1 // object.cc -- support for an object file for linking in gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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"
42 #include "compressed_output.h"
43 #include "incremental.h"
48 // Struct Read_symbols_data.
50 // Destroy any remaining File_view objects.
52 Read_symbols_data::~Read_symbols_data()
54 if (this->section_headers
!= NULL
)
55 delete this->section_headers
;
56 if (this->section_names
!= NULL
)
57 delete this->section_names
;
58 if (this->symbols
!= NULL
)
60 if (this->symbol_names
!= NULL
)
61 delete this->symbol_names
;
62 if (this->versym
!= NULL
)
64 if (this->verdef
!= NULL
)
66 if (this->verneed
!= NULL
)
72 // Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX
73 // section and read it in. SYMTAB_SHNDX is the index of the symbol
74 // table we care about.
76 template<int size
, bool big_endian
>
78 Xindex::initialize_symtab_xindex(Object
* object
, unsigned int symtab_shndx
)
80 if (!this->symtab_xindex_
.empty())
83 gold_assert(symtab_shndx
!= 0);
85 // Look through the sections in reverse order, on the theory that it
86 // is more likely to be near the end than the beginning.
87 unsigned int i
= object
->shnum();
91 if (object
->section_type(i
) == elfcpp::SHT_SYMTAB_SHNDX
92 && this->adjust_shndx(object
->section_link(i
)) == symtab_shndx
)
94 this->read_symtab_xindex
<size
, big_endian
>(object
, i
, NULL
);
99 object
->error(_("missing SHT_SYMTAB_SHNDX section"));
102 // Read in the symtab_xindex_ array, given the section index of the
103 // SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the
106 template<int size
, bool big_endian
>
108 Xindex::read_symtab_xindex(Object
* object
, unsigned int xindex_shndx
,
109 const unsigned char* pshdrs
)
111 section_size_type bytecount
;
112 const unsigned char* contents
;
114 contents
= object
->section_contents(xindex_shndx
, &bytecount
, false);
117 const unsigned char* p
= (pshdrs
119 * elfcpp::Elf_sizes
<size
>::shdr_size
));
120 typename
elfcpp::Shdr
<size
, big_endian
> shdr(p
);
121 bytecount
= convert_to_section_size_type(shdr
.get_sh_size());
122 contents
= object
->get_view(shdr
.get_sh_offset(), bytecount
, true, false);
125 gold_assert(this->symtab_xindex_
.empty());
126 this->symtab_xindex_
.reserve(bytecount
/ 4);
127 for (section_size_type i
= 0; i
< bytecount
; i
+= 4)
129 unsigned int shndx
= elfcpp::Swap
<32, big_endian
>::readval(contents
+ i
);
130 // We preadjust the section indexes we save.
131 this->symtab_xindex_
.push_back(this->adjust_shndx(shndx
));
135 // Symbol symndx has a section of SHN_XINDEX; return the real section
139 Xindex::sym_xindex_to_shndx(Object
* object
, unsigned int symndx
)
141 if (symndx
>= this->symtab_xindex_
.size())
143 object
->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
145 return elfcpp::SHN_UNDEF
;
147 unsigned int shndx
= this->symtab_xindex_
[symndx
];
148 if (shndx
< elfcpp::SHN_LORESERVE
|| shndx
>= object
->shnum())
150 object
->error(_("extended index for symbol %u out of range: %u"),
152 return elfcpp::SHN_UNDEF
;
159 // Report an error for this object file. This is used by the
160 // elfcpp::Elf_file interface, and also called by the Object code
164 Object::error(const char* format
, ...) const
167 va_start(args
, format
);
169 if (vasprintf(&buf
, format
, args
) < 0)
172 gold_error(_("%s: %s"), this->name().c_str(), buf
);
176 // Return a view of the contents of a section.
179 Object::section_contents(unsigned int shndx
, section_size_type
* plen
,
182 Location
loc(this->do_section_contents(shndx
));
183 *plen
= convert_to_section_size_type(loc
.data_size
);
186 static const unsigned char empty
[1] = { '\0' };
189 return this->get_view(loc
.file_offset
, *plen
, true, cache
);
192 // Read the section data into SD. This is code common to Sized_relobj_file
193 // and Sized_dynobj, so we put it into Object.
195 template<int size
, bool big_endian
>
197 Object::read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>* elf_file
,
198 Read_symbols_data
* sd
)
200 const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
202 // Read the section headers.
203 const off_t shoff
= elf_file
->shoff();
204 const unsigned int shnum
= this->shnum();
205 sd
->section_headers
= this->get_lasting_view(shoff
, shnum
* shdr_size
,
208 // Read the section names.
209 const unsigned char* pshdrs
= sd
->section_headers
->data();
210 const unsigned char* pshdrnames
= pshdrs
+ elf_file
->shstrndx() * shdr_size
;
211 typename
elfcpp::Shdr
<size
, big_endian
> shdrnames(pshdrnames
);
213 if (shdrnames
.get_sh_type() != elfcpp::SHT_STRTAB
)
214 this->error(_("section name section has wrong type: %u"),
215 static_cast<unsigned int>(shdrnames
.get_sh_type()));
217 sd
->section_names_size
=
218 convert_to_section_size_type(shdrnames
.get_sh_size());
219 sd
->section_names
= this->get_lasting_view(shdrnames
.get_sh_offset(),
220 sd
->section_names_size
, false,
224 // If NAME is the name of a special .gnu.warning section, arrange for
225 // the warning to be issued. SHNDX is the section index. Return
226 // whether it is a warning section.
229 Object::handle_gnu_warning_section(const char* name
, unsigned int shndx
,
230 Symbol_table
* symtab
)
232 const char warn_prefix
[] = ".gnu.warning.";
233 const int warn_prefix_len
= sizeof warn_prefix
- 1;
234 if (strncmp(name
, warn_prefix
, warn_prefix_len
) == 0)
236 // Read the section contents to get the warning text. It would
237 // be nicer if we only did this if we have to actually issue a
238 // warning. Unfortunately, warnings are issued as we relocate
239 // sections. That means that we can not lock the object then,
240 // as we might try to issue the same warning multiple times
242 section_size_type len
;
243 const unsigned char* contents
= this->section_contents(shndx
, &len
,
247 const char* warning
= name
+ warn_prefix_len
;
248 contents
= reinterpret_cast<const unsigned char*>(warning
);
249 len
= strlen(warning
);
251 std::string
warning(reinterpret_cast<const char*>(contents
), len
);
252 symtab
->add_warning(name
+ warn_prefix_len
, this, warning
);
258 // If NAME is the name of the special section which indicates that
259 // this object was compiled with -fsplit-stack, mark it accordingly.
262 Object::handle_split_stack_section(const char* name
)
264 if (strcmp(name
, ".note.GNU-split-stack") == 0)
266 this->uses_split_stack_
= true;
269 if (strcmp(name
, ".note.GNU-no-split-stack") == 0)
271 this->has_no_split_stack_
= true;
279 // To copy the symbols data read from the file to a local data structure.
280 // This function is called from do_layout only while doing garbage
284 Relobj::copy_symbols_data(Symbols_data
* gc_sd
, Read_symbols_data
* sd
,
285 unsigned int section_header_size
)
287 gc_sd
->section_headers_data
=
288 new unsigned char[(section_header_size
)];
289 memcpy(gc_sd
->section_headers_data
, sd
->section_headers
->data(),
290 section_header_size
);
291 gc_sd
->section_names_data
=
292 new unsigned char[sd
->section_names_size
];
293 memcpy(gc_sd
->section_names_data
, sd
->section_names
->data(),
294 sd
->section_names_size
);
295 gc_sd
->section_names_size
= sd
->section_names_size
;
296 if (sd
->symbols
!= NULL
)
298 gc_sd
->symbols_data
=
299 new unsigned char[sd
->symbols_size
];
300 memcpy(gc_sd
->symbols_data
, sd
->symbols
->data(),
305 gc_sd
->symbols_data
= NULL
;
307 gc_sd
->symbols_size
= sd
->symbols_size
;
308 gc_sd
->external_symbols_offset
= sd
->external_symbols_offset
;
309 if (sd
->symbol_names
!= NULL
)
311 gc_sd
->symbol_names_data
=
312 new unsigned char[sd
->symbol_names_size
];
313 memcpy(gc_sd
->symbol_names_data
, sd
->symbol_names
->data(),
314 sd
->symbol_names_size
);
318 gc_sd
->symbol_names_data
= NULL
;
320 gc_sd
->symbol_names_size
= sd
->symbol_names_size
;
323 // This function determines if a particular section name must be included
324 // in the link. This is used during garbage collection to determine the
325 // roots of the worklist.
328 Relobj::is_section_name_included(const char* name
)
330 if (is_prefix_of(".ctors", name
)
331 || is_prefix_of(".dtors", name
)
332 || is_prefix_of(".note", name
)
333 || is_prefix_of(".init", name
)
334 || is_prefix_of(".fini", name
)
335 || is_prefix_of(".gcc_except_table", name
)
336 || is_prefix_of(".jcr", name
)
337 || is_prefix_of(".preinit_array", name
)
338 || (is_prefix_of(".text", name
)
339 && strstr(name
, "personality"))
340 || (is_prefix_of(".data", name
)
341 && strstr(name
, "personality"))
342 || (is_prefix_of(".gnu.linkonce.d", name
)
343 && strstr(name
, "personality")))
350 // Finalize the incremental relocation information. Allocates a block
351 // of relocation entries for each symbol, and sets the reloc_bases_
352 // array to point to the first entry in each block. If CLEAR_COUNTS
353 // is TRUE, also clear the per-symbol relocation counters.
356 Relobj::finalize_incremental_relocs(Layout
* layout
, bool clear_counts
)
358 unsigned int nsyms
= this->get_global_symbols()->size();
359 this->reloc_bases_
= new unsigned int[nsyms
];
361 gold_assert(this->reloc_bases_
!= NULL
);
362 gold_assert(layout
->incremental_inputs() != NULL
);
364 unsigned int rindex
= layout
->incremental_inputs()->get_reloc_count();
365 for (unsigned int i
= 0; i
< nsyms
; ++i
)
367 this->reloc_bases_
[i
] = rindex
;
368 rindex
+= this->reloc_counts_
[i
];
370 this->reloc_counts_
[i
] = 0;
372 layout
->incremental_inputs()->set_reloc_count(rindex
);
375 // Class Sized_relobj.
377 // Iterate over local symbols, calling a visitor class V for each GOT offset
378 // associated with a local symbol.
380 template<int size
, bool big_endian
>
382 Sized_relobj
<size
, big_endian
>::do_for_all_local_got_entries(
383 Got_offset_list::Visitor
* v
) const
385 unsigned int nsyms
= this->local_symbol_count();
386 for (unsigned int i
= 0; i
< nsyms
; i
++)
388 Local_got_offsets::const_iterator p
= this->local_got_offsets_
.find(i
);
389 if (p
!= this->local_got_offsets_
.end())
391 const Got_offset_list
* got_offsets
= p
->second
;
392 got_offsets
->for_all_got_offsets(v
);
397 // Class Sized_relobj_file.
399 template<int size
, bool big_endian
>
400 Sized_relobj_file
<size
, big_endian
>::Sized_relobj_file(
401 const std::string
& name
,
402 Input_file
* input_file
,
404 const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
405 : Sized_relobj
<size
, big_endian
>(name
, input_file
, offset
),
406 elf_file_(this, ehdr
),
408 local_symbol_count_(0),
409 output_local_symbol_count_(0),
410 output_local_dynsym_count_(0),
413 local_symbol_offset_(0),
414 local_dynsym_offset_(0),
416 local_plt_offsets_(),
417 kept_comdat_sections_(),
418 has_eh_frame_(false),
419 discarded_eh_frame_shndx_(-1U),
421 deferred_layout_relocs_(),
422 compressed_sections_()
426 template<int size
, bool big_endian
>
427 Sized_relobj_file
<size
, big_endian
>::~Sized_relobj_file()
431 // Set up an object file based on the file header. This sets up the
432 // section information.
