// dynobj.cc -- dynamic object support for gold // Copyright 2006, 2007 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 3 of the License, or // (at your option) any later version. // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, // MA 02110-1301, USA. #include "gold.h" #include #include #include "elfcpp.h" #include "parameters.h" #include "symtab.h" #include "dynobj.h" namespace gold { // Class Dynobj. // Sets up the default soname_ to use, in the (rare) cases we never // see a DT_SONAME entry. Dynobj::Dynobj(const std::string& name, Input_file* input_file, off_t offset) : Object(name, input_file, true, offset), needed_(), unknown_needed_(UNKNOWN_NEEDED_UNSET) { // This will be overridden by a DT_SONAME entry, hopefully. But if // we never see a DT_SONAME entry, our rule is to use the dynamic // object's filename. The only exception is when the dynamic object // is part of an archive (so the filename is the archive's // filename). In that case, we use just the dynobj's name-in-archive. this->soname_ = this->input_file()->found_name(); if (this->offset() != 0) { std::string::size_type open_paren = this->name().find('('); std::string::size_type close_paren = this->name().find(')'); if (open_paren != std::string::npos && close_paren != std::string::npos) { // It's an archive, and name() is of the form 'foo.a(bar.so)'. this->soname_ = this->name().substr(open_paren + 1, close_paren - (open_paren + 1)); } } } // Class Sized_dynobj. template Sized_dynobj::Sized_dynobj( const std::string& name, Input_file* input_file, off_t offset, const elfcpp::Ehdr& ehdr) : Dynobj(name, input_file, offset), elf_file_(this, ehdr) { } // Set up the object. template void Sized_dynobj::setup( const elfcpp::Ehdr& ehdr) { this->set_target(ehdr.get_e_machine(), size, big_endian, ehdr.get_e_ident()[elfcpp::EI_OSABI], ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]); const unsigned int shnum = this->elf_file_.shnum(); this->set_shnum(shnum); } // Find the SHT_DYNSYM section and the various version sections, and // the dynamic section, given the section headers. template void Sized_dynobj::find_dynsym_sections( const unsigned char* pshdrs, unsigned int* pdynsym_shndx, unsigned int* pversym_shndx, unsigned int* pverdef_shndx, unsigned int* pverneed_shndx, unsigned int* pdynamic_shndx) { *pdynsym_shndx = -1U; *pversym_shndx = -1U; *pverdef_shndx = -1U; *pverneed_shndx = -1U; *pdynamic_shndx = -1U; const unsigned int shnum = this->shnum(); const unsigned char* p = pshdrs; for (unsigned int i = 0; i < shnum; ++i, p += This::shdr_size) { typename This::Shdr shdr(p); unsigned int* pi; switch (shdr.get_sh_type()) { case elfcpp::SHT_DYNSYM: pi = pdynsym_shndx; break; case elfcpp::SHT_GNU_versym: pi = pversym_shndx; break; case elfcpp::SHT_GNU_verdef: pi = pverdef_shndx; break; case elfcpp::SHT_GNU_verneed: pi = pverneed_shndx; break; case elfcpp::SHT_DYNAMIC: pi = pdynamic_shndx; break; default: pi = NULL; break; } if (pi == NULL) continue; if (*pi != -1U) this->error(_("unexpected duplicate type %u section: %u, %u"), shdr.get_sh_type(), *pi, i); *pi = i; } } // Read the contents of section SHNDX. PSHDRS points to the section // headers. TYPE is the expected section type. LINK is the expected // section link. Store the data in *VIEW and *VIEW_SIZE. The // section's sh_info field is stored in *VIEW_INFO. template void Sized_dynobj::read_dynsym_section( const unsigned char* pshdrs, unsigned int shndx, elfcpp::SHT type, unsigned int link, File_view** view, section_size_type* view_size, unsigned int* view_info) { if (shndx == -1U) { *view = NULL; *view_size = 0; *view_info = 0; return; } typename This::Shdr shdr(pshdrs + shndx * This::shdr_size); gold_assert(shdr.get_sh_type() == type); if (shdr.get_sh_link() != link) this->error(_("unexpected link in section %u header: %u != %u"), shndx, shdr.get_sh_link(), link); *view = this->get_lasting_view(shdr.get_sh_offset(), shdr.get_sh_size(), false); *view_size = convert_to_section_size_type(shdr.get_sh_size()); *view_info = shdr.get_sh_info(); } // Read the dynamic tags. Set the soname field if this shared object // has a DT_SONAME tag. Record the DT_NEEDED tags. PSHDRS points to // the section headers. DYNAMIC_SHNDX is the section index of the // SHT_DYNAMIC section. STRTAB_SHNDX, STRTAB, and STRTAB_SIZE are the // section index and contents of a string table which may be the one // associated with the SHT_DYNAMIC section. template void Sized_dynobj::read_dynamic(const unsigned char* pshdrs, unsigned int dynamic_shndx, unsigned int strtab_shndx, const unsigned char* strtabu, off_t strtab_size) { typename This::Shdr dynamicshdr(pshdrs + dynamic_shndx * This::shdr_size); gold_assert(dynamicshdr.get_sh_type() == elfcpp::SHT_DYNAMIC); const off_t dynamic_size = dynamicshdr.get_sh_size(); const unsigned char* pdynamic = this->get_view(dynamicshdr.get_sh_offset(), dynamic_size, false); const unsigned int link = dynamicshdr.get_sh_link(); if (link != strtab_shndx) { if (link >= this->shnum()) { this->error(_("DYNAMIC section %u link out of range: %u"), dynamic_shndx, link); return; } typename This::Shdr strtabshdr(pshdrs + link * This::shdr_size); if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB) { this->error(_("DYNAMIC section %u link %u is not a strtab"), dynamic_shndx, link); return; } strtab_size = strtabshdr.get_sh_size(); strtabu = this->get_view(strtabshdr.get_sh_offset(), strtab_size, false); } const char* const strtab = reinterpret_cast(strtabu); for (const unsigned char* p = pdynamic; p < pdynamic + dynamic_size; p += This::dyn_size) { typename This::Dyn dyn(p); switch (dyn.get_d_tag()) { case elfcpp::DT_NULL: // We should always see DT_NULL at the end of the dynamic // tags. return; case elfcpp::DT_SONAME: { off_t val = dyn.get_d_val(); if (val >= strtab_size) this->error(_("DT_SONAME value out of range: %lld >= %lld"), static_cast(val), static_cast(strtab_size)); else this->set_soname_string(strtab + val); } break; case elfcpp::DT_NEEDED: { off_t val = dyn.get_d_val(); if (val >= strtab_size) this->error(_("DT_NEEDED value out of range: %lld >= %lld"), static_cast(val), static_cast(strtab_size)); else this->add_needed(strtab + val); } break; default: break; } } this->error(_("missing DT_NULL in dynamic segment")); } // Read the symbols and sections from a dynamic object. We read the // dynamic symbols, not the normal symbols. template void Sized_dynobj::do_read_symbols(Read_symbols_data* sd) { this->read_section_data(&this->elf_file_, sd); const unsigned char* const pshdrs = sd->section_headers->data(); unsigned int dynsym_shndx; unsigned int versym_shndx; unsigned int verdef_shndx; unsigned int verneed_shndx; unsigned int dynamic_shndx; this->find_dynsym_sections(pshdrs, &dynsym_shndx, &versym_shndx, &verdef_shndx, &verneed_shndx, &dynamic_shndx); unsigned int strtab_shndx = -1U; sd->symbols = NULL; sd->symbols_size = 0; sd->external_symbols_offset = 0; sd->symbol_names = NULL; sd->symbol_names_size = 0; if (dynsym_shndx != -1U) { // Get the dynamic symbols. typename This::Shdr dynsymshdr(pshdrs + dynsym_shndx * This::shdr_size); gold_assert(dynsymshdr.get_sh_type() == elfcpp::SHT_DYNSYM); sd->symbols = this->get_lasting_view(dynsymshdr.get_sh_offset(), dynsymshdr.get_sh_size(), false); sd->symbols_size = convert_to_section_size_type(dynsymshdr.get_sh_size()); // Get the symbol names. strtab_shndx = dynsymshdr.get_sh_link(); if (strtab_shndx >= this->shnum()) { this->error(_("invalid dynamic symbol table name index: %u"), strtab_shndx); return; } typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size); if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB) { this->error(_("dynamic symbol table name section " "has wrong type: %u"), static_cast(strtabshdr.get_sh_type())); return; } sd->symbol_names = this->get_lasting_view(strtabshdr.get_sh_offset(), strtabshdr.get_sh_size(), true); sd->symbol_names_size = convert_to_section_size_type(strtabshdr.get_sh_size()); // Get the version information. unsigned int dummy; this->read_dynsym_section(pshdrs, versym_shndx, elfcpp::SHT_GNU_versym, dynsym_shndx, &sd->versym, &sd->versym_size, &dummy); // We require that the version definition and need section link // to the same string table as the dynamic symbol table. This // is not a technical requirement, but it always happens in // practice. We could change this if necessary. this->read_dynsym_section(pshdrs, verdef_shndx, elfcpp::SHT_GNU_verdef, strtab_shndx, &sd->verdef, &sd->verdef_size, &sd->verdef_info); this->read_dynsym_section(pshdrs, verneed_shndx, elfcpp::SHT_GNU_verneed, strtab_shndx, &sd->verneed, &sd->verneed_size, &sd->verneed_info); } // Read the SHT_DYNAMIC section to find whether this shared object // has a DT_SONAME tag and to record any DT_NEEDED tags. This // doesn't really have anything to do with reading the symbols, but // this is a convenient place to do it. if (dynamic_shndx != -1U) this->read_dynamic(pshdrs, dynamic_shndx, strtab_shndx, (sd->symbol_names == NULL ? NULL : sd->symbol_names->data()), sd->symbol_names_size); } // Lay out the input sections for a dynamic object. We don't want to // include sections from a dynamic object, so all that we actually do // here is check for .gnu.warning sections. template void Sized_dynobj::do_layout(Symbol_table* symtab, Layout*, Read_symbols_data* sd) { const unsigned int shnum = this->shnum(); if (shnum == 0) return; // Get the section headers. const unsigned char* pshdrs = sd->section_headers->data(); // Get the section names. const unsigned char* pnamesu = sd->section_names->data(); const char* pnames = reinterpret_cast(pnamesu); // Skip the first, dummy, section. pshdrs += This::shdr_size; for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size) { typename This::Shdr shdr(pshdrs); if (shdr.get_sh_name() >= sd->section_names_size) { this->error(_("bad section name offset for section %u: %lu"), i, static_cast(shdr.get_sh_name())); return; } const char* name = pnames + shdr.get_sh_name(); this->handle_gnu_warning_section(name, i, symtab); } delete sd->section_headers; sd->section_headers = NULL; delete