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[binutils.git] / gold / object.cc
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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.
23 #include "gold.h"
25 #include <cerrno>
26 #include <cstring>
27 #include <cstdarg>
28 #include "demangle.h"
29 #include "libiberty.h"
31 #include "gc.h"
32 #include "target-select.h"
33 #include "dwarf_reader.h"
34 #include "layout.h"
35 #include "output.h"
36 #include "symtab.h"
37 #include "cref.h"
38 #include "reloc.h"
39 #include "object.h"
40 #include "dynobj.h"
41 #include "plugin.h"
43 namespace gold
46 // Class Xindex.
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>
53 void
54 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
56 if (!this->symtab_xindex_.empty())
57 return;
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();
64 while (i > 0)
66 --i;
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);
71 return;
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
80 // section headers.
82 template<int size, bool big_endian>
83 void
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;
89 if (pshdrs == NULL)
90 contents = object->section_contents(xindex_shndx, &bytecount, false);
91 else
93 const unsigned char* p = (pshdrs
94 + (xindex_shndx
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
112 // index.
114 unsigned int
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"),
120 symndx);
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"),
127 symndx, shndx);
128 return elfcpp::SHN_UNDEF;
130 return shndx;
133 // Class Object.
135 // Report an error for this object file. This is used by the
136 // elfcpp::Elf_file interface, and also called by the Object code
137 // itself.
139 void
140 Object::error(const char* format, ...) const
142 va_list args;
143 va_start(args, format);
144 char* buf = NULL;
145 if (vasprintf(&buf, format, args) < 0)
146 gold_nomem();
147 va_end(args);
148 gold_error(_("%s: %s"), this->name().c_str(), buf);
149 free(buf);
152 // Return a view of the contents of a section.
154 const unsigned char*
155 Object::section_contents(unsigned int shndx, section_size_type* plen,
156 bool cache)
158 Location loc(this->do_section_contents(shndx));
159 *plen = convert_to_section_size_type(loc.data_size);
160 if (*plen == 0)
162 static const unsigned char empty[1] = { '\0' };
163 return empty;
165 return this->get_view(loc.file_offset, *plen, true, cache);
168 // Read the section data into SD. This is code common to Sized_relobj
169 // and Sized_dynobj, so we put it into Object.
171 template<int size, bool big_endian>
172 void
173 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
174 Read_symbols_data* sd)
176 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
178 // Read the section headers.
179 const off_t shoff = elf_file->shoff();
180 const unsigned int shnum = this->shnum();
181 sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
182 true, true);
184 // Read the section names.
185 const unsigned char* pshdrs = sd->section_headers->data();
186 const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
187 typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
189 if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
190 this->error(_("section name section has wrong type: %u"),
191 static_cast<unsigned int>(shdrnames.get_sh_type()));
193 sd->section_names_size =
194 convert_to_section_size_type(shdrnames.get_sh_size());
195 sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
196 sd->section_names_size, false,
197 false);
200 // If NAME is the name of a special .gnu.warning section, arrange for
201 // the warning to be issued. SHNDX is the section index. Return
202 // whether it is a warning section.
204 bool
205 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
206 Symbol_table* symtab)
208 const char warn_prefix[] = ".gnu.warning.";
209 const int warn_prefix_len = sizeof warn_prefix - 1;
210 if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
212 // Read the section contents to get the warning text. It would
213 // be nicer if we only did this if we have to actually issue a
214 // warning. Unfortunately, warnings are issued as we relocate
215 // sections. That means that we can not lock the object then,
216 // as we might try to issue the same warning multiple times
217 // simultaneously.
218 section_size_type len;
219 const unsigned char* contents = this->section_contents(shndx, &len,
220 false);
221 if (len == 0)
223 const char* warning = name + warn_prefix_len;
224 contents = reinterpret_cast<const unsigned char*>(warning);
225 len = strlen(warning);
227 std::string warning(reinterpret_cast<const char*>(contents), len);
228 symtab->add_warning(name + warn_prefix_len, this, warning);
229 return true;
231 return false;
234 // Class Relobj
236 // To copy the symbols data read from the file to a local data structure.
237 // This function is called from do_layout only while doing garbage
238 // collection.
240 void
241 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
242 unsigned int section_header_size)
244 gc_sd->section_headers_data =
245 new unsigned char[(section_header_size)];
246 memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
247 section_header_size);
248 gc_sd->section_names_data =
249 new unsigned char[sd->section_names_size];
250 memcpy(gc_sd->section_names_data, sd->section_names->data(),
251 sd->section_names_size);
252 gc_sd->section_names_size = sd->section_names_size;
253 if (sd->symbols != NULL)
255 gc_sd->symbols_data =
256 new unsigned char[sd->symbols_size];
257 memcpy(gc_sd->symbols_data, sd->symbols->data(),
258 sd->symbols_size);
260 else
262 gc_sd->symbols_data = NULL;
264 gc_sd->symbols_size = sd->symbols_size;
265 gc_sd->external_symbols_offset = sd->external_symbols_offset;
266 if (sd->symbol_names != NULL)
268 gc_sd->symbol_names_data =
269 new unsigned char[sd->symbol_names_size];
270 memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
271 sd->symbol_names_size);
273 else
275 gc_sd->symbol_names_data = NULL;
277 gc_sd->symbol_names_size = sd->symbol_names_size;
280 // This function determines if a particular section name must be included
281 // in the link. This is used during garbage collection to determine the
282 // roots of the worklist.
284 bool
285 Relobj::is_section_name_included(const char* name)
287 if (is_prefix_of(".ctors", name)
288 || is_prefix_of(".dtors", name)
289 || is_prefix_of(".note", name)
290 || is_prefix_of(".init", name)
291 || is_prefix_of(".fini", name)
292 || is_prefix_of(".gcc_except_table", name)
293 || is_prefix_of(".jcr", name)
294 || is_prefix_of(".preinit_array", name)
295 || (is_prefix_of(".text", name)
296 && strstr(name, "personality"))
297 || (is_prefix_of(".data", name)
298 && strstr(name, "personality"))
299 || (is_prefix_of(".gnu.linkonce.d", name) &&
300 strstr(name, "personality")))
302 return true;
304 return false;
307 // Class Sized_relobj.
309 template<int size, bool big_endian>
310 Sized_relobj<size, big_endian>::Sized_relobj(
311 const std::string& name,
312 Input_file* input_file,
313 off_t offset,
314 const elfcpp::Ehdr<size, big_endian>& ehdr)
315 : Relobj(name, input_file, offset),
316 elf_file_(this, ehdr),
317 symtab_shndx_(-1U),
318 local_symbol_count_(0),
319 output_local_symbol_count_(0),
320 output_local_dynsym_count_(0),
321 symbols_(),
322 defined_count_(0),
323 local_symbol_offset_(0),
324 local_dynsym_offset_(0),
325 local_values_(),
326 local_got_offsets_(),
327 kept_comdat_sections_(),
328 has_eh_frame_(false),
329 discarded_eh_frame_shndx_(-1U)
333 template<int size, bool big_endian>
334 Sized_relobj<size, big_endian>::~Sized_relobj()
338 // Set up an object file based on the file header. This sets up the
339 // target and reads the section information.
341 template<int size, bool big_endian>
342 void
343 Sized_relobj<size, big_endian>::setup(Target *target)
345 this->set_target(target);
347 const unsigned int shnum = this->elf_file_.shnum();
348 this->set_shnum(shnum);
351 // Find the SHT_SYMTAB section, given the section headers. The ELF
352 // standard says that maybe in the future there can be more than one
353 // SHT_SYMTAB section. Until somebody figures out how that could
354 // work, we assume there is only one.
356 template<int size, bool big_endian>
357 void
358 Sized_relobj<size, big_endian>::find_symtab(const unsigned char* pshdrs)
360 const unsigned int shnum = this->shnum();
361 this->symtab_shndx_ = 0;
362 if (shnum > 0)
364 // Look through the sections in reverse order, since gas tends
365 // to put the symbol table at the end.
366 const unsigned char* p = pshdrs + shnum * This::shdr_size;
367 unsigned int i = shnum;
368 unsigned int xindex_shndx = 0;
369 unsigned int xindex_link = 0;
370 while (i > 0)
372 --i;
373 p -= This::shdr_size;
374 typename This::Shdr shdr(p);
375 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
377 this->symtab_shndx_ = i;
378 if (xindex_shndx > 0 && xindex_link == i)
380 Xindex* xindex =
381 new Xindex(this->elf_file_.large_shndx_offset());
382 xindex->read_symtab_xindex<size, big_endian>(this,
383 xindex_shndx,
384 pshdrs);
385 this->set_xindex(xindex);
387 break;
390 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
391 // one. This will work if it follows the SHT_SYMTAB
392 // section.
393 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
395 xindex_shndx = i;
396 xindex_link = this->adjust_shndx(shdr.get_sh_link());
402 // Return the Xindex structure to use for object with lots of
403 // sections.