434 template<int size
, bool big_endian
>
436 Sized_relobj_file
<size
, big_endian
>::do_setup()
438 const unsigned int shnum
= this->elf_file_
.shnum();
439 this->set_shnum(shnum
);
442 // Find the SHT_SYMTAB section, given the section headers. The ELF
443 // standard says that maybe in the future there can be more than one
444 // SHT_SYMTAB section. Until somebody figures out how that could
445 // work, we assume there is only one.
447 template<int size
, bool big_endian
>
449 Sized_relobj_file
<size
, big_endian
>::find_symtab(const unsigned char* pshdrs
)
451 const unsigned int shnum
= this->shnum();
452 this->symtab_shndx_
= 0;
455 // Look through the sections in reverse order, since gas tends
456 // to put the symbol table at the end.
457 const unsigned char* p
= pshdrs
+ shnum
* This::shdr_size
;
458 unsigned int i
= shnum
;
459 unsigned int xindex_shndx
= 0;
460 unsigned int xindex_link
= 0;
464 p
-= This::shdr_size
;
465 typename
This::Shdr
shdr(p
);
466 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB
)
468 this->symtab_shndx_
= i
;
469 if (xindex_shndx
> 0 && xindex_link
== i
)
472 new Xindex(this->elf_file_
.large_shndx_offset());
473 xindex
->read_symtab_xindex
<size
, big_endian
>(this,
476 this->set_xindex(xindex
);
481 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
482 // one. This will work if it follows the SHT_SYMTAB
484 if (shdr
.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX
)
487 xindex_link
= this->adjust_shndx(shdr
.get_sh_link());
493 // Return the Xindex structure to use for object with lots of
496 template<int size
, bool big_endian
>
498 Sized_relobj_file
<size
, big_endian
>::do_initialize_xindex()
500 gold_assert(this->symtab_shndx_
!= -1U);
501 Xindex
* xindex
= new Xindex(this->elf_file_
.large_shndx_offset());
502 xindex
->initialize_symtab_xindex
<size
, big_endian
>(this, this->symtab_shndx_
);
506 // Return whether SHDR has the right type and flags to be a GNU
507 // .eh_frame section.
509 template<int size
, bool big_endian
>
511 Sized_relobj_file
<size
, big_endian
>::check_eh_frame_flags(
512 const elfcpp::Shdr
<size
, big_endian
>* shdr
) const
514 elfcpp::Elf_Word sh_type
= shdr
->get_sh_type();
515 return ((sh_type
== elfcpp::SHT_PROGBITS
516 || sh_type
== elfcpp::SHT_X86_64_UNWIND
)
517 && (shdr
->get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
520 // Return whether there is a GNU .eh_frame section, given the section
521 // headers and the section names.
523 template<int size
, bool big_endian
>
525 Sized_relobj_file
<size
, big_endian
>::find_eh_frame(
526 const unsigned char* pshdrs
,
528 section_size_type names_size
) const
530 const unsigned int shnum
= this->shnum();
531 const unsigned char* p
= pshdrs
+ This::shdr_size
;
532 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
534 typename
This::Shdr
shdr(p
);
535 if (this->check_eh_frame_flags(&shdr
))
537 if (shdr
.get_sh_name() >= names_size
)
539 this->error(_("bad section name offset for section %u: %lu"),
540 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
544 const char* name
= names
+ shdr
.get_sh_name();
545 if (strcmp(name
, ".eh_frame") == 0)
552 // Build a table for any compressed debug sections, mapping each section index
553 // to the uncompressed size.
555 template<int size
, bool big_endian
>
556 Compressed_section_map
*
557 build_compressed_section_map(
558 const unsigned char* pshdrs
,
561 section_size_type names_size
,
562 Sized_relobj_file
<size
, big_endian
>* obj
)
564 Compressed_section_map
* uncompressed_sizes
= new Compressed_section_map();
565 const unsigned int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
566 const unsigned char* p
= pshdrs
+ shdr_size
;
567 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= shdr_size
)
569 typename
elfcpp::Shdr
<size
, big_endian
> shdr(p
);
570 if (shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
571 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
573 if (shdr
.get_sh_name() >= names_size
)
575 obj
->error(_("bad section name offset for section %u: %lu"),
576 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
580 const char* name
= names
+ shdr
.get_sh_name();
581 if (is_compressed_debug_section(name
))
583 section_size_type len
;
584 const unsigned char* contents
=
585 obj
->section_contents(i
, &len
, false);
586 uint64_t uncompressed_size
= get_uncompressed_size(contents
, len
);
587 if (uncompressed_size
!= -1ULL)
588 (*uncompressed_sizes
)[i
] =
589 convert_to_section_size_type(uncompressed_size
);
593 return uncompressed_sizes
;
596 // Read the sections and symbols from an object file.
598 template<int size
, bool big_endian
>
600 Sized_relobj_file
<size
, big_endian
>::do_read_symbols(Read_symbols_data
* sd
)
602 this->read_section_data(&this->elf_file_
, sd
);
604 const unsigned char* const pshdrs
= sd
->section_headers
->data();
606 this->find_symtab(pshdrs
);
608 const unsigned char* namesu
= sd
->section_names
->data();
609 const char* names
= reinterpret_cast<const char*>(namesu
);
610 if (memmem(names
, sd
->section_names_size
, ".eh_frame", 10) != NULL
)
612 if (this->find_eh_frame(pshdrs
, names
, sd
->section_names_size
))
613 this->has_eh_frame_
= true;
615 if (memmem(names
, sd
->section_names_size
, ".zdebug_", 8) != NULL
)
616 this->compressed_sections_
=
617 build_compressed_section_map(pshdrs
, this->shnum(), names
,
618 sd
->section_names_size
, this);
621 sd
->symbols_size
= 0;
622 sd
->external_symbols_offset
= 0;
623 sd
->symbol_names
= NULL
;
624 sd
->symbol_names_size
= 0;
626 if (this->symtab_shndx_
== 0)
628 // No symbol table. Weird but legal.
632 // Get the symbol table section header.
633 typename
This::Shdr
symtabshdr(pshdrs
634 + this->symtab_shndx_
* This::shdr_size
);
635 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
637 // If this object has a .eh_frame section, we need all the symbols.
638 // Otherwise we only need the external symbols. While it would be
639 // simpler to just always read all the symbols, I've seen object
640 // files with well over 2000 local symbols, which for a 64-bit
641 // object file format is over 5 pages that we don't need to read
644 const int sym_size
= This::sym_size
;
645 const unsigned int loccount
= symtabshdr
.get_sh_info();
646 this->local_symbol_count_
= loccount
;
647 this->local_values_
.resize(loccount
);
648 section_offset_type locsize
= loccount
* sym_size
;
649 off_t dataoff
= symtabshdr
.get_sh_offset();
650 section_size_type datasize
=
651 convert_to_section_size_type(symtabshdr
.get_sh_size());
652 off_t extoff
= dataoff
+ locsize
;
653 section_size_type extsize
= datasize
- locsize
;
655 off_t readoff
= this->has_eh_frame_
? dataoff
: extoff
;
656 section_size_type readsize
= this->has_eh_frame_
? datasize
: extsize
;
660 // No external symbols. Also weird but also legal.
664 File_view
* fvsymtab
= this->get_lasting_view(readoff
, readsize
, true, false);
666 // Read the section header for the symbol names.
667 unsigned int strtab_shndx
= this->adjust_shndx(symtabshdr
.get_sh_link());
668 if (strtab_shndx
>= this->shnum())
670 this->error(_("invalid symbol table name index: %u"), strtab_shndx
);
673 typename
This::Shdr
strtabshdr(pshdrs
+ strtab_shndx
* This::shdr_size
);
674 if (strtabshdr
.get_sh_type() != elfcpp::SHT_STRTAB
)
676 this->error(_("symbol table name section has wrong type: %u"),
677 static_cast<unsigned int>(strtabshdr
.get_sh_type()));
681 // Read the symbol names.
682 File_view
* fvstrtab
= this->get_lasting_view(strtabshdr
.get_sh_offset(),
683 strtabshdr
.get_sh_size(),
686 sd
->symbols
= fvsymtab
;
687 sd
->symbols_size
= readsize
;
688 sd
->external_symbols_offset
= this->has_eh_frame_
? locsize
: 0;
689 sd
->symbol_names
= fvstrtab
;
690 sd
->symbol_names_size
=
691 convert_to_section_size_type(strtabshdr
.get_sh_size());
694 // Return the section index of symbol SYM. Set *VALUE to its value in
695 // the object file. Set *IS_ORDINARY if this is an ordinary section
696 // index, not a special code between SHN_LORESERVE and SHN_HIRESERVE.
697 // Note that for a symbol which is not defined in this object file,
698 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
699 // the final value of the symbol in the link.
701 template<int size
, bool big_endian
>
703 Sized_relobj_file
<size
, big_endian
>::symbol_section_and_value(unsigned int sym
,
707 section_size_type symbols_size
;
708 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
712 const size_t count
= symbols_size
/ This::sym_size
;
713 gold_assert(sym
< count
);
715 elfcpp::Sym
<size
, big_endian
> elfsym(symbols
+ sym
* This::sym_size
);
716 *value
= elfsym
.get_st_value();
718 return this->adjust_sym_shndx(sym
, elfsym
.get_st_shndx(), is_ordinary
);
721 // Return whether to include a section group in the link. LAYOUT is
722 // used to keep track of which section groups we have already seen.
723 // INDEX is the index of the section group and SHDR is the section
724 // header. If we do not want to include this group, we set bits in
725 // OMIT for each section which should be discarded.
727 template<int size
, bool big_endian
>
729 Sized_relobj_file
<size
, big_endian
>::include_section_group(
730 Symbol_table
* symtab
,
734 const unsigned char* shdrs
,
735 const char* section_names
,
736 section_size_type section_names_size
,
737 std::vector
<bool>* omit
)
739 // Read the section contents.
740 typename
This::Shdr
shdr(shdrs
+ index
* This::shdr_size
);
741 const unsigned char* pcon
= this->get_view(shdr
.get_sh_offset(),
742 shdr
.get_sh_size(), true, false);
743 const elfcpp::Elf_Word
* pword
=
744 reinterpret_cast<const elfcpp::Elf_Word
*>(pcon
);
746 // The first word contains flags. We only care about COMDAT section
747 // groups. Other section groups are always included in the link
748 // just like ordinary sections.
749 elfcpp::Elf_Word flags
= elfcpp::Swap
<32, big_endian
>::readval(pword
);
751 // Look up the group signature, which is the name of a symbol. This
752 // is a lot of effort to go to to read a string. Why didn't they
753 // just have the group signature point into the string table, rather
754 // than indirect through a symbol?
756 // Get the appropriate symbol table header (this will normally be
757 // the single SHT_SYMTAB section, but in principle it need not be).
758 const unsigned int link
= this->adjust_shndx(shdr
.get_sh_link());
759 typename
This::Shdr
symshdr(this, this->elf_file_
.section_header(link
));
761 // Read the symbol table entry.
762 unsigned int symndx
= shdr
.get_sh_info();
763 if (symndx
>= symshdr
.get_sh_size() / This::sym_size
)
765 this->error(_("section group %u info %u out of range"),
769 off_t symoff
= symshdr
.get_sh_offset() + symndx
* This::sym_size
;
770 const unsigned char* psym
= this->get_view(symoff
, This::sym_size
, true,
772 elfcpp::Sym
<size
, big_endian
> sym(psym
);
774 // Read the symbol table names.