sd->section_names; sd->section_names = NULL; } // Add an entry to the vector mapping version numbers to version // strings. template void Sized_dynobj::set_version_map( Version_map* version_map, unsigned int ndx, const char* name) const { if (ndx >= version_map->size()) version_map->resize(ndx + 1); if ((*version_map)[ndx] != NULL) this->error(_("duplicate definition for version %u"), ndx); (*version_map)[ndx] = name; } // Add mappings for the version definitions to VERSION_MAP. template void Sized_dynobj::make_verdef_map( Read_symbols_data* sd, Version_map* version_map) const { if (sd->verdef == NULL) return; const char* names = reinterpret_cast(sd->symbol_names->data()); section_size_type names_size = sd->symbol_names_size; const unsigned char* pverdef = sd->verdef->data(); section_size_type verdef_size = sd->verdef_size; const unsigned int count = sd->verdef_info; const unsigned char* p = pverdef; for (unsigned int i = 0; i < count; ++i) { elfcpp::Verdef verdef(p); if (verdef.get_vd_version() != elfcpp::VER_DEF_CURRENT) { this->error(_("unexpected verdef version %u"), verdef.get_vd_version()); return; } const section_size_type vd_ndx = verdef.get_vd_ndx(); // The GNU linker clears the VERSYM_HIDDEN bit. I'm not // sure why. // The first Verdaux holds the name of this version. Subsequent // ones are versions that this one depends upon, which we don't // care about here. const section_size_type vd_cnt = verdef.get_vd_cnt(); if (vd_cnt < 1) { this->error(_("verdef vd_cnt field too small: %u"), static_cast(vd_cnt)); return; } const section_size_type vd_aux = verdef.get_vd_aux(); if ((p - pverdef) + vd_aux >= verdef_size) { this->error(_("verdef vd_aux field out of range: %u"), static_cast(vd_aux)); return; } const unsigned char* pvda = p + vd_aux; elfcpp::Verdaux verdaux(pvda); const section_size_type vda_name = verdaux.get_vda_name(); if (vda_name >= names_size) { this->error(_("verdaux vda_name field out of range: %u"), static_cast(vda_name)); return; } this->set_version_map(version_map, vd_ndx, names + vda_name); const section_size_type vd_next = verdef.get_vd_next(); if ((p - pverdef) + vd_next >= verdef_size) { this->error(_("verdef vd_next field out of range: %u"), static_cast(vd_next)); return; } p += vd_next; } } // Add mappings for the required versions to VERSION_MAP. template void Sized_dynobj::make_verneed_map( Read_symbols_data* sd, Version_map* version_map) const { if (sd->verneed == NULL) return; const char* names = reinterpret_cast(sd->symbol_names->data()); section_size_type names_size = sd->symbol_names_size; const unsigned char* pverneed = sd->verneed->data(); const section_size_type verneed_size = sd->verneed_size; const unsigned int count = sd->verneed_info; const unsigned char* p = pverneed; for (unsigned int i = 0; i < count; ++i) { elfcpp::Verneed verneed(p); if (verneed.get_vn_version() != elfcpp::VER_NEED_CURRENT) { this->error(_("unexpected verneed version %u"), verneed.get_vn_version()); return; } const section_size_type vn_aux = verneed.get_vn_aux(); if ((p - pverneed) + vn_aux >= verneed_size) { this->error(_("verneed vn_aux field out of range: %u"), static_cast(vn_aux)); return; } const unsigned int vn_cnt = verneed.get_vn_cnt(); const unsigned char* pvna = p + vn_aux; for (unsigned int j = 0; j < vn_cnt; ++j) { elfcpp::Vernaux vernaux(pvna); const unsigned int vna_name = vernaux.get_vna_name(); if (vna_name >= names_size) { this->error(_("vernaux vna_name field out of range: %u"), static_cast(vna_name)); return; } this->set_version_map(version_map, vernaux.get_vna_other(), names + vna_name); const section_size_type vna_next = vernaux.get_vna_next(); if ((pvna - pverneed) + vna_next >= verneed_size) { this->error(_("verneed vna_next field out of range: %u"), static_cast(vna_next)); return; } pvna += vna_next; } const section_size_type vn_next = verneed.get_vn_next(); if ((p - pverneed) + vn_next >= verneed_size) { this->error(_("verneed vn_next field out of range: %u"), static_cast(vn_next)); return; } p += vn_next; } } // Create a vector mapping version numbers to version strings. template void Sized_dynobj::make_version_map( Read_symbols_data* sd, Version_map* version_map) const { if (sd->verdef == NULL && sd->verneed == NULL) return; // A guess at the maximum version number we will see. If this is // wrong we will be less efficient but still correct. version_map->reserve(sd->verdef_info + sd->verneed_info * 10); this->make_verdef_map(sd, version_map); this->make_verneed_map(sd, version_map); } // Add the dynamic symbols to the symbol table. template void Sized_dynobj::do_add_symbols(Symbol_table* symtab, Read_symbols_data* sd) { if (sd->symbols == NULL) { gold_assert(sd->symbol_names == NULL); gold_assert(sd->versym == NULL && sd->verdef == NULL && sd->verneed == NULL); return; } const int sym_size = This::sym_size; const size_t symcount = sd->symbols_size / sym_size; gold_assert(sd->external_symbols_offset == 0); if (symcount * sym_size != sd->symbols_size) { this->error(_("size of dynamic symbols is not multiple of symbol size")); return; } Version_map