405 template<int size, bool big_endian>
406 Xindex*
407 Sized_relobj<size, big_endian>::do_initialize_xindex()
409 gold_assert(this->symtab_shndx_ != -1U);
410 Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
411 xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
412 return xindex;
415 // Return whether SHDR has the right type and flags to be a GNU
416 // .eh_frame section.
418 template<int size, bool big_endian>
419 bool
420 Sized_relobj<size, big_endian>::check_eh_frame_flags(
421 const elfcpp::Shdr<size, big_endian>* shdr) const
423 return (shdr->get_sh_type() == elfcpp::SHT_PROGBITS
424 && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
427 // Return whether there is a GNU .eh_frame section, given the section
428 // headers and the section names.
430 template<int size, bool big_endian>
431 bool
432 Sized_relobj<size, big_endian>::find_eh_frame(
433 const unsigned char* pshdrs,
434 const char* names,
435 section_size_type names_size) const
437 const unsigned int shnum = this->shnum();
438 const unsigned char* p = pshdrs + This::shdr_size;
439 for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
441 typename This::Shdr shdr(p);
442 if (this->check_eh_frame_flags(&shdr))
444 if (shdr.get_sh_name() >= names_size)
446 this->error(_("bad section name offset for section %u: %lu"),
447 i, static_cast<unsigned long>(shdr.get_sh_name()));
448 continue;
451 const char* name = names + shdr.get_sh_name();
452 if (strcmp(name, ".eh_frame") == 0)
453 return true;
456 return false;
459 // Read the sections and symbols from an object file.
461 template<int size, bool big_endian>
462 void
463 Sized_relobj<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
465 this->read_section_data(&this->elf_file_, sd);
467 const unsigned char* const pshdrs = sd->section_headers->data();
469 this->find_symtab(pshdrs);
471 const unsigned char* namesu = sd->section_names->data();
472 const char* names = reinterpret_cast<const char*>(namesu);
473 if (memmem(names, sd->section_names_size, ".eh_frame", 10) != NULL)
475 if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
476 this->has_eh_frame_ = true;
479 sd->symbols = NULL;
480 sd->symbols_size = 0;
481 sd->external_symbols_offset = 0;
482 sd->symbol_names = NULL;
483 sd->symbol_names_size = 0;
485 if (this->symtab_shndx_ == 0)
487 // No symbol table. Weird but legal.
488 return;
491 // Get the symbol table section header.
492 typename This::Shdr symtabshdr(pshdrs
493 + this->symtab_shndx_ * This::shdr_size);
494 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
496 // If this object has a .eh_frame section, we need all the symbols.
497 // Otherwise we only need the external symbols. While it would be
498 // simpler to just always read all the symbols, I've seen object
499 // files with well over 2000 local symbols, which for a 64-bit
500 // object file format is over 5 pages that we don't need to read
501 // now.
503 const int sym_size = This::sym_size;
504 const unsigned int loccount = symtabshdr.get_sh_info();
505 this->local_symbol_count_ = loccount;
506 this->local_values_.resize(loccount);
507 section_offset_type locsize = loccount * sym_size;
508 off_t dataoff = symtabshdr.get_sh_offset();
509 section_size_type datasize =
510 convert_to_section_size_type(symtabshdr.get_sh_size());
511 off_t extoff = dataoff + locsize;
512 section_size_type extsize = datasize - locsize;
514 off_t readoff = this->has_eh_frame_ ? dataoff : extoff;
515 section_size_type readsize = this->has_eh_frame_ ? datasize : extsize;
517 if (readsize == 0)
519 // No external symbols. Also weird but also legal.
520 return;
523 File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
525 // Read the section header for the symbol names.
526 unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
527 if (strtab_shndx >= this->shnum())
529 this->error(_("invalid symbol table name index: %u"), strtab_shndx);
530 return;
532 typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
533 if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
535 this->error(_("symbol table name section has wrong type: %u"),
536 static_cast<unsigned int>(strtabshdr.get_sh_type()));
537 return;
540 // Read the symbol names.
541 File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
542 strtabshdr.get_sh_size(),
543 false, true);
545 sd->symbols = fvsymtab;
546 sd->symbols_size = readsize;
547 sd->external_symbols_offset = this->has_eh_frame_ ? locsize : 0;
548 sd->symbol_names = fvstrtab;
549 sd->symbol_names_size =
550 convert_to_section_size_type(strtabshdr.get_sh_size());
553 // Return the section index of symbol SYM. Set *VALUE to its value in
554 // the object file. Set *IS_ORDINARY if this is an ordinary section
555 // index. not a special cod between SHN_LORESERVE and SHN_HIRESERVE.
556 // Note that for a symbol which is not defined in this object file,
557 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
558 // the final value of the symbol in the link.
560 template<int size, bool big_endian>
561 unsigned int
562 Sized_relobj<size, big_endian>::symbol_section_and_value(unsigned int sym,
563 Address* value,
564 bool* is_ordinary)
566 section_size_type symbols_size;
567 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
568 &symbols_size,
569 false);
571 const size_t count = symbols_size / This::sym_size;
572 gold_assert(sym < count);
574 elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
575 *value = elfsym.get_st_value();
577 return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
580 // Return whether to include a section group in the link. LAYOUT is
581 // used to keep track of which section groups we have already seen.
582 // INDEX is the index of the section group and SHDR is the section
583 // header. If we do not want to include this group, we set bits in
584 // OMIT for each section which should be discarded.
586 template<int size, bool big_endian>
587 bool
588 Sized_relobj<size, big_endian>::include_section_group(
589 Symbol_table* symtab,
590 Layout* layout,
591 unsigned int index,
592 const char* name,
593 const unsigned char* shdrs,
594 const char* section_names,
595 section_size_type section_names_size,
596 std::vector<bool>* omit)
598 // Read the section contents.
599 typename This::Shdr shdr(shdrs + index * This::shdr_size);
600 const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
601 shdr.get_sh_size(), true, false);
602 const elfcpp::Elf_Word* pword =
603 reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
605 // The first word contains flags. We only care about COMDAT section
606 // groups. Other section groups are always included in the link
607 // just like ordinary sections.
608 elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
610 // Look up the group signature, which is the name of a symbol. This
611 // is a lot of effort to go to to read a string. Why didn't they
612 // just have the group signature point into the string table, rather
613 // than indirect through a symbol?
615 // Get the appropriate symbol table header (this will normally be
616 // the single SHT_SYMTAB section, but in principle it need not be).
617 const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
618 typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
620 // Read the symbol table entry.
621 unsigned int symndx = shdr.get_sh_info();
622 if (symndx >= symshdr.get_sh_size() / This::sym_size)
624 this->error(_("section group %u info %u out of range"),
625 index, symndx);
626 return false;
628 off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
629 const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
630 false);
631 elfcpp::Sym<size, big_endian> sym(psym);
633 // Read the symbol table names.
634 section_size_type symnamelen;
635 const unsigned char* psymnamesu;
636 psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
637 &symnamelen, true);
638 const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
640 // Get the section group signature.
641 if (sym.get_st_name() >= symnamelen)
643 this->error(_("symbol %u name offset %u out of range"),
644 symndx, sym.get_st_name());
645 return false;
648 std::string signature(psymnames + sym.get_st_name());
650 // It seems that some versions of gas will create a section group
651 // associated with a section symbol, and then fail to give a name to
652 // the section symbol. In such a case, use the name of the section.
653 if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
655 bool is_ordinary;
656 unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
657 sym.get_st_shndx(),
658 &is_ordinary);
659 if (!is_ordinary || sym_shndx >= this->shnum())
661 this->error(_("symbol %u invalid section index %u"),
662 symndx, sym_shndx);
663 return false;
665 typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
666 if (member_shdr.get_sh_name() < section_names_size)
667 signature = section_names + member_shdr.get_sh_name();
670 // Record this section group in the layout, and see whether we've already
671 // seen one with the same signature.
672 bool include_group;
673 bool is_comdat;
674 Kept_section* kept_section = NULL;
676 if ((flags & elfcpp::GRP_COMDAT) == 0)
678 include_group = true;
679 is_comdat = false;
681 else
683 include_group = layout->find_or_add_kept_section(signature,
684 this, index, true,
685 true, &kept_section);
686 is_comdat = true;
689 size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
691 std::vector<unsigned int> shndxes;
692 bool relocate_group = include_group && parameters->options().relocatable();
693 if (relocate_group)
694 shndxes.reserve(count - 1);
696 for (size_t i = 1; i < count; ++i)
698 elfcpp::Elf_Word shndx =
699 this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
701 if (relocate_group)
702 shndxes.push_back(shndx);
704 if (shndx >= this->shnum())
706 this->error(_("section %u in section group %u out of range"),
707 shndx, index);
708 continue;
711 // Check for an earlier section number, since we're going to get
712 // it wrong--we may have already decided to include the section.
713 if (shndx < index)
714 this->error(_("invalid section group %u refers to earlier section %u"),
715 index, shndx);
717 // Get the name of the member section.