775 section_size_type symnamelen
;
776 const unsigned char* psymnamesu
;
777 psymnamesu
= this->section_contents(this->adjust_shndx(symshdr
.get_sh_link()),
779 const char* psymnames
= reinterpret_cast<const char*>(psymnamesu
);
781 // Get the section group signature.
782 if (sym
.get_st_name() >= symnamelen
)
784 this->error(_("symbol %u name offset %u out of range"),
785 symndx
, sym
.get_st_name());
789 std::string
signature(psymnames
+ sym
.get_st_name());
791 // It seems that some versions of gas will create a section group
792 // associated with a section symbol, and then fail to give a name to
793 // the section symbol. In such a case, use the name of the section.
794 if (signature
[0] == '\0' && sym
.get_st_type() == elfcpp::STT_SECTION
)
797 unsigned int sym_shndx
= this->adjust_sym_shndx(symndx
,
800 if (!is_ordinary
|| sym_shndx
>= this->shnum())
802 this->error(_("symbol %u invalid section index %u"),
806 typename
This::Shdr
member_shdr(shdrs
+ sym_shndx
* This::shdr_size
);
807 if (member_shdr
.get_sh_name() < section_names_size
)
808 signature
= section_names
+ member_shdr
.get_sh_name();
811 // Record this section group in the layout, and see whether we've already
812 // seen one with the same signature.
815 Kept_section
* kept_section
= NULL
;
817 if ((flags
& elfcpp::GRP_COMDAT
) == 0)
819 include_group
= true;
824 include_group
= layout
->find_or_add_kept_section(signature
,
826 true, &kept_section
);
830 if (is_comdat
&& include_group
)
832 Incremental_inputs
* incremental_inputs
= layout
->incremental_inputs();
833 if (incremental_inputs
!= NULL
)
834 incremental_inputs
->report_comdat_group(this, signature
.c_str());
837 size_t count
= shdr
.get_sh_size() / sizeof(elfcpp::Elf_Word
);
839 std::vector
<unsigned int> shndxes
;
840 bool relocate_group
= include_group
&& parameters
->options().relocatable();
842 shndxes
.reserve(count
- 1);
844 for (size_t i
= 1; i
< count
; ++i
)
846 elfcpp::Elf_Word shndx
=
847 this->adjust_shndx(elfcpp::Swap
<32, big_endian
>::readval(pword
+ i
));
850 shndxes
.push_back(shndx
);
852 if (shndx
>= this->shnum())
854 this->error(_("section %u in section group %u out of range"),
859 // Check for an earlier section number, since we're going to get
860 // it wrong--we may have already decided to include the section.
862 this->error(_("invalid section group %u refers to earlier section %u"),
865 // Get the name of the member section.
866 typename
This::Shdr
member_shdr(shdrs
+ shndx
* This::shdr_size
);
867 if (member_shdr
.get_sh_name() >= section_names_size
)
869 // This is an error, but it will be diagnosed eventually
870 // in do_layout, so we don't need to do anything here but
874 std::string
mname(section_names
+ member_shdr
.get_sh_name());
879 kept_section
->add_comdat_section(mname
, shndx
,
880 member_shdr
.get_sh_size());
884 (*omit
)[shndx
] = true;
888 Relobj
* kept_object
= kept_section
->object();
889 if (kept_section
->is_comdat())
891 // Find the corresponding kept section, and store
892 // that info in the discarded section table.
893 unsigned int kept_shndx
;
895 if (kept_section
->find_comdat_section(mname
, &kept_shndx
,
898 // We don't keep a mapping for this section if
899 // it has a different size. The mapping is only
900 // used for relocation processing, and we don't
901 // want to treat the sections as similar if the
902 // sizes are different. Checking the section
903 // size is the approach used by the GNU linker.
904 if (kept_size
== member_shdr
.get_sh_size())
905 this->set_kept_comdat_section(shndx
, kept_object
,
911 // The existing section is a linkonce section. Add
912 // a mapping if there is exactly one section in the
913 // group (which is true when COUNT == 2) and if it
916 && (kept_section
->linkonce_size()
917 == member_shdr
.get_sh_size()))
918 this->set_kept_comdat_section(shndx
, kept_object
,
919 kept_section
->shndx());
926 layout
->layout_group(symtab
, this, index
, name
, signature
.c_str(),
927 shdr
, flags
, &shndxes
);
929 return include_group
;
932 // Whether to include a linkonce section in the link. NAME is the
933 // name of the section and SHDR is the section header.
935 // Linkonce sections are a GNU extension implemented in the original
936 // GNU linker before section groups were defined. The semantics are
937 // that we only include one linkonce section with a given name. The
938 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
939 // where T is the type of section and SYMNAME is the name of a symbol.
940 // In an attempt to make linkonce sections interact well with section
941 // groups, we try to identify SYMNAME and use it like a section group
942 // signature. We want to block section groups with that signature,
943 // but not other linkonce sections with that signature. We also use
944 // the full name of the linkonce section as a normal section group
947 template<int size
, bool big_endian
>
949 Sized_relobj_file
<size
, big_endian
>::include_linkonce_section(
953 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
955 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
956 // In general the symbol name we want will be the string following
957 // the last '.'. However, we have to handle the case of
958 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
959 // some versions of gcc. So we use a heuristic: if the name starts
960 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
961 // we look for the last '.'. We can't always simply skip
962 // ".gnu.linkonce.X", because we have to deal with cases like
963 // ".gnu.linkonce.d.rel.ro.local".
964 const char* const linkonce_t
= ".gnu.linkonce.t.";
966 if (strncmp(name
, linkonce_t
, strlen(linkonce_t
)) == 0)
967 symname
= name
+ strlen(linkonce_t
);
969 symname
= strrchr(name
, '.') + 1;
970 std::string
sig1(symname
);
971 std::string
sig2(name
);
974 bool include1
= layout
->find_or_add_kept_section(sig1
, this, index
, false,
976 bool include2
= layout
->find_or_add_kept_section(sig2
, this, index
, false,
981 // We are not including this section because we already saw the
982 // name of the section as a signature. This normally implies
983 // that the kept section is another linkonce section. If it is
984 // the same size, record it as the section which corresponds to
986 if (kept2
->object() != NULL
987 && !kept2
->is_comdat()
988 && kept2
->linkonce_size() == sh_size
)
989 this->set_kept_comdat_section(index
, kept2
->object(), kept2
->shndx());
993 // The section is being discarded on the basis of its symbol
994 // name. This means that the corresponding kept section was
995 // part of a comdat group, and it will be difficult to identify
996 // the specific section within that group that corresponds to
997 // this linkonce section. We'll handle the simple case where
998 // the group has only one member section. Otherwise, it's not
1000 unsigned int kept_shndx
;
1002 if (kept1
->object() != NULL
1003 && kept1
->is_comdat()
1004 && kept1
->find_single_comdat_section(&kept_shndx
, &kept_size
)
1005 && kept_size
== sh_size
)
1006 this->set_kept_comdat_section(index
, kept1
->object(), kept_shndx
);
1010 kept1
->set_linkonce_size(sh_size
);
1011 kept2
->set_linkonce_size(sh_size
);
1014 return include1
&& include2
;
1017 // Layout an input section.
1019 template<int size
, bool big_endian
>
1021 Sized_relobj_file
<size
, big_endian
>::layout_section(
1025 const typename
This::Shdr
& shdr
,
1026 unsigned int reloc_shndx
,
1027 unsigned int reloc_type
)
1030 Output_section
* os
= layout
->layout(this, shndx
, name
, shdr
,
1031 reloc_shndx
, reloc_type
, &offset
);
1033 this->output_sections()[shndx
] = os
;
1035 this->section_offsets()[shndx
] = invalid_address
;
1037 this->section_offsets()[shndx
] = convert_types
<Address
, off_t
>(offset
);
1039 // If this section requires special handling, and if there are
1040 // relocs that apply to it, then we must do the special handling
1041 // before we apply the relocs.
1042 if (offset
== -1 && reloc_shndx
!= 0)
1043 this->set_relocs_must_follow_section_writes();
1046 // Layout an input .eh_frame section.
1048 template<int size
, bool big_endian
>
1050 Sized_relobj_file
<size
, big_endian
>::layout_eh_frame_section(
1052 const unsigned char* symbols_data
,
1053 section_size_type symbols_size
,
1054 const unsigned char* symbol_names_data
,
1055 section_size_type symbol_names_size
,
1057 const typename
This::Shdr
& shdr
,
1058 unsigned int reloc_shndx
,
1059 unsigned int reloc_type
)
1061 gold_assert(this->has_eh_frame_
);
1064 Output_section
* os
= layout
->layout_eh_frame(this,
1074 this->output_sections()[shndx
] = os
;
1075 if (os
== NULL
|| offset
== -1)
1077 // An object can contain at most one section holding exception
1078 // frame information.
1079 gold_assert(this->discarded_eh_frame_shndx_
== -1U);
1080 this->discarded_eh_frame_shndx_
= shndx
;
1081 this->section_offsets()[shndx
] = invalid_address
;
1084 this->section_offsets()[shndx
] = convert_types
<Address
, off_t
>(offset
);
1086 // If this section requires special handling, and if there are
1087 // relocs that aply to it, then we must do the special handling
1088 // before we apply the relocs.
1089 if (os
!= NULL
&& offset
== -1 && reloc_shndx
!= 0)
1090 this->set_relocs_must_follow_section_writes();
1093 // Lay out the input sections. We walk through the sections and check
1094 // whether they should be included in the link. If they should, we
1095 // pass them to the Layout object, which will return an output section
1097 // During garbage collection (--gc-sections) and identical code folding
1098 // (--icf), this function is called twice. When it is called the first
1099 // time, it is for setting up some sections as roots to a work-list for
1100 // --gc-sections and to do comdat processing. Actual layout happens the
1101 // second time around after all the relevant sections have been determined.
1102 // The first time, is_worklist_ready or is_icf_ready is false. It is then
1103 // set to true after the garbage collection worklist or identical code
1104 // folding is processed and the relevant sections to be kept are
1105 // determined. Then, this function is called again to layout the sections.
1107 template<int size
, bool big_endian
>
1109 Sized_relobj_file
<size
, big_endian
>::do_layout(Symbol_table
* symtab
,
1111 Read_symbols_data
* sd
)
1113 const unsigned int shnum
= this->shnum();
1114 bool is_gc_pass_one
= ((parameters
->options().gc_sections()
1115 && !symtab
->gc()->is_worklist_ready())
1116 || (parameters
->options().icf_enabled()
1117 && !symtab
->icf()->is_icf_ready()));
1119 bool is_gc_pass_two
= ((parameters
->options().gc_sections()
1120 && symtab
->gc()->is_worklist_ready())
1121 || (parameters
->options().icf_enabled()
1122 && symtab
->icf()->is_icf_ready()));
1124 bool is_gc_or_icf
= (parameters
->options().gc_sections()
1125 || parameters
->options().icf_enabled());
1127 // Both is_gc_pass_one and is_gc_pass_two should not be true.
1128 gold_assert(!(is_gc_pass_one
&& is_gc_pass_two
));
1132 Symbols_data
* gc_sd
= NULL
;
1135 // During garbage collection save the symbols data to use it when
1136 // re-entering this function.
