// object.cc -- support for an object file for linking in gold // Copyright 2006, 2007, 2008, 2009 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 #include "demangle.h" #include "libiberty.h" #include "gc.h" #include "target-select.h" #include "dwarf_reader.h" #include "layout.h" #include "output.h" #include "symtab.h" #include "cref.h" #include "reloc.h" #include "object.h" #include "dynobj.h" #include "plugin.h" namespace gold { // Class Xindex. // Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX // section and read it in. SYMTAB_SHNDX is the index of the symbol // table we care about. template void Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx) { if (!this->symtab_xindex_.empty()) return; gold_assert(symtab_shndx != 0); // Look through the sections in reverse order, on the theory that it // is more likely to be near the end than the beginning. unsigned int i = object->shnum(); while (i > 0) { --i; if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX && this->adjust_shndx(object->section_link(i)) == symtab_shndx) { this->read_symtab_xindex(object, i, NULL); return; } } object->error(_("missing SHT_SYMTAB_SHNDX section")); } // Read in the symtab_xindex_ array, given the section index of the // SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the // section headers. template void Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx, const unsigned char* pshdrs) { section_size_type bytecount; const unsigned char* contents; if (pshdrs == NULL) contents = object->section_contents(xindex_shndx, &bytecount, false); else { const unsigned char* p = (pshdrs + (xindex_shndx * elfcpp::Elf_sizes::shdr_size)); typename elfcpp::Shdr shdr(p); bytecount = convert_to_section_size_type(shdr.get_sh_size()); contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false); } gold_assert(this->symtab_xindex_.empty()); this->symtab_xindex_.reserve(bytecount / 4); for (section_size_type i = 0; i < bytecount; i += 4) { unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i); // We preadjust the section indexes we save. this->symtab_xindex_.push_back(this->adjust_shndx(shndx)); } } // Symbol symndx has a section of SHN_XINDEX; return the real section // index. unsigned int Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx) { if (symndx >= this->symtab_xindex_.size()) { object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"), symndx); return elfcpp::SHN_UNDEF; } unsigned int shndx = this->symtab_xindex_[symndx]; if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum()) { object->error(_("extended index for symbol %u out of range: %u"), symndx, shndx); return elfcpp::SHN_UNDEF; } return shndx; } // Class Object. // Set the target based on fields in the ELF file header. void Object::set_target(int machine, int size, bool big_endian, int osabi, int abiversion) { Target* target = select_target(machine, size, big_endian, osabi, abiversion); if (target == NULL) gold_fatal(_("%s: unsupported ELF machine number %d"), this->name().c_str(), machine); this->target_ = target; } // Report an error for this object file. This is used by the // elfcpp::Elf_file interface, and also called by the Object code // itself. void Object::error(const char* format, ...) const { va_list args; va_start(args, format); char* buf = NULL; if (vasprintf(&buf, format, args) < 0) gold_nomem(); va_end(args); gold_error(_("%s: %s"), this->name().c_str(), buf); free(buf); } // Return a view of the contents of a section. const unsigned char* Object::section_contents(unsigned int shndx, section_size_type* plen, bool cache) { Location loc(this->do_section_contents(shndx)); *plen = convert_to_section_size_type(loc.data_size); return this->get_view(loc.file_offset, *plen, true, cache); } // Read the section data into SD. This is code common to Sized_relobj // and Sized_dynobj, so we put it into Object. template void Object::read_section_data(elfcpp::Elf_file* elf_file, Read_symbols_data* sd) { const int shdr_size = elfcpp::Elf_sizes::shdr_size; // Read the section headers. const off_t shoff = elf_file->shoff(); const unsigned int shnum = this->shnum(); sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size, true, true); // Read the section names. const unsigned char* pshdrs = sd->section_headers->data(); const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size; typename elfcpp::Shdr shdrnames(pshdrnames); if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB) this->error(_("section name section has wrong type: %u"), static_cast(shdrnames.get_sh_type())); sd->section_names_size = convert_to_section_size_type(shdrnames.get_sh_size()); sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(), sd->section_names_size, false, false); } // If NAME is the name of a special .gnu.warning section, arrange for // the warning to be issued. SHNDX is the section index. Return // whether it is a warning section. bool Object::handle_gnu_warning_section(const char* name, unsigned int shndx, Symbol_table* symtab) { const char warn_prefix[] = ".gnu.warning."; const int warn_prefix_len = sizeof warn_prefix - 1; if (strncmp(name, warn_prefix, warn_prefix_len) == 0) { // Read the section contents to get the warning text. It would // be nicer if we only did this if we have to actually issue a // warning. Unfortunately, warnings are issued as we relocate // sections. That means that we can not lock the object then, // as we might try to issue the same warning multiple times // simultaneously. section_size_type len; const unsigned char* contents = this->section_contents(shndx, &len, false); std::string warning(reinterpret_cast(contents), len); symtab->add_warning(name + warn_prefix_len, this, warning); return true; } return false; } // Class Relobj // To copy the symbols data read from the file to a local data structure. // This function is called from do_layout only while doing garbage // collection. void Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd, unsigned int section_header_size) { gc_sd->section_headers_data = new unsigned char[(section_header_size)]; memcpy(gc_sd->section_headers_data, sd->section_headers->data(), section_header_size); gc_sd->section_names_data = new unsigned char[sd->section_names_size]; memcpy(gc_sd->section_names_data, sd->section_names->data(), sd->section_names_size); gc_sd->section_names_size = sd->section_names_size; if (sd->symbols != NULL) { gc_sd->symbols_data = new unsigned char[sd->symbols_size]; memcpy(gc_sd->symbols_data, sd->symbols->data(), sd->symbols_size); } else { gc_sd->symbols_data = NULL; } gc_sd->symbols_size = sd->symbols_size; gc_sd->external_symbols_offset = sd->external_symbols_offset; if (sd->symbol_names != NULL) { gc_sd->symbol_names_data = new unsigned char[sd->symbol_names_size]; memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(), sd->symbol_names_size); } else { gc_sd->symbol_names_data = NULL; } gc_sd->symbol_names_size = sd->symbol_names_size; } // This function determines if a particular section name must be included // in the link. This is used during garbage collection to determine the // roots of the worklist. bool Relobj::is_section_name_included(const char* name) { if (is_prefix_of(".ctors", name) || is_prefix_of(".dtors", name) || is_prefix_of(".note", name) || is_prefix_of(".init", name) || is_prefix_of(".fini", name) || is_prefix_of(".gcc_except_table", name) || is_prefix_of(".jcr", name) || is_prefix_of(".preinit_array", name) || (is_prefix_of(".text", name) && strstr(name, "personality")) || (is_prefix_of(".data", name) && strstr(name, "personality")) || (is_prefix_of(".gnu.linkonce.d", name) && strstr(name, "personality"))) { return true; } return false; } // Class Sized_relobj. template Sized_relobj::Sized_relobj( const std::string& name, Input_file* input_file, off_t offset, const elfcpp::Ehdr& ehdr) : Relobj(name, input_file, offset), elf_file_(this, ehdr), symtab_shndx_(-1U), local_symbol_count_(0), output_local_symbol_count_(0), output_local_dynsym_count_(0), symbols_(), defined_count_(0), local_symbol_offset_(0), local_dynsym_offset_(0), local_values_(), local_got_offsets_(), kept_comdat_sections_(), comdat_groups_(), has_eh_frame_(false) { } template Sized_relobj::~Sized_relobj() { } // Set up an object file based on the file header. This sets up the // target and reads the section information. template void Sized_relobj::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_SYMTAB section, given the section headers. The ELF // standard says that maybe in the future there can be more than one // SHT_SYMTAB section. Until somebody figures out how that could // work, we assume there is only one. template void Sized_relobj::find_symtab(const unsigned char* pshdrs) { const unsigned int shnum = this->shnum(); this->symtab_shndx_ = 0; if (shnum > 0) { // Look through the sections in reverse order, since gas tends // to put the symbol table at the end. const unsigned char* p = pshdrs + shnum * This::shdr_size; unsigned int i = shnum; unsigned int xindex_shndx = 0; unsigned int xindex_link = 0; while (i > 0) { --i; p -= This::shdr_size; typename This::Shdr shdr(p); if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB) { this->symtab_shndx_ = i; if (xindex_shndx > 0 && xindex_link == i) { Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset()); xindex->read_symtab_xindex(this, xindex_shndx, pshdrs); this->set_xindex(xindex); } break; } // Try to pick up the SHT_SYMTAB_SHNDX section, if there is // one. This will work if it follows the SHT_SYMTAB // section. if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX) { xindex_shndx = i; xindex_link = this->adjust_shndx(shdr.get_sh_link()); } } } } // Return the Xindex structure to use for object with lots of // sections. template Xindex* Sized_relobj::do_initialize_xindex() { gold_assert(this->symtab_shndx_ != -1U); Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset()); xindex->initialize_symtab_xindex(this, this->symtab_shndx_); return xindex; } // Return whether SHDR has the right type and flags to be a GNU // .eh_frame section. template bool Sized_relobj::check_eh_frame_flags( const elfcpp::Shdr* shdr) const { return (shdr->get_sh_type() == elfcpp::SHT_PROGBITS && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0); } // Return whether there is a GNU .eh_frame section, given the section // headers and the section names. template bool Sized_relobj::find_eh_frame( const unsigned char* pshdrs, const char* names, section_size_type names_size) const { const unsigned int shnum = this->shnum(); const unsigned char* p = pshdrs + This::shdr_size; for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size) { typename This::Shdr shdr(p); if (this->check_eh_frame_flags(&shdr)) { if (shdr.get_sh_name() >= names_size) { this->error(_("bad section name offset for section %u: %lu"), i, static_cast(shdr.get_sh_name())); continue; } const char* name = names + shdr.get_sh_name(); if (strcmp(name, ".eh_frame") == 0) return true; } } return false; } // Read the sections and symbols from an object file. template void Sized_relobj::do_read_symbols(Read_symbols_data* sd) { this->read_section_data(&this->elf_file_, sd); const unsigned char* const pshdrs = sd->section_headers->data(); this->find_symtab(pshdrs); const unsigned char* namesu = sd->section_names->data(); const char* names = reinterpret_cast(namesu); if (memmem(names, sd->section_names_size, ".eh_frame", 10) != NULL) { if (this->find_eh_frame(pshdrs, names, sd->section_names_size)) this->has_eh_frame_ = true; } sd->symbols = NULL; sd->symbols_size = 0; sd->external_symbols_offset = 0; sd->symbol_names = NULL; sd->symbol_names_size = 0; if (this->symtab_shndx_ == 0) { // No symbol table. Weird but legal. return; } // Get the symbol table section header. typename This::Shdr symtabshdr(pshdrs + this->symtab_shndx_ * This::shdr_size); gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB); // If this object has a .eh_frame section, we need all the symbols. // Otherwise we only need the external symbols. While it would be // simpler to just always read all the symbols, I've seen object // files with well over 2000 local symbols, which for a 64-bit // object file format is over 5 pages that we don't need to read // now. const int sym_size = This::sym_size; const unsigned int loccount = symtabshdr.get_sh_info(); this->local_symbol_count_ = loccount; this->local_values_.resize(loccount); section_offset_type locsize = loccount * sym_size; off_t dataoff = symtabshdr.get_sh_offset(); section_size_type datasize = convert_to_section_size_type(symtabshdr.get_sh_size()); off_t extoff = dataoff + locsize; section_size_type extsize = datasize - locsize; off_t readoff = this->has_eh_frame_ ? dataoff : extoff; section_size_type readsize = this->has_eh_frame_ ? datasize : extsize; if (readsize == 0) { // No external symbols. Also weird but also legal. return; } File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false); // Read the section header for the symbol names. unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link()); if (strtab_shndx >= this->shnum()) { this->error(_("invalid 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(_("symbol table name section has wrong type: %u"), static_cast(strtabshdr.get_sh_type())); return; } // Read the symbol names. File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(), strtabshdr.get_sh_size(), false, true); sd->symbols = fvsymtab; sd->symbols_size = readsize; sd->external_symbols_offset = this->has_eh_frame_ ? locsize : 0; sd->symbol_names = fvstrtab; sd->symbol_names_size = convert_to_section_size_type(strtabshdr.get_sh_size()); } // Return the section index of symbol SYM. Set *VALUE to its value in // the object file. Set *IS_ORDINARY if this is an ordinary section // index. not a special cod between SHN_LORESERVE and SHN_HIRESERVE. // Note that for a symbol which is not defined in this object file, // this will set *VALUE to 0 and return SHN_UNDEF; it will not return // the final value of the symbol in the link. template unsigned int Sized_relobj::symbol_section_and_value(unsigned int sym, Address* value, bool* is_ordinary) { section_size_type symbols_size; const unsigned char* symbols = this->section_contents(this->symtab_shndx_, &symbols_size, false); const size_t count = symbols_size / This::sym_size; gold_assert(sym < count); elfcpp::Sym elfsym(symbols + sym * This::sym_size); *value = elfsym.get_st_value(); return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary); } // Return whether to include a section group in the link. LAYOUT is // used to keep track of which section groups we have already seen. // INDEX is the index of the section group and SHDR is the section // header. If we do not want to include this group, we set bits in // OMIT for each section which should be discarded. template bool Sized_relobj::include_section_group( Symbol_table* symtab, Layout* layout, unsigned int index, const char* name, const unsigned char* shdrs, const char* section_names, section_size_type section_names_size, std::vector* omit) { // Read the section contents. typename This::Shdr shdr(shdrs + index * This::shdr_size); const unsigned char* pcon = this->get_view(shdr.get_sh_offset(), shdr.get_sh_size(), true, false); const elfcpp::Elf_Word* pword = reinterpret_cast(pcon); // The first word contains flags. We only care about COMDAT section // groups. Other section groups are always included in the link // just like ordinary sections. elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword); // Look up the group signature, which is the name of a symbol. This // is a lot of effort to go to to read a string. Why didn't they // just have the group signature point into the string table, rather // than indirect through a symbol? // Get the appropriate symbol table header (this will normally be // the single SHT_SYMTAB section, but in principle it need not be). const unsigned int link = this->adjust_shndx(shdr.get_sh_link()); typename This::Shdr symshdr(this, this->elf_file_.section_header(link)); // Read the symbol table entry. unsigned int symndx = shdr.get_sh_info(); if (symndx >= symshdr.get_sh_size() / This::sym_size) { this->error(_("section group %u info %u out of range"), index, symndx); return false; } off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size; const unsigned char* psym = this->get_view(symoff, This::sym_size, true, false); elfcpp::Sym sym(psym); // Read the symbol table names. section_size_type symnamelen; const unsigned char* psymnamesu; psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()), &symnamelen, true); const char* psymnames = reinterpret_cast(psymnamesu); // Get the section group signature. if (sym.get_st_name() >= symnamelen) { this->error(_("symbol %u name offset %u out of range"), symndx, sym.get_st_name()); return false; } std::string signature(psymnames + sym.get_st_name()); // It seems that some versions of gas will create a section group // associated with a section symbol, and then fail to give a name to // the section symbol. In such a case, use the name of the section. if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION) { bool is_ordinary; unsigned int sym_shndx = this->adjust_sym_shndx(symndx, sym.get_st_shndx(), &is_ordinary); if (!is_ordinary || sym_shndx >= this->shnum()) { this->error(_("symbol %u invalid section index %u"), symndx, sym_shndx); return false; } typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size); if (member_shdr.get_sh_name() < section_names_size) signature = section_names + member_shdr.get_sh_name(); } // Record this section group in the layout, and see whether we've already // seen one with the same signature. bool include_group = ((flags & elfcpp::GRP_COMDAT) == 0 || layout->add_comdat(this, index, signature, true)); Sized_relobj* kept_object = NULL; Comdat_group* kept_group = NULL; if (!include_group) { // This group is being discarded. Find the object and group // that was kept in its place. unsigned int kept_group_index = 0; Relobj* kept_relobj = layout->find_kept_object(signature, &kept_group_index); kept_object = static_cast*>(kept_relobj); if (kept_object != NULL) kept_group = kept_object->find_comdat_group(kept_group_index); } else if (flags & elfcpp::GRP_COMDAT) { // This group is being kept. Create the table to map section names // to section indexes and add it to the table of groups. kept_group = new Comdat_group(); this->add_comdat_group(index, kept_group); } size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word); std::vector shndxes; bool relocate_group = include_group && parameters->options().relocatable(); if (relocate_group) shndxes.reserve(count - 1); for (size_t i = 1; i < count; ++i) { elfcpp::Elf_Word secnum = this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i)); if (relocate_group) shndxes.push_back(secnum); if (secnum >= this->shnum()) { this->error(_("section %u in section group %u out of range"), secnum, index); continue; } // Check for an earlier section number, since we're going to get // it wrong--we may have already decided to include the section. if (secnum < index) this->error(_("invalid section group %u refers to earlier section %u"), index, secnum); // Get the name of the member section. typename This::Shdr member_shdr(shdrs + secnum * This::shdr_size); if (member_shdr.get_sh_name() >= section_names_size) { // This is an error, but it will be diagnosed eventually // in do_layout, so we don't need to do anything here but // ignore it. continue; } std::string mname(section_names + member_shdr.get_sh_name()); if (!include_group) { (*omit)[secnum] = true; if (kept_group != NULL) { // Find the corresponding kept section, and store that info // in the discarded section table. Comdat_group::const_iterator p = kept_group->find(mname); if (p != kept_group->end()) { Kept_comdat_section* kept = new Kept_comdat_section(kept_object, p->second); this->set_kept_comdat_section(secnum, kept); } } } else if (flags & elfcpp::GRP_COMDAT) { // Add the section to the kept group table. gold_assert(kept_group != NULL); kept_group->insert(std::make_pair(mname, secnum)); } } if (relocate_group) layout->layout_group(symtab, this, index, name, signature.c_str(), shdr, flags, &shndxes); return include_group; } // Whether to include a linkonce section in the link. NAME is the // name of the section and SHDR is the section header. // Linkonce sections are a GNU extension implemented in the original // GNU linker before section groups were defined. The semantics are // that we only include one linkonce section with a given name. The // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME, // where T is the type of section and SYMNAME is the name of a symbol. // In an attempt to make linkonce sections interact well with section // groups, we try to identify SYMNAME and use it like a section group // signature. We want to block section groups with that signature, // but not other linkonce sections with that signature. We also use // the full name of the linkonce section as a normal section group // signature. template bool Sized_relobj::include_linkonce_section( Layout* layout, unsigned int index, const char* name, const elfcpp::Shdr&) { // In general the symbol name we want will be the string following // the last '.'. However, we have to handle the case of // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by // some versions of gcc. So we use a heuristic: if the name starts // with ".gnu.linkonce.t.", we use everything after that. Otherwise // we look for the last '.'