718 typename This::Shdr member_shdr(shdrs + shndx * This::shdr_size);
719 if (member_shdr.get_sh_name() >= section_names_size)
721 // This is an error, but it will be diagnosed eventually
722 // in do_layout, so we don't need to do anything here but
723 // ignore it.
724 continue;
726 std::string mname(section_names + member_shdr.get_sh_name());
728 if (include_group)
730 if (is_comdat)
731 kept_section->add_comdat_section(mname, shndx,
732 member_shdr.get_sh_size());
734 else
736 (*omit)[shndx] = true;
738 if (is_comdat)
740 Relobj* kept_object = kept_section->object();
741 if (kept_section->is_comdat())
743 // Find the corresponding kept section, and store
744 // that info in the discarded section table.
745 unsigned int kept_shndx;
746 uint64_t kept_size;
747 if (kept_section->find_comdat_section(mname, &kept_shndx,
748 &kept_size))
750 // We don't keep a mapping for this section if
751 // it has a different size. The mapping is only
752 // used for relocation processing, and we don't
753 // want to treat the sections as similar if the
754 // sizes are different. Checking the section
755 // size is the approach used by the GNU linker.
756 if (kept_size == member_shdr.get_sh_size())
757 this->set_kept_comdat_section(shndx, kept_object,
758 kept_shndx);
761 else
763 // The existing section is a linkonce section. Add
764 // a mapping if there is exactly one section in the
765 // group (which is true when COUNT == 2) and if it
766 // is the same size.
767 if (count == 2
768 && (kept_section->linkonce_size()
769 == member_shdr.get_sh_size()))
770 this->set_kept_comdat_section(shndx, kept_object,
771 kept_section->shndx());
777 if (relocate_group)
778 layout->layout_group(symtab, this, index, name, signature.c_str(),
779 shdr, flags, &shndxes);
781 return include_group;
784 // Whether to include a linkonce section in the link. NAME is the
785 // name of the section and SHDR is the section header.
787 // Linkonce sections are a GNU extension implemented in the original
788 // GNU linker before section groups were defined. The semantics are
789 // that we only include one linkonce section with a given name. The
790 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
791 // where T is the type of section and SYMNAME is the name of a symbol.
792 // In an attempt to make linkonce sections interact well with section
793 // groups, we try to identify SYMNAME and use it like a section group
794 // signature. We want to block section groups with that signature,
795 // but not other linkonce sections with that signature. We also use
796 // the full name of the linkonce section as a normal section group
797 // signature.
799 template<int size, bool big_endian>
800 bool
801 Sized_relobj<size, big_endian>::include_linkonce_section(
802 Layout* layout,
803 unsigned int index,
804 const char* name,
805 const elfcpp::Shdr<size, big_endian>& shdr)
807 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
808 // In general the symbol name we want will be the string following
809 // the last '.'. However, we have to handle the case of
810 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
811 // some versions of gcc. So we use a heuristic: if the name starts
812 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
813 // we look for the last '.'. We can't always simply skip
814 // ".gnu.linkonce.X", because we have to deal with cases like
815 // ".gnu.linkonce.d.rel.ro.local".
816 const char* const linkonce_t = ".gnu.linkonce.t.";
817 const char* symname;
818 if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
819 symname = name + strlen(linkonce_t);
820 else
821 symname = strrchr(name, '.') + 1;
822 std::string sig1(symname);
823 std::string sig2(name);
824 Kept_section* kept1;
825 Kept_section* kept2;
826 bool include1 = layout->find_or_add_kept_section(sig1, this, index, false,
827 false, &kept1);
828 bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
829 true, &kept2);
831 if (!include2)
833 // We are not including this section because we already saw the
834 // name of the section as a signature. This normally implies
835 // that the kept section is another linkonce section. If it is
836 // the same size, record it as the section which corresponds to
837 // this one.
838 if (kept2->object() != NULL
839 && !kept2->is_comdat()
840 && kept2->linkonce_size() == sh_size)
841 this->set_kept_comdat_section(index, kept2->object(), kept2->shndx());
843 else if (!include1)
845 // The section is being discarded on the basis of its symbol
846 // name. This means that the corresponding kept section was
847 // part of a comdat group, and it will be difficult to identify
848 // the specific section within that group that corresponds to
849 // this linkonce section. We'll handle the simple case where
850 // the group has only one member section. Otherwise, it's not
851 // worth the effort.
852 unsigned int kept_shndx;
853 uint64_t kept_size;
854 if (kept1->object() != NULL
855 && kept1->is_comdat()
856 && kept1->find_single_comdat_section(&kept_shndx, &kept_size)
857 && kept_size == sh_size)
858 this->set_kept_comdat_section(index, kept1->object(), kept_shndx);
860 else
862 kept1->set_linkonce_size(sh_size);
863 kept2->set_linkonce_size(sh_size);
866 return include1 && include2;
869 // Layout an input section.
871 template<int size, bool big_endian>
872 inline void
873 Sized_relobj<size, big_endian>::layout_section(Layout* layout,
874 unsigned int shndx,
875 const char* name,
876 typename This::Shdr& shdr,
877 unsigned int reloc_shndx,
878 unsigned int reloc_type)
880 off_t offset;
881 Output_section* os = layout->layout(this, shndx, name, shdr,
882 reloc_shndx, reloc_type, &offset);
884 this->output_sections()[shndx] = os;
885 if (offset == -1)
886 this->section_offsets_[shndx] = invalid_address;
887 else
888 this->section_offsets_[shndx] = convert_types<Address, off_t>(offset);
890 // If this section requires special handling, and if there are
891 // relocs that apply to it, then we must do the special handling
892 // before we apply the relocs.
893 if (offset == -1 && reloc_shndx != 0)
894 this->set_relocs_must_follow_section_writes();
897 // Lay out the input sections. We walk through the sections and check
898 // whether they should be included in the link. If they should, we
899 // pass them to the Layout object, which will return an output section
900 // and an offset.
901 // During garbage collection (--gc-sections) and identical code folding
902 // (--icf), this function is called twice. When it is called the first
903 // time, it is for setting up some sections as roots to a work-list for
904 // --gc-sections and to do comdat processing. Actual layout happens the
905 // second time around after all the relevant sections have been determined.
906 // The first time, is_worklist_ready or is_icf_ready is false. It is then
907 // set to true after the garbage collection worklist or identical code
908 // folding is processed and the relevant sections to be kept are
909 // determined. Then, this function is called again to layout the sections.
911 template<int size, bool big_endian>
912 void
913 Sized_relobj<size, big_endian>::do_layout(Symbol_table* symtab,
914 Layout* layout,
915 Read_symbols_data* sd)
917 const unsigned int shnum = this->shnum();
918 bool is_gc_pass_one = ((parameters->options().gc_sections()
919 && !symtab->gc()->is_worklist_ready())
920 || (parameters->options().icf()
921 && !symtab->icf()->is_icf_ready()));
923 bool is_gc_pass_two = ((parameters->options().gc_sections()
924 && symtab->gc()->is_worklist_ready())
925 || (parameters->options().icf()
926 && symtab->icf()->is_icf_ready()));
928 bool is_gc_or_icf = (parameters->options().gc_sections()
929 || parameters->options().icf());
931 // Both is_gc_pass_one and is_gc_pass_two should not be true.
932 gold_assert(!(is_gc_pass_one && is_gc_pass_two));
934 if (shnum == 0)
935 return;
936 Symbols_data* gc_sd = NULL;
937 if (is_gc_pass_one)
939 // During garbage collection save the symbols data to use it when
940 // re-entering this function.
941 gc_sd = new Symbols_data;
942 this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
943 this->set_symbols_data(gc_sd);
945 else if (is_gc_pass_two)
947 gc_sd = this->get_symbols_data();
950 const unsigned char* section_headers_data = NULL;
951 section_size_type section_names_size;
952 const unsigned char* symbols_data = NULL;
953 section_size_type symbols_size;
954 section_offset_type external_symbols_offset;
955 const unsigned char* symbol_names_data = NULL;
956 section_size_type symbol_names_size;
958 if (is_gc_or_icf)
960 section_headers_data = gc_sd->section_headers_data;
961 section_names_size = gc_sd->section_names_size;
962 symbols_data = gc_sd->symbols_data;
963 symbols_size = gc_sd->symbols_size;
964 external_symbols_offset = gc_sd->external_symbols_offset;
965 symbol_names_data = gc_sd->symbol_names_data;
966 symbol_names_size = gc_sd->symbol_names_size;
968 else
970 section_headers_data = sd->section_headers->data();
971 section_names_size = sd->section_names_size;
972 if (sd->symbols != NULL)
973 symbols_data = sd->symbols->data();
974 symbols_size = sd->symbols_size;
975 external_symbols_offset = sd->external_symbols_offset;
976 if (sd->symbol_names != NULL)
977 symbol_names_data = sd->symbol_names->data();
978 symbol_names_size = sd->symbol_names_size;
981 // Get the section headers.