1137 gc_sd
= new Symbols_data
;
1138 this->copy_symbols_data(gc_sd
, sd
, This::shdr_size
* shnum
);
1139 this->set_symbols_data(gc_sd
);
1141 else if (is_gc_pass_two
)
1143 gc_sd
= this->get_symbols_data();
1146 const unsigned char* section_headers_data
= NULL
;
1147 section_size_type section_names_size
;
1148 const unsigned char* symbols_data
= NULL
;
1149 section_size_type symbols_size
;
1150 section_offset_type external_symbols_offset
;
1151 const unsigned char* symbol_names_data
= NULL
;
1152 section_size_type symbol_names_size
;
1156 section_headers_data
= gc_sd
->section_headers_data
;
1157 section_names_size
= gc_sd
->section_names_size
;
1158 symbols_data
= gc_sd
->symbols_data
;
1159 symbols_size
= gc_sd
->symbols_size
;
1160 external_symbols_offset
= gc_sd
->external_symbols_offset
;
1161 symbol_names_data
= gc_sd
->symbol_names_data
;
1162 symbol_names_size
= gc_sd
->symbol_names_size
;
1166 section_headers_data
= sd
->section_headers
->data();
1167 section_names_size
= sd
->section_names_size
;
1168 if (sd
->symbols
!= NULL
)
1169 symbols_data
= sd
->symbols
->data();
1170 symbols_size
= sd
->symbols_size
;
1171 external_symbols_offset
= sd
->external_symbols_offset
;
1172 if (sd
->symbol_names
!= NULL
)
1173 symbol_names_data
= sd
->symbol_names
->data();
1174 symbol_names_size
= sd
->symbol_names_size
;
1177 // Get the section headers.
1178 const unsigned char* shdrs
= section_headers_data
;
1179 const unsigned char* pshdrs
;
1181 // Get the section names.
1182 const unsigned char* pnamesu
= (is_gc_or_icf
)
1183 ? gc_sd
->section_names_data
1184 : sd
->section_names
->data();
1186 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
1188 // If any input files have been claimed by plugins, we need to defer
1189 // actual layout until the replacement files have arrived.
1190 const bool should_defer_layout
=
1191 (parameters
->options().has_plugins()
1192 && parameters
->options().plugins()->should_defer_layout());
1193 unsigned int num_sections_to_defer
= 0;
1195 // For each section, record the index of the reloc section if any.
1196 // Use 0 to mean that there is no reloc section, -1U to mean that
1197 // there is more than one.
1198 std::vector
<unsigned int> reloc_shndx(shnum
, 0);
1199 std::vector
<unsigned int> reloc_type(shnum
, elfcpp::SHT_NULL
);
1200 // Skip the first, dummy, section.
1201 pshdrs
= shdrs
+ This::shdr_size
;
1202 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
1204 typename
This::Shdr
shdr(pshdrs
);
1206 // Count the number of sections whose layout will be deferred.
1207 if (should_defer_layout
&& (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
))
1208 ++num_sections_to_defer
;
1210 unsigned int sh_type
= shdr
.get_sh_type();
1211 if (sh_type
== elfcpp::SHT_REL
|| sh_type
== elfcpp::SHT_RELA
)
1213 unsigned int target_shndx
= this->adjust_shndx(shdr
.get_sh_info());
1214 if (target_shndx
== 0 || target_shndx
>= shnum
)
1216 this->error(_("relocation section %u has bad info %u"),
1221 if (reloc_shndx
[target_shndx
] != 0)
1222 reloc_shndx
[target_shndx
] = -1U;
1225 reloc_shndx
[target_shndx
] = i
;
1226 reloc_type
[target_shndx
] = sh_type
;
1231 Output_sections
& out_sections(this->output_sections());
1232 std::vector
<Address
>& out_section_offsets(this->section_offsets());
1234 if (!is_gc_pass_two
)
1236 out_sections
.resize(shnum
);
1237 out_section_offsets
.resize(shnum
);
1240 // If we are only linking for symbols, then there is nothing else to
1242 if (this->input_file()->just_symbols())
1244 if (!is_gc_pass_two
)
1246 delete sd
->section_headers
;
1247 sd
->section_headers
= NULL
;
1248 delete sd
->section_names
;
1249 sd
->section_names
= NULL
;
1254 if (num_sections_to_defer
> 0)
1256 parameters
->options().plugins()->add_deferred_layout_object(this);
1257 this->deferred_layout_
.reserve(num_sections_to_defer
);
1260 // Whether we've seen a .note.GNU-stack section.
1261 bool seen_gnu_stack
= false;
1262 // The flags of a .note.GNU-stack section.
1263 uint64_t gnu_stack_flags
= 0;
1265 // Keep track of which sections to omit.
1266 std::vector
<bool> omit(shnum
, false);
1268 // Keep track of reloc sections when emitting relocations.
1269 const bool relocatable
= parameters
->options().relocatable();
1270 const bool emit_relocs
= (relocatable
1271 || parameters
->options().emit_relocs());
1272 std::vector
<unsigned int> reloc_sections
;
1274 // Keep track of .eh_frame sections.
1275 std::vector
<unsigned int> eh_frame_sections
;
1277 // Skip the first, dummy, section.
1278 pshdrs
= shdrs
+ This::shdr_size
;
1279 for (unsigned int i
= 1; i
< shnum
; ++i
, pshdrs
+= This::shdr_size
)
1281 typename
This::Shdr
shdr(pshdrs
);
1283 if (shdr
.get_sh_name() >= section_names_size
)
1285 this->error(_("bad section name offset for section %u: %lu"),
1286 i
, static_cast<unsigned long>(shdr
.get_sh_name()));
1290 const char* name
= pnames
+ shdr
.get_sh_name();
1292 if (!is_gc_pass_two
)
1294 if (this->handle_gnu_warning_section(name
, i
, symtab
))
1296 if (!relocatable
&& !parameters
->options().shared())
1300 // The .note.GNU-stack section is special. It gives the
1301 // protection flags that this object file requires for the stack
1303 if (strcmp(name
, ".note.GNU-stack") == 0)
1305 seen_gnu_stack
= true;
1306 gnu_stack_flags
|= shdr
.get_sh_flags();
1310 // The .note.GNU-split-stack section is also special. It
1311 // indicates that the object was compiled with
1313 if (this->handle_split_stack_section(name
))
1315 if (!relocatable
&& !parameters
->options().shared())
1319 // Skip attributes section.
1320 if (parameters
->target().is_attributes_section(name
))
1325 bool discard
= omit
[i
];
1328 if (shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
1330 if (!this->include_section_group(symtab
, layout
, i
, name
,
1336 else if ((shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) == 0
1337 && Layout::is_linkonce(name
))
1339 if (!this->include_linkonce_section(layout
, i
, name
, shdr
))
1344 // Add the section to the incremental inputs layout.
1345 Incremental_inputs
* incremental_inputs
= layout
->incremental_inputs();
1346 if (incremental_inputs
!= NULL
1348 && (shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1349 || shdr
.get_sh_type() == elfcpp::SHT_NOBITS
1350 || shdr
.get_sh_type() == elfcpp::SHT_NOTE
))
1352 off_t sh_size
= shdr
.get_sh_size();
1353 section_size_type uncompressed_size
;
1354 if (this->section_is_compressed(i
, &uncompressed_size
))
1355 sh_size
= uncompressed_size
;
1356 incremental_inputs
->report_input_section(this, i
, name
, sh_size
);
1361 // Do not include this section in the link.
1362 out_sections
[i
] = NULL
;
1363 out_section_offsets
[i
] = invalid_address
;
1368 if (is_gc_pass_one
&& parameters
->options().gc_sections())
1370 if (this->is_section_name_included(name
)
1371 || shdr
.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1372 || shdr
.get_sh_type() == elfcpp::SHT_FINI_ARRAY
)
1374 symtab
->gc()->worklist().push(Section_id(this, i
));
1376 // If the section name XXX can be represented as a C identifier
1377 // it cannot be discarded if there are references to
1378 // __start_XXX and __stop_XXX symbols. These need to be
1379 // specially handled.
1380 if (is_cident(name
))
1382 symtab
->gc()->add_cident_section(name
, Section_id(this, i
));
1386 // When doing a relocatable link we are going to copy input
1387 // reloc sections into the output. We only want to copy the
1388 // ones associated with sections which are not being discarded.
1389 // However, we don't know that yet for all sections. So save
1390 // reloc sections and process them later. Garbage collection is
1391 // not triggered when relocatable code is desired.
1393 && (shdr
.get_sh_type() == elfcpp::SHT_REL
1394 || shdr
.get_sh_type() == elfcpp::SHT_RELA
))
1396 reloc_sections
.push_back(i
);
1400 if (relocatable
&& shdr
.get_sh_type() == elfcpp::SHT_GROUP
)
1403 // The .eh_frame section is special. It holds exception frame
1404 // information that we need to read in order to generate the
1405 // exception frame header. We process these after all the other
1406 // sections so that the exception frame reader can reliably
1407 // determine which sections are being discarded, and discard the
1408 // corresponding information.
1410 && strcmp(name
, ".eh_frame") == 0
1411 && this->check_eh_frame_flags(&shdr
))
1415 out_sections
[i
] = reinterpret_cast<Output_section
*>(1);
1416 out_section_offsets
[i
] = invalid_address
;
1418 else if (should_defer_layout
)
1419 this->deferred_layout_
.push_back(Deferred_layout(i
, name
,
1424 eh_frame_sections
.push_back(i
);
1428 if (is_gc_pass_two
&& parameters
->options().gc_sections())
1430 // This is executed during the second pass of garbage
1431 // collection. do_layout has been called before and some
1432 // sections have been already discarded. Simply ignore
1433 // such sections this time around.
1434 if (out_sections
[i
] == NULL
)
1436 gold_assert(out_section_offsets
[i
] == invalid_address
);
1439 if (((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0)
1440 && symtab
->gc()->is_section_garbage(this, i
))
1442 if (parameters
->options().print_gc_sections())
1443 gold_info(_("%s: removing unused section from '%s'"
1445 program_name
, this->section_name(i
).c_str(),
1446 this->name().c_str());
1447 out_sections
[i
] = NULL
;
1448 out_section_offsets
[i
] = invalid_address
;
1453 if (is_gc_pass_two
&& parameters
->options().icf_enabled())
1455 if (out_sections
[i
] == NULL
)
1457 gold_assert(out_section_offsets
[i
] == invalid_address
);
1460 if (((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0)
1461 && symtab
->icf()->is_section_folded(this, i
))
1463 if (parameters
->options().print_icf_sections())
1466 symtab
->icf()->get_folded_section(this, i
);
1467 Relobj
* folded_obj
=
1468 reinterpret_cast<Relobj
*>(folded
.first
);
1469 gold_info(_("%s: ICF folding section '%s' in file '%s'"
1470 "into '%s' in file '%s'"),
1471 program_name
, this->section_name(i
).c_str(),
1472 this->name().c_str(),
1473 folded_obj
->section_name(folded
.second
).c_str(),
1474 folded_obj
->name().c_str());
1476 out_sections
[i
] = NULL
;
1477 out_section_offsets
[i
] = invalid_address
;
1482 // Defer layout here if input files are claimed by plugins. When gc
1483 // is turned on this function is called twice. For the second call
1484 // should_defer_layout should be false.
1485 if (should_defer_layout
&& (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
))
1487 gold_assert(!is_gc_pass_two
);
1488 this->deferred_layout_
.push_back(Deferred_layout(i
, name
,
1492 // Put dummy values here; real values will be supplied by
1493 // do_layout_deferred_sections.
1494 out_sections
[i
] = reinterpret_cast<Output_section
*>(2);
1495 out_section_offsets
[i
] = invalid_address
;
1499 // During gc_pass_two if a section that was previously deferred is
1500 // found, do not layout the section as layout_deferred_sections will
1501 // do it later from gold.cc.
