1 // dynobj.cc -- dynamic object support for gold
3 // Copyright 2006, 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
29 #include "parameters.h"
38 // Sets up the default soname_ to use, in the (rare) cases we never
39 // see a DT_SONAME entry.
41 Dynobj::Dynobj(const std::string& name, Input_file* input_file, off_t offset)
42 : Object(name, input_file, true, offset),
44 unknown_needed_(UNKNOWN_NEEDED_UNSET)
46 // This will be overridden by a DT_SONAME entry, hopefully. But if
47 // we never see a DT_SONAME entry, our rule is to use the dynamic
48 // object's filename. The only exception is when the dynamic object
49 // is part of an archive (so the filename is the archive's
50 // filename). In that case, we use just the dynobj's name-in-archive.
51 this->soname_ = this->input_file()->found_name();
52 if (this->offset() != 0)
54 std::string::size_type open_paren = this->name().find('(');
55 std::string::size_type close_paren = this->name().find(')');
56 if (open_paren != std::string::npos && close_paren != std::string::npos)
58 // It's an archive, and name() is of the form 'foo.a(bar.so)'.
59 this->soname_ = this->name().substr(open_paren + 1,
60 close_paren - (open_paren + 1));
65 // Class Sized_dynobj.
67 template<int size, bool big_endian>
68 Sized_dynobj<size, big_endian>::Sized_dynobj(
69 const std::string& name,
70 Input_file* input_file,
72 const elfcpp::Ehdr<size, big_endian>& ehdr)
73 : Dynobj(name, input_file, offset),
80 template<int size, bool big_endian>
82 Sized_dynobj<size, big_endian>::setup(
83 const elfcpp::Ehdr<size, big_endian>& ehdr)
85 this->set_target(ehdr.get_e_machine(), size, big_endian,
86 ehdr.get_e_ident()[elfcpp::EI_OSABI],
87 ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
89 const unsigned int shnum = this->elf_file_.shnum();
90 this->set_shnum(shnum);
93 // Find the SHT_DYNSYM section and the various version sections, and
94 // the dynamic section, given the section headers.
96 template<int size, bool big_endian>
98 Sized_dynobj<size, big_endian>::find_dynsym_sections(
99 const unsigned char* pshdrs,
100 unsigned int* pdynsym_shndx,
101 unsigned int* pversym_shndx,
102 unsigned int* pverdef_shndx,
103 unsigned int* pverneed_shndx,
104 unsigned int* pdynamic_shndx)
106 *pdynsym_shndx = -1U;
107 *pversym_shndx = -1U;
108 *pverdef_shndx = -1U;
109 *pverneed_shndx = -1U;
110 *pdynamic_shndx = -1U;
112 const unsigned int shnum = this->shnum();
113 const unsigned char* p = pshdrs;
114 for (unsigned int i = 0; i < shnum; ++i, p += This::shdr_size)
116 typename This::Shdr shdr(p);
119 switch (shdr.get_sh_type())
121 case elfcpp::SHT_DYNSYM:
124 case elfcpp::SHT_GNU_versym:
127 case elfcpp::SHT_GNU_verdef:
130 case elfcpp::SHT_GNU_verneed:
133 case elfcpp::SHT_DYNAMIC:
145 this->error(_("unexpected duplicate type %u section: %u, %u"),
146 shdr.get_sh_type(), *pi, i);
152 // Read the contents of section SHNDX. PSHDRS points to the section
153 // headers. TYPE is the expected section type. LINK is the expected
154 // section link. Store the data in *VIEW and *VIEW_SIZE. The
155 // section's sh_info field is stored in *VIEW_INFO.
157 template<int size, bool big_endian>
159 Sized_dynobj<size, big_endian>::read_dynsym_section(
160 const unsigned char* pshdrs,
165 section_size_type* view_size,
166 unsigned int* view_info)
176 typename This::Shdr shdr(pshdrs + shndx * This::shdr_size);
178 gold_assert(shdr.get_sh_type() == type);
180 if (shdr.get_sh_link() != link)
181 this->error(_("unexpected link in section %u header: %u != %u"),
182 shndx, shdr.get_sh_link(), link);
184 *view = this->get_lasting_view(shdr.get_sh_offset(), shdr.get_sh_size(),
186 *view_size = convert_to_section_size_type(shdr.get_sh_size());
187 *view_info = shdr.get_sh_info();
190 // Read the dynamic tags. Set the soname field if this shared object
191 // has a DT_SONAME tag. Record the DT_NEEDED tags. PSHDRS points to
192 // the section headers. DYNAMIC_SHNDX is the section index of the
193 // SHT_DYNAMIC section. STRTAB_SHNDX, STRTAB, and STRTAB_SIZE are the
194 // section index and contents of a string table which may be the one
195 // associated with the SHT_DYNAMIC section.