982 const unsigned char* shdrs = section_headers_data;
983 const unsigned char* pshdrs;
985 // Get the section names.
986 const unsigned char* pnamesu = (is_gc_or_icf)
987 ? gc_sd->section_names_data
988 : sd->section_names->data();
990 const char* pnames = reinterpret_cast<const char*>(pnamesu);
992 // If any input files have been claimed by plugins, we need to defer
993 // actual layout until the replacement files have arrived.
994 const bool should_defer_layout =
995 (parameters->options().has_plugins()
996 && parameters->options().plugins()->should_defer_layout());
997 unsigned int num_sections_to_defer = 0;
999 // For each section, record the index of the reloc section if any.
1000 // Use 0 to mean that there is no reloc section, -1U to mean that
1001 // there is more than one.
1002 std::vector<unsigned int> reloc_shndx(shnum, 0);
1003 std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
1004 // Skip the first, dummy, section.
1005 pshdrs = shdrs + This::shdr_size;
1006 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1008 typename This::Shdr shdr(pshdrs);
1010 // Count the number of sections whose layout will be deferred.
1011 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1012 ++num_sections_to_defer;
1014 unsigned int sh_type = shdr.get_sh_type();
1015 if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1017 unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1018 if (target_shndx == 0 || target_shndx >= shnum)
1020 this->error(_("relocation section %u has bad info %u"),
1021 i, target_shndx);
1022 continue;
1025 if (reloc_shndx[target_shndx] != 0)
1026 reloc_shndx[target_shndx] = -1U;
1027 else
1029 reloc_shndx[target_shndx] = i;
1030 reloc_type[target_shndx] = sh_type;
1035 Output_sections& out_sections(this->output_sections());
1036 std::vector<Address>& out_section_offsets(this->section_offsets_);
1038 if (!is_gc_pass_two)
1040 out_sections.resize(shnum);
1041 out_section_offsets.resize(shnum);
1044 // If we are only linking for symbols, then there is nothing else to
1045 // do here.
1046 if (this->input_file()->just_symbols())
1048 if (!is_gc_pass_two)
1050 delete sd->section_headers;
1051 sd->section_headers = NULL;
1052 delete sd->section_names;
1053 sd->section_names = NULL;
1055 return;
1058 if (num_sections_to_defer > 0)
1060 parameters->options().plugins()->add_deferred_layout_object(this);
1061 this->deferred_layout_.reserve(num_sections_to_defer);
1064 // Whether we've seen a .note.GNU-stack section.
1065 bool seen_gnu_stack = false;
1066 // The flags of a .note.GNU-stack section.
1067 uint64_t gnu_stack_flags = 0;
1069 // Keep track of which sections to omit.
1070 std::vector<bool> omit(shnum, false);
1072 // Keep track of reloc sections when emitting relocations.
1073 const bool relocatable = parameters->options().relocatable();
1074 const bool emit_relocs = (relocatable
1075 || parameters->options().emit_relocs());
1076 std::vector<unsigned int> reloc_sections;
1078 // Keep track of .eh_frame sections.
1079 std::vector<unsigned int> eh_frame_sections;
1081 // Skip the first, dummy, section.
1082 pshdrs = shdrs + This::shdr_size;
1083 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1085 typename This::Shdr shdr(pshdrs);
1087 if (shdr.get_sh_name() >= section_names_size)
1089 this->error(_("bad section name offset for section %u: %lu"),
1090 i, static_cast<unsigned long>(shdr.get_sh_name()));
1091 return;
1094 const char* name = pnames + shdr.get_sh_name();
1096 if (!is_gc_pass_two)
1098 if (this->handle_gnu_warning_section(name, i, symtab))
1100 if (!relocatable)
1101 omit[i] = true;
1104 // The .note.GNU-stack section is special. It gives the
1105 // protection flags that this object file requires for the stack
1106 // in memory.
1107 if (strcmp(name, ".note.GNU-stack") == 0)
1109 seen_gnu_stack = true;
1110 gnu_stack_flags |= shdr.get_sh_flags();
1111 omit[i] = true;
1114 bool discard = omit[i];
1115 if (!discard)
1117 if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1119 if (!this->include_section_group(symtab, layout, i, name,
1120 shdrs, pnames,
1121 section_names_size,
1122 &omit))
1123 discard = true;
1125 else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1126 && Layout::is_linkonce(name))
1128 if (!this->include_linkonce_section(layout, i, name, shdr))
1129 discard = true;
1133 if (discard)
1135 // Do not include this section in the link.
1136 out_sections[i] = NULL;
1137 out_section_offsets[i] = invalid_address;
1138 continue;
1142 if (is_gc_pass_one && parameters->options().gc_sections())
1144 if (is_section_name_included(name)
1145 || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1146 || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1148 symtab->gc()->worklist().push(Section_id(this, i));
1152 // When doing a relocatable link we are going to copy input
1153 // reloc sections into the output. We only want to copy the
1154 // ones associated with sections which are not being discarded.
1155 // However, we don't know that yet for all sections. So save
1156 // reloc sections and process them later. Garbage collection is
1157 // not triggered when relocatable code is desired.
1158 if (emit_relocs
1159 && (shdr.get_sh_type() == elfcpp::SHT_REL
1160 || shdr.get_sh_type() == elfcpp::SHT_RELA))
1162 reloc_sections.push_back(i);
1163 continue;
1166 if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1167 continue;
1169 // The .eh_frame section is special. It holds exception frame
1170 // information that we need to read in order to generate the
1171 // exception frame header. We process these after all the other
1172 // sections so that the exception frame reader can reliably
1173 // determine which sections are being discarded, and discard the
1174 // corresponding information.
1175 if (!relocatable
1176 && strcmp(name, ".eh_frame") == 0
1177 && this->check_eh_frame_flags(&shdr))
1179 if (is_gc_pass_one)
1181 out_sections[i] = reinterpret_cast<Output_section*>(1);
1182 out_section_offsets[i] = invalid_address;
1184 else
1185 eh_frame_sections.push_back(i);
1186 continue;
1189 if (is_gc_pass_two && parameters->options().gc_sections())
1191 // This is executed during the second pass of garbage
1192 // collection. do_layout has been called before and some
1193 // sections have been already discarded. Simply ignore
1194 // such sections this time around.
1195 if (out_sections[i] == NULL)
1197 gold_assert(out_section_offsets[i] == invalid_address);
1198 continue;
1200 if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1201 && symtab->gc()->is_section_garbage(this, i))
1203 if (parameters->options().print_gc_sections())
1204 gold_info(_("%s: removing unused section from '%s'"
1205 " in file '%s'"),
1206 program_name, this->section_name(i).c_str(),
1207 this->name().c_str());
1208 out_sections[i] = NULL;
1209 out_section_offsets[i] = invalid_address;
1210 continue;
1214 if (is_gc_pass_two && parameters->options().icf())
1216 if (out_sections[i] == NULL)
1218 gold_assert(out_section_offsets[i] == invalid_address);
1219 continue;
1221 if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1222 && symtab->icf()->is_section_folded(this, i))
1224 if (parameters->options().print_icf_sections())
1226 Section_id folded =
1227 symtab->icf()->get_folded_section(this, i);
1228 Relobj* folded_obj =
1229 reinterpret_cast<Relobj*>(folded.first);
1230 gold_info(_("%s: ICF folding section '%s' in file '%s'"
1231 "into '%s' in file '%s'"),
1232 program_name, this->section_name(i).c_str(),
1233 this->name().c_str(),
1234 folded_obj->section_name(folded.second).c_str(),
1235 folded_obj->name().c_str());
1237 out_sections[i] = NULL;
1238 out_section_offsets[i] = invalid_address;
1239 continue;
1243 // Defer layout here if input files are claimed by plugins. When gc
1244 // is turned on this function is called twice. For the second call
1245 // should_defer_layout should be false.
1246 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1248 gold_assert(!is_gc_pass_two);
1249 this->deferred_layout_.push_back(Deferred_layout(i, name,
1250 pshdrs,
1251 reloc_shndx[i],
1252 reloc_type[i]));
1253 // Put dummy values here; real values will be supplied by
1254 // do_layout_deferred_sections.
1255 out_sections[i] = reinterpret_cast<Output_section*>(2);
1256 out_section_offsets[i] = invalid_address;
1257 continue;
1260 // During gc_pass_two if a section that was previously deferred is
1261 // found, do not layout the section as layout_deferred_sections will
1262 // do it later from gold.cc.
1263 if (is_gc_pass_two
1264 && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1265 continue;
1267 if (is_gc_pass_one)
1269 // This is during garbage collection. The out_sections are
1270 // assigned in the second call to this function.
1271 out_sections[i] = reinterpret_cast<Output_section*>(1);
1272 out_section_offsets[i] = invalid_address;
1274 else
1276 // When garbage collection is switched on the actual layout
1277 // only happens in the second call.