1503 && (out_sections
[i
] == reinterpret_cast<Output_section
*>(2)))
1508 // This is during garbage collection. The out_sections are
1509 // assigned in the second call to this function.
1510 out_sections
[i
] = reinterpret_cast<Output_section
*>(1);
1511 out_section_offsets
[i
] = invalid_address
;
1515 // When garbage collection is switched on the actual layout
1516 // only happens in the second call.
1517 this->layout_section(layout
, i
, name
, shdr
, reloc_shndx
[i
],
1522 if (!is_gc_pass_two
)
1523 layout
->layout_gnu_stack(seen_gnu_stack
, gnu_stack_flags
, this);
1525 // When doing a relocatable link handle the reloc sections at the
1526 // end. Garbage collection and Identical Code Folding is not
1527 // turned on for relocatable code.
1529 this->size_relocatable_relocs();
1531 gold_assert(!(is_gc_or_icf
) || reloc_sections
.empty());
1533 for (std::vector
<unsigned int>::const_iterator p
= reloc_sections
.begin();
1534 p
!= reloc_sections
.end();
1537 unsigned int i
= *p
;
1538 const unsigned char* pshdr
;
1539 pshdr
= section_headers_data
+ i
* This::shdr_size
;
1540 typename
This::Shdr
shdr(pshdr
);
1542 unsigned int data_shndx
= this->adjust_shndx(shdr
.get_sh_info());
1543 if (data_shndx
>= shnum
)
1545 // We already warned about this above.
1549 Output_section
* data_section
= out_sections
[data_shndx
];
1550 if (data_section
== reinterpret_cast<Output_section
*>(2))
1552 // The layout for the data section was deferred, so we need
1553 // to defer the relocation section, too.
1554 const char* name
= pnames
+ shdr
.get_sh_name();
1555 this->deferred_layout_relocs_
.push_back(
1556 Deferred_layout(i
, name
, pshdr
, 0, elfcpp::SHT_NULL
));
1557 out_sections
[i
] = reinterpret_cast<Output_section
*>(2);
1558 out_section_offsets
[i
] = invalid_address
;
1561 if (data_section
== NULL
)
1563 out_sections
[i
] = NULL
;
1564 out_section_offsets
[i
] = invalid_address
;
1568 Relocatable_relocs
* rr
= new Relocatable_relocs();
1569 this->set_relocatable_relocs(i
, rr
);
1571 Output_section
* os
= layout
->layout_reloc(this, i
, shdr
, data_section
,
1573 out_sections
[i
] = os
;
1574 out_section_offsets
[i
] = invalid_address
;
1577 // Handle the .eh_frame sections at the end.
1578 gold_assert(!is_gc_pass_one
|| eh_frame_sections
.empty());
1579 for (std::vector
<unsigned int>::const_iterator p
= eh_frame_sections
.begin();
1580 p
!= eh_frame_sections
.end();
1583 gold_assert(external_symbols_offset
!= 0);
1585 unsigned int i
= *p
;
1586 const unsigned char* pshdr
;
1587 pshdr
= section_headers_data
+ i
* This::shdr_size
;
1588 typename
This::Shdr
shdr(pshdr
);
1590 this->layout_eh_frame_section(layout
,
1603 delete[] gc_sd
->section_headers_data
;
1604 delete[] gc_sd
->section_names_data
;
1605 delete[] gc_sd
->symbols_data
;
1606 delete[] gc_sd
->symbol_names_data
;
1607 this->set_symbols_data(NULL
);
1611 delete sd
->section_headers
;
1612 sd
->section_headers
= NULL
;
1613 delete sd
->section_names
;
1614 sd
->section_names
= NULL
;
1618 // Layout sections whose layout was deferred while waiting for
1619 // input files from a plugin.
1621 template<int size
, bool big_endian
>
1623 Sized_relobj_file
<size
, big_endian
>::do_layout_deferred_sections(Layout
* layout
)
1625 typename
std::vector
<Deferred_layout
>::iterator deferred
;
1627 for (deferred
= this->deferred_layout_
.begin();
1628 deferred
!= this->deferred_layout_
.end();
1631 typename
This::Shdr
shdr(deferred
->shdr_data_
);
1632 // If the section is not included, it is because the garbage collector
1633 // decided it is not needed. Avoid reverting that decision.
1634 if (!this->is_section_included(deferred
->shndx_
))
1637 if (parameters
->options().relocatable()
1638 || deferred
->name_
!= ".eh_frame"
1639 || !this->check_eh_frame_flags(&shdr
))
1640 this->layout_section(layout
, deferred
->shndx_
, deferred
->name_
.c_str(),
1641 shdr
, deferred
->reloc_shndx_
,
1642 deferred
->reloc_type_
);
1645 // Reading the symbols again here may be slow.
1646 Read_symbols_data sd
;
1647 this->read_symbols(&sd
);
1648 this->layout_eh_frame_section(layout
,
1651 sd
.symbol_names
->data(),
1652 sd
.symbol_names_size
,
1655 deferred
->reloc_shndx_
,
1656 deferred
->reloc_type_
);
1660 this->deferred_layout_
.clear();
1662 // Now handle the deferred relocation sections.
1664 Output_sections
& out_sections(this->output_sections());
1665 std::vector
<Address
>& out_section_offsets(this->section_offsets());
1667 for (deferred
= this->deferred_layout_relocs_
.begin();
1668 deferred
!= this->deferred_layout_relocs_
.end();
1671 unsigned int shndx
= deferred
->shndx_
;
1672 typename
This::Shdr
shdr(deferred
->shdr_data_
);
1673 unsigned int data_shndx
= this->adjust_shndx(shdr
.get_sh_info());
1675 Output_section
* data_section
= out_sections
[data_shndx
];
1676 if (data_section
== NULL
)
1678 out_sections
[shndx
] = NULL
;
1679 out_section_offsets
[shndx
] = invalid_address
;
1683 Relocatable_relocs
* rr
= new Relocatable_relocs();
1684 this->set_relocatable_relocs(shndx
, rr
);
1686 Output_section
* os
= layout
->layout_reloc(this, shndx
, shdr
,
1688 out_sections
[shndx
] = os
;
1689 out_section_offsets
[shndx
] = invalid_address
;
1693 // Add the symbols to the symbol table.
1695 template<int size
, bool big_endian
>
1697 Sized_relobj_file
<size
, big_endian
>::do_add_symbols(Symbol_table
* symtab
,
1698 Read_symbols_data
* sd
,
1701 if (sd
->symbols
== NULL
)
1703 gold_assert(sd
->symbol_names
== NULL
);
1707 const int sym_size
= This::sym_size
;
1708 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
1710 if (symcount
* sym_size
!= sd
->symbols_size
- sd
->external_symbols_offset
)
1712 this->error(_("size of symbols is not multiple of symbol size"));
1716 this->symbols_
.resize(symcount
);
1718 const char* sym_names
=
1719 reinterpret_cast<const char*>(sd
->symbol_names
->data());
1720 symtab
->add_from_relobj(this,
1721 sd
->symbols
->data() + sd
->external_symbols_offset
,
1722 symcount
, this->local_symbol_count_
,
1723 sym_names
, sd
->symbol_names_size
,
1725 &this->defined_count_
);
1729 delete sd
->symbol_names
;
1730 sd
->symbol_names
= NULL
;
1733 // Find out if this object, that is a member of a lib group, should be included
1734 // in the link. We check every symbol defined by this object. If the symbol
1735 // table has a strong undefined reference to that symbol, we have to include
1738 template<int size
, bool big_endian
>
1739 Archive::Should_include
1740 Sized_relobj_file
<size
, big_endian
>::do_should_include_member(
1741 Symbol_table
* symtab
,
1743 Read_symbols_data
* sd
,
1746 char* tmpbuf
= NULL
;
1747 size_t tmpbuflen
= 0;
1748 const char* sym_names
=
1749 reinterpret_cast<const char*>(sd
->symbol_names
->data());
1750 const unsigned char* syms
=
1751 sd
->symbols
->data() + sd
->external_symbols_offset
;
1752 const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
1753 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
1756 const unsigned char* p
= syms
;
1758 for (size_t i
= 0; i
< symcount
; ++i
, p
+= sym_size
)
1760 elfcpp::Sym
<size
, big_endian
> sym(p
);
1761 unsigned int st_shndx
= sym
.get_st_shndx();
1762 if (st_shndx
== elfcpp::SHN_UNDEF
)
1765 unsigned int st_name
= sym
.get_st_name();
1766 const char* name
= sym_names
+ st_name
;
1768 Archive::Should_include t
= Archive::should_include_member(symtab
,
1774 if (t
== Archive::SHOULD_INCLUDE_YES
)
1783 return Archive::SHOULD_INCLUDE_UNKNOWN
;
1786 // Iterate over global defined symbols, calling a visitor class V for each.
1788 template<int size
, bool big_endian
>
1790 Sized_relobj_file
<size
, big_endian
>::do_for_all_global_symbols(
1791 Read_symbols_data
* sd
,
1792 Library_base::Symbol_visitor_base
* v
)
1794 const char* sym_names
=
1795 reinterpret_cast<const char*>(sd
->symbol_names
->data());
1796 const unsigned char* syms
=
1797 sd
->symbols
->data() + sd
->external_symbols_offset
;
1798 const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
1799 size_t symcount
= ((sd
->symbols_size
- sd
->external_symbols_offset
)
1801 const unsigned char* p
= syms
;
1803 for (size_t i
= 0; i
< symcount
; ++i
, p
+= sym_size
)
1805 elfcpp::Sym
<size
, big_endian
> sym(p
);
1806 if (sym
.get_st_shndx() != elfcpp::SHN_UNDEF
)
1807 v
->visit(sym_names
+ sym
.get_st_name());
1811 // Return whether the local symbol SYMNDX has a PLT offset.
1813 template<int size
, bool big_endian
>
1815 Sized_relobj_file
<size
, big_endian
>::local_has_plt_offset(
1816 unsigned int symndx
) const
1818 typename
Local_plt_offsets::const_iterator p
=
1819 this->local_plt_offsets_
.find(symndx
);
1820 return p
!= this->local_plt_offsets_
.end();
1823 // Get the PLT offset of a local symbol.
1825 template<int size
, bool big_endian
>
1827 Sized_relobj_file
<size
, big_endian
>::local_plt_offset(unsigned int symndx
) const
1829 typename
Local_plt_offsets::const_iterator p
=
1830 this->local_plt_offsets_
.find(symndx
);
1831 gold_assert(p
!= this->local_plt_offsets_
.end());
1835 // Set the PLT offset of a local symbol.
1837 template<int size
, bool big_endian
>
1839 Sized_relobj_file
<size
, big_endian
>::set_local_plt_offset(
1840 unsigned int symndx
, unsigned int plt_offset
)
1842 std::pair
<typename
Local_plt_offsets::iterator
, bool> ins
=
1843 this->local_plt_offsets_
.insert(std::make_pair(symndx
, plt_offset
));
1844 gold_assert(ins
.second
);
1847 // First pass over the local symbols. Here we add their names to
1848 // *POOL and *DYNPOOL, and we store the symbol value in
1849 // THIS->LOCAL_VALUES_. This function is always called from a
1850 // singleton thread. This is followed by a call to
1851 // finalize_local_symbols.
1853 template<int size
, bool big_endian
>
1855 Sized_relobj_file
<size
, big_endian
>::do_count_local_symbols(Stringpool
* pool
,
1856 Stringpool
* dynpool
)
1858 gold_assert(this->symtab_shndx_
!= -1U);
1859 if (this->symtab_shndx_
== 0)
1861 // This object has no symbols. Weird but legal.
1865 // Read the symbol table section header.