version_map; this->make_version_map(sd, &version_map); const char* sym_names = reinterpret_cast(sd->symbol_names->data()); symtab->add_from_dynobj(this, sd->symbols->data(), symcount, sym_names, sd->symbol_names_size, (sd->versym == NULL ? NULL : sd->versym->data()), sd->versym_size, &version_map); delete sd->symbols; sd->symbols = NULL; delete sd->symbol_names; sd->symbol_names = NULL; if (sd->versym != NULL) { delete sd->versym; sd->versym = NULL; } if (sd->verdef != NULL) { delete sd->verdef; sd->verdef = NULL; } if (sd->verneed != NULL) { delete sd->verneed; sd->verneed = NULL; } } // Given a vector of hash codes, compute the number of hash buckets to // use. unsigned int Dynobj::compute_bucket_count(const std::vector& hashcodes, bool for_gnu_hash_table) { // FIXME: Implement optional hash table optimization. // Array used to determine the number of hash table buckets to use // based on the number of symbols there are. If there are fewer // than 3 symbols we use 1 bucket, fewer than 17 symbols we use 3 // buckets, fewer than 37 we use 17 buckets, and so forth. We never // use more than 32771 buckets. This is straight from the old GNU // linker. static const unsigned int buckets[] = { 1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 1031, 2053, 4099, 8209, 16411, 32771 }; const int buckets_count = sizeof buckets / sizeof buckets[0]; unsigned int symcount = hashcodes.size(); unsigned int ret = 1; for (int i = 0; i < buckets_count; ++i) { if (symcount < buckets[i]) break; ret = buckets[i]; } if (for_gnu_hash_table && ret < 2) ret = 2; return ret; } // The standard ELF hash function. This hash function must not // change, as the dynamic linker uses it also. uint32_t Dynobj::elf_hash(const char* name) { const unsigned char* nameu = reinterpret_cast(name); uint32_t h = 0; unsigned char c; while ((c = *nameu++) != '\0') { h = (h << 4) + c; uint32_t g = h & 0xf0000000; if (g != 0) { h ^= g >> 24; // The ELF ABI says h &= ~g, but using xor is equivalent in // this case (since g was set from h) and may save one // instruction. h ^= g; } } return h; } // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN. // DYNSYMS is a vector with all the global dynamic symbols. // LOCAL_DYNSYM_COUNT is the number of local symbols in the dynamic // symbol table. void Dynobj::create_elf_hash_table(const std::vector& dynsyms, unsigned int local_dynsym_count, unsigned char** pphash, unsigned int* phashlen) { unsigned int dynsym_count = dynsyms.size(); // Get the hash values for all the symbols. std::vector dynsym_hashvals(dynsym_count); for (unsigned int i = 0; i < dynsym_count; ++i) dynsym_hashvals[i] = Dynobj::elf_hash(dynsyms[i]->name()); const unsigned int bucketcount = Dynobj::compute_bucket_count(dynsym_hashvals, false); std::vector bucket(bucketcount); std::vector chain(local_dynsym_count + dynsym_count); for (unsigned int i = 0; i < dynsym_count; ++i) { unsigned int dynsym_index = dynsyms[i]->dynsym_index(); unsigned int bucketpos = dynsym_hashvals[i] % bucketcount; chain[dynsym_index] = bucket[bucketpos]; bucket[bucketpos] = dynsym_index; } unsigned int hashlen = ((2 + bucketcount + local_dynsym_count + dynsym_count) * 4); unsigned char* phash = new unsigned char[hashlen]; if (parameters->is_big_endian()) { #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG) Dynobj::sized_create_elf_hash_table(bucket, chain, phash, hashlen); #else gold_unreachable(); #endif } else { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE) Dynobj::sized_create_elf_hash_table(bucket, chain, phash, hashlen); #else gold_unreachable(); #endif } *pphash = phash; *phashlen = hashlen; } // Fill in an ELF hash table. template void Dynobj::sized_create_elf_hash_table(const std::vector& bucket, const std::vector& chain, unsigned char* phash, unsigned int hashlen) { unsigned char* p = phash; const unsigned int bucketcount = bucket.size(); const unsigned int chaincount = chain.size(); elfcpp::Swap<32, big_endian>::writeval(p, bucketcount); p += 4; elfcpp::Swap<32, big_endian>::writeval(p, chaincount); p += 4; for (unsigned int i = 0; i < bucketcount; ++i) { elfcpp::Swap<32, big_endian>::writeval(p, bucket[i]); p += 4; } for (unsigned int i = 0; i < chaincount; ++i) { elfcpp::Swap<32, big_endian>::writeval(p, chain[i]); p += 4; } gold_assert(static_cast(p - phash) == hashlen); } // The hash function used for the GNU hash table. This hash function // must not change, as the dynamic linker uses it also. uint32_t Dynobj::gnu_hash(const char* name) { const unsigned char* nameu = reinterpret_cast(name); uint32_t h = 5381; unsigned char c; while ((c = *nameu++) != '\0') h = (h << 5) + h + c; return h; } // Create a GNU hash table, setting *PPHASH and *PHASHLEN. GNU hash // tables are an extension to ELF which are recognized by the GNU // dynamic linker. They are referenced using dynamic tag DT_GNU_HASH. // TARGET is the target. DYNSYMS is a vector with all the global // symbols which will be going into the dynamic symbol table. // LOCAL_DYNSYM_COUNT is the number of local symbols in the dynamic // symbol table. void Dynobj::create_gnu_hash_table(const std::vector& dynsyms, unsigned int local_dynsym_count, unsigned char** pphash, unsigned int* phashlen) { const unsigned int count = dynsyms.size(); // Sort the dynamic symbols into two vectors. Symbols which we do // not want to put into the hash table we store into // UNHASHED_DYNSYMS. Symbols which we do want to store we put into // HASHED_DYNSYMS. DYNSYM_HASHVALS is parallel to HASHED_DYNSYMS, // and records the hash codes. std::vector unhashed_dynsyms; unhashed_dynsyms.reserve(count); std::vector hashed_dynsyms; hashed_dynsyms.reserve(count); std::vector dynsym_hashvals; dynsym_hashvals.reserve(count); for (unsigned int i = 0; i < count; ++i) { Symbol* sym = dynsyms[i]; // FIXME: Should put on unhashed_dynsyms if the symbol is // hidden. if (sym->is_undefined()) unhashed_dynsyms.push_back(sym); else { hashed_dynsyms.push_back(sym); dynsym_hashvals.push_back(Dynobj::gnu_hash(sym->name())); } } // Put the unhashed symbols at the start of the global portion of // the dynamic symbol table. const unsigned int unhashed_count = unhashed_dynsyms.size(); unsigned int unhashed_dynsym_index = local_dynsym_count; for (unsigned int i = 0; i < unhashed_count; ++i) { unhashed_dynsyms[i]->set_dynsym_index(unhashed_dynsym_index); ++unhashed_dynsym_index; } // For the actual data generation we call out to a templatized // function. int size = parameters->get_size(); bool big_endian = parameters->is_big_endian(); if (size == 32) { if (big_endian) { #ifdef HAVE_TARGET_32_BIG Dynobj::sized_create_gnu_hash_table<32, true>(hashed_dynsyms, dynsym_hashvals, unhashed_dynsym_index, pphash, phashlen); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_32_LITTLE Dynobj::sized_create_gnu_hash_table<32, false>(hashed_dynsyms, dynsym_hashvals, unhashed_dynsym_index, pphash, phashlen); #else gold_unreachable(); #endif } } else if (size == 64) { if (big_endian) { #ifdef HAVE_TARGET_64_BIG Dynobj::sized_create_gnu_hash_table<64, true>(hashed_dynsyms, dynsym_hashvals, unhashed_dynsym_index, pphash, phashlen); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_64_LITTLE Dynobj::sized_create_gnu_hash_table<64, false>(hashed_dynsyms, dynsym_hashvals, unhashed_dynsym_index, pphash, phashlen); #else gold_unreachable(); #endif } } else gold_unreachable(); } // Create the actual data for a GNU hash table. This is just a copy // of the code from the old GNU linker. template void Dynobj::sized_create_gnu_hash_table( const std::vector& hashed_dynsyms, const std::vector& dynsym_hashvals, unsigned int unhashed_dynsym_count, unsigned char** pphash, unsigned int* phashlen) { if (hashed_dynsyms.empty()) { // Special case for the empty hash table. unsigned int hashlen = 5 * 4 + size / 8; unsigned char* phash = new unsigned char[hashlen]; // One empty bucket. elfcpp::Swap<32, big_endian>::writeval(phash, 1); // Symbol index above unhashed symbols. elfcpp::Swap<32, big_endian>::writeval(phash + 4, unhashed_dynsym_count); // One word for bitmask. elfcpp::Swap<32, big_endian>::writeval(phash + 8, 1); // Only bloom filter. elfcpp::Swap<32, big_endian>::writeval(phash + 12, 0); // No valid hashes. elfcpp::Swap::writeval(phash + 16, 0); // No hashes in only bucket. elfcpp::Swap<32, big_endian>::writeval(phash + 16 + size / 8, 0); *phashlen = hashlen; *pphash = phash; return; } const unsigned int bucketcount = Dynobj::compute_bucket_count(dynsym_hashvals, true); const unsigned int nsyms = hashed_dynsyms.size(); uint32_t maskbitslog2 = 1; uint32_t x = nsyms >> 1; while (x != 0) { ++maskbitslog2; x >>= 1; } if (maskbitslog2 < 3) maskbitslog2 = 5; else if (((1U << (maskbitslog2 - 2)) & nsyms) != 0) maskbitslog2 += 3; else maskbitslog2 += 2; uint32_t shift1; if (size == 32) shift1 = 5; else { if (maskbitslog2 == 5) maskbitslog2 = 6; shift1 = 6; } uint32_t mask = (1U << shift1) - 1U; uint32_t shift2 = maskbitslog2; uint32_t maskbits = 1U << maskbitslog2; uint32_t maskwords = 1U << (maskbitslog2 - shift1); typedef typename elfcpp::Elf_types::Elf_WXword Word; std::vector bitmask(maskwords); std::vector counts(bucketcount); std::vector indx(bucketcount); uint32_t symindx = unhashed_dynsym_count; // Count the number of times each hash bucket is used. for (unsigned int i = 0; i < nsyms; ++i) ++counts[dynsym_hashvals[i] % bucketcount]; unsigned int cnt = symindx; for (unsigned int i = 0; i < bucketcount; ++i) { indx[i] = cnt; cnt += counts[i]; } unsigned int hashlen = (4 + bucketcount + nsyms) * 4; hashlen += maskbits / 8; unsigned char* phash = new unsigned char[hashlen]; elfcpp::Swap<32, big_endian>::writeval(phash, bucketcount); elfcpp::Swap<32, big_endian>::writeval(phash + 4, symindx); elfcpp::Swap<32, big_endian>::writeval(phash + 8, maskwords); elfcpp::Swap<32, big_endian>::writeval(phash + 12, shift2); unsigned char* p = phash + 16 + maskbits / 8; for (unsigned int i = 0; i < bucketcount; ++i) { if (counts[i] == 0) elfcpp::Swap<32, big_endian>::writeval(p, 0); else elfcpp::Swap<32, big_endian>::writeval(p, indx[i]); p += 4; } for (unsigned int i = 0; i < nsyms; ++i) { Symbol* sym = hashed_dynsyms[i]; uint32_t hashval = dynsym_hashvals[i]; unsigned int bucket = hashval % bucketcount; unsigned int val = ((hashval >> shift1) & ((maskbits >> shift1) - 1)); bitmask[val] |= (static_cast(1U)) << (hashval & mask); bitmask[val] |= (static_cast(1U)) << ((hashval >> shift2) & mask); val = hashval & ~ 1U; if (counts[bucket] == 1) { // Last element terminates the chain. val |= 1; } elfcpp::Swap<32, big_endian>::writeval(p + (indx[bucket] - symindx) * 4, val); --counts[bucket]; sym->set_dynsym_index(indx[bucket]); ++indx[bucket]; } p = phash + 16; for (unsigned int i = 0; i < maskwords; ++i) { elfcpp::Swap::writeval(p, bitmask[i]); p += size / 8; } *phashlen = hashlen; *pphash = phash; } // Verdef methods. // Write this definition to a buffer for the output section. template unsigned char* Verdef::write(const Stringpool* dynpool, bool is_last, unsigned char* pb ACCEPT_SIZE_ENDIAN) const { const int verdef_size = elfcpp::Elf_sizes::verdef_size; const int verdaux_size = elfcpp::Elf_sizes::verdaux_size; elfcpp::Verdef_write vd(pb); vd.set_vd_version(elfcpp::VER_DEF_CURRENT); vd.set_vd_flags((this->is_base_ ? elfcpp::VER_FLG_BASE : 0) | (this->is_weak_ ? elfcpp::VER_FLG_WEAK : 0)); vd.set_vd_ndx(this->index()); vd.set_vd_cnt(1 + this->deps_.size()); vd.set_vd_hash(Dynobj::elf_hash(this->name())); vd.set_vd_aux(verdef_size); vd.set_vd_next(is_last ? 0 : verdef_size + (1 + this->deps_.size()) * verdaux_size); pb += verdef_size; elfcpp::Verdaux_write vda(pb); vda.set_vda_name(dynpool->get_offset(this->name())); vda.set_vda_next(this->deps_.empty() ? 0 : verdaux_size); pb += verdaux_size; Deps::const_iterator p; unsigned int i; for (p = this->deps_.begin(), i = 0; p != this->deps_.end(); ++p, ++i) { elfcpp::Verdaux_write vda(pb); vda.set_vda_name(dynpool->get_offset(*p)); vda.set_vda_next(i + 1 >= this->deps_.size() ? 0 : verdaux_size); pb += verdaux_size; } return pb; } // Verneed methods. Verneed::~Verneed() { for (Need_versions::iterator p = this->need_versions_.begin(); p != this->need_versions_.end(); ++p) delete *p; } // Add a new version to this file reference. Verneed_version* Verneed::add_name(const char* name) { Verneed_version* vv = new Verneed_version(name); this->need_versions_.push_back(vv); return vv; } // Set the version indexes starting at INDEX. unsigned int Verneed::finalize(unsigned int index) { for (Need_versions::iterator p = this->need_versions_.begin(); p != this->need_versions_.end(); ++p) { (*p)->set_index(index); ++index; } return index; } // Write this list of referenced versions to a buffer for the output // section. template unsigned char* Verneed::write(const Stringpool* dynpool, bool is_last, unsigned char* pb ACCEPT_SIZE_ENDIAN) const { const int verneed_size = elfcpp::Elf_sizes::verneed_size; const int vernaux_size = elfcpp::Elf_sizes::vernaux_size; elfcpp::Verneed_write vn(pb); vn.set_vn_version(elfcpp::VER_NEED_CURRENT); vn.set_vn_cnt(this->need_versions_.size()); vn.set_vn_file(dynpool->get_offset(this->filename())); vn.set_vn_aux(verneed_size); vn.set_vn_next(is_last ? 0 : verneed_size + this->need_versions_.size() * vernaux_size); pb += verneed_size; Need_versions::const_iterator p; unsigned int i; for (p = this->need_versions_.begin(), i = 0; p != this->need_versions_.end(); ++p, ++i) { elfcpp::Vernaux_write vna(pb); vna.set_vna_hash(Dynobj::elf_hash((*p)->version())); // FIXME: We need to sometimes set VER_FLG_WEAK here. vna.set_vna_flags(0); vna.set_vna_other((*p)->index()); vna.set_vna_name(dynpool->get_offset((*p)->version())); vna.set_vna_next(i + 1 >= this->need_versions_.size() ? 0 : vernaux_size); pb += vernaux_size; } return pb; } // Versions methods. Versions::~Versions() { for (Defs::iterator p = this->defs_.begin(); p != this->defs_.end(); ++p) delete *p; for (Needs::iterator p = this->needs_.begin(); p != this->needs_.end(); ++p) delete *p; } // Return the dynamic object which a symbol refers to. Dynobj* Versions::get_dynobj_for_sym(const Symbol_table* symtab, const Symbol* sym) const { if (sym->is_copied_from_dynobj()) return symtab->get_copy_source(sym); else { Object* object = sym->object(); gold_assert(object->is_dynamic()); return static_cast(object); } } // Record version information for a symbol going into the dynamic // symbol table. void Versions::record_version(const Symbol_table* symtab, Stringpool* dynpool, const Symbol* sym) { gold_assert(!this->is_finalized_); gold_assert(sym->version() != NULL); Stringpool::Key version_key; const char* version = dynpool->add(sym->version(), false, &version_key); if (!sym->is_from_dynobj() && !sym->is_copied_from_dynobj()) { if (parameters->output_is_shared()) this->add_def(sym, version, version_key); } else { // This is a version reference. Dynobj* dynobj = this->get_dynobj_for_sym(symtab, sym); this->add_need(dynpool, dynobj->soname(), version, version_key); } } // We've found a symbol SYM defined in version VERSION. void Versions::add_def(const Symbol* sym, const char* version, Stringpool::Key version_key) { Key k(version_key, 0); Version_base* const