197 template<int size, bool big_endian>
199 Sized_dynobj<size, big_endian>::read_dynamic(const unsigned char* pshdrs,
200 unsigned int dynamic_shndx,
201 unsigned int strtab_shndx,
202 const unsigned char* strtabu,
205 typename This::Shdr dynamicshdr(pshdrs + dynamic_shndx * This::shdr_size);
206 gold_assert(dynamicshdr.get_sh_type() == elfcpp::SHT_DYNAMIC);
208 const off_t dynamic_size = dynamicshdr.get_sh_size();
209 const unsigned char* pdynamic = this->get_view(dynamicshdr.get_sh_offset(),
210 dynamic_size, false);
212 const unsigned int link = dynamicshdr.get_sh_link();
213 if (link != strtab_shndx)
215 if (link >= this->shnum())
217 this->error(_("DYNAMIC section %u link out of range: %u"),
218 dynamic_shndx, link);
222 typename This::Shdr strtabshdr(pshdrs + link * This::shdr_size);
223 if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
225 this->error(_("DYNAMIC section %u link %u is not a strtab"),
226 dynamic_shndx, link);
230 strtab_size = strtabshdr.get_sh_size();
231 strtabu = this->get_view(strtabshdr.get_sh_offset(), strtab_size, false);
234 const char* const strtab = reinterpret_cast<const char*>(strtabu);
236 for (const unsigned char* p = pdynamic;
237 p < pdynamic + dynamic_size;
240 typename This::Dyn dyn(p);
242 switch (dyn.get_d_tag())
244 case elfcpp::DT_NULL:
245 // We should always see DT_NULL at the end of the dynamic
249 case elfcpp::DT_SONAME:
251 off_t val = dyn.get_d_val();
252 if (val >= strtab_size)
253 this->error(_("DT_SONAME value out of range: %lld >= %lld"),
254 static_cast<long long>(val),
255 static_cast<long long>(strtab_size));
257 this->set_soname_string(strtab + val);
261 case elfcpp::DT_NEEDED:
263 off_t val = dyn.get_d_val();
264 if (val >= strtab_size)
265 this->error(_("DT_NEEDED value out of range: %lld >= %lld"),
266 static_cast<long long>(val),
267 static_cast<long long>(strtab_size));
269 this->add_needed(strtab + val);
278 this->error(_("missing DT_NULL in dynamic segment"));
281 // Read the symbols and sections from a dynamic object. We read the
282 // dynamic symbols, not the normal symbols.
284 template<int size, bool big_endian>
286 Sized_dynobj<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
288 this->read_section_data(&this->elf_file_, sd);
290 const unsigned char* const pshdrs = sd->section_headers->data();
292 unsigned int dynsym_shndx;
293 unsigned int versym_shndx;
294 unsigned int verdef_shndx;
295 unsigned int verneed_shndx;
296 unsigned int dynamic_shndx;
297 this->find_dynsym_sections(pshdrs, &dynsym_shndx, &versym_shndx,
298 &verdef_shndx, &verneed_shndx, &dynamic_shndx);
300 unsigned int strtab_shndx = -1U;
303 sd->symbols_size = 0;
304 sd->external_symbols_offset = 0;
305 sd->symbol_names = NULL;
306 sd->symbol_names_size = 0;
308 if (dynsym_shndx != -1U)
310 // Get the dynamic symbols.
311 typename This::Shdr dynsymshdr(pshdrs + dynsym_shndx * This::shdr_size);
312 gold_assert(dynsymshdr.get_sh_type() == elfcpp::SHT_DYNSYM);
314 sd->symbols = this->get_lasting_view(dynsymshdr.get_sh_offset(),
315 dynsymshdr.get_sh_size(), false);
317 convert_to_section_size_type(dynsymshdr.get_sh_size());
319 // Get the symbol names.
320 strtab_shndx = dynsymshdr.get_sh_link();
321 if (strtab_shndx >= this->shnum())
323 this->error(_("invalid dynamic symbol table name index: %u"),
327 typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
328 if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
330 this->error(_("dynamic symbol table name section "
331 "has wrong type: %u"),
332 static_cast<unsigned int>(strtabshdr.get_sh_type()));
336 sd->symbol_names = this->get_lasting_view(strtabshdr.get_sh_offset(),
337 strtabshdr.get_sh_size(),
339 sd->symbol_names_size =
340 convert_to_section_size_type(strtabshdr.get_sh_size());
342 // Get the version information.
345 this->read_dynsym_section(pshdrs, versym_shndx, elfcpp::SHT_GNU_versym,
346 dynsym_shndx, &sd->versym, &sd->versym_size,
349 // We require that the version definition and need section link
350 // to the same string table as the dynamic symbol table. This
351 // is not a technical requirement, but it always happens in
352 // practice. We could change this if necessary.
354 this->read_dynsym_section(pshdrs, verdef_shndx, elfcpp::SHT_GNU_verdef,
355 strtab_shndx, &sd->verdef, &sd->verdef_size,
358 this->read_dynsym_section(pshdrs, verneed_shndx, elfcpp::SHT_GNU_verneed,
359 strtab_shndx, &sd->verneed, &sd->verneed_size,
363 // Read the SHT_DYNAMIC section to find whether this shared object
364 // has a DT_SONAME tag and to record any DT_NEEDED tags. This
365 // doesn't really have anything to do with reading the symbols, but
366 // this is a convenient place to do it.
367 if (dynamic_shndx != -1U)
368 this->read_dynamic(pshdrs, dynamic_shndx, strtab_shndx,
369 (sd->symbol_names == NULL
371 : sd->symbol_names->data()),
372 sd->symbol_names_size);
375 // Lay out the input sections for a dynamic object. We don't want to
376 // include sections from a dynamic object, so all that we actually do
377 // here is check for .gnu.warning sections.
379 template<int size, bool big_endian>
381 Sized_dynobj<size, big_endian>::do_layout(Symbol_table* symtab,
383 Read_symbols_data* sd)
385 const unsigned int shnum = this->shnum();
389 // Get the section headers.
390 const unsigned char* pshdrs = sd->section_headers->data();
392 // Get the section names.
393 const unsigned char* pnamesu = sd->section_names->data();
394 const char* pnames = reinterpret_cast<const char*>(pnamesu);
396 // Skip the first, dummy, section.
397 pshdrs += This::shdr_size;
398 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
400 typename This::Shdr shdr(pshdrs);
402 if (shdr.get_sh_name() >= sd->section_names_size)
404 this->error(_("bad section name offset for section %u: %lu"),
405 i, static_cast<unsigned long>(shdr.get_sh_name()));
409 const char* name = pnames + shdr.get_sh_name();
411 this->handle_gnu_warning_section(name, i, symtab);
414 delete sd->section_headers;
415 sd->section_headers = NULL;
416 delete sd->section_names;
417 sd->section_names = NULL;
420 // Add an entry to the vector mapping version numbers to version
423 template<int size, bool big_endian>
425 Sized_dynobj<size, big_endian>::set_version_map(
426 Version_map* version_map,
428 const char* name) const
430 if (ndx >= version_map->size())
431 version_map->resize(ndx + 1);
432 if ((*version_map)[ndx] != NULL)
433 this->error(_("duplicate definition for version %u"), ndx);
434 (*version_map)[ndx] = name;
437 // Add mappings for the version definitions to VERSION_MAP.