1866 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1867 typename
This::Shdr
symtabshdr(this,
1868 this->elf_file_
.section_header(symtab_shndx
));
1869 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1871 // Read the local symbols.
1872 const int sym_size
= This::sym_size
;
1873 const unsigned int loccount
= this->local_symbol_count_
;
1874 gold_assert(loccount
== symtabshdr
.get_sh_info());
1875 off_t locsize
= loccount
* sym_size
;
1876 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1877 locsize
, true, true);
1879 // Read the symbol names.
1880 const unsigned int strtab_shndx
=
1881 this->adjust_shndx(symtabshdr
.get_sh_link());
1882 section_size_type strtab_size
;
1883 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
1886 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
1888 // Loop over the local symbols.
1890 const Output_sections
& out_sections(this->output_sections());
1891 unsigned int shnum
= this->shnum();
1892 unsigned int count
= 0;
1893 unsigned int dyncount
= 0;
1894 // Skip the first, dummy, symbol.
1896 bool strip_all
= parameters
->options().strip_all();
1897 bool discard_all
= parameters
->options().discard_all();
1898 bool discard_locals
= parameters
->options().discard_locals();
1899 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
1901 elfcpp::Sym
<size
, big_endian
> sym(psyms
);
1903 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1906 unsigned int shndx
= this->adjust_sym_shndx(i
, sym
.get_st_shndx(),
1908 lv
.set_input_shndx(shndx
, is_ordinary
);
1910 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
1911 lv
.set_is_section_symbol();
1912 else if (sym
.get_st_type() == elfcpp::STT_TLS
)
1913 lv
.set_is_tls_symbol();
1914 else if (sym
.get_st_type() == elfcpp::STT_GNU_IFUNC
)
1915 lv
.set_is_ifunc_symbol();
1917 // Save the input symbol value for use in do_finalize_local_symbols().
1918 lv
.set_input_value(sym
.get_st_value());
1920 // Decide whether this symbol should go into the output file.
1922 if ((shndx
< shnum
&& out_sections
[shndx
] == NULL
)
1923 || shndx
== this->discarded_eh_frame_shndx_
)
1925 lv
.set_no_output_symtab_entry();
1926 gold_assert(!lv
.needs_output_dynsym_entry());
1930 if (sym
.get_st_type() == elfcpp::STT_SECTION
)
1932 lv
.set_no_output_symtab_entry();
1933 gold_assert(!lv
.needs_output_dynsym_entry());
1937 if (sym
.get_st_name() >= strtab_size
)
1939 this->error(_("local symbol %u section name out of range: %u >= %u"),
1940 i
, sym
.get_st_name(),
1941 static_cast<unsigned int>(strtab_size
));
1942 lv
.set_no_output_symtab_entry();
1946 const char* name
= pnames
+ sym
.get_st_name();
1948 // If needed, add the symbol to the dynamic symbol table string pool.
1949 if (lv
.needs_output_dynsym_entry())
1951 dynpool
->add(name
, true, NULL
);
1956 || (discard_all
&& lv
.may_be_discarded_from_output_symtab()))
1958 lv
.set_no_output_symtab_entry();
1962 // If --discard-locals option is used, discard all temporary local
1963 // symbols. These symbols start with system-specific local label
1964 // prefixes, typically .L for ELF system. We want to be compatible
1965 // with GNU ld so here we essentially use the same check in
1966 // bfd_is_local_label(). The code is different because we already
1969 // - the symbol is local and thus cannot have global or weak binding.
1970 // - the symbol is not a section symbol.
1971 // - the symbol has a name.
1973 // We do not discard a symbol if it needs a dynamic symbol entry.
1975 && sym
.get_st_type() != elfcpp::STT_FILE
1976 && !lv
.needs_output_dynsym_entry()
1977 && lv
.may_be_discarded_from_output_symtab()
1978 && parameters
->target().is_local_label_name(name
))
1980 lv
.set_no_output_symtab_entry();
1984 // Discard the local symbol if -retain_symbols_file is specified
1985 // and the local symbol is not in that file.
1986 if (!parameters
->options().should_retain_symbol(name
))
1988 lv
.set_no_output_symtab_entry();
1992 // Add the symbol to the symbol table string pool.
1993 pool
->add(name
, true, NULL
);
1997 this->output_local_symbol_count_
= count
;
1998 this->output_local_dynsym_count_
= dyncount
;
2001 // Compute the final value of a local symbol.
2003 template<int size
, bool big_endian
>
2004 typename Sized_relobj_file
<size
, big_endian
>::Compute_final_local_value_status
2005 Sized_relobj_file
<size
, big_endian
>::compute_final_local_value_internal(
2007 const Symbol_value
<size
>* lv_in
,
2008 Symbol_value
<size
>* lv_out
,
2010 const Output_sections
& out_sections
,
2011 const std::vector
<Address
>& out_offsets
,
2012 const Symbol_table
* symtab
)
2014 // We are going to overwrite *LV_OUT, if it has a merged symbol value,
2015 // we may have a memory leak.
2016 gold_assert(lv_out
->has_output_value());
2019 unsigned int shndx
= lv_in
->input_shndx(&is_ordinary
);
2021 // Set the output symbol value.
2025 if (shndx
== elfcpp::SHN_ABS
|| Symbol::is_common_shndx(shndx
))
2026 lv_out
->set_output_value(lv_in
->input_value());
2029 this->error(_("unknown section index %u for local symbol %u"),
2031 lv_out
->set_output_value(0);
2032 return This::CFLV_ERROR
;
2037 if (shndx
>= this->shnum())
2039 this->error(_("local symbol %u section index %u out of range"),
2041 lv_out
->set_output_value(0);
2042 return This::CFLV_ERROR
;
2045 Output_section
* os
= out_sections
[shndx
];
2046 Address secoffset
= out_offsets
[shndx
];
2047 if (symtab
->is_section_folded(this, shndx
))
2049 gold_assert(os
== NULL
&& secoffset
== invalid_address
);
2050 // Get the os of the section it is folded onto.
2051 Section_id folded
= symtab
->icf()->get_folded_section(this,
2053 gold_assert(folded
.first
!= NULL
);
2054 Sized_relobj_file
<size
, big_endian
>* folded_obj
= reinterpret_cast
2055 <Sized_relobj_file
<size
, big_endian
>*>(folded
.first
);
2056 os
= folded_obj
->output_section(folded
.second
);
2057 gold_assert(os
!= NULL
);
2058 secoffset
= folded_obj
->get_output_section_offset(folded
.second
);
2060 // This could be a relaxed input section.
2061 if (secoffset
== invalid_address
)
2063 const Output_relaxed_input_section
* relaxed_section
=
2064 os
->find_relaxed_input_section(folded_obj
, folded
.second
);
2065 gold_assert(relaxed_section
!= NULL
);
2066 secoffset
= relaxed_section
->address() - os
->address();
2072 // This local symbol belongs to a section we are discarding.
2073 // In some cases when applying relocations later, we will
2074 // attempt to match it to the corresponding kept section,
2075 // so we leave the input value unchanged here.
2076 return This::CFLV_DISCARDED
;
2078 else if (secoffset
== invalid_address
)
2082 // This is a SHF_MERGE section or one which otherwise
2083 // requires special handling.
2084 if (shndx
== this->discarded_eh_frame_shndx_
)
2086 // This local symbol belongs to a discarded .eh_frame
2087 // section. Just treat it like the case in which
2088 // os == NULL above.
2089 gold_assert(this->has_eh_frame_
);
2090 return This::CFLV_DISCARDED
;
2092 else if (!lv_in
->is_section_symbol())
2094 // This is not a section symbol. We can determine
2095 // the final value now.
2096 lv_out
->set_output_value(
2097 os
->output_address(this, shndx
, lv_in
->input_value()));
2099 else if (!os
->find_starting_output_address(this, shndx
, &start
))
2101 // This is a section symbol, but apparently not one in a
2102 // merged section. First check to see if this is a relaxed
2103 // input section. If so, use its address. Otherwise just
2104 // use the start of the output section. This happens with
2105 // relocatable links when the input object has section
2106 // symbols for arbitrary non-merge sections.
2107 const Output_section_data
* posd
=
2108 os
->find_relaxed_input_section(this, shndx
);
2111 Address relocatable_link_adjustment
=
2112 relocatable
? os
->address() : 0;
2113 lv_out
->set_output_value(posd
->address()
2114 - relocatable_link_adjustment
);
2117 lv_out
->set_output_value(os
->address());
2121 // We have to consider the addend to determine the
2122 // value to use in a relocation. START is the start
2123 // of this input section. If we are doing a relocatable
2124 // link, use offset from start output section instead of
2126 Address adjusted_start
=
2127 relocatable
? start
- os
->address() : start
;
2128 Merged_symbol_value
<size
>* msv
=
2129 new Merged_symbol_value
<size
>(lv_in
->input_value(),
2131 lv_out
->set_merged_symbol_value(msv
);
2134 else if (lv_in
->is_tls_symbol())
2135 lv_out
->set_output_value(os
->tls_offset()
2137 + lv_in
->input_value());
2139 lv_out
->set_output_value((relocatable
? 0 : os
->address())
2141 + lv_in
->input_value());
2143 return This::CFLV_OK
;
2146 // Compute final local symbol value. R_SYM is the index of a local
2147 // symbol in symbol table. LV points to a symbol value, which is
2148 // expected to hold the input value and to be over-written by the
2149 // final value. SYMTAB points to a symbol table. Some targets may want
2150 // to know would-be-finalized local symbol values in relaxation.
2151 // Hence we provide this method. Since this method updates *LV, a
2152 // callee should make a copy of the original local symbol value and
2153 // use the copy instead of modifying an object's local symbols before
2154 // everything is finalized. The caller should also free up any allocated
2155 // memory in the return value in *LV.
2156 template<int size
, bool big_endian
>
2157 typename Sized_relobj_file
<size
, big_endian
>::Compute_final_local_value_status
2158 Sized_relobj_file
<size
, big_endian
>::compute_final_local_value(
2160 const Symbol_value
<size
>* lv_in
,
2161 Symbol_value
<size
>* lv_out
,
2162 const Symbol_table
* symtab
)
2164 // This is just a wrapper of compute_final_local_value_internal.
2165 const bool relocatable
= parameters
->options().relocatable();
2166 const Output_sections
& out_sections(this->output_sections());
2167 const std::vector
<Address
>& out_offsets(this->section_offsets());
2168 return this->compute_final_local_value_internal(r_sym
, lv_in
, lv_out
,
2169 relocatable
, out_sections
,
2170 out_offsets
, symtab
);
2173 // Finalize the local symbols. Here we set the final value in
2174 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
2175 // This function is always called from a singleton thread. The actual
2176 // output of the local symbols will occur in a separate task.
2178 template<int size
, bool big_endian
>
2180 Sized_relobj_file
<size
, big_endian
>::do_finalize_local_symbols(
2183 Symbol_table
* symtab
)
2185 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
2187 const unsigned int loccount
= this->local_symbol_count_
;
2188 this->local_symbol_offset_
= off
;
2190 const bool relocatable
= parameters
->options().relocatable();
2191 const Output_sections
& out_sections(this->output_sections());
2192 const std::vector
<Address
>& out_offsets(this->section_offsets());
2194 for (unsigned int i
= 1; i
< loccount
; ++i
)
2196 Symbol_value
<size
>* lv
= &this->local_values_
[i
];
2198 Compute_final_local_value_status cflv_status
=
2199 this->compute_final_local_value_internal(i
, lv
, lv
, relocatable
,
2200 out_sections
, out_offsets
,
2202 switch (cflv_status
)
2205 if (!lv
->is_output_symtab_index_set())
2207 lv
->set_output_symtab_index(index
);
2211 case CFLV_DISCARDED
:
2222 // Set the output dynamic symbol table indexes for the local variables.