. We can't always simply skip // ".gnu.linkonce.X", because we have to deal with cases like // ".gnu.linkonce.d.rel.ro.local". const char* const linkonce_t = ".gnu.linkonce.t."; const char* symname; if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0) symname = name + strlen(linkonce_t); else symname = strrchr(name, '.') + 1; std::string sig1(symname); std::string sig2(name); bool include1 = layout->add_comdat(this, index, sig1, false); bool include2 = layout->add_comdat(this, index, sig2, true); if (!include2) { // The section is being discarded on the basis of its section // name (i.e., the kept section was also a linkonce section). // In this case, the section index stored with the layout object // is the linkonce section that was kept. unsigned int kept_group_index = 0; Relobj* kept_relobj = layout->find_kept_object(sig2, &kept_group_index); if (kept_relobj != NULL) { Sized_relobj* kept_object = static_cast*>(kept_relobj); Kept_comdat_section* kept = new Kept_comdat_section(kept_object, kept_group_index); this->set_kept_comdat_section(index, kept); } } else if (!include1) { // The section is being discarded on the basis of its symbol // name. This means that the corresponding kept section was // part of a comdat group, and it will be difficult to identify // the specific section within that group that corresponds to // this linkonce section. We'll handle the simple case where // the group has only one member section. Otherwise, it's not // worth the effort. unsigned int kept_group_index = 0; Relobj* kept_relobj = layout->find_kept_object(sig1, &kept_group_index); if (kept_relobj != NULL) { Sized_relobj* kept_object = static_cast*>(kept_relobj); Comdat_group* kept_group = kept_object->find_comdat_group(kept_group_index); if (kept_group != NULL && kept_group->size() == 1) { Comdat_group::const_iterator p = kept_group->begin(); gold_assert(p != kept_group->end()); Kept_comdat_section* kept = new Kept_comdat_section(kept_object, p->second); this->set_kept_comdat_section(index, kept); } } } return include1 && include2; } // Layout an input section. template inline void Sized_relobj::layout_section(Layout* layout, unsigned int shndx, const char* name, typename This::Shdr& shdr, unsigned int reloc_shndx, unsigned int reloc_type) { off_t offset; Output_section* os = layout->layout(this, shndx, name, shdr, reloc_shndx, reloc_type, &offset); this->output_sections()[shndx] = os; if (offset == -1) this->section_offsets_[shndx] = invalid_address; else this->section_offsets_[shndx] = convert_types(offset); // If this section requires special handling, and if there are // relocs that apply to it, then we must do the special handling // before we apply the relocs. if (offset == -1 && reloc_shndx != 0) this->set_relocs_must_follow_section_writes(); } // Lay out the input sections. We walk through the sections and check // whether they should be included in the link. If they should, we // pass them to the Layout object, which will return an output section // and an offset. // During garbage collection (gc-sections), this function is called // twice. When it is called the first time, it is for setting up some // sections as roots to a work-list and to do comdat processing. Actual // layout happens the second time around after all the relevant sections // have been determined. The first time, is_worklist_ready is false. // It is then set to true after the worklist is processed and the relevant // sections are determined. Then, this function is called again to // layout the sections. template void Sized_relobj::do_layout(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd) { const unsigned int shnum = this->shnum(); bool is_gc_pass_one = (parameters->options().gc_sections() && !symtab->gc()->is_worklist_ready()); bool is_gc_pass_two = (parameters->options().gc_sections() && symtab->gc()->is_worklist_ready()); if (shnum == 0) return; Symbols_data* gc_sd = NULL; if (is_gc_pass_one) { // During garbage collection save the symbols data to use it when // re-entering this function. gc_sd = new Symbols_data; this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum); this->set_symbols_data(gc_sd); } else if (is_gc_pass_two) { gc_sd = this->get_symbols_data(); } const unsigned char* section_headers_data = NULL; section_size_type section_names_size; const unsigned char* symbols_data = NULL; section_size_type symbols_size; section_offset_type external_symbols_offset; const unsigned char* symbol_names_data = NULL; section_size_type symbol_names_size; if (parameters->options().gc_sections()) { section_headers_data = gc_sd->section_headers_data; section_names_size = gc_sd->section_names_size; symbols_data = gc_sd->symbols_data; symbols_size = gc_sd->symbols_size; external_symbols_offset = gc_sd->external_symbols_offset; symbol_names_data = gc_sd->symbol_names_data; symbol_names_size = gc_sd->symbol_names_size; } else { section_headers_data = sd->section_headers->data(); section_names_size = sd->section_names_size; if (sd->symbols != NULL) symbols_data = sd->symbols->data(); symbols_size = sd->symbols_size; external_symbols_offset = sd->external_symbols_offset; if (sd->symbol_names != NULL) symbol_names_data = sd->symbol_names->data(); symbol_names_size = sd->symbol_names_size; } // Get the section headers. const unsigned char* shdrs = section_headers_data; const unsigned char* pshdrs; // Get the section names. const unsigned char* pnamesu = parameters->options().gc_sections() ? gc_sd->section_names_data : sd->section_names->data(); const char* pnames = reinterpret_cast(pnamesu); // If any input files have been claimed by plugins, we need to defer // actual layout until the replacement files have arrived. const bool should_defer_layout = (parameters->options().has_plugins() && parameters->options().plugins()->should_defer_layout()); unsigned int num_sections_to_defer = 0; // For each section, record the index of the reloc section if any. // Use 0 to mean that there is no reloc section, -1U to mean that // there is more than one. std::vector reloc_shndx(shnum, 0); std::vector reloc_type(shnum, elfcpp::SHT_NULL); // Skip the first, dummy, section. pshdrs = shdrs + This::shdr_size; for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size) { typename This::Shdr shdr(pshdrs); // Count the number of sections whose layout will be deferred. if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC)) ++num_sections_to_defer; unsigned int sh_type = shdr.get_sh_type(); if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA) { unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info()); if (target_shndx == 0 || target_shndx >= shnum) { this->error(_("relocation section %u has bad info %u"), i, target_shndx); continue; } if (reloc_shndx[target_shndx] != 0) reloc_shndx[target_shndx] = -1U; else { reloc_shndx[target_shndx] = i; reloc_type[target_shndx] = sh_type; } } } Output_sections& out_sections(this->output_sections()); std::vector