439 template<int size, bool big_endian>
441 Sized_dynobj<size, big_endian>::make_verdef_map(
442 Read_symbols_data* sd,
443 Version_map* version_map) const
445 if (sd->verdef == NULL)
448 const char* names = reinterpret_cast<const char*>(sd->symbol_names->data());
449 section_size_type names_size = sd->symbol_names_size;
451 const unsigned char* pverdef = sd->verdef->data();
452 section_size_type verdef_size = sd->verdef_size;
453 const unsigned int count = sd->verdef_info;
455 const unsigned char* p = pverdef;
456 for (unsigned int i = 0; i < count; ++i)
458 elfcpp::Verdef<size, big_endian> verdef(p);
460 if (verdef.get_vd_version() != elfcpp::VER_DEF_CURRENT)
462 this->error(_("unexpected verdef version %u"),
463 verdef.get_vd_version());
467 const section_size_type vd_ndx = verdef.get_vd_ndx();
469 // The GNU linker clears the VERSYM_HIDDEN bit. I'm not
472 // The first Verdaux holds the name of this version. Subsequent
473 // ones are versions that this one depends upon, which we don't
475 const section_size_type vd_cnt = verdef.get_vd_cnt();
478 this->error(_("verdef vd_cnt field too small: %u"),
479 static_cast<unsigned int>(vd_cnt));
483 const section_size_type vd_aux = verdef.get_vd_aux();
484 if ((p - pverdef) + vd_aux >= verdef_size)
486 this->error(_("verdef vd_aux field out of range: %u"),
487 static_cast<unsigned int>(vd_aux));
491 const unsigned char* pvda = p + vd_aux;
492 elfcpp::Verdaux<size, big_endian> verdaux(pvda);
494 const section_size_type vda_name = verdaux.get_vda_name();
495 if (vda_name >= names_size)
497 this->error(_("verdaux vda_name field out of range: %u"),
498 static_cast<unsigned int>(vda_name));
502 this->set_version_map(version_map, vd_ndx, names + vda_name);
504 const section_size_type vd_next = verdef.get_vd_next();
505 if ((p - pverdef) + vd_next >= verdef_size)
507 this->error(_("verdef vd_next field out of range: %u"),
508 static_cast<unsigned int>(vd_next));
516 // Add mappings for the required versions to VERSION_MAP.
518 template<int size, bool big_endian>
520 Sized_dynobj<size, big_endian>::make_verneed_map(
521 Read_symbols_data* sd,
522 Version_map* version_map) const
524 if (sd->verneed == NULL)
527 const char* names = reinterpret_cast<const char*>(sd->symbol_names->data());
528 section_size_type names_size = sd->symbol_names_size;
530 const unsigned char* pverneed = sd->verneed->data();
531 const section_size_type verneed_size = sd->verneed_size;
532 const unsigned int count = sd->verneed_info;
534 const unsigned char* p = pverneed;
535 for (unsigned int i = 0; i < count; ++i)
537 elfcpp::Verneed<size, big_endian> verneed(p);
539 if (verneed.get_vn_version() != elfcpp::VER_NEED_CURRENT)
541 this->error(_("unexpected verneed version %u"),
542 verneed.get_vn_version());
546 const section_size_type vn_aux = verneed.get_vn_aux();
548 if ((p - pverneed) + vn_aux >= verneed_size)
550 this->error(_("verneed vn_aux field out of range: %u"),
551 static_cast<unsigned int>(vn_aux));
555 const unsigned int vn_cnt = verneed.get_vn_cnt();
556 const unsigned char* pvna = p + vn_aux;
557 for (unsigned int j = 0; j < vn_cnt; ++j)
559 elfcpp::Vernaux<size, big_endian> vernaux(pvna);
561 const unsigned int vna_name = vernaux.get_vna_name();
562 if (vna_name >= names_size)
564 this->error(_("vernaux vna_name field out of range: %u"),
565 static_cast<unsigned int>(vna_name));
569 this->set_version_map(version_map, vernaux.get_vna_other(),
572 const section_size_type vna_next = vernaux.get_vna_next();
573 if ((pvna - pverneed) + vna_next >= verneed_size)
575 this->error(_("verneed vna_next field out of range: %u"),
576 static_cast<unsigned int>(vna_next));
583 const section_size_type vn_next = verneed.get_vn_next();
584 if ((p - pverneed) + vn_next >= verneed_size)
586 this->error(_("verneed vn_next field out of range: %u"),
587 static_cast<unsigned int>(vn_next));
595 // Create a vector mapping version numbers to version strings.
597 template<int size, bool big_endian>
599 Sized_dynobj<size, big_endian>::make_version_map(
600 Read_symbols_data* sd,
601 Version_map* version_map) const
603 if (sd->verdef == NULL && sd->verneed == NULL)
606 // A guess at the maximum version number we will see. If this is
607 // wrong we will be less efficient but still correct.
608 version_map->reserve(sd->verdef_info + sd->verneed_info * 10);
610 this->make_verdef_map(sd, version_map);
611 this->make_verneed_map(sd, version_map);
614 // Add the dynamic symbols to the symbol table.