2224 template<int size
, bool big_endian
>
2226 Sized_relobj_file
<size
, big_endian
>::do_set_local_dynsym_indexes(
2229 const unsigned int loccount
= this->local_symbol_count_
;
2230 for (unsigned int i
= 1; i
< loccount
; ++i
)
2232 Symbol_value
<size
>& lv(this->local_values_
[i
]);
2233 if (lv
.needs_output_dynsym_entry())
2235 lv
.set_output_dynsym_index(index
);
2242 // Set the offset where local dynamic symbol information will be stored.
2243 // Returns the count of local symbols contributed to the symbol table by
2246 template<int size
, bool big_endian
>
2248 Sized_relobj_file
<size
, big_endian
>::do_set_local_dynsym_offset(off_t off
)
2250 gold_assert(off
== static_cast<off_t
>(align_address(off
, size
>> 3)));
2251 this->local_dynsym_offset_
= off
;
2252 return this->output_local_dynsym_count_
;
2255 // If Symbols_data is not NULL get the section flags from here otherwise
2256 // get it from the file.
2258 template<int size
, bool big_endian
>
2260 Sized_relobj_file
<size
, big_endian
>::do_section_flags(unsigned int shndx
)
2262 Symbols_data
* sd
= this->get_symbols_data();
2265 const unsigned char* pshdrs
= sd
->section_headers_data
2266 + This::shdr_size
* shndx
;
2267 typename
This::Shdr
shdr(pshdrs
);
2268 return shdr
.get_sh_flags();
2270 // If sd is NULL, read the section header from the file.
2271 return this->elf_file_
.section_flags(shndx
);
2274 // Get the section's ent size from Symbols_data. Called by get_section_contents
2277 template<int size
, bool big_endian
>
2279 Sized_relobj_file
<size
, big_endian
>::do_section_entsize(unsigned int shndx
)
2281 Symbols_data
* sd
= this->get_symbols_data();
2282 gold_assert(sd
!= NULL
);
2284 const unsigned char* pshdrs
= sd
->section_headers_data
2285 + This::shdr_size
* shndx
;
2286 typename
This::Shdr
shdr(pshdrs
);
2287 return shdr
.get_sh_entsize();
2290 // Write out the local symbols.
2292 template<int size
, bool big_endian
>
2294 Sized_relobj_file
<size
, big_endian
>::write_local_symbols(
2296 const Stringpool
* sympool
,
2297 const Stringpool
* dynpool
,
2298 Output_symtab_xindex
* symtab_xindex
,
2299 Output_symtab_xindex
* dynsym_xindex
,
2302 const bool strip_all
= parameters
->options().strip_all();
2305 if (this->output_local_dynsym_count_
== 0)
2307 this->output_local_symbol_count_
= 0;
2310 gold_assert(this->symtab_shndx_
!= -1U);
2311 if (this->symtab_shndx_
== 0)
2313 // This object has no symbols. Weird but legal.
2317 // Read the symbol table section header.
2318 const unsigned int symtab_shndx
= this->symtab_shndx_
;
2319 typename
This::Shdr
symtabshdr(this,
2320 this->elf_file_
.section_header(symtab_shndx
));
2321 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
2322 const unsigned int loccount
= this->local_symbol_count_
;
2323 gold_assert(loccount
== symtabshdr
.get_sh_info());
2325 // Read the local symbols.
2326 const int sym_size
= This::sym_size
;
2327 off_t locsize
= loccount
* sym_size
;
2328 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
2329 locsize
, true, false);
2331 // Read the symbol names.
2332 const unsigned int strtab_shndx
=
2333 this->adjust_shndx(symtabshdr
.get_sh_link());
2334 section_size_type strtab_size
;
2335 const unsigned char* pnamesu
= this->section_contents(strtab_shndx
,
2338 const char* pnames
= reinterpret_cast<const char*>(pnamesu
);
2340 // Get views into the output file for the portions of the symbol table
2341 // and the dynamic symbol table that we will be writing.
2342 off_t output_size
= this->output_local_symbol_count_
* sym_size
;
2343 unsigned char* oview
= NULL
;
2344 if (output_size
> 0)
2345 oview
= of
->get_output_view(symtab_off
+ this->local_symbol_offset_
,
2348 off_t dyn_output_size
= this->output_local_dynsym_count_
* sym_size
;
2349 unsigned char* dyn_oview
= NULL
;
2350 if (dyn_output_size
> 0)
2351 dyn_oview
= of
->get_output_view(this->local_dynsym_offset_
,
2354 const Output_sections
out_sections(this->output_sections());
2356 gold_assert(this->local_values_
.size() == loccount
);
2358 unsigned char* ov
= oview
;
2359 unsigned char* dyn_ov
= dyn_oview
;
2361 for (unsigned int i
= 1; i
< loccount
; ++i
, psyms
+= sym_size
)
2363 elfcpp::Sym
<size
, big_endian
> isym(psyms
);
2365 Symbol_value
<size
>& lv(this->local_values_
[i
]);
2368 unsigned int st_shndx
= this->adjust_sym_shndx(i
, isym
.get_st_shndx(),
2372 gold_assert(st_shndx
< out_sections
.size());
2373 if (out_sections
[st_shndx
] == NULL
)
2375 st_shndx
= out_sections
[st_shndx
]->out_shndx();
2376 if (st_shndx
>= elfcpp::SHN_LORESERVE
)
2378 if (lv
.has_output_symtab_entry())
2379 symtab_xindex
->add(lv
.output_symtab_index(), st_shndx
);
2380 if (lv
.has_output_dynsym_entry())
2381 dynsym_xindex
->add(lv
.output_dynsym_index(), st_shndx
);
2382 st_shndx
= elfcpp::SHN_XINDEX
;
2386 // Write the symbol to the output symbol table.
2387 if (lv
.has_output_symtab_entry())
2389 elfcpp::Sym_write
<size
, big_endian
> osym(ov
);
2391 gold_assert(isym
.get_st_name() < strtab_size
);
2392 const char* name
= pnames
+ isym
.get_st_name();
2393 osym
.put_st_name(sympool
->get_offset(name
));
2394 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
2395 osym
.put_st_size(isym
.get_st_size());
2396 osym
.put_st_info(isym
.get_st_info());
2397 osym
.put_st_other(isym
.get_st_other());
2398 osym
.put_st_shndx(st_shndx
);
2403 // Write the symbol to the output dynamic symbol table.
2404 if (lv
.has_output_dynsym_entry())
2406 gold_assert(dyn_ov
< dyn_oview
+ dyn_output_size
);
2407 elfcpp::Sym_write
<size
, big_endian
> osym(dyn_ov
);
2409 gold_assert(isym
.get_st_name() < strtab_size
);
2410 const char* name
= pnames
+ isym
.get_st_name();
2411 osym
.put_st_name(dynpool
->get_offset(name
));
2412 osym
.put_st_value(this->local_values_
[i
].value(this, 0));
2413 osym
.put_st_size(isym
.get_st_size());
2414 osym
.put_st_info(isym
.get_st_info());
2415 osym
.put_st_other(isym
.get_st_other());
2416 osym
.put_st_shndx(st_shndx
);
2423 if (output_size
> 0)
2425 gold_assert(ov
- oview
== output_size
);
2426 of
->write_output_view(symtab_off
+ this->local_symbol_offset_
,
2427 output_size
, oview
);
2430 if (dyn_output_size
> 0)
2432 gold_assert(dyn_ov
- dyn_oview
== dyn_output_size
);
2433 of
->write_output_view(this->local_dynsym_offset_
, dyn_output_size
,
2438 // Set *INFO to symbolic information about the offset OFFSET in the
2439 // section SHNDX. Return true if we found something, false if we
2442 template<int size
, bool big_endian
>
2444 Sized_relobj_file
<size
, big_endian
>::get_symbol_location_info(
2447 Symbol_location_info
* info
)
2449 if (this->symtab_shndx_
== 0)
2452 section_size_type symbols_size
;
2453 const unsigned char* symbols
= this->section_contents(this->symtab_shndx_
,
2457 unsigned int symbol_names_shndx
=
2458 this->adjust_shndx(this->section_link(this->symtab_shndx_
));
2459 section_size_type names_size
;
2460 const unsigned char* symbol_names_u
=
2461 this->section_contents(symbol_names_shndx
, &names_size
, false);
2462 const char* symbol_names
= reinterpret_cast<const char*>(symbol_names_u
);
2464 const int sym_size
= This::sym_size
;
2465 const size_t count
= symbols_size
/ sym_size
;
2467 const unsigned char* p
= symbols
;
2468 for (size_t i
= 0; i
< count
; ++i
, p
+= sym_size
)
2470 elfcpp::Sym
<size
, big_endian
> sym(p
);
2472 if (sym
.get_st_type() == elfcpp::STT_FILE
)
2474 if (sym
.get_st_name() >= names_size
)
2475 info
->source_file
= "(invalid)";
2477 info
->source_file
= symbol_names
+ sym
.get_st_name();
2482 unsigned int st_shndx
= this->adjust_sym_shndx(i
, sym
.get_st_shndx(),
2485 && st_shndx
== shndx
2486 && static_cast<off_t
>(sym
.get_st_value()) <= offset
2487 && (static_cast<off_t
>(sym
.get_st_value() + sym
.get_st_size())
2490 if (sym
.get_st_name() > names_size
)
2491 info
->enclosing_symbol_name
= "(invalid)";
2494 info
->enclosing_symbol_name
= symbol_names
+ sym
.get_st_name();
2495 if (parameters
->options().do_demangle())
2497 char* demangled_name
= cplus_demangle(
2498 info
->enclosing_symbol_name
.c_str(),
2499 DMGL_ANSI
| DMGL_PARAMS
);
2500 if (demangled_name
!= NULL
)
2502 info
->enclosing_symbol_name
.assign(demangled_name
);
2503 free(demangled_name
);
2514 // Look for a kept section corresponding to the given discarded section,
2515 // and return its output address. This is used only for relocations in
2516 // debugging sections. If we can't find the kept section, return 0.
2518 template<int size
, bool big_endian
>
2519 typename Sized_relobj_file
<size
, big_endian
>::Address
2520 Sized_relobj_file
<size
, big_endian
>::map_to_kept_section(
2524 Relobj
* kept_object
;
2525 unsigned int kept_shndx
;
2526 if (this->get_kept_comdat_section(shndx
, &kept_object
, &kept_shndx
))
2528 Sized_relobj_file
<size
, big_endian
>* kept_relobj
=
2529 static_cast<Sized_relobj_file
<size
, big_endian
>*>(kept_object
);
2530 Output_section
* os
= kept_relobj
->output_section(kept_shndx
);
2531 Address offset
= kept_relobj
->get_output_section_offset(kept_shndx
);
2532 if (os
!= NULL
&& offset
!= invalid_address
)
2535 return os
->address() + offset
;
2542 // Get symbol counts.
2544 template<int size
, bool big_endian
>
2546 Sized_relobj_file
<size
, big_endian
>::do_get_global_symbol_counts(
2547 const Symbol_table
*,
2551 *defined
= this->defined_count_
;
2553 for (typename
Symbols::const_iterator p
= this->symbols_
.begin();
2554 p
!= this->symbols_
.end();
2557 && (*p
)->source() == Symbol::FROM_OBJECT
2558 && (*p
)->object() == this
2559 && (*p
)->is_defined())
2564 // Input_objects methods.
2566 // Add a regular relocatable object to the list. Return false if this
2567 // object should be ignored.
2570 Input_objects::add_object(Object
* obj
)
2572 // Print the filename if the -t/--trace option is selected.