& out_section_offsets(this->section_offsets_); if (!is_gc_pass_two) { out_sections.resize(shnum); out_section_offsets.resize(shnum); } // If we are only linking for symbols, then there is nothing else to // do here. if (this->input_file()->just_symbols()) { if (!is_gc_pass_two) { delete sd->section_headers; sd->section_headers = NULL; delete sd->section_names; sd->section_names = NULL; } return; } if (num_sections_to_defer > 0) { parameters->options().plugins()->add_deferred_layout_object(this); this->deferred_layout_.reserve(num_sections_to_defer); } // Whether we've seen a .note.GNU-stack section. bool seen_gnu_stack = false; // The flags of a .note.GNU-stack section. uint64_t gnu_stack_flags = 0; // Keep track of which sections to omit. std::vector omit(shnum, false); // Keep track of reloc sections when emitting relocations. const bool relocatable = parameters->options().relocatable(); const bool emit_relocs = (relocatable || parameters->options().emit_relocs()); std::vector reloc_sections; // Keep track of .eh_frame sections. std::vector eh_frame_sections; // Skip the first, dummy, section. pshdrs = shdrs + 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() >= 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(); if (!is_gc_pass_two) { if (this->handle_gnu_warning_section(name, i, symtab)) { if (!relocatable) omit[i] = true; } // The .note.GNU-stack section is special. It gives the // protection flags that this object file requires for the stack // in memory. if (strcmp(name, ".note.GNU-stack") == 0) { seen_gnu_stack = true; gnu_stack_flags |= shdr.get_sh_flags(); omit[i] = true; } bool discard = omit[i]; if (!discard) { if (shdr.get_sh_type() == elfcpp::SHT_GROUP) { if (!this->include_section_group(symtab, layout, i, name, shdrs, pnames, section_names_size, &omit)) discard = true; } else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0 && Layout::is_linkonce(name)) { if (!this->include_linkonce_section(layout, i, name, shdr)) discard = true; } } if (discard) { // Do not include this section in the link. out_sections[i] = NULL; out_section_offsets[i] = invalid_address; continue; } } if (is_gc_pass_one) { if (is_section_name_included(name) || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY) { symtab->gc()->worklist().push(Section_id(this, i)); } } // When doing a relocatable link we are going to copy input // reloc sections into the output. We only want to copy the // ones associated with sections which are not being discarded. // However, we don't know that yet for all sections. So save // reloc sections and process them later. Garbage collection is // not triggered when relocatable code is desired. if (emit_relocs && (shdr.get_sh_type() == elfcpp::SHT_REL || shdr.get_sh_type() == elfcpp::SHT_RELA)) { reloc_sections.push_back(i); continue; } if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP) continue; // The .eh_frame section is special. It holds exception frame // information that we need to read in order to generate the // exception frame header. We process these after all the other // sections so that the exception frame reader can reliably // determine which sections are being discarded, and discard the // corresponding information. if (!relocatable && strcmp(name, ".eh_frame") == 0 && this->check_eh_frame_flags(&shdr)) { if (is_gc_pass_one) { out_sections[i] = reinterpret_cast(1); out_section_offsets[i] = invalid_address; } else eh_frame_sections.push_back(i); continue; } if (is_gc_pass_two) { // This is executed during the second pass of garbage // collection. do_layout has been called before and some // sections have been already discarded. Simply ignore // such sections this time around. if (out_sections[i] == NULL) { gold_assert(out_section_offsets[i] == invalid_address); continue; } if ((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0) if (symtab->gc()->referenced_list().find(Section_id(this,i)) == symtab->gc()->referenced_list().end()) { if (parameters->options().print_gc_sections()) gold_info(_("%s: removing unused section from '%s'" " in file '%s"), program_name, this->section_name(i).c_str(), this->name().c_str()); out_sections[i] = NULL; out_section_offsets[i] = invalid_address; continue; } } // Defer layout here if input files are claimed by plugins. When gc // is turned on this function is called twice. For the second call // should_defer_layout should be false. if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC)) { gold_assert(!is_gc_pass_two); this->deferred_layout_.push_back(Deferred_layout(i, name, pshdrs, reloc_shndx[i], reloc_type[i])); // Put dummy values here; real values will be supplied by // do_layout_deferred_sections. out_sections[i] = reinterpret_cast(2); out_section_offsets[i] = invalid_address; continue; } // During gc_pass_two if a section that was previously deferred is // found, do not layout the section as layout_deferred_sections will // do it later from gold.cc. if (is_gc_pass_two && (out_sections[i] == reinterpret_cast(2))) continue; if (is_gc_pass_one) { // This is during garbage collection. The out_sections are // assigned in the second call to this function. out_sections[i] = reinterpret_cast(1); out_section_offsets[i] = invalid_address; } else { // When garbage collection is switched on the actual layout // only happens in the second call. this->layout_section(layout, i, name, shdr, reloc_shndx[i], reloc_type[i]); } } if (!is_gc_pass_one) layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags); // When doing a relocatable link handle the reloc sections at the // end. Garbage collection is not turned on for relocatable code. if (emit_relocs) this->size_relocatable_relocs(); gold_assert(!parameters->options().gc_sections() || reloc_sections.empty()); for (std::vector::const_iterator p = reloc_sections.begin(); p != reloc_sections.end(); ++p) { unsigned int i = *p; const unsigned char* pshdr; pshdr = section_headers_data + i * This::shdr_size; typename This::Shdr shdr(pshdr); unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info()); if (data_shndx >= shnum) { // We already warned about this above. continue; } Output_section* data_section = out_sections[data_shndx]; if (data_section == NULL) { out_sections[i] = NULL; out_section_offsets[i] = invalid_address; continue; } Relocatable_relocs* rr = new Relocatable_relocs(); this->set_relocatable_relocs(i, rr); Output_section* os = layout->layout_reloc(this, i, shdr, data_section, rr); out_sections[i] = os; out_section_offsets[i] = invalid_address; } // Handle the .eh_frame sections at the end. gold_assert(!is_gc_pass_one || eh_frame_sections.empty()); for (std::vector::const_iterator p = eh_frame_sections.begin(); p != eh_frame_sections.end(); ++p) { gold_assert(this->has_eh_frame_); gold_assert(external_symbols_offset != 0); unsigned int i = *p; const unsigned char *pshdr; pshdr = section_headers_data + i * This::shdr_size; typename This::Shdr shdr(pshdr); off_t offset; Output_section* os = layout->layout_eh_frame(this, symbols_data, symbols_size, symbol_names_data, symbol_names_size, i, shdr, reloc_shndx[i], reloc_type[i], &offset); out_sections[i] = os; if (offset == -1) out_section_offsets[i] = invalid_address; else out_section_offsets[i] = convert_types(offset); // If this section requires special handling, and if there are // relocs that apply to it, then we must do the special handling // before we apply the relocs. if (offset == -1 && reloc_shndx[i] != 0) this->set_relocs_must_follow_section_writes(); } if (is_gc_pass_two) { delete[] gc_sd->section_headers_data; delete[] gc_sd->section_names_data; delete[] gc_sd->symbols_data; delete[] gc_sd->symbol_names_data; } else { delete sd->section_headers; sd->section_headers = NULL; delete sd->section_names; sd->section_names = NULL; } } // Layout sections whose layout was deferred while waiting for // input files from a plugin. template void Sized_relobj::do_layout_deferred_sections(Layout* layout) { typename std::vector::iterator deferred; for (deferred = this->deferred_layout_.begin(); deferred != this->deferred_layout_.end(); ++deferred) { typename This::Shdr shdr(deferred->shdr_data_); this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(), shdr, deferred->reloc_shndx_, deferred->reloc_type_); } this->deferred_layout_.clear(); } // Add