned char* pshdrs
= sd
->section_headers
->data();
194 const unsigned char* pshdrnames
= pshdrs
+ elf_file
->shstrndx() * shdr_size
;
195 typename
elfcpp::Shdr
<size
, big_endian
> shdrnames(pshdrnames
);
197 if (shdrnames
.get_sh_type() != elfcpp::SHT_STRTAB
)
198 this->error(_("section name section has wrong type: %u"),
199 static_cast<unsigned int>(shdrnames
.get_sh_type()));
201 sd
->section_names_size
=
202 convert_to_section_size_type(shdrnames
.get_sh_size());
203 sd
->section_names
= this->get_lasting_view(shdrnames
.get_sh_offset(),
204 sd
->section_names_size
, false,
208 // If NAME is the name of a special .gnu.warning section, arrange for
209 // the warning to be issued. SHNDX is the section index. Return
210 // whether it is a warning section.
213 Object::handle_gnu_warning_section(const char* name
, unsigned int shndx
,
214 Symbol_table
* symtab
)
216 const char warn_prefix
[] = ".gnu.warning.";
217 const int warn_prefix_len
= sizeof warn_prefix
- 1;
218 if (strncmp(name
, warn_prefix
, warn_prefix_len
) == 0)
220 // Read the section contents to get the warning text. It would
221 // be nicer if we only did this if we have to actually issue a
222 // warning. Unfortunately, warnings are issued as we relocate
223 // sections. That means that we can not lock the object then,
224 // as we might try to issue the same warning multiple times
226 section_size_type len
;
227 const unsigned char* contents
= this->section_contents(shndx
, &len
,
229 std::string
warning(reinterpret_cast<const char*>(contents
), len
);
230 symtab
->add_warning(name
+ warn_prefix_len
, this, warning
);
238 // To copy the symbols data read from the file to a local data structure.
239 // This function is called from do_layout only while doing garbage
243 Relobj::copy_symbols_data(Symbols_data
* gc_sd
, Read_symbols_data
* sd
,
244 unsigned int section_header_size
)
246 gc_sd
->section_headers_data
=
247 new unsigned char[(section_header_size
)];
248 memcpy(gc_sd
->section_headers_data
, sd
->section_headers
->data(),
249 section_header_size
);
250 gc_sd
->section_names_data
=
251 new unsigned char[sd
->section_names_size
];
252 memcpy(gc_sd
->section_names_data
, sd
->section_names
->data(),
253 sd
->section_names_size
);
254 gc_sd
->section_names_size
= sd
->section_names_size
;
255 if (sd
->symbols
!= NULL
)
257 gc_sd
->symbols_data
=
258 new unsigned char[sd
->symbols_size
];
259 memcpy(gc_sd
->symbols_data
, sd
->symbols
->data(),
264 gc_sd
->symbols_data
= NULL
;
266 gc_sd
->symbols_size
= sd
->symbols_size
;
267 gc_sd
->external_symbols_offset
= sd
->external_symbols_offset
;
268 if (sd
->symbol_names
!= NULL
)
270 gc_sd
->symbol_names_data
=
271 new unsigned char[sd
->symbol_names_size
];
272 memcpy(gc_sd
->symbol_names_data
, sd
->symbol_names
->data(),
273 sd
->symbol_names_size
);
277 gc_sd
->symbol_names_data
= NULL
;
279 gc_sd
->symbol_names_size
= sd
->symbol_names_size
;
282 // This function determines if a particular section name must be included
283 // in the link. This is used during garbage collection to determine the
284 // roots of the worklist.
287 Relobj::is_section_name_included(const char* name
)
289 if (is_prefix_of(".ctors", name
)
290 || is_prefix_of(".dtors", name
)
291 || is_prefix_of(".note", name
)
292 || is_prefix_of(".init", name
)
293 || is_prefix_of(".fini", name
)
294 || is_prefix_of(".gcc_except_table", name
)
295 || is_prefix_of(".jcr", name
)
296 || is_prefix_of(".preinit_array", name
)
297 || (is_prefix_of(".text", name
)
298 && strstr(name
, "personality"))
299 || (is_prefix_of(".data", name
)
300 && strstr(name
, "personality"))
301 || (is_prefix_of(".gnu.linkonce.d", name
) &&
302 strstr(name
, "personality")))
309 // Class Sized_relobj.
311 template<int size
, bool big_endian
>
312 Sized_relobj
<size
, big_endian
>::Sized_relobj(
313 const std::string
& name
,
314 Input_file
* input_file
,
316 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
317 : Relobj(name
, input_file
, offset
),
318 elf_file_(this, ehdr
),
320 local_symbol_count_(0),
321 output_local_symbol_count_(0),
322 output_local_dynsym_count_(0),
325 local_symbol_offset_(0),
326 local_dynsym_offset_(0),
328 local_got_offsets_(),
329 kept_comdat_sections_(),
335 template<int size
, bool big_endian
>
336 Sized_relobj
<size
, big_endian
>::~Sized_relobj()
340 // Set up an object file based on the file header. This sets up the
341 // target and reads the section information.
343 template<int size
, bool big_endian
>
345 Sized_relobj
<size
, big_endian
>::setup(
346 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
348 this->set_target(ehdr
.get_e_machine(), size
, big_endian
,
349 ehdr
.get_e_ident()[elfcpp::EI_OSABI
],
350 ehdr
.get_e_ident()[elfcpp::EI_ABIVERSION
]);
352 const unsigned int shnum
= this->elf_file_
.shnum();
353 this->set_shnum(shnum
);
356 // Find the SHT_SYMTAB section, given the section headers. The ELF
357 // standard says that maybe in the future there can be more than one
358 // SHT_SYMTAB section. Until somebody figures out how that could
359 // work, we assume there is only one.
361 template<int size
, bool big_endian
>
363 Sized_relobj
<size
, big_endian
>::find_symtab(const unsigned char* pshdrs
)
365 const unsigned int shnum
= this->shnum();
366 this->symtab_shndx_
= 0;
369 // Look through the sections in reverse order, since gas tends
370 // to put the symbol table at the end.
371 const unsigned char* p
= pshdrs
+ shnum
* This::shdr_size
;
372 unsigned int i
= shnum
;
373 unsigned int xindex_shndx
= 0;
374 unsigned int xindex_link
= 0;
378 p
-= This::shdr_size
;
379 typename
This::Shdr
shdr(p
);
380 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB
)
382 this->symtab_shndx_
= i
;
383 if (xindex_shndx
> 0 && xindex_link
== i
)
386 new Xindex(this->elf_file_
.large_shndx_offset());
387 xindex
->read_symtab_xindex
<size
, big_endian
>(this,
390 this->set_xindex(xindex
);
395 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
396 // one. This will work if it follows the SHT_SYMTAB
398 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX
)
401 xindex_link
= this->adjust_shndx(shdr
.get_sh_link());
407 // Return the Xindex structure to use for object with lots of
410 template<int size
, bool big_endian
>
412 Sized_relobj
<size
, big_endian
>::do_initialize_xindex()
414 gold_assert(this->symtab_shndx_
!= -1U);
415 Xindex
* xindex
= new Xindex(this->elf_file_
.large_shndx_offset());
416 xindex
->initialize_symtab_xindex
<size
, big_endian
>(this, this->symtab_shndx_
);
420 // Return whether SHDR has the right type and flags to be a GNU
421 // .eh_frame section.
423 template<int size
, bool big_endian
>
425 Sized_relobj
<size
, big_endian
>::check_eh_frame_flags(
426 const elfcpp::Shdr
<size
, big_endian
>* shdr
) const
428 return (shdr
->get_sh_type() == elfcpp::SHT_PROGBITS
429 && (shdr
->get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
432 // Return whether there is a GNU .eh_frame section, given the section
433 // headers and the section names.
435 template<int size
, bool big_endian
>
437 Sized_relobj
<size
, big_endian
>::find_eh_frame(
438 const unsigned char* pshdrs
,
440 section_size_type names_size
) const
442 const unsigned int shnum
= this->shnum();
443 const unsigned char* p
= pshdrs
+ This::shdr_size
;
444 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
446 typename
This::Shdr
shdr(p
);
447 if (this->check_eh_frame_flags(&shdr
))
449 if (shdr
.get_sh_name() >= names_size
)
451 this->error(_("bad section name offset for section %u: %lu"),
452 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
456 const char* name
= names
+ shdr
.get_sh_name();
457 if (strcmp(name
, ".eh_frame") == 0)
464 // Read the sections and symbols from an object file.