vbnull = NULL; std::pair ins = this->version_table_.insert(std::make_pair(k, vbnull)); if (!ins.second) { // We already have an entry for this version. Version_base* vb = ins.first->second; // We have now seen a symbol in this version, so it is not // weak. gold_assert(vb != NULL); vb->clear_weak(); // FIXME: When we support version scripts, we will need to // check whether this symbol should be forced local. } else { // If we are creating a shared object, it is an error to // find a definition of a symbol with a version which is not // in the version script. if (parameters->output_is_shared()) { gold_error(_("symbol %s has undefined version %s"), sym->demangled_name().c_str(), version); return; } // If this is the first version we are defining, first define // the base version. FIXME: Should use soname here when // creating a shared object. Verdef* vdbase = new Verdef(parameters->output_file_name(), true, false, true); this->defs_.push_back(vdbase); // When creating a regular executable, automatically define // a new version. Verdef* vd = new Verdef(version, false, false, false); this->defs_.push_back(vd); ins.first->second = vd; } } // Add a reference to version NAME in file FILENAME. void Versions::add_need(Stringpool* dynpool, const char* filename, const char* name, Stringpool::Key name_key) { Stringpool::Key filename_key; filename = dynpool->add(filename, true, &filename_key); Key k(name_key, filename_key); Version_base* const vbnull = NULL; std::pair ins = this->version_table_.insert(std::make_pair(k, vbnull)); if (!ins.second) { // We already have an entry for this filename/version. return; } // See whether we already have this filename. We don't expect many // version references, so we just do a linear search. This could be // replaced by a hash table. Verneed* vn = NULL; for (Needs::iterator p = this->needs_.begin(); p != this->needs_.end(); ++p) { if ((*p)->filename() == filename) { vn = *p; break; } } if (vn == NULL) { // We have a new filename. vn = new Verneed(filename); this->needs_.push_back(vn); } ins.first->second = vn->add_name(name); } // Set the version indexes. Create a new dynamic version symbol for // each new version definition. unsigned int Versions::finalize(const Target* target, Symbol_table* symtab, unsigned int dynsym_index, std::vector* syms) { gold_assert(!this->is_finalized_); unsigned int vi = 1; for (Defs::iterator p = this->defs_.begin(); p != this->defs_.end(); ++p) { (*p)->set_index(vi); ++vi; // Create a version symbol if necessary. if (!(*p)->is_symbol_created()) { Symbol* vsym = symtab->define_as_constant(target, (*p)->name(), (*p)->name(), 0, 0, elfcpp::STT_OBJECT, elfcpp::STB_GLOBAL, elfcpp::STV_DEFAULT, 0, false); vsym->set_needs_dynsym_entry(); vsym->set_dynsym_index(dynsym_index); ++dynsym_index; syms->push_back(vsym); // The name is already in the dynamic pool. } } // Index 1 is used for global symbols. if (vi == 1) { gold_assert(this->defs_.empty()); vi = 2; } for (Needs::iterator p = this->needs_.begin(); p != this->needs_.end(); ++p) vi = (*p)->finalize(vi); this->is_finalized_ = true; return dynsym_index; } // Return the version index to use for a symbol. This does two hash // table lookups: one in DYNPOOL and one in this->version_table_. // Another approach alternative would be store a pointer in SYM, which // would increase the size of the symbol table. Or perhaps we could // use a hash table from dynamic symbol pointer values to Version_base // pointers. unsigned int Versions::version_index(const Symbol_table* symtab, const Stringpool* dynpool, const Symbol* sym) const { Stringpool::Key version_key; const char* version = dynpool->find(sym->version(), &version_key); gold_assert(version != NULL); Key k; if (!sym->is_from_dynobj() && !sym->is_copied_from_dynobj()) { if (!parameters->output_is_shared()) return elfcpp::VER_NDX_GLOBAL; k = Key(version_key, 0); } else { Dynobj* dynobj = this->get_dynobj_for_sym(symtab, sym); Stringpool::Key filename_key; const char* filename = dynpool->find(dynobj->soname(), &filename_key); gold_assert(filename != NULL); k = Key(version_key, filename_key); } Version_table::const_iterator p = this->version_table_.find(k); gold_assert(p != this->version_table_.end()); return p->second->index(); } // Return an allocated buffer holding the contents of the symbol // version section. template void Versions::symbol_section_contents(const Symbol_table* symtab, const Stringpool* dynpool, unsigned int local_symcount, const std::vector& syms, unsigned char** pp, unsigned int* psize ACCEPT_SIZE_ENDIAN) const { gold_assert(this->is_finalized_); unsigned int sz = (local_symcount + syms.size()) * 2; unsigned char* pbuf = new unsigned char[sz]; for (unsigned int i = 0; i < local_symcount; ++i) elfcpp::Swap<16, big_endian>::writeval(pbuf + i * 2, elfcpp::VER_NDX_LOCAL); for (std::vector::const_iterator p = syms.begin(); p != syms.end(); ++p) { unsigned int version_index; const char* version = (*p)->version(); if (version == NULL) version_index = elfcpp::VER_NDX_GLOBAL; else version_index = this->version_index(symtab, dynpool, *p); elfcpp::Swap<16, big_endian>::writeval(pbuf + (*p)->dynsym_index() * 2, version_index); } *pp = pbuf; *psize = sz; } // Return an allocated buffer holding the contents of the version // definition section. template void Versions::def_section_contents(const Stringpool* dynpool, unsigned char** pp, unsigned int* psize, unsigned int* pentries ACCEPT_SIZE_ENDIAN) const { gold_assert(this->is_finalized_); gold_assert(!this->defs_.empty()); const int verdef_size = elfcpp::Elf_sizes::verdef_size; const int verdaux_size = elfcpp::Elf_sizes::verdaux_size; unsigned int sz = 0; for (Defs::const_iterator p = this->defs_.begin(); p != this->defs_.end(); ++p) { sz += verdef_size + verdaux_size; sz += (*p)->count_dependencies() * verdaux_size; } unsigned char* pbuf = new unsigned char[sz]; unsigned char* pb = pbuf; Defs::const_iterator p; unsigned int i; for (p = this->defs_.begin(), i = 0; p != this->defs_.end(); ++p, ++i) pb = (*p)->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)( dynpool, i + 1 >= this->defs_.size(), pb SELECT_SIZE_ENDIAN(size, big_endian)); gold_assert(static_cast(pb - pbuf) == sz); *pp = pbuf; *psize = sz; *pentries = this->defs_.size(); } // Return an allocated buffer holding the contents of the version // reference section. template void Versions::need_section_contents(const Stringpool* dynpool, unsigned char** pp, unsigned int *psize, unsigned int *pentries ACCEPT_SIZE_ENDIAN) const { gold_assert(this->is_finalized_); gold_assert(!this->needs_.empty()); const int verneed_size = elfcpp::Elf_sizes::verneed_size; const int vernaux_size = elfcpp::Elf_sizes::vernaux_size; unsigned int sz = 0; for (Needs::const_iterator p = this->needs_.begin(); p != this->needs_.end(); ++p) { sz += verneed_size; sz += (*p)->count_versions() * vernaux_size; } unsigned char* pbuf = new unsigned char[sz]; unsigned char* pb = pbuf; Needs::const_iterator p; unsigned int i; for (p = this->needs_.begin(), i = 0; p != this->needs_.end(); ++p, ++i) pb = (*p)->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)( dynpool, i + 1 >= this->needs_.size(), pb SELECT_SIZE_ENDIAN(size, big_endian)); gold_assert(static_cast(pb - pbuf) == sz); *pp = pbuf; *psize = sz; *pentries = this->needs_.size(); } // Instantiate the templates we need. We could use the configure // script to restrict this to only the ones for implemented targets. #ifdef HAVE_TARGET_32_LITTLE template class Sized_dynobj<32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Sized_dynobj<32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Sized_dynobj<64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Sized_dynobj<64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template void Versions::symbol_section_contents<32, false>( const Symbol_table*, const Stringpool*, unsigned int, const std::vector&, unsigned char**, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(32, false)) const; #endif #ifdef HAVE_TARGET_32_BIG template void Versions::symbol_section_contents<32, true>( const Symbol_table*, const Stringpool*, unsigned int, const std::vector&, unsigned char**, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(32, true)) const; #endif #ifdef HAVE_TARGET_64_LITTLE template void Versions::symbol_section_contents<64, false>( const Symbol_table*, const Stringpool*, unsigned int, const std::vector&, unsigned char**, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(64, false)) const; #endif #ifdef HAVE_TARGET_64_BIG template void Versions::symbol_section_contents<64, true>( const Symbol_table*, const Stringpool*, unsigned int, const std::vector&, unsigned char**, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(64, true)) const; #endif #ifdef HAVE_TARGET_32_LITTLE template void Versions::def_section_contents<32, false>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(32, false)) const; #endif #ifdef HAVE_TARGET_32_BIG template void Versions::def_section_contents<32, true>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(32, true)) const; #endif #ifdef HAVE_TARGET_64_LITTLE template void Versions::def_section_contents<64, false>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(64, false)) const; #endif #ifdef HAVE_TARGET_64_BIG template void Versions::def_section_contents<64, true>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(64, true)) const; #endif #ifdef HAVE_TARGET_32_LITTLE template void Versions::need_section_contents<32, false>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(32, false)) const; #endif #ifdef HAVE_TARGET_32_BIG template void Versions::need_section_contents<32, true>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(32, true)) const; #endif #ifdef HAVE_TARGET_64_LITTLE template void Versions::need_section_contents<64, false>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(64, false)) const; #endif #ifdef HAVE_TARGET_64_BIG template void Versions::need_section_contents<64, true>( const Stringpool*, unsigned char**, unsigned int*, unsigned int* ACCEPT_SIZE_ENDIAN_EXPLICIT(64, true)) const; #endif } // End namespace gold.