the symbols to the symbol table. template void Sized_relobj::do_add_symbols(Symbol_table* symtab, Read_symbols_data* sd, Layout*) { if (sd->symbols == NULL) { gold_assert(sd->symbol_names == NULL); return; } const int sym_size = This::sym_size; size_t symcount = ((sd->symbols_size - sd->external_symbols_offset) / sym_size); if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset) { this->error(_("size of symbols is not multiple of symbol size")); return; } this->symbols_.resize(symcount); const char* sym_names = reinterpret_cast(sd->symbol_names->data()); symtab->add_from_relobj(this, sd->symbols->data() + sd->external_symbols_offset, symcount, this->local_symbol_count_, sym_names, sd->symbol_names_size, &this->symbols_, &this->defined_count_); delete sd->symbols; sd->symbols = NULL; delete sd->symbol_names; sd->symbol_names = NULL; } // First pass over the local symbols. Here we add their names to // *POOL and *DYNPOOL, and we store the symbol value in // THIS->LOCAL_VALUES_. This function is always called from a // singleton thread. This is followed by a call to // finalize_local_symbols. template void Sized_relobj::do_count_local_symbols(Stringpool* pool, Stringpool* dynpool) { gold_assert(this->symtab_shndx_ != -1U); if (this->symtab_shndx_ == 0) { // This object has no symbols. Weird but legal. return; } // Read the symbol table section header. const unsigned int symtab_shndx = this->symtab_shndx_; typename This::Shdr symtabshdr(this, this->elf_file_.section_header(symtab_shndx)); gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB); // Read the local symbols. const int sym_size = This::sym_size; const unsigned int loccount = this->local_symbol_count_; gold_assert(loccount == symtabshdr.get_sh_info()); off_t locsize = loccount * sym_size; const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(), locsize, true, true); // Read the symbol names. const unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link()); section_size_type strtab_size; const unsigned char* pnamesu = this->section_contents(strtab_shndx, &strtab_size, true); const char* pnames = reinterpret_cast(pnamesu); // Loop over the local symbols. const Output_sections& out_sections(this->output_sections()); unsigned int shnum = this->shnum(); unsigned int count = 0; unsigned int dyncount = 0; // Skip the first, dummy, symbol. psyms += sym_size; for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size) { elfcpp::Sym sym(psyms); Symbol_value& lv(this->local_values_[i]); bool is_ordinary; unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(), &is_ordinary); lv.set_input_shndx(shndx, is_ordinary); if (sym.get_st_type() == elfcpp::STT_SECTION) lv.set_is_section_symbol(); else if (sym.get_st_type() == elfcpp::STT_TLS) lv.set_is_tls_symbol(); // Save the input symbol value for use in do_finalize_local_symbols(). lv.set_input_value(sym.get_st_value()); // Decide whether this symbol should go into the output file. if (shndx < shnum && out_sections[shndx] == NULL) { lv.set_no_output_symtab_entry(); gold_assert(!lv.needs_output_dynsym_entry()); continue; } if (sym.get_st_type() == elfcpp::STT_SECTION) { lv.set_no_output_symtab_entry(); gold_assert(!lv.needs_output_dynsym_entry()); continue; } if (sym.get_st_name() >= strtab_size) { this->error(_("local symbol %u section name out of range: %u >= %u"), i, sym.get_st_name(), static_cast(strtab_size)); lv.set_no_output_symtab_entry(); continue; } // Add the symbol to the symbol table string pool. const char* name = pnames + sym.get_st_name(); pool->add(name, true, NULL); ++count; // If needed, add the symbol to the dynamic symbol table string pool. if (lv.needs_output_dynsym_entry()) { dynpool->add(name, true, NULL); ++dyncount; } } this->output_local_symbol_count_ = count; this->output_local_dynsym_count_ = dyncount; } // Finalize the local symbols. Here we set the final value in // THIS->LOCAL_VALUES_ and set their output symbol table indexes. // This function is always called from a singleton thread. The actual // output of the local symbols will occur in a separate task. template unsigned int Sized_relobj::do_finalize_local_symbols(unsigned int index, off_t off) { gold_assert(off == static_cast(align_address(off, size >> 3))); const unsigned int loccount = this->local_symbol_count_; this->local_symbol_offset_ = off; const Output_sections& out_sections(this->output_sections()); const std::vector
& out_offsets(this->section_offsets_); unsigned int shnum = this->shnum(); for (unsigned int i = 1; i < loccount; ++i) { Symbol_value& lv(this->local_values_[i]); bool is_ordinary; unsigned int shndx = lv.input_shndx(&is_ordinary); // Set the output symbol value. if (!is_ordinary) { if (shndx == elfcpp::SHN_ABS || shndx == elfcpp::SHN_COMMON) lv.set_output_value(lv.input_value()); else { this->error(_("unknown section index %u for local symbol %u"), shndx, i); lv.set_output_value(0); } } else { if (shndx >= shnum) { this->error(_("local symbol %u section index %u out of range"), i, shndx); shndx = 0; } Output_section* os = out_sections[shndx]; if (os == NULL) { // This local symbol belongs to a section we are discarding. // In some cases when applying relocations later, we will // attempt to match it to the corresponding kept section, // so we leave the input value unchanged here. continue; } else if (out_offsets[shndx] == invalid_address) { // This is a SHF_MERGE section or one which otherwise // requires special handling. We get the output address // of the start of the merged section. If this is not a // section symbol, we can then determine the final // value. If it is a section symbol, we can not, as in // that case we have to consider the addend to determine // the value to use in a relocation. if (!lv.is_section_symbol()) lv.set_output_value(os->output_address(this, shndx, lv.input_value())); else { section_offset_type start = os->starting_output_address(this, shndx); Merged_symbol_value* msv = new Merged_symbol_value(lv.input_value(), start); lv.set_merged_symbol_value(msv); } } else if (lv.is_tls_symbol()) lv.set_output_value(os->tls_offset() + out_offsets[shndx] + lv.input_value()); else lv.set_output_value(os->address() + out_offsets[shndx] + lv.input_value()); } if (lv.needs_output_symtab_entry()) { lv.set_output_symtab_index(index); ++index; } } return index; } // Set the output dynamic symbol table indexes for the local variables. template unsigned int Sized_relobj::do_set_local_dynsym_indexes(unsigned int index) { const unsigned int loccount = this->local_symbol_count_; for (unsigned int i = 1; i < loccount; ++i) { Symbol_value& lv(this->local_values_[i]); if (lv.needs_output_dynsym_entry()) { lv.set_output_dynsym_index(index); ++index; } } return index; } // Set the offset where local dynamic symbol information will be stored. // Returns the count of local symbols contributed to the symbol table by // this object. template unsigned int Sized_relobj::do_set_local_dynsym_offset(off_t off) { gold_assert(off == static_cast(align_address(off, size >> 3))); this->local_dynsym_offset_ = off; return this->output_local_dynsym_count_; } // Write out the local symbols. template void Sized_relobj::write_local_symbols( Output_file* of, const Stringpool* sympool, const