466 template<int size
, bool big_endian
>
468 Sized_relobj
<size
, big_endian
>::do_read_symbols(Read_symbols_data
* sd
)
470 this->read_section_data(&this->elf_file_
, sd
);
472 const unsigned char* const pshdrs
= sd
->section_headers
->data();
474 this->find_symtab(pshdrs
);
476 const unsigned char* namesu
= sd
->section_names
->data();
477 const char* names
= reinterpret_cast<const char*>(namesu
);
478 if (memmem(names
, sd
->section_names_size
, ".eh_frame", 10) != NULL
)
480 if (this->find_eh_frame(pshdrs
, names
, sd
->section_names_size
))
481 this->has_eh_frame_
= true;
485 sd
->symbols_size
= 0;
486 sd
->external_symbols_offset
= 0;
487 sd
->symbol_names
= NULL
;
488 sd
->symbol_names_size
= 0;
490 if (this->symtab_shndx_
== 0)
492 // No symbol table. Weird but legal.
496 // Get the symbol table section header.
497 typename
This::Shdr
symtabshdr(pshdrs
498 + this->symtab_shndx_
* This::shdr_size
);
499 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
501 // If this object has a .eh_frame section, we need all the symbols.
502 // Otherwise we only need the external symbols. While it would be
503 // simpler to just always read all the symbols, I've seen object
504 // files with well over 2000 local symbols, which for a 64-bit
505 // object file format is over 5 pages that we don't need to read
508 const int sym_size
= This::sym_size
;
509 const unsigned int loccount
= symtabshdr
.get_sh_info();
510 this->local_symbol_count_
= loccount
;
511 this->local_values_
.resize(loccount
);
512 section_offset_type locsize
= loccount
* sym_size
;
513 off_t dataoff
= symtabshdr
.get_sh_offset();
514 section_size_type datasize
=
515 convert_to_section_size_type(symtabshdr
.get_sh_size());
516 off_t extoff
= dataoff
+ locsize
;
517 section_size_type extsize
= datasize
- locsize
;
519 off_t readoff
= this->has_eh_frame_
? dataoff
: extoff
;
520 section_size_type readsize
= this->has_eh_frame_
? datasize
: extsize
;
524 // No external symbols. Also weird but also legal.
528 File_view
* fvsymtab
= this->get_lasting_view(readoff
, readsize
, true, false);
530 // Read the section header for the symbol names.
531 unsigned int strtab_shndx
= this->adjust_shndx(symtabshdr
.get_sh_link());
532 if (strtab_shndx
>= this->shnum())
534 this->error(_("invalid symbol table name index: %u"), strtab_shndx
);
537 typename
This::Shdr
strtabshdr(pshdrs
+ strtab_shndx
* This::shdr_size
);
538 if (strtabshdr
.get_sh_type() != elfcpp::SHT_STRTAB
)
540 this->error(_("symbol table name section has wrong type: %u"),
541 static_cast<unsigned int>(strtabshdr
.get_sh_type()));
545 // Read the symbol names.
546 File_view
* fvstrtab
= this->get_lasting_view(strtabshdr
.get_sh_offset(),
547 strtabshdr
.get_sh_size(),
550 sd
->symbols
= fvsymtab
;
551 sd
->symbols_size
= readsize
;
552 sd
->external_symbols_offset
= this->has_eh_frame_
? locsize
: 0;
553 sd
->symbol_names
= fvstrtab
;
554 sd
->symbol_names_size
=
555 convert_to_section_size_type(strtabshdr
.get_sh_size());
558 // Return the section index of symbol SYM. Set *VALUE to its value in
559 // the object file. Set *IS_ORDINARY if this is an ordinary section
560 // index. not a special cod between SHN_LORESERVE and SHN_HIRESERVE.
561 // Note that for a symbol which is not defined in this object file,
562 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
563 // the final value of the symbol in the link.
565 template<int size
, bool big_endian
>
567 Sized_relobj
<size
, big_endian
>::symbol_section_and_value(unsigned int sym
,
571 section_size_type symbols_size
;
572 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
576 const size_t count
= symbols_size
/ This::sym_size
;
577 gold_assert(sym
< count
);
579 elfcpp::Sym
<size
, big_endian
> elfsym(symbols
+ sym
* This::sym_size
);
580 *value
= elfsym
.get_st_value();
582 return this->adjust_sym_shndx(sym
, elfsym
.get_st_shndx(), is_ordinary
);
585 // Return whether to include a section group in the link. LAYOUT is
586 // used to keep track of which section groups we have already seen.
587 // INDEX is the index of the section group and SHDR is the section
588 // header. If we do not want to include this group, we set bits in
589 // OMIT for each section which should be discarded.
591 template<int size
, bool big_endian
>
593 Sized_relobj
<size
, big_endian
>::include_section_group(
594 Symbol_table
* symtab
,
598 const unsigned char* shdrs
,
599 const char* section_names
,
600 section_size_type section_names_size
,
601 std::vector
<bool>* omit
)
603 // Read the section contents.
604 typename
This::Shdr
shdr(shdrs
+ index
* This::shdr_size
);
605 const unsigned char* pcon
= this->get_view(shdr
.get_sh_offset(),
606 shdr
.get_sh_size(), true, false);
607 const elfcpp::Elf_Word
* pword
=
608 reinterpret_cast<const elfcpp::Elf_Word
*>(pcon
);
610 // The first word contains flags. We only care about COMDAT section
611 // groups. Other section groups are always included in the link
612 // just like ordinary sections.
613 elfcpp::Elf_Word flags
= elfcpp::Swap
<32, big_endian
>::readval(pword
);
615 // Look up the group signature, which is the name of a symbol. This
616 // is a lot of effort to go to to read a string. Why didn't they
617 // just have the group signature point into the string table, rather
618 // than indirect through a symbol?
620 // Get the appropriate symbol table header (this will normally be
621 // the single SHT_SYMTAB section, but in principle it need not be).
622 const unsigned int link
= this->adjust_shndx(shdr
.get_sh_link());
623 typename
This::Shdr
symshdr(this, this->elf_file_
.section_header(link
));
625 // Read the symbol table entry.
626 unsigned int symndx
= shdr
.get_sh_info();
627 if (symndx
>= symshdr
.get_sh_size() / This::sym_size
)
629 this->error(_("section group %u info %u out of range"),
633 off_t symoff
= symshdr
.get_sh_offset() + symndx
* This::sym_size
;
634 const unsigned char* psym
= this->get_view(symoff
, This::sym_size
, true,
636 elfcpp::Sym
<size
, big_endian
> sym(psym
);
638 // Read the symbol table names.
639 section_size_type symnamelen
;
640 const unsigned char* psymnamesu
;
641 psymnamesu
= this->section_contents(this->adjust_shndx(symshdr
.get_sh_link()),
643 const char* psymnames
= reinterpret_cast<const char*>(psymnamesu
);
645 // Get the section group signature.
646 if (sym
.get_st_name() >= symnamelen
)
648 this->error(_("symbol %u name offset %u out of range"),
649 symndx
, sym
.get_st_name());
653 std::string
signature(psymnames
+ sym
.get_st_name());
655 // It seems that some versions of gas will create a section group
656 // associated with a section symbol, and then fail to give a name to
657 // the section symbol. In such a case, use the name of the section.
658 if (signature
[0] == '\0' && sym
.get_st_type() == elfcpp::STT_SECTION
)
661 unsigned int sym_shndx
= this->adjust_sym_shndx(symndx
,
664 if (!is_ordinary
|| sym_shndx
>= this->shnum())
666 this->error(_("symbol %u invalid section index %u"),
670 typename
This::Shdr
member_shdr(shdrs
+ sym_shndx
* This::shdr_size
);
671 if (member_shdr
.get_sh_name() < section_names_size
)
672 signature
= section_names
+ member_shdr
.get_sh_name();
675 // Record this section group in the layout, and see whether we've already
676 // seen one with the same signature.