616 template<int size, bool big_endian>
618 Sized_dynobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
619 Read_symbols_data* sd)
621 if (sd->symbols == NULL)
623 gold_assert(sd->symbol_names == NULL);
624 gold_assert(sd->versym == NULL && sd->verdef == NULL
625 && sd->verneed == NULL);
629 const int sym_size = This::sym_size;
630 const size_t symcount = sd->symbols_size / sym_size;
631 gold_assert(sd->external_symbols_offset == 0);
632 if (symcount * sym_size != sd->symbols_size)
634 this->error(_("size of dynamic symbols is not multiple of symbol size"));
638 Version_map version_map;
639 this->make_version_map(sd, &version_map);
641 const char* sym_names =
642 reinterpret_cast<const char*>(sd->symbol_names->data());
643 symtab->add_from_dynobj(this, sd->symbols->data(), symcount,
644 sym_names, sd->symbol_names_size,
647 : sd->versym->data()),
653 delete sd->symbol_names;
654 sd->symbol_names = NULL;
655 if (sd->versym != NULL)
660 if (sd->verdef != NULL)
665 if (sd->verneed != NULL)
672 // Given a vector of hash codes, compute the number of hash buckets to
676 Dynobj::compute_bucket_count(const std::vector<uint32_t>& hashcodes,
677 bool for_gnu_hash_table)
679 // FIXME: Implement optional hash table optimization.
681 // Array used to determine the number of hash table buckets to use
682 // based on the number of symbols there are. If there are fewer
683 // than 3 symbols we use 1 bucket, fewer than 17 symbols we use 3
684 // buckets, fewer than 37 we use 17 buckets, and so forth. We never
685 // use more than 32771 buckets. This is straight from the old GNU
687 static const unsigned int buckets[] =
689 1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 1031, 2053, 4099, 8209,
692 const int buckets_count = sizeof buckets / sizeof buckets[0];
694 unsigned int symcount = hashcodes.size();
695 unsigned int ret = 1;
696 for (int i = 0; i < buckets_count; ++i)
698 if (symcount < buckets[i])
703 if (for_gnu_hash_table && ret < 2)
709 // The standard ELF hash function. This hash function must not
710 // change, as the dynamic linker uses it also.
713 Dynobj::elf_hash(const char* name)
715 const unsigned char* nameu = reinterpret_cast<const unsigned char*>(name);
718 while ((c = *nameu++) != '\0')
721 uint32_t g = h & 0xf0000000;
725 // The ELF ABI says h &= ~g, but using xor is equivalent in
726 // this case (since g was set from h) and may save one
734 // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN.
735 // DYNSYMS is a vector with all the global dynamic symbols.
736 // LOCAL_DYNSYM_COUNT is the number of local symbols in the dynamic
740 Dynobj::create_elf_hash_table(const std::vector<Symbol*>& dynsyms,
741 unsigned int local_dynsym_count,
742 unsigned char** pphash,
743 unsigned int* phashlen)
745 unsigned int dynsym_count = dynsyms.size();
747 // Get the hash values for all the symbols.
748 std::vector<uint32_t> dynsym_hashvals(dynsym_count);
749 for (unsigned int i = 0; i < dynsym_count; ++i)
750 dynsym_hashvals[i] = Dynobj::elf_hash(dynsyms[i]->name());
752 const unsigned int bucketcount =
753 Dynobj::compute_bucket_count(dynsym_hashvals, false);
755 std::vector<uint32_t> bucket(bucketcount);
756 std::vector<uint32_t> chain(local_dynsym_count + dynsym_count);
758 for (unsigned int i = 0; i < dynsym_count; ++i)
760 unsigned int dynsym_index = dynsyms[i]->dynsym_index();
761 unsigned int bucketpos = dynsym_hashvals[i] % bucketcount;
762 chain[dynsym_index] = bucket[bucketpos];
763 bucket[bucketpos] = dynsym_index;
766 unsigned int hashlen = ((2
771 unsigned char* phash = new unsigned char[hashlen];
773 if (parameters->is_big_endian())
775 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
776 Dynobj::sized_create_elf_hash_table<true>(bucket, chain, phash,
784 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
785 Dynobj::sized_create_elf_hash_table<false>(bucket, chain, phash,
796 // Fill in an ELF hash table.
798 template<bool big_endian>
800 Dynobj::sized_create_elf_hash_table(const std::vector<uint32_t>& bucket,
801 const std::vector<uint32_t>& chain,
802 unsigned char* phash,
803 unsigned int hashlen)
805 unsigned char* p = phash;
807 const unsigned int bucketcount = bucket.size();
808 const unsigned int chaincount = chain.size();
810 elfcpp::Swap<32, big_endian>::writeval(p, bucketcount);
812 elfcpp::Swap<32, big_endian>::writeval(p, chaincount);
815 for (unsigned int i = 0; i < bucketcount; ++i)
817 elfcpp::Swap<32, big_endian>::writeval(p, bucket[i]);
821 for (unsigned int i = 0; i < chaincount; ++i)
823 elfcpp::Swap<32, big_endian>::writeval(p, chain[i]);
827 gold_assert(static_cast<unsigned int>(p - phash) == hashlen);
830 // The hash function used for the GNU hash table. This hash function
831 // must not change, as the dynamic linker uses it also.
834 Dynobj::gnu_hash(const char* name)
836 const unsigned char* nameu = reinterpret_cast<const unsigned char*>(name);
839 while ((c = *nameu++) != '\0')
840 h = (h << 5) + h + c;
844 // Create a GNU hash table, setting *PPHASH and *PHASHLEN. GNU hash
845 // tables are an extension to ELF which are recognized by the GNU
846 // dynamic linker. They are referenced using dynamic tag DT_GNU_HASH.
847 // TARGET is the target. DYNSYMS is a vector with all the global
848 // symbols which will be going into the dynamic symbol table.
849 // LOCAL_DYNSYM_COUNT is the number of local symbols in the dynamic
853 Dynobj::create_gnu_hash_table(const std::vector<Symbol*>& dynsyms,
854 unsigned int local_dynsym_count,
855 unsigned char** pphash,
856 unsigned int* phashlen)
858 const unsigned int count = dynsyms.size();
860 // Sort the dynamic symbols into two vectors. Symbols which we do
861 // not want to put into the hash table we store into
862 // UNHASHED_DYNSYMS. Symbols which we do want to store we put into
863 // HASHED_DYNSYMS. DYNSYM_HASHVALS is parallel to HASHED_DYNSYMS,
864 // and records the hash codes.