2573 if (parameters
->options().trace())
2574 gold_info("%s", obj
->name().c_str());
2576 if (!obj
->is_dynamic())
2577 this->relobj_list_
.push_back(static_cast<Relobj
*>(obj
));
2580 // See if this is a duplicate SONAME.
2581 Dynobj
* dynobj
= static_cast<Dynobj
*>(obj
);
2582 const char* soname
= dynobj
->soname();
2584 std::pair
<Unordered_set
<std::string
>::iterator
, bool> ins
=
2585 this->sonames_
.insert(soname
);
2588 // We have already seen a dynamic object with this soname.
2592 this->dynobj_list_
.push_back(dynobj
);
2595 // Add this object to the cross-referencer if requested.
2596 if (parameters
->options().user_set_print_symbol_counts()
2597 || parameters
->options().cref())
2599 if (this->cref_
== NULL
)
2600 this->cref_
= new Cref();
2601 this->cref_
->add_object(obj
);
2607 // For each dynamic object, record whether we've seen all of its
2608 // explicit dependencies.
2611 Input_objects::check_dynamic_dependencies() const
2613 bool issued_copy_dt_needed_error
= false;
2614 for (Dynobj_list::const_iterator p
= this->dynobj_list_
.begin();
2615 p
!= this->dynobj_list_
.end();
2618 const Dynobj::Needed
& needed((*p
)->needed());
2619 bool found_all
= true;
2620 Dynobj::Needed::const_iterator pneeded
;
2621 for (pneeded
= needed
.begin(); pneeded
!= needed
.end(); ++pneeded
)
2623 if (this->sonames_
.find(*pneeded
) == this->sonames_
.end())
2629 (*p
)->set_has_unknown_needed_entries(!found_all
);
2631 // --copy-dt-needed-entries aka --add-needed is a GNU ld option
2632 // that gold does not support. However, they cause no trouble
2633 // unless there is a DT_NEEDED entry that we don't know about;
2634 // warn only in that case.
2636 && !issued_copy_dt_needed_error
2637 && (parameters
->options().copy_dt_needed_entries()
2638 || parameters
->options().add_needed()))
2640 const char* optname
;
2641 if (parameters
->options().copy_dt_needed_entries())
2642 optname
= "--copy-dt-needed-entries";
2644 optname
= "--add-needed";
2645 gold_error(_("%s is not supported but is required for %s in %s"),
2646 optname
, (*pneeded
).c_str(), (*p
)->name().c_str());
2647 issued_copy_dt_needed_error
= true;
2652 // Start processing an archive.
2655 Input_objects::archive_start(Archive
* archive
)
2657 if (parameters
->options().user_set_print_symbol_counts()
2658 || parameters
->options().cref())
2660 if (this->cref_
== NULL
)
2661 this->cref_
= new Cref();
2662 this->cref_
->add_archive_start(archive
);
2666 // Stop processing an archive.
2669 Input_objects::archive_stop(Archive
* archive
)
2671 if (parameters
->options().user_set_print_symbol_counts()
2672 || parameters
->options().cref())
2673 this->cref_
->add_archive_stop(archive
);
2676 // Print symbol counts
2679 Input_objects::print_symbol_counts(const Symbol_table
* symtab
) const
2681 if (parameters
->options().user_set_print_symbol_counts()
2682 && this->cref_
!= NULL
)
2683 this->cref_
->print_symbol_counts(symtab
);
2686 // Print a cross reference table.
2689 Input_objects::print_cref(const Symbol_table
* symtab
, FILE* f
) const
2691 if (parameters
->options().cref() && this->cref_
!= NULL
)
2692 this->cref_
->print_cref(symtab
, f
);
2695 // Relocate_info methods.
2697 // Return a string describing the location of a relocation when file
2698 // and lineno information is not available. This is only used in
2701 template<int size
, bool big_endian
>
2703 Relocate_info
<size
, big_endian
>::location(size_t, off_t offset
) const
2705 Sized_dwarf_line_info
<size
, big_endian
> line_info(this->object
);
2706 std::string ret
= line_info
.addr2line(this->data_shndx
, offset
, NULL
);
2710 ret
= this->object
->name();
2712 Symbol_location_info info
;
2713 if (this->object
->get_symbol_location_info(this->data_shndx
, offset
, &info
))
2715 if (!info
.source_file
.empty())
2718 ret
+= info
.source_file
;
2720 size_t len
= info
.enclosing_symbol_name
.length() + 100;
2721 char* buf
= new char[len
];
2722 snprintf(buf
, len
, _(":function %s"),
2723 info
.enclosing_symbol_name
.c_str());
2730 ret
+= this->object
->section_name(this->data_shndx
);
2732 snprintf(buf
, sizeof buf
, "+0x%lx)", static_cast<long>(offset
));
2737 } // End namespace gold.
2742 using namespace gold
;
2744 // Read an ELF file with the header and return the appropriate
2745 // instance of Object.
2747 template<int size
, bool big_endian
>
2749 make_elf_sized_object(const std::string
& name
, Input_file
* input_file
,
2750 off_t offset
, const elfcpp::Ehdr
<size
, big_endian
>& ehdr
,
2751 bool* punconfigured
)
2753 Target
* target
= select_target(ehdr
.get_e_machine(), size
, big_endian
,
2754 ehdr
.get_e_ident()[elfcpp::EI_OSABI
],
2755 ehdr
.get_e_ident()[elfcpp::EI_ABIVERSION
]);
2757 gold_fatal(_("%s: unsupported ELF machine number %d"),
2758 name
.c_str(), ehdr
.get_e_machine());
2760 if (!parameters
->target_valid())
2761 set_parameters_target(target
);
2762 else if (target
!= ¶meters
->target())
2764 if (punconfigured
!= NULL
)
2765 *punconfigured
= true;
2767 gold_error(_("%s: incompatible target"), name
.c_str());
2771 return target
->make_elf_object
<size
, big_endian
>(name
, input_file
, offset
,
2775 } // End anonymous namespace.
2780 // Return whether INPUT_FILE is an ELF object.
2783 is_elf_object(Input_file
* input_file
, off_t offset
,
2784 const unsigned char** start
, int* read_size
)
2786 off_t filesize
= input_file
->file().filesize();
2787 int want
= elfcpp::Elf_recognizer::max_header_size
;
2788 if (filesize
- offset
< want
)
2789 want
= filesize
- offset
;
2791 const unsigned char* p
= input_file
->file().get_view(offset
, 0, want
,
2796 return elfcpp::Elf_recognizer::is_elf_file(p
, want
);
2799 // Read an ELF file and return the appropriate instance of Object.
2802 make_elf_object(const std::string
& name
, Input_file
* input_file
, off_t offset
,
2803 const unsigned char* p
, section_offset_type bytes
,
2804 bool* punconfigured
)
2806 if (punconfigured
!= NULL
)
2807 *punconfigured
= false;
2810 bool big_endian
= false;
2812 if (!elfcpp::Elf_recognizer::is_valid_header(p
, bytes
, &size
,
2813 &big_endian
, &error
))
2815 gold_error(_("%s: %s"), name
.c_str(), error
.c_str());
2823 #ifdef HAVE_TARGET_32_BIG
2824 elfcpp::Ehdr
<32, true> ehdr(p
);
2825 return make_elf_sized_object
<32, true>(name
, input_file
,
2826 offset
, ehdr
, punconfigured
);
2828 if (punconfigured
!= NULL
)
2829 *punconfigured
= true;
2831 gold_error(_("%s: not configured to support "
2832 "32-bit big-endian object"),
2839 #ifdef HAVE_TARGET_32_LITTLE
2840 elfcpp::Ehdr
<32, false> ehdr(p
);
2841 return make_elf_sized_object
<32, false>(name
, input_file
,
2842 offset
, ehdr
, punconfigured
);
2844 if (punconfigured
!= NULL
)
2845 *punconfigured
= true;
2847 gold_error(_("%s: not configured to support "
2848 "32-bit little-endian object"),
2854 else if (size
== 64)
2858 #ifdef HAVE_TARGET_64_BIG
2859 elfcpp::Ehdr
<64, true> ehdr(p
);
2860 return make_elf_sized_object
<64, true>(name
, input_file
,
2861 offset
, ehdr
, punconfigured
);
2863 if (punconfigured
!= NULL
)
2864 *punconfigured
= true;
2866 gold_error(_("%s: not configured to support "
2867 "64-bit big-endian object"),
2874 #ifdef HAVE_TARGET_64_LITTLE
2875 elfcpp::Ehdr
<64, false> ehdr(p
);
2876 return make_elf_sized_object
<64, false>(name
, input_file
,
2877 offset
, ehdr
, punconfigured
);
2879 if (punconfigured
!= NULL
)
2880 *punconfigured
= true;
2882 gold_error(_("%s: not configured to support "
2883 "64-bit little-endian object"),
2893 // Instantiate the templates we need.
2895 #ifdef HAVE_TARGET_32_LITTLE
2898 Object::read_section_data
<32, false>(elfcpp::Elf_file
<32, false, Object
>*,
2899 Read_symbols_data
*);
2902 #ifdef HAVE_TARGET_32_BIG
2905 Object::read_section_data
<32, true>(elfcpp::Elf_file
<32, true, Object
>*,
2906 Read_symbols_data
*);
2909 #ifdef HAVE_TARGET_64_LITTLE
2912 Object::read_section_data
<64, false>(elfcpp::Elf_file
<64, false, Object
>*,
2913 Read_symbols_data
*);
2916 #ifdef HAVE_TARGET_64_BIG
2919 Object::read_section_data
<64, true>(elfcpp::Elf_file
<64, true, Object
>*,
2920 Read_symbols_data
*);
2923 #ifdef HAVE_TARGET_32_LITTLE
2925 class Sized_relobj_file
<32, false>;
2928 #ifdef HAVE_TARGET_32_BIG
2930 class Sized_relobj_file
<32, true>;
2933 #ifdef HAVE_TARGET_64_LITTLE
2935 class Sized_relobj_file
<64, false>;
2938 #ifdef HAVE_TARGET_64_BIG
2940 class Sized_relobj_file
<64, true>;
2943 #ifdef HAVE_TARGET_32_LITTLE
2945 struct Relocate_info
<32, false>;
2948 #ifdef HAVE_TARGET_32_BIG
2950 struct Relocate_info
<32, true>;
2953 #ifdef HAVE_TARGET_64_LITTLE
2955 struct Relocate_info
<64, false>;
2958 #ifdef HAVE_TARGET_64_BIG
2960 struct Relocate_info
<64, true>;
2963 #ifdef HAVE_TARGET_32_LITTLE
2966 Xindex::initialize_symtab_xindex
<32, false>(Object
*, unsigned int);
2970 Xindex::read_symtab_xindex
<32, false>(Object
*, unsigned int,
2971 const unsigned char*);
2974 #ifdef HAVE_TARGET_32_BIG
2977 Xindex::initialize_symtab_xindex
<32, true>(Object
*, unsigned int);
2981 Xindex::read_symtab_xindex
<32, true>(Object
*, unsigned int,
2982 const unsigned char*);
2985 #ifdef HAVE_TARGET_64_LITTLE
2988 Xindex::initialize_symtab_xindex
<64, false>(Object
*, unsigned int);
2992 Xindex::read_symtab_xindex
<64, false>(Object
*, unsigned int,
2993 const unsigned char*);
2996 #ifdef HAVE_TARGET_64_BIG
2999 Xindex::initialize_symtab_xindex
<64, true>(Object
*, unsigned int);
3003 Xindex::read_symtab_xindex
<64, true>(Object
*, unsigned int,
3004 const unsigned char*);
3007 } // End namespace gold.