677 bool include_group
= ((flags
& elfcpp::GRP_COMDAT
) == 0
678 || layout
->add_comdat(this, index
, signature
, true));
680 Sized_relobj
<size
, big_endian
>* kept_object
= NULL
;
681 Comdat_group
* kept_group
= NULL
;
685 // This group is being discarded. Find the object and group
686 // that was kept in its place.
687 unsigned int kept_group_index
= 0;
688 Relobj
* kept_relobj
= layout
->find_kept_object(signature
,
690 kept_object
= static_cast<Sized_relobj
<size
, big_endian
>*>(kept_relobj
);
691 if (kept_object
!= NULL
)
692 kept_group
= kept_object
->find_comdat_group(kept_group_index
);
694 else if (flags
& elfcpp::GRP_COMDAT
)
696 // This group is being kept. Create the table to map section names
697 // to section indexes and add it to the table of groups.
698 kept_group
= new Comdat_group();
699 this->add_comdat_group(index
, kept_group
);
702 size_t count
= shdr
.get_sh_size() / sizeof(elfcpp::Elf_Word
);
704 std::vector
<unsigned int> shndxes
;
705 bool relocate_group
= include_group
&& parameters
->options().relocatable();
707 shndxes
.reserve(count
- 1);
709 for (size_t i
= 1; i
< count
; ++i
)
711 elfcpp::Elf_Word secnum
=
712 this->adjust_shndx(elfcpp::Swap
<32, big_endian
>::readval(pword
+ i
));
715 shndxes
.push_back(secnum
);
717 if (secnum
>= this->shnum())
719 this->error(_("section %u in section group %u out of range"),
724 // Check for an earlier section number, since we're going to get
725 // it wrong--we may have already decided to include the section.
727 this->error(_("invalid section group %u refers to earlier section %u"),
730 // Get the name of the member section.
731 typename
This::Shdr
member_shdr(shdrs
+ secnum
* This::shdr_size
);
732 if (member_shdr
.get_sh_name() >= section_names_size
)
734 // This is an error, but it will be diagnosed eventually
735 // in do_layout, so we don't need to do anything here but
739 std::string
mname(section_names
+ member_shdr
.get_sh_name());
743 (*omit
)[secnum
] = true;
744 if (kept_group
!= NULL
)
746 // Find the corresponding kept section, and store that info
747 // in the discarded section table.
748 Comdat_group::const_iterator p
= kept_group
->find(mname
);
749 if (p
!= kept_group
->end())
751 Kept_comdat_section
* kept
=
752 new Kept_comdat_section(kept_object
, p
->second
);
753 this->set_kept_comdat_section(secnum
, kept
);
757 else if (flags
& elfcpp::GRP_COMDAT
)
759 // Add the section to the kept group table.
760 gold_assert(kept_group
!= NULL
);
761 kept_group
->insert(std::make_pair(mname
, secnum
));
766 layout
->layout_group(symtab
, this, index
, name
, signature
.c_str(),
767 shdr
, flags
, &shndxes
);
769 return include_group
;
772 // Whether to include a linkonce section in the link. NAME is the
773 // name of the section and SHDR is the section header.
775 // Linkonce sections are a GNU extension implemented in the original
776 // GNU linker before section groups were defined. The semantics are
777 // that we only include one linkonce section with a given name. The
778 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
779 // where T is the type of section and SYMNAME is the name of a symbol.
780 // In an attempt to make linkonce sections interact well with section
781 // groups, we try to identify SYMNAME and use it like a section group
782 // signature. We want to block section groups with that signature,
783 // but not other linkonce sections with that signature. We also use
784 // the full name of the linkonce section as a normal section group
787 template<int size
, bool big_endian
>
789 Sized_relobj
<size
, big_endian
>::include_linkonce_section(
793 const elfcpp::Shdr
<size
, big_endian
>&)
795 // In general the symbol name we want will be the string following
796 // the last '.'. However, we have to handle the case of
797 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
798 // some versions of gcc. So we use a heuristic: if the name starts
799 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
800 // we look for the last '.'. We can't always simply skip
801 // ".gnu.linkonce.X", because we have to deal with cases like
802 // ".gnu.linkonce.d.rel.ro.local".
803 const char* const linkonce_t
= ".gnu.linkonce.t.";
805 if (strncmp(name
, linkonce_t
, strlen(linkonce_t
)) == 0)
806 symname
= name
+ strlen(linkonce_t
);
808 symname
= strrchr(name
, '.') + 1;
809 std::string
sig1(symname
);
810 std::string
sig2(name
);
811 bool include1
= layout
->add_comdat(this, index
, sig1
, false);
812 bool include2
= layout
->add_comdat(this, index
, sig2
, true);
816 // The section is being discarded on the basis of its section
817 // name (i.e., the kept section was also a linkonce section).
818 // In this case, the section index stored with the layout object
819 // is the linkonce section that was kept.
820 unsigned int kept_group_index
= 0;
821 Relobj
* kept_relobj
= layout
->find_kept_object(sig2
, &kept_group_index
);
822 if (kept_relobj
!= NULL
)
824 Sized_relobj
<size
, big_endian
>* kept_object
825 = static_cast<Sized_relobj
<size
, big_endian
>*>(kept_relobj
);
826 Kept_comdat_section
* kept
=
827 new Kept_comdat_section(kept_object
, kept_group_index
);
828 this->set_kept_comdat_section(index
, kept
);
833 // The section is being discarded on the basis of its symbol
834 // name. This means that the corresponding kept section was
835 // part of a comdat group, and it will be difficult to identify
836 // the specific section within that group that corresponds to
837 // this linkonce section. We'll handle the simple case where
838 // the group has only one member section. Otherwise, it's not
840 unsigned int kept_group_index
= 0;
841 Relobj
* kept_relobj
= layout
->find_kept_object(sig1
, &kept_group_index
);
842 if (kept_relobj
!= NULL
)
844 Sized_relobj
<size
, big_endian
>* kept_object
=
845 static_cast<Sized_relobj
<size
, big_endian
>*>(kept_relobj
);
846 Comdat_group
* kept_group
=
847 kept_object
->find_comdat_group(kept_group_index
);
848 if (kept_group
!= NULL
&& kept_group
->size() == 1)
850 Comdat_group::const_iterator p
= kept_group
->begin();
851 gold_assert(p
!= kept_group
->end());
852 Kept_comdat_section
* kept
=
853 new Kept_comdat_section(kept_object
, p
->second
);
854 this->set_kept_comdat_section(index
, kept
);
859 return include1
&& include2
;
862 // Layout an input section.
864 template<int size
, bool big_endian
>
866 Sized_relobj
<size
, big_endian
>::layout_section(Layout
* layout
,
869 typename
This::Shdr
& shdr
,
870 unsigned int reloc_shndx
,
871 unsigned int reloc_type
)
874 Output_section
* os
= layout
->layout(this, shndx
, name
, shdr
,
875 reloc_shndx
, reloc_type
, &offset
);
877 this->output_sections()[shndx
] = os
;
879 this->section_offsets_
[shndx
] = invalid_address
;
881 this->section_offsets_
[shndx
] = convert_types
<Address
, off_t
>(offset
);
883 // If this section requires special handling, and if there are
884 // relocs that apply to it, then we must do the special handling
885 // before we apply the relocs.
886 if (offset
== -1 && reloc_shndx
!= 0)
887 this->set_relocs_must_follow_section_writes();
890 // Lay out the input sections. We walk through the sections and check
891 // whether they should be included in the link. If they should, we
892 // pass them to the Layout object, which will return an output section
894 // During garbage collection (gc-sections), this function is called
895 // twice. When it is called the first time, it is for setting up some
896 // sections as roots to a work-list and to do comdat processing. Actual
897 // layout happens the second time around after all the relevant sections
898 // have been determined. The first time, is_worklist_ready is false.
899 // It is then set to true after the worklist is processed and the relevant
900 // sections are determined. Then, this function is called again to
901 // layout the sections.