866 std::vector<Symbol*> unhashed_dynsyms;
867 unhashed_dynsyms.reserve(count);
869 std::vector<Symbol*> hashed_dynsyms;
870 hashed_dynsyms.reserve(count);
872 std::vector<uint32_t> dynsym_hashvals;
873 dynsym_hashvals.reserve(count);
875 for (unsigned int i = 0; i < count; ++i)
877 Symbol* sym = dynsyms[i];
879 // FIXME: Should put on unhashed_dynsyms if the symbol is
881 if (sym->is_undefined())
882 unhashed_dynsyms.push_back(sym);
885 hashed_dynsyms.push_back(sym);
886 dynsym_hashvals.push_back(Dynobj::gnu_hash(sym->name()));
890 // Put the unhashed symbols at the start of the global portion of
891 // the dynamic symbol table.
892 const unsigned int unhashed_count = unhashed_dynsyms.size();
893 unsigned int unhashed_dynsym_index = local_dynsym_count;
894 for (unsigned int i = 0; i < unhashed_count; ++i)
896 unhashed_dynsyms[i]->set_dynsym_index(unhashed_dynsym_index);
897 ++unhashed_dynsym_index;
900 // For the actual data generation we call out to a templatized
902 int size = parameters->get_size();
903 bool big_endian = parameters->is_big_endian();
908 #ifdef HAVE_TARGET_32_BIG
909 Dynobj::sized_create_gnu_hash_table<32, true>(hashed_dynsyms,
911 unhashed_dynsym_index,
920 #ifdef HAVE_TARGET_32_LITTLE
921 Dynobj::sized_create_gnu_hash_table<32, false>(hashed_dynsyms,
923 unhashed_dynsym_index,
935 #ifdef HAVE_TARGET_64_BIG
936 Dynobj::sized_create_gnu_hash_table<64, true>(hashed_dynsyms,
938 unhashed_dynsym_index,
947 #ifdef HAVE_TARGET_64_LITTLE
948 Dynobj::sized_create_gnu_hash_table<64, false>(hashed_dynsyms,
950 unhashed_dynsym_index,
962 // Create the actual data for a GNU hash table. This is just a copy
963 // of the code from the old GNU linker.
965 template<int size, bool big_endian>
967 Dynobj::sized_create_gnu_hash_table(
968 const std::vector<Symbol*>& hashed_dynsyms,
969 const std::vector<uint32_t>& dynsym_hashvals,
970 unsigned int unhashed_dynsym_count,
971 unsigned char** pphash,
972 unsigned int* phashlen)
974 if (hashed_dynsyms.empty())
976 // Special case for the empty hash table.
977 unsigned int hashlen = 5 * 4 + size / 8;
978 unsigned char* phash = new unsigned char[hashlen];
980 elfcpp::Swap<32, big_endian>::writeval(phash, 1);
981 // Symbol index above unhashed symbols.
982 elfcpp::Swap<32, big_endian>::writeval(phash + 4, unhashed_dynsym_count);
983 // One word for bitmask.
984 elfcpp::Swap<32, big_endian>::writeval(phash + 8, 1);
985 // Only bloom filter.
986 elfcpp::Swap<32, big_endian>::writeval(phash + 12, 0);
988 elfcpp::Swap<size, big_endian>::writeval(phash + 16, 0);
989 // No hashes in only bucket.
990 elfcpp::Swap<32, big_endian>::writeval(phash + 16 + size / 8, 0);
998 const unsigned int bucketcount =
999 Dynobj::compute_bucket_count(dynsym_hashvals, true);
1001 const unsigned int nsyms = hashed_dynsyms.size();
1003 uint32_t maskbitslog2 = 1;
1004 uint32_t x = nsyms >> 1;
1010 if (maskbitslog2 < 3)
1012 else if (((1U << (maskbitslog2 - 2)) & nsyms) != 0)
1022 if (maskbitslog2 == 5)
1026 uint32_t mask = (1U << shift1) - 1U;
1027 uint32_t shift2 = maskbitslog2;
1028 uint32_t maskbits = 1U << maskbitslog2;
1029 uint32_t maskwords = 1U << (maskbitslog2 - shift1);
1031 typedef typename elfcpp::Elf_types<size>::Elf_WXword Word;
1032 std::vector<Word> bitmask(maskwords);
1033 std::vector<uint32_t> counts(bucketcount);
1034 std::vector<uint32_t> indx(bucketcount);
1035 uint32_t symindx = unhashed_dynsym_count;
1037 // Count the number of times each hash bucket is used.
1038 for (unsigned int i = 0; i < nsyms; ++i)
1039 ++counts[dynsym_hashvals[i] % bucketcount];
1041 unsigned int cnt = symindx;
1042 for (unsigned int i = 0; i < bucketcount; ++i)
1048 unsigned int hashlen = (4 + bucketcount + nsyms) * 4;
1049 hashlen += maskbits / 8;
1050 unsigned char* phash = new unsigned char[hashlen];
1052 elfcpp::Swap<32, big_endian>::writeval(phash, bucketcount);
1053 elfcpp::Swap<32, big_endian>::writeval(phash + 4, symindx);
1054 elfcpp::Swap<32, big_endian>::writeval(phash + 8, maskwords);
1055 elfcpp::Swap<32, big_endian>::writeval(phash + 12, shift2);
1057 unsigned char* p = phash + 16 + maskbits / 8;
1058 for (unsigned int i = 0; i < bucketcount; ++i)
1061 elfcpp::Swap<32, big_endian>::writeval(p, 0);
1063 elfcpp::Swap<32, big_endian>::writeval(p, indx[i]);
1067 for (unsigned int i = 0; i < nsyms; ++i)
1069 Symbol* sym = hashed_dynsyms[i];
1070 uint32_t hashval = dynsym_hashvals[i];
1072 unsigned int bucket = hashval % bucketcount;
1073 unsigned int val = ((hashval >> shift1)
1074 & ((maskbits >> shift1) - 1));
1075 bitmask[val] |= (static_cast<Word>(1U)) << (hashval & mask);
1076 bitmask[val] |= (static_cast<Word>(1U)) << ((hashval >> shift2) & mask);
1077 val = hashval & ~ 1U;
1078 if (counts[bucket] == 1)
1080 // Last element terminates the chain.