1278 this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1279 reloc_type[i]);
1283 if (!is_gc_pass_one)
1284 layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags);
1286 // When doing a relocatable link handle the reloc sections at the
1287 // end. Garbage collection and Identical Code Folding is not
1288 // turned on for relocatable code.
1289 if (emit_relocs)
1290 this->size_relocatable_relocs();
1292 gold_assert(!(is_gc_or_icf) || reloc_sections.empty());
1294 for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1295 p != reloc_sections.end();
1296 ++p)
1298 unsigned int i = *p;
1299 const unsigned char* pshdr;
1300 pshdr = section_headers_data + i * This::shdr_size;
1301 typename This::Shdr shdr(pshdr);
1303 unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1304 if (data_shndx >= shnum)
1306 // We already warned about this above.
1307 continue;
1310 Output_section* data_section = out_sections[data_shndx];
1311 if (data_section == NULL)
1313 out_sections[i] = NULL;
1314 out_section_offsets[i] = invalid_address;
1315 continue;
1318 Relocatable_relocs* rr = new Relocatable_relocs();
1319 this->set_relocatable_relocs(i, rr);
1321 Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1322 rr);
1323 out_sections[i] = os;
1324 out_section_offsets[i] = invalid_address;
1327 // Handle the .eh_frame sections at the end.
1328 gold_assert(!is_gc_pass_one || eh_frame_sections.empty());
1329 for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1330 p != eh_frame_sections.end();
1331 ++p)
1333 gold_assert(this->has_eh_frame_);
1334 gold_assert(external_symbols_offset != 0);
1336 unsigned int i = *p;
1337 const unsigned char *pshdr;
1338 pshdr = section_headers_data + i * This::shdr_size;
1339 typename This::Shdr shdr(pshdr);
1341 off_t offset;
1342 Output_section* os = layout->layout_eh_frame(this,
1343 symbols_data,
1344 symbols_size,
1345 symbol_names_data,
1346 symbol_names_size,
1347 i, shdr,
1348 reloc_shndx[i],
1349 reloc_type[i],
1350 &offset);
1351 out_sections[i] = os;
1352 if (offset == -1)
1354 // An object can contain at most one section holding exception
1355 // frame information.
1356 gold_assert(this->discarded_eh_frame_shndx_ == -1U);
1357 this->discarded_eh_frame_shndx_ = i;
1358 out_section_offsets[i] = invalid_address;
1360 else
1361 out_section_offsets[i] = convert_types<Address, off_t>(offset);
1363 // If this section requires special handling, and if there are
1364 // relocs that apply to it, then we must do the special handling
1365 // before we apply the relocs.
1366 if (offset == -1 && reloc_shndx[i] != 0)
1367 this->set_relocs_must_follow_section_writes();
1370 if (is_gc_pass_two)
1372 delete[] gc_sd->section_headers_data;
1373 delete[] gc_sd->section_names_data;
1374 delete[] gc_sd->symbols_data;
1375 delete[] gc_sd->symbol_names_data;
1376 this->set_symbols_data(NULL);
1378 else
1380 delete sd->section_headers;
1381 sd->section_headers = NULL;
1382 delete sd->section_names;
1383 sd->section_names = NULL;
1387 // Layout sections whose layout was deferred while waiting for
1388 // input files from a plugin.
1390 template<int size, bool big_endian>
1391 void
1392 Sized_relobj<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1394 typename std::vector<Deferred_layout>::iterator deferred;
1396 for (deferred = this->deferred_layout_.begin();
1397 deferred != this->deferred_layout_.end();
1398 ++deferred)
1400 typename This::Shdr shdr(deferred->shdr_data_);
1401 this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1402 shdr, deferred->reloc_shndx_, deferred->reloc_type_);
1405 this->deferred_layout_.clear();
1408 // Add the symbols to the symbol table.
1410 template<int size, bool big_endian>
1411 void
1412 Sized_relobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1413 Read_symbols_data* sd,
1414 Layout*)
1416 if (sd->symbols == NULL)
1418 gold_assert(sd->symbol_names == NULL);
1419 return;
1422 const int sym_size = This::sym_size;
1423 size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1424 / sym_size);
1425 if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1427 this->error(_("size of symbols is not multiple of symbol size"));
1428 return;
1431 this->symbols_.resize(symcount);
1433 const char* sym_names =
1434 reinterpret_cast<const char*>(sd->symbol_names->data());
1435 symtab->add_from_relobj(this,
1436 sd->symbols->data() + sd->external_symbols_offset,
1437 symcount, this->local_symbol_count_,
1438 sym_names, sd->symbol_names_size,
1439 &this->symbols_,
1440 &this->defined_count_);
1442 delete sd->symbols;
1443 sd->symbols = NULL;
1444 delete sd->symbol_names;
1445 sd->symbol_names = NULL;
1448 // First pass over the local symbols. Here we add their names to
1449 // *POOL and *DYNPOOL, and we store the symbol value in
1450 // THIS->LOCAL_VALUES_. This function is always called from a
1451 // singleton thread. This is followed by a call to
1452 // finalize_local_symbols.
1454 template<int size, bool big_endian>
1455 void
1456 Sized_relobj<size, big_endian>::do_count_local_symbols(Stringpool* pool,
1457 Stringpool* dynpool)
1459 gold_assert(this->symtab_shndx_ != -1U);
1460 if (this->symtab_shndx_ == 0)
1462 // This object has no symbols. Weird but legal.
1463 return;
1466 // Read the symbol table section header.
1467 const unsigned int symtab_shndx = this->symtab_shndx_;
1468 typename This::Shdr symtabshdr(this,
1469 this->elf_file_.section_header(symtab_shndx));
1470 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1472 // Read the local symbols.
1473 const int sym_size = This::sym_size;
1474 const unsigned int loccount = this->local_symbol_count_;
1475 gold_assert(loccount == symtabshdr.get_sh_info());
1476 off_t locsize = loccount * sym_size;
1477 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1478 locsize, true, true);
1480 // Read the symbol names.
1481 const unsigned int strtab_shndx =
1482 this->adjust_shndx(symtabshdr.get_sh_link());
1483 section_size_type strtab_size;
1484 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1485 &strtab_size,
1486 true);
1487 const char* pnames = reinterpret_cast<const char*>(pnamesu);
1489 // Loop over the local symbols.
1491 const Output_sections& out_sections(this->output_sections());
1492 unsigned int shnum = this->shnum();
1493 unsigned int count = 0;
1494 unsigned int dyncount = 0;
1495 // Skip the first, dummy, symbol.
1496 psyms += sym_size;
1497 bool discard_locals = parameters->options().discard_locals();
1498 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1500 elfcpp::Sym<size, big_endian> sym(psyms);
1502 Symbol_value<size>& lv(this->local_values_[i]);
1504 bool is_ordinary;
1505 unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
1506 &is_ordinary);
1507 lv.set_input_shndx(shndx, is_ordinary);
1509 if (sym.get_st_type() == elfcpp::STT_SECTION)
1510 lv.set_is_section_symbol();
1511 else if (sym.get_st_type() == elfcpp::STT_TLS)
1512 lv.set_is_tls_symbol();
1514 // Save the input symbol value for use in do_finalize_local_symbols().
1515 lv.set_input_value(sym.get_st_value());
1517 // Decide whether this symbol should go into the output file.
1519 if ((shndx < shnum && out_sections[shndx] == NULL)
1520 || (shndx == this->discarded_eh_frame_shndx_))
1522 lv.set_no_output_symtab_entry();
1523 gold_assert(!lv.needs_output_dynsym_entry());
1524 continue;
1527 if (sym.get_st_type() == elfcpp::STT_SECTION)
1529 lv.set_no_output_symtab_entry();
1530 gold_assert(!lv.needs_output_dynsym_entry());
1531 continue;
1534 if (sym.get_st_name() >= strtab_size)
1536 this->error(_("local symbol %u section name out of range: %u >= %u"),
1537 i, sym.get_st_name(),
1538 static_cast<unsigned int>(strtab_size));
1539 lv.set_no_output_symtab_entry();
1540 continue;
1543 // If --discard-locals option is used, discard all temporary local
1544 // symbols. These symbols start with system-specific local label
1545 // prefixes, typically .L for ELF system. We want to be compatible
1546 // with GNU ld so here we essentially use the same check in
1547 // bfd_is_local_label(). The code is different because we already
1548 // know that:
1550 // - the symbol is local and thus cannot have global or weak binding.
1551 // - the symbol is not a section symbol.
1552 // - the symbol has a name.
1554 // We do not discard a symbol if it needs a dynamic symbol entry.
1555 const char* name = pnames + sym.get_st_name();
1556 if (discard_locals
1557 && sym.get_st_type() != elfcpp::STT_FILE
1558 && !lv.needs_output_dynsym_entry()
1559 && parameters->target().is_local_label_name(name))
1561 lv.set_no_output_symtab_entry();
1562 continue;
1565 // Add the symbol to the symbol table string pool.