903 template<int size
, bool big_endian
>
905 Sized_relobj
<size
, big_endian
>::do_layout(Symbol_table
* symtab
,
907 Read_symbols_data
* sd
)
909 const unsigned int shnum
= this->shnum();
910 bool is_gc_pass_one
= (parameters
->options().gc_sections()
911 && !symtab
->gc()->is_worklist_ready());
912 bool is_gc_pass_two
= (parameters
->options().gc_sections()
913 && symtab
->gc()->is_worklist_ready());
916 Symbols_data
* gc_sd
= NULL
;
919 // During garbage collection save the symbols data to use it when
920 // re-entering this function.
921 gc_sd
= new Symbols_data
;
922 this->copy_symbols_data(gc_sd
, sd
, This::shdr_size
* shnum
);
923 this->set_symbols_data(gc_sd
);
925 else if (is_gc_pass_two
)
927 gc_sd
= this->get_symbols_data();
930 const unsigned char* section_headers_data
= NULL
;
931 section_size_type section_names_size
;
932 const unsigned char* symbols_data
= NULL
;
933 section_size_type symbols_size
;
934 section_offset_type external_symbols_offset
;
935 const unsigned char* symbol_names_data
= NULL
;
936 section_size_type symbol_names_size
;
938 if (parameters
->options().gc_sections())
940 section_headers_data
= gc_sd
->section_headers_data
;
941 section_names_size
= gc_sd
->section_names_size
;
942 symbols_data
= gc_sd
->symbols_data
;
943 symbols_size
= gc_sd
->symbols_size
;
944 external_symbols_offset
= gc_sd
->external_symbols_offset
;
945 symbol_names_data
= gc_sd
->symbol_names_data
;
946 symbol_names_size
= gc_sd
->symbol_names_size
;
950 section_headers_data
= sd
->section_headers
->data();
951 section_names_size
= sd
->section_names_size
;
952 if (sd
->symbols
!= NULL
)
953 symbols_data
= sd
->symbols
->data();
954 symbols_size
= sd
->symbols_size
;
955 external_symbols_offset
= sd
->external_symbols_offset
;
956 if (sd
->symbol_names
!= NULL
)
957 symbol_names_data
= sd
->symbol_names
->data();
958 symbol_names_size
= sd
->symbol_names_size
;
961 // Get the section headers.
962 const unsigned char* shdrs
= section_headers_data
;
963 const unsigned char* pshdrs
;
965 // Get the section names.
966 const unsigned char* pnamesu
= parameters
->options().gc_sections() ?
967 gc_sd
->section_names_data
:
968 sd
->section_names
->data();
969 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
971 // If any input files have been claimed by plugins, we need to defer
972 // actual layout until the replacement files have arrived.
973 const bool should_defer_layout
=
974 (parameters
->options().has_plugins()
975 && parameters
->options().plugins()->should_defer_layout());
976 unsigned int num_sections_to_defer
= 0;
978 // For each section, record the index of the reloc section if any.
979 // Use 0 to mean that there is no reloc section, -1U to mean that
980 // there is more than one.
981 std::vector
<unsigned int> reloc_shndx(shnum
, 0);
982 std::vector
<unsigned int> reloc_type(shnum
, elfcpp::SHT_NULL
);
983 // Skip the first, dummy, section.
984 pshdrs
= shdrs
+ This::shdr_size
;
985 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
987 typename
This::Shdr
shdr(pshdrs
);
989 // Count the number of sections whose layout will be deferred.
990 if (should_defer_layout
&& (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
))
991 ++num_sections_to_defer
;
993 unsigned int sh_type
= shdr
.get_sh_type();
994 if (sh_type
== elfcpp::SHT_REL
|| sh_type
== elfcpp::SHT_RELA
)
996 unsigned int target_shndx
= this->adjust_shndx(shdr
.get_sh_info());
997 if (target_shndx
== 0 || target_shndx
>= shnum
)
999 this->error(_("relocation section %u has bad info %u"),
1004 if (reloc_shndx
[target_shndx
] != 0)
1005 reloc_shndx
[target_shndx
] = -1U;
1008 reloc_shndx
[target_shndx
] = i
;
1009 reloc_type
[target_shndx
] = sh_type
;
1014 Output_sections
& out_sections(this->output_sections());
1015 std::vector
<Address
>& out_section_offsets(this->section_offsets_
);
1017 if (!is_gc_pass_two
)
1019 out_sections
.resize(shnum
);
1020 out_section_offsets
.resize(shnum
);
1023 // If we are only linking for symbols, then there is nothing else to
1025 if (this->input_file()->just_symbols())
1027 if (!is_gc_pass_two
)
1029 delete sd
->section_headers
;
1030 sd
->section_headers
= NULL
;
1031 delete sd
->section_names
;
1032 sd
->section_names
= NULL
;
1037 if (num_sections_to_defer
> 0)
1039 parameters
->options().plugins()->add_deferred_layout_object(this);
1040 this->deferred_layout_
.reserve(num_sections_to_defer
);
1043 // Whether we've seen a .note.GNU-stack section.
1044 bool seen_gnu_stack
= false;
1045 // The flags of a .note.GNU-stack section.
1046 uint64_t gnu_stack_flags
= 0;
1048 // Keep track of which sections to omit.
1049 std::vector
<bool> omit(shnum
, false);
1051 // Keep track of reloc sections when emitting relocations.
1052 const bool relocatable
= parameters
->options().relocatable();
1053 const bool emit_relocs
= (relocatable
1054 || parameters
->options().emit_relocs());
1055 std::vector
<unsigned int> reloc_sections
;
1057 // Keep track of .eh_frame sections.
1058 std::vector
<unsigned int> eh_frame_sections
;
1060 // Skip the first, dummy, section.
1061 pshdrs
= shdrs
+ This::shdr_size
;
1062 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
1064 typename
This::Shdr
shdr(pshdrs
);
1066 if (shdr
.get_sh_name() >= section_names_size
)
1068 this->error(_("bad section name offset for section %u: %lu"),
1069 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
1073 const char* name
= pnames
+ shdr
.get_sh_name();
1075 if (!is_gc_pass_two
)
1077 if (this->handle_gnu_warning_section(name
, i
, symtab
))
1083 // The .note.GNU-stack section is special. It gives the
1084 // protection flags that this object file requires for the stack
1086 if (strcmp(name
, ".note.GNU-stack") == 0)
1088 seen_gnu_stack
= true;
1089 gnu_stack_flags
|= shdr
.get_sh_flags();
1093 bool discard
= omit
[i
];
1096 if (shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
1098 if (!this->include_section_group(symtab
, layout
, i
, name
,
1104 else if ((shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) == 0
1105 && Layout::is_linkonce(name
))
1107 if (!this->include_linkonce_section(layout
, i
, name
, shdr
))
1114 // Do not include this section in the link.
1115 out_sections
[i
] = NULL
;
1116 out_section_offsets
[i
] = invalid_address
;
1123 if (is_section_name_included(name
)
1124 || shdr
.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1125 || shdr
.get_sh_type() == elfcpp::SHT_FINI_ARRAY
)
1127 symtab
->gc()->worklist().push(Section_id(this, i
));
1131 // When doing a relocatable link we are going to copy input
1132 // reloc sections into the output. We only want to copy the
1133 // ones associated with sections which are not being discarded.
1134 // However, we don't know that yet for all sections. So save
1135 // reloc sections and process them later. Garbage collection is
1136 // not triggered when relocatable code is desired.
1138 && (shdr
.get_sh_type() == elfcpp::SHT_REL
1139 || shdr
.get_sh_type() == elfcpp::SHT_RELA
))
1141 reloc_sections
.push_back(i
);
1145 if (relocatable
&& shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
1148 // The .eh_frame section is special. It holds exception frame
1149 // information that we need to read in order to generate the
1150 // exception frame header. We process these after all the other
1151 // sections so that the exception frame reader can reliably
1152 // determine which sections are being discarded, and discard the
1153 // corresponding information.
1155 && strcmp(name
, ".eh_frame") == 0
1156 && this->check_eh_frame_flags(&shdr
))
1160 out_sections
[i
] = reinterpret_cast<Output_section
*>(1);
1161 out_section_offsets
[i
] = invalid_address
;
1164 eh_frame_sections
.push_back(i
);
1170 // This is executed during the second pass of garbage
1171 // collection. do_layout has been called before and some
1172 // sections have been already discarded. Simply ignore
1173 // such sections this time around.