1083 elfcpp::Swap<32, big_endian>::writeval(p + (indx[bucket] - symindx) * 4,
1087 sym->set_dynsym_index(indx[bucket]);
1092 for (unsigned int i = 0; i < maskwords; ++i)
1094 elfcpp::Swap<size, big_endian>::writeval(p, bitmask[i]);
1098 *phashlen = hashlen;
1104 // Write this definition to a buffer for the output section.
1106 template<int size, bool big_endian>
1108 Verdef::write(const Stringpool* dynpool, bool is_last, unsigned char* pb
1109 ACCEPT_SIZE_ENDIAN) const
1111 const int verdef_size = elfcpp::Elf_sizes<size>::verdef_size;
1112 const int verdaux_size = elfcpp::Elf_sizes<size>::verdaux_size;
1114 elfcpp::Verdef_write<size, big_endian> vd(pb);
1115 vd.set_vd_version(elfcpp::VER_DEF_CURRENT);
1116 vd.set_vd_flags((this->is_base_ ? elfcpp::VER_FLG_BASE : 0)
1117 | (this->is_weak_ ? elfcpp::VER_FLG_WEAK : 0));
1118 vd.set_vd_ndx(this->index());
1119 vd.set_vd_cnt(1 + this->deps_.size());
1120 vd.set_vd_hash(Dynobj::elf_hash(this->name()));
1121 vd.set_vd_aux(verdef_size);
1122 vd.set_vd_next(is_last
1124 : verdef_size + (1 + this->deps_.size()) * verdaux_size);
1127 elfcpp::Verdaux_write<size, big_endian> vda(pb);
1128 vda.set_vda_name(dynpool->get_offset(this->name()));
1129 vda.set_vda_next(this->deps_.empty() ? 0 : verdaux_size);
1132 Deps::const_iterator p;
1134 for (p = this->deps_.begin(), i = 0;
1135 p != this->deps_.end();
1138 elfcpp::Verdaux_write<size, big_endian> vda(pb);
1139 vda.set_vda_name(dynpool->get_offset(*p));
1140 vda.set_vda_next(i + 1 >= this->deps_.size() ? 0 : verdaux_size);
1151 for (Need_versions::iterator p = this->need_versions_.begin();
1152 p != this->need_versions_.end();
1157 // Add a new version to this file reference.
1160 Verneed::add_name(const char* name)
1162 Verneed_version* vv = new Verneed_version(name);
1163 this->need_versions_.push_back(vv);
1167 // Set the version indexes starting at INDEX.
1170 Verneed::finalize(unsigned int index)
1172 for (Need_versions::iterator p = this->need_versions_.begin();
1173 p != this->need_versions_.end();
1176 (*p)->set_index(index);
1182 // Write this list of referenced versions to a buffer for the output
1185 template<int size, bool big_endian>
1187 Verneed::write(const Stringpool* dynpool, bool is_last,
1188 unsigned char* pb ACCEPT_SIZE_ENDIAN) const
1190 const int verneed_size = elfcpp::Elf_sizes<size>::verneed_size;
1191 const int vernaux_size = elfcpp::Elf_sizes<size>::vernaux_size;
1193 elfcpp::Verneed_write<size, big_endian> vn(pb);
1194 vn.set_vn_version(elfcpp::VER_NEED_CURRENT);
1195 vn.set_vn_cnt(this->need_versions_.size());
1196 vn.set_vn_file(dynpool->get_offset(this->filename()));
1197 vn.set_vn_aux(verneed_size);
1198 vn.set_vn_next(is_last
1200 : verneed_size + this->need_versions_.size() * vernaux_size);
1203 Need_versions::const_iterator p;
1205 for (p = this->need_versions_.begin(), i = 0;
1206 p != this->need_versions_.end();
1209 elfcpp::Vernaux_write<size, big_endian> vna(pb);
1210 vna.set_vna_hash(Dynobj::elf_hash((*p)->version()));
1211 // FIXME: We need to sometimes set VER_FLG_WEAK here.
1212 vna.set_vna_flags(0);
1213 vna.set_vna_other((*p)->index());
1214 vna.set_vna_name(dynpool->get_offset((*p)->version()));
1215 vna.set_vna_next(i + 1 >= this->need_versions_.size()
1224 // Versions methods.
1226 Versions::~Versions()
1228 for (Defs::iterator p = this->defs_.begin();
1229 p != this->defs_.end();
1233 for (Needs::iterator p = this->needs_.begin();
1234 p != this->needs_.end();
1239 // Return the dynamic object which a symbol refers to.
1242 Versions::get_dynobj_for_sym(const Symbol_table* symtab,
1243 const Symbol* sym) const
1245 if (sym->is_copied_from_dynobj())
1246 return symtab->get_copy_source(sym);
1249 Object* object = sym->object();
1250 gold_assert(object->is_dynamic());
1251 return static_cast<Dynobj*>(object);
1255 // Record version information for a symbol going into the dynamic
1259 Versions::record_version(const Symbol_table* symtab,
1260 Stringpool* dynpool, const Symbol* sym)
1262 gold_assert(!this->is_finalized_);
1263 gold_assert(sym->version() != NULL);
1265 Stringpool::Key version_key;
1266 const char* version = dynpool->add(sym->version(), false, &version_key);
1268 if (!sym->is_from_dynobj() && !sym->is_copied_from_dynobj())
1270 if (parameters->output_is_shared())
1271 this->add_def(sym, version, version_key);
1275 // This is a version reference.
1276 Dynobj* dynobj = this->get_dynobj_for_sym(symtab, sym);
1277 this->add_need(dynpool, dynobj->soname(), version, version_key);
1281 // We've found a symbol SYM defined in version VERSION.