1566 pool->add(name, true, NULL);
1567 ++count;
1569 // If needed, add the symbol to the dynamic symbol table string pool.
1570 if (lv.needs_output_dynsym_entry())
1572 dynpool->add(name, true, NULL);
1573 ++dyncount;
1577 this->output_local_symbol_count_ = count;
1578 this->output_local_dynsym_count_ = dyncount;
1581 // Finalize the local symbols. Here we set the final value in
1582 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
1583 // This function is always called from a singleton thread. The actual
1584 // output of the local symbols will occur in a separate task.
1586 template<int size, bool big_endian>
1587 unsigned int
1588 Sized_relobj<size, big_endian>::do_finalize_local_symbols(unsigned int index,
1589 off_t off,
1590 Symbol_table* symtab)
1592 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1594 const unsigned int loccount = this->local_symbol_count_;
1595 this->local_symbol_offset_ = off;
1597 const bool relocatable = parameters->options().relocatable();
1598 const Output_sections& out_sections(this->output_sections());
1599 const std::vector<Address>& out_offsets(this->section_offsets_);
1600 unsigned int shnum = this->shnum();
1602 for (unsigned int i = 1; i < loccount; ++i)
1604 Symbol_value<size>& lv(this->local_values_[i]);
1606 bool is_ordinary;
1607 unsigned int shndx = lv.input_shndx(&is_ordinary);
1609 // Set the output symbol value.
1611 if (!is_ordinary)
1613 if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
1614 lv.set_output_value(lv.input_value());
1615 else
1617 this->error(_("unknown section index %u for local symbol %u"),
1618 shndx, i);
1619 lv.set_output_value(0);
1622 else
1624 if (shndx >= shnum)
1626 this->error(_("local symbol %u section index %u out of range"),
1627 i, shndx);
1628 shndx = 0;
1631 Output_section* os = out_sections[shndx];
1632 Address secoffset = out_offsets[shndx];
1633 if (symtab->is_section_folded(this, shndx))
1635 gold_assert (os == NULL && secoffset == invalid_address);
1636 // Get the os of the section it is folded onto.
1637 Section_id folded = symtab->icf()->get_folded_section(this,
1638 shndx);
1639 gold_assert(folded.first != NULL);
1640 Sized_relobj<size, big_endian>* folded_obj = reinterpret_cast
1641 <Sized_relobj<size, big_endian>*>(folded.first);
1642 os = folded_obj->output_section(folded.second);
1643 gold_assert(os != NULL);
1644 secoffset = folded_obj->get_output_section_offset(folded.second);
1645 gold_assert(secoffset != invalid_address);
1648 if (os == NULL)
1650 // This local symbol belongs to a section we are discarding.
1651 // In some cases when applying relocations later, we will
1652 // attempt to match it to the corresponding kept section,
1653 // so we leave the input value unchanged here.
1654 continue;
1656 else if (secoffset == invalid_address)
1658 uint64_t start;
1660 // This is a SHF_MERGE section or one which otherwise
1661 // requires special handling.
1662 if (shndx == this->discarded_eh_frame_shndx_)
1664 // This local symbol belongs to a discarded .eh_frame
1665 // section. Just treat it like the case in which
1666 // os == NULL above.
1667 gold_assert(this->has_eh_frame_);
1668 continue;
1670 else if (!lv.is_section_symbol())
1672 // This is not a section symbol. We can determine
1673 // the final value now.
1674 lv.set_output_value(os->output_address(this, shndx,
1675 lv.input_value()));
1677 else if (!os->find_starting_output_address(this, shndx, &start))
1679 // This is a section symbol, but apparently not one
1680 // in a merged section. Just use the start of the
1681 // output section. This happens with relocatable
1682 // links when the input object has section symbols
1683 // for arbitrary non-merge sections.
1684 lv.set_output_value(os->address());
1686 else
1688 // We have to consider the addend to determine the
1689 // value to use in a relocation. START is the start
1690 // of this input section.
1691 Merged_symbol_value<size>* msv =
1692 new Merged_symbol_value<size>(lv.input_value(), start);
1693 lv.set_merged_symbol_value(msv);
1696 else if (lv.is_tls_symbol())
1697 lv.set_output_value(os->tls_offset()
1698 + secoffset
1699 + lv.input_value());
1700 else
1701 lv.set_output_value((relocatable ? 0 : os->address())
1702 + secoffset
1703 + lv.input_value());
1706 if (lv.needs_output_symtab_entry())
1708 lv.set_output_symtab_index(index);
1709 ++index;
1712 return index;
1715 // Set the output dynamic symbol table indexes for the local variables.
1717 template<int size, bool big_endian>
1718 unsigned int
1719 Sized_relobj<size, big_endian>::do_set_local_dynsym_indexes(unsigned int index)
1721 const unsigned int loccount = this->local_symbol_count_;
1722 for (unsigned int i = 1; i < loccount; ++i)
1724 Symbol_value<size>& lv(this->local_values_[i]);
1725 if (lv.needs_output_dynsym_entry())
1727 lv.set_output_dynsym_index(index);
1728 ++index;
1731 return index;
1734 // Set the offset where local dynamic symbol information will be stored.
1735 // Returns the count of local symbols contributed to the symbol table by
1736 // this object.
1738 template<int size, bool big_endian>
1739 unsigned int
1740 Sized_relobj<size, big_endian>::do_set_local_dynsym_offset(off_t off)
1742 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1743 this->local_dynsym_offset_ = off;
1744 return this->output_local_dynsym_count_;
1747 // If Symbols_data is not NULL get the section flags from here otherwise
1748 // get it from the file.
1750 template<int size, bool big_endian>
1751 uint64_t
1752 Sized_relobj<size, big_endian>::do_section_flags(unsigned int shndx)
1754 Symbols_data* sd = this->get_symbols_data();
1755 if (sd != NULL)
1757 const unsigned char* pshdrs = sd->section_headers_data
1758 + This::shdr_size * shndx;
1759 typename This::Shdr shdr(pshdrs);
1760 return shdr.get_sh_flags();
1762 // If sd is NULL, read the section header from the file.
1763 return this->elf_file_.section_flags(shndx);
1766 // Get the section's ent size from Symbols_data. Called by get_section_contents
1767 // in icf.cc
1769 template<int size, bool big_endian>
1770 uint64_t
1771 Sized_relobj<size, big_endian>::do_section_entsize(unsigned int shndx)
1773 Symbols_data* sd = this->get_symbols_data();
1774 gold_assert (sd != NULL);
1776 const unsigned char* pshdrs = sd->section_headers_data
1777 + This::shdr_size * shndx;
1778 typename This::Shdr shdr(pshdrs);
1779 return shdr.get_sh_entsize();
1783 // Write out the local symbols.
1785 template<int size, bool big_endian>
1786 void
1787 Sized_relobj<size, big_endian>::write_local_symbols(
1788 Output_file* of,
1789 const Stringpool* sympool,
1790 const Stringpool* dynpool,
1791 Output_symtab_xindex* symtab_xindex,
1792 Output_symtab_xindex* dynsym_xindex)
1794 const bool strip_all = parameters->options().strip_all();
1795 if (strip_all)
1797 if (this->output_local_dynsym_count_ == 0)
1798 return;
1799 this->output_local_symbol_count_ = 0;
1802 gold_assert(this->symtab_shndx_ != -1U);
1803 if (this->symtab_shndx_ == 0)
1805 // This object has no symbols. Weird but legal.
1806 return;
1809 // Read the symbol table section header.
1810 const unsigned int symtab_shndx = this->symtab_shndx_;
1811 typename This::Shdr symtabshdr(this,
1812 this->elf_file_.section_header(symtab_shndx));
1813 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1814 const unsigned int loccount = this->local_symbol_count_;
1815 gold_assert(loccount == symtabshdr.get_sh_info());
1817 // Read the local symbols.
1818 const int sym_size = This::sym_size;
1819 off_t locsize = loccount * sym_size;
1820 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1821 locsize, true, false);
1823 // Read the symbol names.
1824 const unsigned int strtab_shndx =
1825 this->adjust_shndx(symtabshdr.get_sh_link());
1826 section_size_type strtab_size;
1827 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1828 &strtab_size,
1829 false);
1830 const char* pnames = reinterpret_cast<const char*>(pnamesu);
1832 // Get views into the output file for the portions of the symbol table
1833 // and the dynamic symbol table that we will be writing.