1174 if (out_sections
[i
] == NULL
)
1176 gold_assert(out_section_offsets
[i
] == invalid_address
);
1179 if ((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0)
1180 if (symtab
->gc()->referenced_list().find(Section_id(this,i
))
1181 == symtab
->gc()->referenced_list().end())
1183 if (parameters
->options().print_gc_sections())
1184 gold_info(_("%s: removing unused section from '%s'"
1186 program_name
, this->section_name(i
).c_str(),
1187 this->name().c_str());
1188 out_sections
[i
] = NULL
;
1189 out_section_offsets
[i
] = invalid_address
;
1193 // Defer layout here if input files are claimed by plugins. When gc
1194 // is turned on this function is called twice. For the second call
1195 // should_defer_layout should be false.
1196 if (should_defer_layout
&& (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
))
1198 gold_assert(!is_gc_pass_two
);
1199 this->deferred_layout_
.push_back(Deferred_layout(i
, name
,
1203 // Put dummy values here; real values will be supplied by
1204 // do_layout_deferred_sections.
1205 out_sections
[i
] = reinterpret_cast<Output_section
*>(2);
1206 out_section_offsets
[i
] = invalid_address
;
1209 // During gc_pass_two if a section that was previously deferred is
1210 // found, do not layout the section as layout_deferred_sections will
1211 // do it later from gold.cc.
1213 && (out_sections
[i
] == reinterpret_cast<Output_section
*>(2)))
1218 // This is during garbage collection. The out_sections are
1219 // assigned in the second call to this function.
1220 out_sections
[i
] = reinterpret_cast<Output_section
*>(1);
1221 out_section_offsets
[i
] = invalid_address
;
1225 // When garbage collection is switched on the actual layout
1226 // only happens in the second call.
1227 this->layout_section(layout
, i
, name
, shdr
, reloc_shndx
[i
],
1232 if (!is_gc_pass_one
)
1233 layout
->layout_gnu_stack(seen_gnu_stack
, gnu_stack_flags
);
1235 // When doing a relocatable link handle the reloc sections at the
1236 // end. Garbage collection is not turned on for relocatable code.
1238 this->size_relocatable_relocs();
1239 gold_assert(!parameters
->options().gc_sections() || reloc_sections
.empty());
1240 for (std::vector
<unsigned int>::const_iterator p
= reloc_sections
.begin();
1241 p
!= reloc_sections
.end();
1244 unsigned int i
= *p
;
1245 const unsigned char* pshdr
;
1246 pshdr
= section_headers_data
+ i
* This::shdr_size
;
1247 typename
This::Shdr
shdr(pshdr
);
1249 unsigned int data_shndx
= this->adjust_shndx(shdr
.get_sh_info());
1250 if (data_shndx
>= shnum
)
1252 // We already warned about this above.
1256 Output_section
* data_section
= out_sections
[data_shndx
];
1257 if (data_section
== NULL
)
1259 out_sections
[i
] = NULL
;
1260 out_section_offsets
[i
] = invalid_address
;
1264 Relocatable_relocs
* rr
= new Relocatable_relocs();
1265 this->set_relocatable_relocs(i
, rr
);
1267 Output_section
* os
= layout
->layout_reloc(this, i
, shdr
, data_section
,
1269 out_sections
[i
] = os
;
1270 out_section_offsets
[i
] = invalid_address
;
1273 // Handle the .eh_frame sections at the end.
1274 gold_assert(!is_gc_pass_one
|| eh_frame_sections
.empty());
1275 for (std::vector
<unsigned int>::const_iterator p
= eh_frame_sections
.begin();
1276 p
!= eh_frame_sections
.end();
1279 gold_assert(this->has_eh_frame_
);
1280 gold_assert(external_symbols_offset
!= 0);
1282 unsigned int i
= *p
;
1283 const unsigned char *pshdr
;
1284 pshdr
= section_headers_data
+ i
* This::shdr_size
;
1285 typename
This::Shdr
shdr(pshdr
);
1288 Output_section
* os
= layout
->layout_eh_frame(this,
1297 out_sections
[i
] = os
;
1299 out_section_offsets
[i
] = invalid_address
;
1301 out_section_offsets
[i
] = convert_types
<Address
, off_t
>(offset
);
1303 // If this section requires special handling, and if there are
1304 // relocs that apply to it, then we must do the special handling
1305 // before we apply the relocs.
1306 if (offset
== -1 && reloc_shndx
[i
] != 0)
1307 this->set_relocs_must_follow_section_writes();
1312 delete[] gc_sd
->section_headers_data
;
1313 delete[] gc_sd
->section_names_data
;
1314 delete[] gc_sd
->symbols_data
;
1315 delete[] gc_sd
->symbol_names_data
;
1319 delete sd
->section_headers
;
1320 sd
->section_headers
= NULL
;
1321 delete sd
->section_names
;
1322 sd
->section_names
= NULL
;
1326 // Layout sections whose layout was deferred while waiting for
1327 // input files from a plugin.
1329 template<int size
, bool big_endian
>
1331 Sized_relobj
<size
, big_endian
>::do_layout_deferred_sections(Layout
* layout
)
1333 typename
std::vector
<Deferred_layout
>::iterator deferred
;
1335 for (deferred
= this->deferred_layout_
.begin();
1336 deferred
!= this->deferred_layout_
.end();
1339 typename
This::Shdr
shdr(deferred
->shdr_data_
);
1340 this->layout_section(layout
, deferred
->shndx_
, deferred
->name_
.c_str(),
1341 shdr
, deferred
->reloc_shndx_
, deferred
->reloc_type_
);
1344 this->deferred_layout_
.clear();
1347 // Add the symbols to the symbol table.
1349 template<int size
, bool big_endian
>
1351 Sized_relobj
<size
, big_endian
>::do_add_symbols(Symbol_table
* symtab
,
1352 Read_symbols_data
* sd
,
1355 if (sd
->symbols
== NULL
)
1357 gold_assert(sd
->symbol_names
== NULL
);
1361 const int sym_size
= This::sym_size
;
1362 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
1364 if (symcount
* sym_size
!= sd
->symbols_size
- sd
->external_symbols_offset
)
1366 this->error(_("size of symbols is not multiple of symbol size"));
1370 this->symbols_
.resize(symcount
);
1372 const char* sym_names
=
1373 reinterpret_cast<const char*>(sd
->symbol_names
->data());
1374 symtab
->add_from_relobj(this,
1375 sd
->symbols
->data() + sd
->external_symbols_offset
,
1376 symcount
, this->local_symbol_count_
,
1377 sym_names
, sd
->symbol_names_size
,
1379 &this->defined_count_
);
1383 delete sd
->symbol_names
;
1384 sd
->symbol_names
= NULL
;
1387 // First pass over the local symbols. Here we add their names to
1388 // *POOL and *DYNPOOL, and we store the symbol value in
1389 // THIS->LOCAL_VALUES_. This function is always called from a
1390 // singleton thread. This is followed by a call to
1391 // finalize_local_symbols.
1393 template<int size
, bool big_endian
>
1395 Sized_relobj
<size
, big_endian
>::do_count_local_symbols(Stringpool
* pool
,
1396 Stringpool
* dynpool
)
1398 gold_assert(this->symtab_shndx_
!= -1U);
1399 if (this->symtab_shndx_
== 0)
1401 // This object has no symbols. Weird but legal.
1405 // Read the symbol table section header.
1406 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1407 typename
This::Shdr
symtabshdr(this,
1408 this->elf_file_
.section_header(symtab_shndx
));
1409 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1411 // Read the local symbols.
1412 const int sym_size
= This::sym_size
;
1413 const unsigned int loccount
= this->local_symbol_count_
;
1414 gold_assert(loccount
== symtabshdr
.get_sh_info());
1415 off_t locsize
= loccount
* sym_size
;
1416 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1417 locsize
, true, true);
1419 // Read the symbol names.
1420 const unsigned int strtab_shndx
=
1421 this->adjust_shndx(symtabshdr
.get_sh_link());
1422 section_size_type strtab_size
;
1423 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
1426 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
1428 // Loop over the local symbols.
1430 const Output_sections
& out_sections(this->output_sections());
1431 unsigned int shnum
= this->shnum();
1432 unsigned int count
= 0;
1433 unsigned int dyncount
= 0;
1434 // Skip the first, dummy, symbol.