1284 Versions::add_def(const Symbol* sym, const char* version,
1285 Stringpool::Key version_key)
1287 Key k(version_key, 0);
1288 Version_base* const vbnull = NULL;
1289 std::pair<Version_table::iterator, bool> ins =
1290 this->version_table_.insert(std::make_pair(k, vbnull));
1294 // We already have an entry for this version.
1295 Version_base* vb = ins.first->second;
1297 // We have now seen a symbol in this version, so it is not
1301 // FIXME: When we support version scripts, we will need to
1302 // check whether this symbol should be forced local.
1306 // If we are creating a shared object, it is an error to
1307 // find a definition of a symbol with a version which is not
1308 // in the version script.
1309 if (parameters->output_is_shared())
1311 gold_error(_("symbol %s has undefined version %s"),
1312 sym->demangled_name().c_str(), version);
1316 // If this is the first version we are defining, first define
1317 // the base version. FIXME: Should use soname here when
1318 // creating a shared object.
1319 Verdef* vdbase = new Verdef(parameters->output_file_name(), true, false,
1321 this->defs_.push_back(vdbase);
1323 // When creating a regular executable, automatically define
1325 Verdef* vd = new Verdef(version, false, false, false);
1326 this->defs_.push_back(vd);
1327 ins.first->second = vd;
1331 // Add a reference to version NAME in file FILENAME.
1334 Versions::add_need(Stringpool* dynpool, const char* filename, const char* name,
1335 Stringpool::Key name_key)
1337 Stringpool::Key filename_key;
1338 filename = dynpool->add(filename, true, &filename_key);
1340 Key k(name_key, filename_key);
1341 Version_base* const vbnull = NULL;
1342 std::pair<Version_table::iterator, bool> ins =
1343 this->version_table_.insert(std::make_pair(k, vbnull));
1347 // We already have an entry for this filename/version.
1351 // See whether we already have this filename. We don't expect many
1352 // version references, so we just do a linear search. This could be
1353 // replaced by a hash table.
1355 for (Needs::iterator p = this->needs_.begin();
1356 p != this->needs_.end();
1359 if ((*p)->filename() == filename)
1368 // We have a new filename.
1369 vn = new Verneed(filename);
1370 this->needs_.push_back(vn);
1373 ins.first->second = vn->add_name(name);
1376 // Set the version indexes. Create a new dynamic version symbol for
1377 // each new version definition.
1380 Versions::finalize(const Target* target, Symbol_table* symtab,
1381 unsigned int dynsym_index, std::vector<Symbol*>* syms)
1383 gold_assert(!this->is_finalized_);
1385 unsigned int vi = 1;
1387 for (Defs::iterator p = this->defs_.begin();
1388 p != this->defs_.end();
1391 (*p)->set_index(vi);
1394 // Create a version symbol if necessary.
1395 if (!(*p)->is_symbol_created())
1397 Symbol* vsym = symtab->define_as_constant(target, (*p)->name(),
1401 elfcpp::STV_DEFAULT, 0,
1403 vsym->set_needs_dynsym_entry();
1404 vsym->set_dynsym_index(dynsym_index);
1406 syms->push_back(vsym);
1407 // The name is already in the dynamic pool.
1411 // Index 1 is used for global symbols.
1414 gold_assert(this->defs_.empty());
1418 for (Needs::iterator p = this->needs_.begin();
1419 p != this->needs_.end();
1421 vi = (*p)->finalize(vi);
1423 this->is_finalized_ = true;
1425 return dynsym_index;
1428 // Return the version index to use for a symbol. This does two hash
1429 // table lookups: one in DYNPOOL and one in this->version_table_.
1430 // Another approach alternative would be store a pointer in SYM, which
1431 // would increase the size of the symbol table. Or perhaps we could
1432 // use a hash table from dynamic symbol pointer values to Version_base
1436 Versions::version_index(const Symbol_table* symtab, const Stringpool* dynpool,
1437 const Symbol* sym) const
1439 Stringpool::Key version_key;
1440 const char* version = dynpool->find(sym->version(), &version_key);
1441 gold_assert(version != NULL);
1444 if (!sym->is_from_dynobj() && !sym->is_copied_from_dynobj())
1446 if (!parameters->output_is_shared())
1447 return elfcpp::VER_NDX_GLOBAL;
1448 k = Key(version_key, 0);
1452 Dynobj* dynobj = this->get_dynobj_for_sym(symtab, sym);
1454 Stringpool::Key filename_key;
1455 const char* filename = dynpool->find(dynobj->soname(), &filename_key);
1456 gold_assert(filename != NULL);
1458 k = Key(version_key, filename_key);
1461 Version_table::const_iterator p = this->version_table_.find(k);
1462 gold_assert(p != this->version_table_.end());
1464 return p->second->index();
1467 // Return an allocated buffer holding the contents of the symbol
1470 template<int size, bool big_endian>
1472 Versions::symbol_section_contents(const Symbol_table* symtab,
1473 const Stringpool* dynpool,
1474 unsigned int local_symcount,
1475 const std::vector<Symbol*>& syms,
1478 ACCEPT_SIZE_ENDIAN) const
1480 gold_assert(this->is_finalized_);
1482 unsigned int sz = (local_symcount + syms.size()) * 2;
1483 unsigned char* pbuf = new unsigned char[sz];
1485 for (unsigned int i = 0; i < local_symcount; ++i)
1486 elfcpp::Swap<16, big_endian>::writeval(pbuf + i * 2,
1487 elfcpp::VER_NDX_LOCAL);
1489 for (std::vector<Symbol*>::const_iterator p = syms.begin();
1493 unsigned int version_index;
1494 const char* version = (*p)->version();
1495 if (version == NULL)
1496 version_index = elfcpp::VER_NDX_GLOBAL;
1498 version_index = this->version_index(symtab, dynpool, *p);
1499 elfcpp::Swap<16, big_endian>::writeval(pbuf + (*p)->dynsym_index() * 2,
1507 // Return an allocated buffer holding the contents of the version
1508 // definition section.