1834 off_t output_size = this->output_local_symbol_count_ * sym_size;
1835 unsigned char* oview = NULL;
1836 if (output_size > 0)
1837 oview = of->get_output_view(this->local_symbol_offset_, output_size);
1839 off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
1840 unsigned char* dyn_oview = NULL;
1841 if (dyn_output_size > 0)
1842 dyn_oview = of->get_output_view(this->local_dynsym_offset_,
1843 dyn_output_size);
1845 const Output_sections out_sections(this->output_sections());
1847 gold_assert(this->local_values_.size() == loccount);
1849 unsigned char* ov = oview;
1850 unsigned char* dyn_ov = dyn_oview;
1851 psyms += sym_size;
1852 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1854 elfcpp::Sym<size, big_endian> isym(psyms);
1856 Symbol_value<size>& lv(this->local_values_[i]);
1858 bool is_ordinary;
1859 unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1860 &is_ordinary);
1861 if (is_ordinary)
1863 gold_assert(st_shndx < out_sections.size());
1864 if (out_sections[st_shndx] == NULL)
1865 continue;
1866 st_shndx = out_sections[st_shndx]->out_shndx();
1867 if (st_shndx >= elfcpp::SHN_LORESERVE)
1869 if (lv.needs_output_symtab_entry() && !strip_all)
1870 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
1871 if (lv.needs_output_dynsym_entry())
1872 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
1873 st_shndx = elfcpp::SHN_XINDEX;
1877 // Write the symbol to the output symbol table.
1878 if (!strip_all && lv.needs_output_symtab_entry())
1880 elfcpp::Sym_write<size, big_endian> osym(ov);
1882 gold_assert(isym.get_st_name() < strtab_size);
1883 const char* name = pnames + isym.get_st_name();
1884 osym.put_st_name(sympool->get_offset(name));
1885 osym.put_st_value(this->local_values_[i].value(this, 0));
1886 osym.put_st_size(isym.get_st_size());
1887 osym.put_st_info(isym.get_st_info());
1888 osym.put_st_other(isym.get_st_other());
1889 osym.put_st_shndx(st_shndx);
1891 ov += sym_size;
1894 // Write the symbol to the output dynamic symbol table.
1895 if (lv.needs_output_dynsym_entry())
1897 gold_assert(dyn_ov < dyn_oview + dyn_output_size);
1898 elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
1900 gold_assert(isym.get_st_name() < strtab_size);
1901 const char* name = pnames + isym.get_st_name();
1902 osym.put_st_name(dynpool->get_offset(name));
1903 osym.put_st_value(this->local_values_[i].value(this, 0));
1904 osym.put_st_size(isym.get_st_size());
1905 osym.put_st_info(isym.get_st_info());
1906 osym.put_st_other(isym.get_st_other());
1907 osym.put_st_shndx(st_shndx);
1909 dyn_ov += sym_size;
1914 if (output_size > 0)
1916 gold_assert(ov - oview == output_size);
1917 of->write_output_view(this->local_symbol_offset_, output_size, oview);
1920 if (dyn_output_size > 0)
1922 gold_assert(dyn_ov - dyn_oview == dyn_output_size);
1923 of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
1924 dyn_oview);
1928 // Set *INFO to symbolic information about the offset OFFSET in the
1929 // section SHNDX. Return true if we found something, false if we
1930 // found nothing.
1932 template<int size, bool big_endian>
1933 bool
1934 Sized_relobj<size, big_endian>::get_symbol_location_info(
1935 unsigned int shndx,
1936 off_t offset,
1937 Symbol_location_info* info)
1939 if (this->symtab_shndx_ == 0)
1940 return false;
1942 section_size_type symbols_size;
1943 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
1944 &symbols_size,
1945 false);
1947 unsigned int symbol_names_shndx =
1948 this->adjust_shndx(this->section_link(this->symtab_shndx_));
1949 section_size_type names_size;
1950 const unsigned char* symbol_names_u =
1951 this->section_contents(symbol_names_shndx, &names_size, false);
1952 const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
1954 const int sym_size = This::sym_size;
1955 const size_t count = symbols_size / sym_size;
1957 const unsigned char* p = symbols;
1958 for (size_t i = 0; i < count; ++i, p += sym_size)
1960 elfcpp::Sym<size, big_endian> sym(p);
1962 if (sym.get_st_type() == elfcpp::STT_FILE)
1964 if (sym.get_st_name() >= names_size)
1965 info->source_file = "(invalid)";
1966 else
1967 info->source_file = symbol_names + sym.get_st_name();
1968 continue;
1971 bool is_ordinary;
1972 unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
1973 &is_ordinary);
1974 if (is_ordinary
1975 && st_shndx == shndx
1976 && static_cast<off_t>(sym.get_st_value()) <= offset
1977 && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
1978 > offset))
1980 if (sym.get_st_name() > names_size)
1981 info->enclosing_symbol_name = "(invalid)";
1982 else
1984 info->enclosing_symbol_name = symbol_names + sym.get_st_name();
1985 if (parameters->options().do_demangle())
1987 char* demangled_name = cplus_demangle(
1988 info->enclosing_symbol_name.c_str(),
1989 DMGL_ANSI | DMGL_PARAMS);
1990 if (demangled_name != NULL)
1992 info->enclosing_symbol_name.assign(demangled_name);
1993 free(demangled_name);
1997 return true;
2001 return false;
2004 // Look for a kept section corresponding to the given discarded section,
2005 // and return its output address. This is used only for relocations in
2006 // debugging sections. If we can't find the kept section, return 0.
2008 template<int size, bool big_endian>
2009 typename Sized_relobj<size, big_endian>::Address
2010 Sized_relobj<size, big_endian>::map_to_kept_section(
2011 unsigned int shndx,
2012 bool* found) const
2014 Relobj* kept_object;
2015 unsigned int kept_shndx;
2016 if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
2018 Sized_relobj<size, big_endian>* kept_relobj =
2019 static_cast<Sized_relobj<size, big_endian>*>(kept_object);
2020 Output_section* os = kept_relobj->output_section(kept_shndx);
2021 Address offset = kept_relobj->get_output_section_offset(kept_shndx);
2022 if (os != NULL && offset != invalid_address)
2024 *found = true;
2025 return os->address() + offset;
2028 *found = false;
2029 return 0;
2032 // Get symbol counts.
2034 template<int size, bool big_endian>
2035 void
2036 Sized_relobj<size, big_endian>::do_get_global_symbol_counts(
2037 const Symbol_table*,
2038 size_t* defined,
2039 size_t* used) const
2041 *defined = this->defined_count_;
2042 size_t count = 0;
2043 for (Symbols::const_iterator p = this->symbols_.begin();
2044 p != this->symbols_.end();
2045 ++p)
2046 if (*p != NULL
2047 && (*p)->source() == Symbol::FROM_OBJECT
2048 && (*p)->object() == this
2049 && (*p)->is_defined())
2050 ++count;
2051 *used = count;
2054 // Input_objects methods.
2056 // Add a regular relocatable object to the list. Return false if this
2057 // object should be ignored.
2059 bool
2060 Input_objects::add_object(Object* obj)
2062 // Set the global target from the first object file we recognize.
2063 Target* target = obj->target();
2064 if (!parameters->target_valid())
2065 set_parameters_target(target);
2066 else if (target != &parameters->target())
2068 obj->error(_("incompatible target"));
2069 return false;
2072 // Print the filename if the -t/--trace option is selected.
2073 if (parameters->options().trace())
2074 gold_info("%s", obj->name().c_str());
2076 if (!obj->is_dynamic())
2077 this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2078 else
2080 // See if this is a duplicate SONAME.
2081 Dynobj* dynobj = static_cast<Dynobj*>(obj);
2082 const char* soname = dynobj->soname();
2084 std::pair<Unordered_set<std::string>::iterator, bool> ins =
2085 this->sonames_.insert(soname);
2086 if (!ins.second)
2088 // We have already seen a dynamic object with this soname.
2089 return false;
2092 this->dynobj_list_.push_back(dynobj);
2095 // Add this object to the cross-referencer if requested.
2096 if (parameters->options().user_set_print_symbol_counts())
2098 if (this->cref_ == NULL)
2099 this->cref_ = new Cref();
2100 this->cref_->add_object(obj);
2103 return true;
2106 // For each dynamic object, record whether we've seen all of its
2107 // explicit dependencies.
2109 void
2110 Input_objects::check_dynamic_dependencies() const
2112 for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2113 p != this->dynobj_list_.end();
2114 ++p)
2116 const Dynobj::Needed& needed((*p)->needed());
2117 bool found_all = true;
2118 for (Dynobj::Needed::const_iterator pneeded = needed.begin();
2119 pneeded != needed.end();
2120 ++pneeded)
2122 if (this->sonames_.find(*pneeded) == this->sonames_.end())
2124 found_all = false;
2125 break;
2128 (*p)->set_has_unknown_needed_entries(!found_all);
2132 // Start processing an archive.
2134 void
2135 Input_objects::archive_start(Archive* archive)
2137 if (parameters->options().user_set_print_symbol_counts())
2139 if (this->cref_ == NULL)
2140 this->cref_ = new Cref();
2141 this->cref_->add_archive_start(archive);
2145 // Stop processing an archive.
2147 void
2148 Input_objects::archive_stop(Archive* archive)
2150 if (parameters->options().user_set_print_symbol_counts())
2151 this->cref_->add_archive_stop(archive);
2154 // Print symbol counts
2156 void
2157 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2159 if (parameters->options().user_set_print_symbol_counts()
2160 && this->cref_ != NULL)
2161 this->cref_->print_symbol_counts(symtab);
2164 // Relocate_info methods.