1436 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
1438 elfcpp::Sym
<size
, big_endian
> sym(psyms
);
1440 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1443 unsigned int shndx
= this->adjust_sym_shndx(i
, sym
.get_st_shndx(),
1445 lv
.set_input_shndx(shndx
, is_ordinary
);
1447 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
1448 lv
.set_is_section_symbol();
1449 else if (sym
.get_st_type() == elfcpp::STT_TLS
)
1450 lv
.set_is_tls_symbol();
1452 // Save the input symbol value for use in do_finalize_local_symbols().
1453 lv
.set_input_value(sym
.get_st_value());
1455 // Decide whether this symbol should go into the output file.
1457 if (shndx
< shnum
&& out_sections
[shndx
] == NULL
)
1459 lv
.set_no_output_symtab_entry();
1460 gold_assert(!lv
.needs_output_dynsym_entry());
1464 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
1466 lv
.set_no_output_symtab_entry();
1467 gold_assert(!lv
.needs_output_dynsym_entry());
1471 if (sym
.get_st_name() >= strtab_size
)
1473 this->error(_("local symbol %u section name out of range: %u >= %u"),
1474 i
, sym
.get_st_name(),
1475 static_cast<unsigned int>(strtab_size
));
1476 lv
.set_no_output_symtab_entry();
1480 // Add the symbol to the symbol table string pool.
1481 const char* name
= pnames
+ sym
.get_st_name();
1482 pool
->add(name
, true, NULL
);
1485 // If needed, add the symbol to the dynamic symbol table string pool.
1486 if (lv
.needs_output_dynsym_entry())
1488 dynpool
->add(name
, true, NULL
);
1493 this->output_local_symbol_count_
= count
;
1494 this->output_local_dynsym_count_
= dyncount
;
1497 // Finalize the local symbols. Here we set the final value in
1498 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
1499 // This function is always called from a singleton thread. The actual
1500 // output of the local symbols will occur in a separate task.
1502 template<int size
, bool big_endian
>
1504 Sized_relobj
<size
, big_endian
>::do_finalize_local_symbols(unsigned int index
,
1507 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
1509 const unsigned int loccount
= this->local_symbol_count_
;
1510 this->local_symbol_offset_
= off
;
1512 const Output_sections
& out_sections(this->output_sections());
1513 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
1514 unsigned int shnum
= this->shnum();
1516 for (unsigned int i
= 1; i
< loccount
; ++i
)
1518 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1521 unsigned int shndx
= lv
.input_shndx(&is_ordinary
);
1523 // Set the output symbol value.
1527 if (shndx
== elfcpp::SHN_ABS
|| shndx
== elfcpp::SHN_COMMON
)
1528 lv
.set_output_value(lv
.input_value());
1531 this->error(_("unknown section index %u for local symbol %u"),
1533 lv
.set_output_value(0);
1540 this->error(_("local symbol %u section index %u out of range"),
1545 Output_section
* os
= out_sections
[shndx
];
1549 // This local symbol belongs to a section we are discarding.
1550 // In some cases when applying relocations later, we will
1551 // attempt to match it to the corresponding kept section,
1552 // so we leave the input value unchanged here.
1555 else if (out_offsets
[shndx
] == invalid_address
)
1557 // This is a SHF_MERGE section or one which otherwise
1558 // requires special handling. We get the output address
1559 // of the start of the merged section. If this is not a
1560 // section symbol, we can then determine the final
1561 // value. If it is a section symbol, we can not, as in
1562 // that case we have to consider the addend to determine
1563 // the value to use in a relocation.
1564 if (!lv
.is_section_symbol())
1565 lv
.set_output_value(os
->output_address(this, shndx
,
1569 section_offset_type start
=
1570 os
->starting_output_address(this, shndx
);
1571 Merged_symbol_value
<size
>* msv
=
1572 new Merged_symbol_value
<size
>(lv
.input_value(), start
);
1573 lv
.set_merged_symbol_value(msv
);
1576 else if (lv
.is_tls_symbol())
1577 lv
.set_output_value(os
->tls_offset()
1578 + out_offsets
[shndx
]
1579 + lv
.input_value());
1581 lv
.set_output_value(os
->address()
1582 + out_offsets
[shndx
]
1583 + lv
.input_value());
1586 if (lv
.needs_output_symtab_entry())
1588 lv
.set_output_symtab_index(index
);
1595 // Set the output dynamic symbol table indexes for the local variables.
1597 template<int size
, bool big_endian
>
1599 Sized_relobj
<size
, big_endian
>::do_set_local_dynsym_indexes(unsigned int index
)
1601 const unsigned int loccount
= this->local_symbol_count_
;
1602 for (unsigned int i
= 1; i
< loccount
; ++i
)
1604 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1605 if (lv
.needs_output_dynsym_entry())
1607 lv
.set_output_dynsym_index(index
);
1614 // Set the offset where local dynamic symbol information will be stored.
1615 // Returns the count of local symbols contributed to the symbol table by
1618 template<int size
, bool big_endian
>
1620 Sized_relobj
<size
, big_endian
>::do_set_local_dynsym_offset(off_t off
)
1622 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
1623 this->local_dynsym_offset_
= off
;
1624 return this->output_local_dynsym_count_
;
1627 // Write out the local symbols.
1629 template<int size
, bool big_endian
>
1631 Sized_relobj
<size
, big_endian
>::write_local_symbols(
1633 const Stringpool
* sympool
,
1634 const Stringpool
* dynpool
,
1635 Output_symtab_xindex
* symtab_xindex
,
1636 Output_symtab_xindex
* dynsym_xindex
)
1638 const bool strip_all
= parameters
->options().strip_all();
1641 if (this->output_local_dynsym_count_
== 0)
1643 this->output_local_symbol_count_
= 0;
1646 gold_assert(this->symtab_shndx_
!= -1U);
1647 if (this->symtab_shndx_
== 0)
1649 // This object has no symbols. Weird but legal.
1653 // Read the symbol table section header.
1654 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1655 typename
This::Shdr
symtabshdr(this,
1656 this->elf_file_
.section_header(symtab_shndx
));
1657 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1658 const unsigned int loccount
= this->local_symbol_count_
;
1659 gold_assert(loccount
== symtabshdr
.get_sh_info());
1661 // Read the local symbols.
1662 const int sym_size
= This::sym_size
;
1663 off_t locsize
= loccount
* sym_size
;
1664 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1665 locsize
, true, false);
1667 // Read the symbol names.
1668 const unsigned int strtab_shndx
=
1669 this->adjust_shndx(symtabshdr
.get_sh_link());
1670 section_size_type strtab_size
;
1671 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
1674 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
1676 // Get views into the output file for the portions of the symbol table
1677 // and the dynamic symbol table that we will be writing.
1678 off_t output_size
= this->output_local_symbol_count_
* sym_size
;
1679 unsigned char* oview
= NULL
;
1680 if (output_size
> 0)
1681 oview
= of
->get_output_view(this->local_symbol_offset_
, output_size
);
1683 off_t dyn_output_size
= this->output_local_dynsym_count_
* sym_size
;
1684 unsigned char* dyn_oview
= NULL
;
1685 if (dyn_output_size
> 0)
1686 dyn_oview
= of
->get_output_view(this->local_dynsym_offset_
,
1689 const Output_sections
out_sections(this->output_sections());
1691 gold_assert(this->local_values_
.size() == loccount
);
1693 unsigned char* ov
= oview
;
1694 unsigned char* dyn_ov
= dyn_oview
;
1696 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
1698 elfcpp::Sym
<size
, big_endian
> isym(psyms
);
1700 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1703 unsigned int st_shndx
= this->adjust_sym_shndx(i
, isym
.get_st_shndx(),
1707 gold_assert(st_shndx
< out_sections
.size());
1708 if (out_sections
[st_shndx
] == NULL
)
1710 st_shndx
= out_sections
[st_shndx
]->out_shndx();
1711 if (st_shndx
>= elfcpp::SHN_LORESERVE
)
1713 if (lv
.needs_output_symtab_entry() && !strip_all
)
1714 symtab_xindex
->add(lv
.output_symtab_index(), st_shndx
);
1715 if (lv
.needs_output_dynsym_entry())
1716 dynsym_xindex
->add(lv
.output_dynsym_index(), st_shndx
);
1717 st_shndx
= elfcpp::SHN_XINDEX
;
1721 // Write the symbol to the output symbol table.