1510 template<int size, bool big_endian>
1512 Versions::def_section_contents(const Stringpool* dynpool,
1513 unsigned char** pp, unsigned int* psize,
1514 unsigned int* pentries
1515 ACCEPT_SIZE_ENDIAN) const
1517 gold_assert(this->is_finalized_);
1518 gold_assert(!this->defs_.empty());
1520 const int verdef_size = elfcpp::Elf_sizes<size>::verdef_size;
1521 const int verdaux_size = elfcpp::Elf_sizes<size>::verdaux_size;
1523 unsigned int sz = 0;
1524 for (Defs::const_iterator p = this->defs_.begin();
1525 p != this->defs_.end();
1528 sz += verdef_size + verdaux_size;
1529 sz += (*p)->count_dependencies() * verdaux_size;
1532 unsigned char* pbuf = new unsigned char[sz];
1534 unsigned char* pb = pbuf;
1535 Defs::const_iterator p;
1537 for (p = this->defs_.begin(), i = 0;
1538 p != this->defs_.end();
1540 pb = (*p)->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
1541 dynpool, i + 1 >= this->defs_.size(), pb
1542 SELECT_SIZE_ENDIAN(size, big_endian));
1544 gold_assert(static_cast<unsigned int>(pb - pbuf) == sz);
1548 *pentries = this->defs_.size();
1551 // Return an allocated buffer holding the contents of the version
1552 // reference section.
1554 template<int size, bool big_endian>
1556 Versions::need_section_contents(const Stringpool* dynpool,
1557 unsigned char** pp, unsigned int *psize,
1558 unsigned int *pentries
1559 ACCEPT_SIZE_ENDIAN) const
1561 gold_assert(this->is_finalized_);
1562 gold_assert(!this->needs_.empty());
1564 const int verneed_size = elfcpp::Elf_sizes<size>::verneed_size;
1565 const int vernaux_size = elfcpp::Elf_sizes<size>::vernaux_size;
1567 unsigned int sz = 0;
1568 for (Needs::const_iterator p = this->needs_.begin();
1569 p != this->needs_.end();
1573 sz += (*p)->count_versions() * vernaux_size;
1576 unsigned char* pbuf = new unsigned char[sz];
1578 unsigned char* pb = pbuf;
1579 Needs::const_iterator p;
1581 for (p = this->needs_.begin(), i = 0;
1582 p != this->needs_.end();
1584 pb = (*p)->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
1585 dynpool, i + 1 >= this->needs_.size(), pb
1586 SELECT_SIZE_ENDIAN(size, big_endian));
1588 gold_assert(static_cast<unsigned int>(pb - pbuf) == sz);
1592 *pentries = this->needs_.size();
1595 // Instantiate the templates we need. We could use the configure
1596 // script to restrict this to only the ones for implemented targets.
1598 #ifdef HAVE_TARGET_32_LITTLE
1600 class Sized_dynobj<32, false>;
1603 #ifdef HAVE_TARGET_32_BIG
1605 class Sized_dynobj<32, true>;
1608 #ifdef HAVE_TARGET_64_LITTLE
1610 class Sized_dynobj<64, false>;
1613 #ifdef HAVE_TARGET_64_BIG
1615 class Sized_dynobj<64, true>;
1618 #ifdef HAVE_TARGET_32_LITTLE
1621 Versions::symbol_section_contents<32, false>(
1622 const Symbol_table*,
1625 const std::vector<Symbol*>&,
1628 ACCEPT_SIZE_ENDIAN_EXPLICIT(32, false)) const;
1631 #ifdef HAVE_TARGET_32_BIG
1634 Versions::symbol_section_contents<32, true>(
1635 const Symbol_table*,
1638 const std::vector<Symbol*>&,
1641 ACCEPT_SIZE_ENDIAN_EXPLICIT(32, true)) const;
1644 #ifdef HAVE_TARGET_64_LITTLE
1647 Versions::symbol_section_contents<64, false>(
1648 const Symbol_table*,
1651 const std::vector<Symbol*>&,
1654 ACCEPT_SIZE_ENDIAN_EXPLICIT(64, false)) const;
1657 #ifdef HAVE_TARGET_64_BIG
1660 Versions::symbol_section_contents<64, true>(
1661 const Symbol_table*,
1664 const std::vector<Symbol*>&,
1667 ACCEPT_SIZE_ENDIAN_EXPLICIT(64, true)) const;
1670 #ifdef HAVE_TARGET_32_LITTLE
1673 Versions::def_section_contents<32, false>(
1678 ACCEPT_SIZE_ENDIAN_EXPLICIT(32, false)) const;
1681 #ifdef HAVE_TARGET_32_BIG
1684 Versions::def_section_contents<32, true>(
1689 ACCEPT_SIZE_ENDIAN_EXPLICIT(32, true)) const;
1692 #ifdef HAVE_TARGET_64_LITTLE
1695 Versions::def_section_contents<64, false>(
1700 ACCEPT_SIZE_ENDIAN_EXPLICIT(64, false)) const;
1703 #ifdef HAVE_TARGET_64_BIG
1706 Versions::def_section_contents<64, true>(
1711 ACCEPT_SIZE_ENDIAN_EXPLICIT(64, true)) const;
1714 #ifdef HAVE_TARGET_32_LITTLE
1717 Versions::need_section_contents<32, false>(
1722 ACCEPT_SIZE_ENDIAN_EXPLICIT(32, false)) const;
1725 #ifdef HAVE_TARGET_32_BIG
1728 Versions::need_section_contents<32, true>(
1733 ACCEPT_SIZE_ENDIAN_EXPLICIT(32, true)) const;
1736 #ifdef HAVE_TARGET_64_LITTLE
1739 Versions::need_section_contents<64, false>(
1744 ACCEPT_SIZE_ENDIAN_EXPLICIT(64, false)) const;
1747 #ifdef HAVE_TARGET_64_BIG
1750 Versions::need_section_contents<64, true>(
1755 ACCEPT_SIZE_ENDIAN_EXPLICIT(64, true)) const;
1758 } // End namespace gold.