2166 // Return a string describing the location of a relocation. This is
2167 // only used in error messages.
2169 template<int size, bool big_endian>
2170 std::string
2171 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
2173 // See if we can get line-number information from debugging sections.
2174 std::string filename;
2175 std::string file_and_lineno; // Better than filename-only, if available.
2177 Sized_dwarf_line_info<size, big_endian> line_info(this->object);
2178 // This will be "" if we failed to parse the debug info for any reason.
2179 file_and_lineno = line_info.addr2line(this->data_shndx, offset);
2181 std::string ret(this->object->name());
2182 ret += ':';
2183 Symbol_location_info info;
2184 if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
2186 ret += " in function ";
2187 ret += info.enclosing_symbol_name;
2188 ret += ":";
2189 filename = info.source_file;
2192 if (!file_and_lineno.empty())
2193 ret += file_and_lineno;
2194 else
2196 if (!filename.empty())
2197 ret += filename;
2198 ret += "(";
2199 ret += this->object->section_name(this->data_shndx);
2200 char buf[100];
2201 // Offsets into sections have to be positive.
2202 snprintf(buf, sizeof(buf), "+0x%lx", static_cast<long>(offset));
2203 ret += buf;
2204 ret += ")";
2206 return ret;
2209 } // End namespace gold.
2211 namespace
2214 using namespace gold;
2216 // Read an ELF file with the header and return the appropriate
2217 // instance of Object.
2219 template<int size, bool big_endian>
2220 Object*
2221 make_elf_sized_object(const std::string& name, Input_file* input_file,
2222 off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr)
2224 Target* target = select_target(ehdr.get_e_machine(), size, big_endian,
2225 ehdr.get_e_ident()[elfcpp::EI_OSABI],
2226 ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
2227 if (target == NULL)
2228 gold_fatal(_("%s: unsupported ELF machine number %d"),
2229 name.c_str(), ehdr.get_e_machine());
2230 return target->make_elf_object<size, big_endian>(name, input_file, offset,
2231 ehdr);
2234 } // End anonymous namespace.
2236 namespace gold
2239 // Return whether INPUT_FILE is an ELF object.
2241 bool
2242 is_elf_object(Input_file* input_file, off_t offset,
2243 const unsigned char** start, int *read_size)
2245 off_t filesize = input_file->file().filesize();
2246 int want = elfcpp::Elf_sizes<64>::ehdr_size;
2247 if (filesize - offset < want)
2248 want = filesize - offset;
2250 const unsigned char* p = input_file->file().get_view(offset, 0, want,
2251 true, false);
2252 *start = p;
2253 *read_size = want;
2255 if (want < 4)
2256 return false;
2258 static unsigned char elfmagic[4] =
2260 elfcpp::ELFMAG0, elfcpp::ELFMAG1,
2261 elfcpp::ELFMAG2, elfcpp::ELFMAG3
2263 return memcmp(p, elfmagic, 4) == 0;
2266 // Read an ELF file and return the appropriate instance of Object.
2268 Object*
2269 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
2270 const unsigned char* p, section_offset_type bytes,
2271 bool* punconfigured)
2273 if (punconfigured != NULL)
2274 *punconfigured = false;
2276 if (bytes < elfcpp::EI_NIDENT)
2278 gold_error(_("%s: ELF file too short"), name.c_str());
2279 return NULL;
2282 int v = p[elfcpp::EI_VERSION];
2283 if (v != elfcpp::EV_CURRENT)
2285 if (v == elfcpp::EV_NONE)
2286 gold_error(_("%s: invalid ELF version 0"), name.c_str());
2287 else
2288 gold_error(_("%s: unsupported ELF version %d"), name.c_str(), v);
2289 return NULL;
2292 int c = p[elfcpp::EI_CLASS];
2293 if (c == elfcpp::ELFCLASSNONE)
2295 gold_error(_("%s: invalid ELF class 0"), name.c_str());
2296 return NULL;
2298 else if (c != elfcpp::ELFCLASS32
2299 && c != elfcpp::ELFCLASS64)
2301 gold_error(_("%s: unsupported ELF class %d"), name.c_str(), c);
2302 return NULL;
2305 int d = p[elfcpp::EI_DATA];
2306 if (d == elfcpp::ELFDATANONE)
2308 gold_error(_("%s: invalid ELF data encoding"), name.c_str());
2309 return NULL;
2311 else if (d != elfcpp::ELFDATA2LSB
2312 && d != elfcpp::ELFDATA2MSB)
2314 gold_error(_("%s: unsupported ELF data encoding %d"), name.c_str(), d);
2315 return NULL;
2318 bool big_endian = d == elfcpp::ELFDATA2MSB;
2320 if (c == elfcpp::ELFCLASS32)
2322 if (bytes < elfcpp::Elf_sizes<32>::ehdr_size)
2324 gold_error(_("%s: ELF file too short"), name.c_str());
2325 return NULL;
2327 if (big_endian)
2329 #ifdef HAVE_TARGET_32_BIG
2330 elfcpp::Ehdr<32, true> ehdr(p);
2331 return make_elf_sized_object<32, true>(name, input_file,
2332 offset, ehdr);
2333 #else
2334 if (punconfigured != NULL)
2335 *punconfigured = true;
2336 else
2337 gold_error(_("%s: not configured to support "
2338 "32-bit big-endian object"),
2339 name.c_str());
2340 return NULL;
2341 #endif
2343 else
2345 #ifdef HAVE_TARGET_32_LITTLE
2346 elfcpp::Ehdr<32, false> ehdr(p);
2347 return make_elf_sized_object<32, false>(name, input_file,
2348 offset, ehdr);
2349 #else
2350 if (punconfigured != NULL)
2351 *punconfigured = true;
2352 else
2353 gold_error(_("%s: not configured to support "
2354 "32-bit little-endian object"),
2355 name.c_str());
2356 return NULL;
2357 #endif
2360 else
2362 if (bytes < elfcpp::Elf_sizes<64>::ehdr_size)
2364 gold_error(_("%s: ELF file too short"), name.c_str());
2365 return NULL;
2367 if (big_endian)
2369 #ifdef HAVE_TARGET_64_BIG
2370 elfcpp::Ehdr<64, true> ehdr(p);
2371 return make_elf_sized_object<64, true>(name, input_file,
2372 offset, ehdr);
2373 #else
2374 if (punconfigured != NULL)
2375 *punconfigured = true;
2376 else
2377 gold_error(_("%s: not configured to support "
2378 "64-bit big-endian object"),
2379 name.c_str());
2380 return NULL;
2381 #endif
2383 else
2385 #ifdef HAVE_TARGET_64_LITTLE
2386 elfcpp::Ehdr<64, false> ehdr(p);
2387 return make_elf_sized_object<64, false>(name, input_file,
2388 offset, ehdr);
2389 #else
2390 if (punconfigured != NULL)
2391 *punconfigured = true;
2392 else
2393 gold_error(_("%s: not configured to support "
2394 "64-bit little-endian object"),
2395 name.c_str());
2396 return NULL;
2397 #endif
2402 // Instantiate the templates we need.
2404 #ifdef HAVE_TARGET_32_LITTLE
2405 template
2406 void
2407 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
2408 Read_symbols_data*);
2409 #endif
2411 #ifdef HAVE_TARGET_32_BIG
2412 template
2413 void
2414 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
2415 Read_symbols_data*);
2416 #endif
2418 #ifdef HAVE_TARGET_64_LITTLE
2419 template
2420 void
2421 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
2422 Read_symbols_data*);
2423 #endif
2425 #ifdef HAVE_TARGET_64_BIG
2426 template
2427 void
2428 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
2429 Read_symbols_data*);
2430 #endif
2432 #ifdef HAVE_TARGET_32_LITTLE
2433 template
2434 class Sized_relobj<32, false>;
2435 #endif
2437 #ifdef HAVE_TARGET_32_BIG
2438 template
2439 class Sized_relobj<32, true>;
2440 #endif
2442 #ifdef HAVE_TARGET_64_LITTLE
2443 template
2444 class Sized_relobj<64, false>;
2445 #endif
2447 #ifdef HAVE_TARGET_64_BIG
2448 template
2449 class Sized_relobj<64, true>;
2450 #endif
2452 #ifdef HAVE_TARGET_32_LITTLE
2453 template
2454 struct Relocate_info<32, false>;
2455 #endif
2457 #ifdef HAVE_TARGET_32_BIG
2458 template
2459 struct Relocate_info<32, true>;
2460 #endif
2462 #ifdef HAVE_TARGET_64_LITTLE
2463 template
2464 struct Relocate_info<64, false>;
2465 #endif
2467 #ifdef HAVE_TARGET_64_BIG
2468 template
2469 struct Relocate_info<64, true>;
2470 #endif
2472 } // End namespace gold.