1722 if (!strip_all
&& lv
.needs_output_symtab_entry())
1724 elfcpp::Sym_write
<size
, big_endian
> osym(ov
);
1726 gold_assert(isym
.get_st_name() < strtab_size
);
1727 const char* name
= pnames
+ isym
.get_st_name();
1728 osym
.put_st_name(sympool
->get_offset(name
));
1729 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
1730 osym
.put_st_size(isym
.get_st_size());
1731 osym
.put_st_info(isym
.get_st_info());
1732 osym
.put_st_other(isym
.get_st_other());
1733 osym
.put_st_shndx(st_shndx
);
1738 // Write the symbol to the output dynamic symbol table.
1739 if (lv
.needs_output_dynsym_entry())
1741 gold_assert(dyn_ov
< dyn_oview
+ dyn_output_size
);
1742 elfcpp::Sym_write
<size
, big_endian
> osym(dyn_ov
);
1744 gold_assert(isym
.get_st_name() < strtab_size
);
1745 const char* name
= pnames
+ isym
.get_st_name();
1746 osym
.put_st_name(dynpool
->get_offset(name
));
1747 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
1748 osym
.put_st_size(isym
.get_st_size());
1749 osym
.put_st_info(isym
.get_st_info());
1750 osym
.put_st_other(isym
.get_st_other());
1751 osym
.put_st_shndx(st_shndx
);
1758 if (output_size
> 0)
1760 gold_assert(ov
- oview
== output_size
);
1761 of
->write_output_view(this->local_symbol_offset_
, output_size
, oview
);
1764 if (dyn_output_size
> 0)
1766 gold_assert(dyn_ov
- dyn_oview
== dyn_output_size
);
1767 of
->write_output_view(this->local_dynsym_offset_
, dyn_output_size
,
1772 // Set *INFO to symbolic information about the offset OFFSET in the
1773 // section SHNDX. Return true if we found something, false if we
1776 template<int size
, bool big_endian
>
1778 Sized_relobj
<size
, big_endian
>::get_symbol_location_info(
1781 Symbol_location_info
* info
)
1783 if (this->symtab_shndx_
== 0)
1786 section_size_type symbols_size
;
1787 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
1791 unsigned int symbol_names_shndx
=
1792 this->adjust_shndx(this->section_link(this->symtab_shndx_
));
1793 section_size_type names_size
;
1794 const unsigned char* symbol_names_u
=
1795 this->section_contents(symbol_names_shndx
, &names_size
, false);
1796 const char* symbol_names
= reinterpret_cast<const char*>(symbol_names_u
);
1798 const int sym_size
= This::sym_size
;
1799 const size_t count
= symbols_size
/ sym_size
;
1801 const unsigned char* p
= symbols
;
1802 for (size_t i
= 0; i
< count
; ++i
, p
+= sym_size
)
1804 elfcpp::Sym
<size
, big_endian
> sym(p
);
1806 if (sym
.get_st_type() == elfcpp::STT_FILE
)
1808 if (sym
.get_st_name() >= names_size
)
1809 info
->source_file
= "(invalid)";
1811 info
->source_file
= symbol_names
+ sym
.get_st_name();
1816 unsigned int st_shndx
= this->adjust_sym_shndx(i
, sym
.get_st_shndx(),
1819 && st_shndx
== shndx
1820 && static_cast<off_t
>(sym
.get_st_value()) <= offset
1821 && (static_cast<off_t
>(sym
.get_st_value() + sym
.get_st_size())
1824 if (sym
.get_st_name() > names_size
)
1825 info
->enclosing_symbol_name
= "(invalid)";
1828 info
->enclosing_symbol_name
= symbol_names
+ sym
.get_st_name();
1829 if (parameters
->options().do_demangle())
1831 char* demangled_name
= cplus_demangle(
1832 info
->enclosing_symbol_name
.c_str(),
1833 DMGL_ANSI
| DMGL_PARAMS
);
1834 if (demangled_name
!= NULL
)
1836 info
->enclosing_symbol_name
.assign(demangled_name
);
1837 free(demangled_name
);
1848 // Look for a kept section corresponding to the given discarded section,
1849 // and return its output address. This is used only for relocations in
1850 // debugging sections. If we can't find the kept section, return 0.
1852 template<int size
, bool big_endian
>
1853 typename Sized_relobj
<size
, big_endian
>::Address
1854 Sized_relobj
<size
, big_endian
>::map_to_kept_section(
1858 Kept_comdat_section
*kept
= this->get_kept_comdat_section(shndx
);
1861 gold_assert(kept
->object_
!= NULL
);
1863 Output_section
* os
= kept
->object_
->output_section(kept
->shndx_
);
1864 Address offset
= kept
->object_
->get_output_section_offset(kept
->shndx_
);
1865 gold_assert(os
!= NULL
&& offset
!= invalid_address
);
1866 return os
->address() + offset
;
1872 // Get symbol counts.
1874 template<int size
, bool big_endian
>
1876 Sized_relobj
<size
, big_endian
>::do_get_global_symbol_counts(
1877 const Symbol_table
*,
1881 *defined
= this->defined_count_
;
1883 for (Symbols::const_iterator p
= this->symbols_
.begin();
1884 p
!= this->symbols_
.end();
1887 && (*p
)->source() == Symbol::FROM_OBJECT
1888 && (*p
)->object() == this
1889 && (*p
)->is_defined())
1894 // Input_objects methods.
1896 // Add a regular relocatable object to the list. Return false if this
1897 // object should be ignored.
1900 Input_objects::add_object(Object
* obj
)
1902 // Set the global target from the first object file we recognize.
1903 Target
* target
= obj
->target();
1904 if (!parameters
->target_valid())
1905 set_parameters_target(target
);
1906 else if (target
!= ¶meters
->target())
1908 obj
->error(_("incompatible target"));
1912 // Print the filename if the -t/--trace option is selected.
1913 if (parameters
->options().trace())
1914 gold_info("%s", obj
->name().c_str());
1916 if (!obj
->is_dynamic())
1917 this->relobj_list_
.push_back(static_cast<Relobj
*>(obj
));
1920 // See if this is a duplicate SONAME.
1921 Dynobj
* dynobj
= static_cast<Dynobj
*>(obj
);
1922 const char* soname
= dynobj
->soname();
1924 std::pair
<Unordered_set
<std::string
>::iterator
, bool> ins
=
1925 this->sonames_
.insert(soname
);
1928 // We have already seen a dynamic object with this soname.
1932 this->dynobj_list_
.push_back(dynobj
);
1934 // If this is -lc, remember the directory in which we found it.
1935 // We use this when issuing warnings about undefined symbols: as
1936 // a heuristic, we don't warn about system libraries found in
1937 // the same directory as -lc.
1938 if (strncmp(soname
, "libc.so", 7) == 0)
1940 const char* object_name
= dynobj
->name().c_str();
1941 const char* base
= lbasename(object_name
);
1942 if (base
!= object_name
)
1943 this->system_library_directory_
.assign(object_name
,
1944 base
- 1 - object_name
);
1948 // Add this object to the cross-referencer if requested.
1949 if (parameters
->options().user_set_print_symbol_counts())
1951 if (this->cref_
== NULL
)
1952 this->cref_
= new Cref();
1953 this->cref_
->add_object(obj
);
1959 // Return whether an object was found in the system library directory.
1962 Input_objects::found_in_system_library_directory(const Object
* object
) const
1964 return (!this->system_library_directory_
.empty()
1965 && object
->name().compare(0,
1966 this->system_library_directory_
.size(),
1967 this->system_library_directory_
) == 0);
1970 // For each dynamic object, record whether we've seen all of its
1971 // explicit dependencies.
1974 Input_objects::check_dynamic_dependencies() const
1976 for (Dynobj_list::const_iterator p
= this->dynobj_list_
.begin();
1977 p
!= this->dynobj_list_
.end();
1980 const Dynobj::Needed
& needed((*p
)->needed());
1981 bool found_all
= true;
1982 for (Dynobj::Needed::const_iterator pneeded
= needed
.begin();
1983 pneeded
!= needed
.end();
1986 if (this->sonames_
.find(*pneeded
) == this->sonames_
.end())
1992 (*p
)->set_has_unknown_needed_entries(!found_all
);
1996 // Start processing an archive.
1999 Input_objects::archive_start(Archive
* archive
)
2001 if (parameters
->options().user_set_print_symbol_counts())
2003 if (this->cref_
== NULL
)
2004 this->cref_
= new Cref();
2005 this->cref_
->add_archive_start(archive
);
2009 // Stop processing an archive.
2012 Input_objects::archive_stop(Archive
* archive
)
2014 if (parameters
->options().user_set_print_symbol_counts())
2015 this->cref_
->add_archive_stop(archive
);
2018 // Print symbol counts
2021 Input_objects::print_symbol_counts(const Symbol_table
* symtab
) const
2023 if (parameters
->options().user_set_print_symbol_counts()
2024 && this->cref_
!= NULL
)
2025 this->cref_
->print_symbol_counts(symtab
);
2028 // Relocate_info methods.
2030 // Return a string describing the location of a relocation. This is
2031 // only used in error messages.
2033 template<int size
, bool big_endian
>
2035 Relocate_info
<size
, big_endian
>::location(size_t, off_t offset
) const
2037 // See if we can get line-number information from debugging sections.
2038 std::string filename
;
2039 std::string file_and_lineno
; // Better than filename-only, if available.
2041 Sized_dwarf_line_info
<size
, big_endian
> line_info(this->object
);
2042 // This will be "" if we failed to parse the debug info for any reason.
2043 file_and_lineno
= line_info
.addr2line(this->data_shndx
, offset
);
2045 std::string
ret(this->object
->name());
2047 Symbol_location_info info
;
2048 if (this->object
->get_symbol_location_info(this->data_shndx
, offset
, &info
))
2050 ret
+= " in function ";
2051 ret
+= info
.enclosing_symbol_name
;
2053 filename
= info
.source_file
;
2056 if (!file_and_lineno
.empty())
2057 ret
+= file_and_lineno
;
2060 if (!filename
.empty())
2063 ret
+= this->object
->section_name(this->data_shndx
);
2065 // Offsets into sections have to be positive.
2066 snprintf(buf
, sizeof(buf
), "+0x%lx", static_cast<long>(offset
));
2073 } // End namespace gold.
2078 using namespace gold
;
2080 // Read an ELF file with the header and return the appropriate
2081 // instance of Object.
2083 template<int size
, bool big_endian
>
2085 make_elf_sized_object(const std::string
& name
, Input_file
* input_file
,
2086 off_t offset
, const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
2088 int et
= ehdr
.get_e_type();
2089 if (et
== elfcpp::ET_REL
)
2091 Sized_relobj
<size
, big_endian
>* obj
=
2092 new Sized_relobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
2096 else if (et
== elfcpp::ET_DYN
)
2098 Sized_dynobj
<size
, big_endian
>* obj
=
2099 new Sized_dynobj
<size
, big_endian
>(name
, input_file
, offset
, ehdr
);
2105 gold_error(_("%s: unsupported ELF file type %d"),
2111 } // End anonymous namespace.
2116 // Read an ELF file and return the appropriate instance of Object.
2119 make_elf_object(const std::string
& name
, Input_file
* input_file
, off_t offset
,
2120 const unsigned char* p
, section_offset_type bytes
)
2122 if (bytes
< elfcpp::EI_NIDENT
)
2124 gold_error(_("%s: ELF file too short"), name
.c_str());
2128 int v
= p
[elfcpp::EI_VERSION
];
2129 if (v
!= elfcpp::EV_CURRENT
)
2131 if (v
== elfcpp::EV_NONE
)
2132 gold_error(_("%s: invalid ELF version 0"), name
.c_str());
2134 gold_error(_("%s: unsupported ELF version %d"), name
.c_str(), v
);
2138 int c
= p
[elfcpp::EI_CLASS
];
2139 if (c
== elfcpp::ELFCLASSNONE
)
2141 gold_error(_("%s: invalid ELF class 0"), name
.c_str());
2144 else if (c
!= elfcpp::ELFCLASS32
2145 && c
!= elfcpp::ELFCLASS64
)
2147 gold_error(_("%s: unsupported ELF class %d"), name
.c_str(), c
);
2151 int d
= p
[elfcpp::EI_DATA
];
2152 if (d
== elfcpp::ELFDATANONE
)
2154 gold_error(_("%s: invalid ELF data encoding"), name
.c_str());
2157 else if (d
!= elfcpp::ELFDATA2LSB
2158 && d
!= elfcpp::ELFDATA2MSB
)
2160 gold_error(_("%s: unsupported ELF data encoding %d"), name
.c_str(), d
);
2164 bool big_endian
= d
== elfcpp::ELFDATA2MSB
;
2166 if (c
== elfcpp::ELFCLASS32
)
2168 if (bytes
< elfcpp::Elf_sizes
<32>::ehdr_size
)
2170 gold_error(_("%s: ELF file too short"), name
.c_str());
2175 #ifdef HAVE_TARGET_32_BIG
2176 elfcpp::Ehdr
<32, true> ehdr(p
);
2177 return make_elf_sized_object
<32, true>(name
, input_file
,
2180 gold_error(_("%s: not configured to support "
2181 "32-bit big-endian object"),
2188 #ifdef HAVE_TARGET_32_LITTLE
2189 elfcpp::Ehdr
<32, false> ehdr(p
);
2190 return make_elf_sized_object
<32, false>(name
, input_file
,
2193 gold_error(_("%s: not configured to support "
2194 "32-bit little-endian object"),
2202 if (bytes
< elfcpp::Elf_sizes
<64>::ehdr_size
)
2204 gold_error(_("%s: ELF file too short"), name
.c_str());
2209 #ifdef HAVE_TARGET_64_BIG
2210 elfcpp::Ehdr
<64, true> ehdr(p
);
2211 return make_elf_sized_object
<64, true>(name
, input_file
,
2214 gold_error(_("%s: not configured to support "
2215 "64-bit big-endian object"),
2222 #ifdef HAVE_TARGET_64_LITTLE
2223 elfcpp::Ehdr
<64, false> ehdr(p
);
2224 return make_elf_sized_object
<64, false>(name
, input_file
,
2227 gold_error(_("%s: not configured to support "
2228 "64-bit little-endian object"),
2236 // Instantiate the templates we need.
2238 #ifdef HAVE_TARGET_32_LITTLE
2241 Object::read_section_data
<32, false>(elfcpp::Elf_file
<32, false, Object
>*,
2242 Read_symbols_data
*);
2245 #ifdef HAVE_TARGET_32_BIG
2248 Object::read_section_data
<32, true>(elfcpp::Elf_file
<32, true, Object
>*,
2249 Read_symbols_data
*);
2252 #ifdef HAVE_TARGET_64_LITTLE
2255 Object::read_section_data
<64, false>(elfcpp::Elf_file
<64, false, Object
>*,
2256 Read_symbols_data
*);
2259 #ifdef HAVE_TARGET_64_BIG
2262 Object::read_section_data
<64, true>(elfcpp::Elf_file
<64, true, Object
>*,
2263 Read_symbols_data
*);
2266 #ifdef HAVE_TARGET_32_LITTLE
2268 class Sized_relobj
<32, false>;
2271 #ifdef HAVE_TARGET_32_BIG
2273 class Sized_relobj
<32, true>;
2276 #ifdef HAVE_TARGET_64_LITTLE
2278 class Sized_relobj
<64, false>;
2281 #ifdef HAVE_TARGET_64_BIG
2283 class Sized_relobj
<64, true>;
2286 #ifdef HAVE_TARGET_32_LITTLE
2288 struct Relocate_info
<32, false>;
2291 #ifdef HAVE_TARGET_32_BIG
2293 struct Relocate_info
<32, true>;
2296 #ifdef HAVE_TARGET_64_LITTLE
2298 struct Relocate_info
<64, false>;
2301 #ifdef HAVE_TARGET_64_BIG
2303 struct Relocate_info
<64, true>;
2306 } // End namespace gold.