Stringpool* dynpool, Output_symtab_xindex* symtab_xindex, Output_symtab_xindex* dynsym_xindex) { const bool strip_all = parameters->options().strip_all(); if (strip_all) { if (this->output_local_dynsym_count_ == 0) return; this->output_local_symbol_count_ = 0; } gold_assert(this->symtab_shndx_ != -1U); if (this->symtab_shndx_ == 0) { // This object has no symbols. Weird but legal. return; } // Read the symbol table section header. const unsigned int symtab_shndx = this->symtab_shndx_; typename This::Shdr symtabshdr(this, this->elf_file_.section_header(symtab_shndx)); gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB); const unsigned int loccount = this->local_symbol_count_; gold_assert(loccount == symtabshdr.get_sh_info()); // Read the local symbols. const int sym_size = This::sym_size; off_t locsize = loccount * sym_size; const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(), locsize, true, false); // Read the symbol names. const unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link()); section_size_type strtab_size; const unsigned char* pnamesu = this->section_contents(strtab_shndx, &strtab_size, false); const char* pnames = reinterpret_cast(pnamesu); // Get views into the output file for the portions of the symbol table // and the dynamic symbol table that we will be writing. off_t output_size = this->output_local_symbol_count_ * sym_size; unsigned char* oview = NULL; if (output_size > 0) oview = of->get_output_view(this->local_symbol_offset_, output_size); off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size; unsigned char* dyn_oview = NULL; if (dyn_output_size > 0) dyn_oview = of->get_output_view(this->local_dynsym_offset_, dyn_output_size); const Output_sections out_sections(this->output_sections()); gold_assert(this->local_values_.size() == loccount); unsigned char* ov = oview; unsigned char* dyn_ov = dyn_oview; psyms += sym_size; for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size) { elfcpp::Sym isym(psyms); Symbol_value& lv(this->local_values_[i]); bool is_ordinary; unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(), &is_ordinary); if (is_ordinary) { gold_assert(st_shndx < out_sections.size()); if (out_sections[st_shndx] == NULL) continue; st_shndx = out_sections[st_shndx]->out_shndx(); if (st_shndx >= elfcpp::SHN_LORESERVE) { if (lv.needs_output_symtab_entry() && !strip_all) symtab_xindex->add(lv.output_symtab_index(), st_shndx); if (lv.needs_output_dynsym_entry()) dynsym_xindex->add(lv.output_dynsym_index(), st_shndx); st_shndx = elfcpp::SHN_XINDEX; } } // Write the symbol to the output symbol table. if (!strip_all && lv.needs_output_symtab_entry()) { elfcpp::Sym_write osym(ov); gold_assert(isym.get_st_name() < strtab_size); const char* name = pnames + isym.get_st_name(); osym.put_st_name(sympool->get_offset(name)); osym.put_st_value(this->local_values_[i].value(this, 0)); osym.put_st_size(isym.get_st_size()); osym.put_st_info(isym.get_st_info()); osym.put_st_other(isym.get_st_other()); osym.put_st_shndx(st_shndx); ov += sym_size; } // Write the symbol to the output dynamic symbol table. if (lv.needs_output_dynsym_entry()) { gold_assert(dyn_ov < dyn_oview + dyn_output_size); elfcpp::Sym_write osym(dyn_ov); gold_assert(isym.get_st_name() < strtab_size); const char* name = pnames + isym.get_st_name(); osym.put_st_name(dynpool->get_offset(name)); osym.put_st_value(this->local_values_[i].value(this, 0)); osym.put_st_size(isym.get_st_size()); osym.put_st_info(isym.get_st_info()); osym.put_st_other(isym.get_st_other()); osym.put_st_shndx(st_shndx); dyn_ov += sym_size; } } if (output_size > 0) { gold_assert(ov - oview == output_size); of->write_output_view(this->local_symbol_offset_, output_size, oview); } if (dyn_output_size > 0) { gold_assert(dyn_ov - dyn_oview == dyn_output_size); of->write_output_view(this->local_dynsym_offset_, dyn_output_size, dyn_oview); } } // Set *INFO to symbolic information about the offset OFFSET in the // section SHNDX. Return true if we found something, false if we // found nothing. template bool Sized_relobj::get_symbol_location_info( unsigned int shndx, off_t offset, Symbol_location_info* info) { if (this->symtab_shndx_ == 0) return false; section_size_type symbols_size; const unsigned char* symbols = this->section_contents(this->symtab_shndx_, &symbols_size, false); unsigned int symbol_names_shndx = this->adjust_shndx(this->section_link(this->symtab_shndx_)); section_size_type names_size; const unsigned char* symbol_names_u = this->section_contents(symbol_names_shndx, &names_size, false); const char* symbol_names = reinterpret_cast(symbol_names_u); const int sym_size = This::sym_size; const size_t count = symbols_size / sym_size; const unsigned char* p = symbols; for (size_t i = 0; i < count; ++i, p += sym_size) { elfcpp::Sym sym(p); if (sym.get_st_type() == elfcpp::STT_FILE) { if (sym.get_st_name() >= names_size) info->source_file = "(invalid)"; else info->source_file = symbol_names + sym.get_st_name(); continue; } bool is_ordinary; unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(), &is_ordinary); if (is_ordinary && st_shndx == shndx && static_cast(sym.get_st_value()) <= offset && (static_cast(sym.get_st_value() + sym.get_st_size()) > offset)) { if (sym.get_st_name() > names_size) info->enclosing_symbol_name = "(invalid)"; else { info->enclosing_symbol_name = symbol_names + sym.get_st_name(); if (parameters->options().do_demangle()) { char* demangled_name = cplus_demangle( info->enclosing_symbol_name.c_str(), DMGL_ANSI | DMGL_PARAMS); if (demangled_name != NULL) { info->enclosing_symbol_name.assign(demangled_name); free(demangled_name); } } } return true; } } return false; } // Look for a kept section corresponding to the given discarded section, // and return its output address. This is used only for relocations in // debugging sections. If we can't find the kept section, return 0. template typename Sized_relobj::Address Sized_relobj::map_to_kept_section( unsigned int shndx, bool* found) const { Kept_comdat_section *kept = this->get_kept_comdat_section(shndx); if (kept != NULL) { gold_assert(kept->object_ != NULL); *found = true; Output_section* os = kept->object_->output_section(kept->shndx_); Address offset = kept->object_->get_output_section_offset(kept->shndx_); gold_assert(os != NULL && offset != invalid_address); return os->address() + offset; } *found = false; return 0; } // Get symbol counts. template void Sized_relobj::do_get_global_symbol_counts( const Symbol_table*, size_t* defined, size_t* used) const { *defined = this->defined_count_; size_t count = 0; for (Symbols::const_iterator p = this->symbols_.begin(); p != this->symbols_.end(); ++p) if (*p != NULL && (*p)->source() == Symbol::FROM_OBJECT && (*p)->object() == this && (*p)->is_defined()) ++count; *used = count; } // Input_objects methods. // Add a regular relocatable object to the list. Return false if this // object should be ignored. bool Input_objects::add_object(Object* obj) { // Set the global target from the first object file we recognize. Target* target = obj->target(); if (!parameters->target_valid()) set_parameters_target(target); else if (target != ¶meters->target()) { obj->error(_("incompatible target")); return false; } // Print the filename if the -t/--trace option is selected. if (parameters->options().trace()) gold_info("%s", obj->name().c_str()); if (!obj->is_dynamic()) this->relobj_list_.push_back(static_cast(obj)); else { // See if this is a duplicate SONAME. Dynobj* dynobj = static_cast(obj); const char* soname = dynobj->soname(); std::pair::iterator, bool> ins = this->sonames_.insert(soname); if (!ins.second) { // We have already seen a dynamic object with this soname. return false; } this->dynobj_list_.push_back(dynobj); // If this is -lc, remember the directory in which we found it. // We use this when issuing warnings about undefined symbols: as // a heuristic, we don't warn about system libraries found in // the same directory as -lc. if (strncmp(soname, "libc.so", 7) == 0) { const char* object_name = dynobj->name().c_str(); const char* base = lbasename(object_name); if (base != object_name) this->system_library_directory_.assign(object_name, base - 1 - object_name); } } // Add this object to the cross-referencer if requested. if (parameters->options().user_set_print_symbol_counts()) { if (this->cref_ == NULL) this->cref_ = new Cref(); this->cref_->add_object(obj); } return true; } // Return whether an object was found in the system library directory. bool Input_objects::found_in_system_library_directory(const Object* object) const { return (!this->system_library_directory_.empty() && object->name().compare(0, this->system_library_directory_.size(), this->system_library_directory_) == 0); } // For each dynamic object, record whether we've seen all of its // explicit dependencies. void Input_objects::check_dynamic_dependencies() const { for (Dynobj_list::const_iterator p = this->dynobj_list_.begin(); p != this->dynobj_list_.end(); ++p) { const Dynobj::Needed& needed((*p)->needed()); bool found_all = true; for (Dynobj::Needed::const_iterator pneeded = needed.begin(); pneeded != needed.end(); ++pneeded) { if (this->sonames_.find(*pneeded) == this->sonames_.end()) { found_all = false; break; } } (*p)->set_has_unknown_needed_entries(!found_all); } } // Start processing an archive. void Input_objects::archive_start(Archive* archive) { if (parameters->options().user_set_print_symbol_counts()) { if (this->cref_ == NULL) this->cref_ = new Cref(); this->cref_->add_archive_start(archive); } } // Stop processing an archive. void Input_objects::archive_stop(Archive* archive) { if (parameters->options().user_set_print_symbol_counts()) this->cref_->add_archive_stop(archive); } // Print symbol counts void Input_objects::print_symbol_counts(const Symbol_table* symtab) const { if (parameters->options().user_set_print_symbol_counts() && this->cref_ != NULL) this->cref_->print_symbol_counts(symtab); } // Relocate_info methods. // Return a string describing the location of a relocation. This is // only used in error messages. template std::string Relocate_info::location(size_t, off_t offset) const { // See if we can get line-number information from debugging sections. std::string filename; std::string file_and_lineno; // Better than filename-only, if available. Sized_dwarf_line_info line_info(this->object); // This will be "" if we failed to parse the debug info for any reason. file_and_lineno = line_info.addr2line(this->data_shndx, offset); std::string ret(this->object->name()); ret += ':'; Symbol_location_info info; if (this->object->get_symbol_location_info(this->data_shndx, offset, &info)) { ret += " in function "; ret += info.enclosing_symbol_name; ret += ":"; filename = info.source_file; } if (!file_and_lineno.empty()) ret += file_and_lineno; else { if (!filename.empty()) ret += filename; ret += "("; ret += this->object->section_name(this->data_shndx); char buf[100]; // Offsets into sections have to be positive. snprintf(buf, sizeof(buf), "+0x%lx", static_cast(offset)); ret += buf; ret += ")"; } return ret; } } // End namespace gold. namespace { using namespace gold; // Read an ELF file with the header and return the appropriate // instance of Object. template Object* make_elf_sized_object(const std::string& name, Input_file* input_file, off_t offset, const elfcpp::Ehdr& ehdr) { int et = ehdr.get_e_type(); if (et == elfcpp::ET_REL) { Sized_relobj* obj = new Sized_relobj(name, input_file, offset, ehdr); obj->setup(ehdr); return obj; } else if (et == elfcpp::ET_DYN) { Sized_dynobj* obj = new Sized_dynobj(name, input_file, offset, ehdr); obj->setup(ehdr); return obj; } else { gold_error(_("%s: unsupported ELF file type %d"), name.c_str(), et); return NULL; } } } // End anonymous namespace. namespace gold { // Read an ELF file and return the appropriate instance of Object. Object* make_elf_object(const std::string& name, Input_file* input_file, off_t offset, const unsigned char* p, section_offset_type bytes) { if (bytes < elfcpp::EI_NIDENT) { gold_error(_("%s: ELF file too short"), name.c_str()); return NULL; } int v = p[elfcpp::EI_VERSION]; if (v != elfcpp::EV_CURRENT) { if (v == elfcpp::EV_NONE) gold_error(_("%s: invalid ELF version 0"), name.c_str()); else gold_error(_("%s: unsupported ELF version %d"), name.c_str(), v); return NULL; } int c = p[elfcpp::EI_CLASS]; if (c == elfcpp::ELFCLASSNONE) { gold_error(_("%s: invalid ELF class 0"), name.c_str()); return NULL; } else if (c != elfcpp::ELFCLASS32 && c != elfcpp::ELFCLASS64) { gold_error(_("%s: unsupported ELF class %d"), name.c_str(), c); return NULL; } int d = p[elfcpp::EI_DATA]; if (d == elfcpp::ELFDATANONE) { gold_error(_("%s: invalid ELF data encoding"), name.c_str()); return NULL; } else if (d != elfcpp::ELFDATA2LSB && d != elfcpp::ELFDATA2MSB) { gold_error(_("%s: unsupported ELF data encoding %d"), name.c_str(), d); return NULL; } bool big_endian = d == elfcpp::ELFDATA2MSB; if (c == elfcpp::ELFCLASS32) { if (bytes < elfcpp::Elf_sizes<32>::ehdr_size) { gold_error(_("%s: ELF file too short"), name.c_str()); return NULL; } if (big_endian) { #ifdef HAVE_TARGET_32_BIG elfcpp::Ehdr<32, true> ehdr(p); return make_elf_sized_object<32, true>(name, input_file, offset, ehdr); #else gold_error(_("%s: not configured to support " "32-bit big-endian object"), name.c_str()); return NULL; #endif } else { #ifdef HAVE_TARGET_32_LITTLE elfcpp::Ehdr<32, false> ehdr(p); return make_elf_sized_object<32, false>(name, input_file, offset, ehdr); #else gold_error(_("%s: not configured to support " "32-bit little-endian object"), name.c_str()); return NULL; #endif } } else { if (bytes < elfcpp::Elf_sizes<64>::ehdr_size) { gold_error(_("%s: ELF file too short"), name.c_str()); return NULL; } if (big_endian) { #ifdef HAVE_TARGET_64_BIG elfcpp::Ehdr<64, true> ehdr(p); return make_elf_sized_object<64, true>(name, input_file, offset, ehdr); #else gold_error(_("%s: not configured to support " "64-bit big-endian object"), name.c_str()); return NULL; #endif } else { #ifdef HAVE_TARGET_64_LITTLE elfcpp::Ehdr<64, false> ehdr(p); return make_elf_sized_object<64, false>(name, input_file, offset, ehdr); #else gold_error(_("%s: not configured to support " "64-bit little-endian object"), name.c_str()); return NULL; #endif } } } // Instantiate the templates we need. #ifdef HAVE_TARGET_32_LITTLE template void Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*, Read_symbols_data*); #endif #ifdef HAVE_TARGET_32_BIG template void Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*, Read_symbols_data*); #endif #ifdef HAVE_TARGET_64_LITTLE template void Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*, Read_symbols_data*); #endif #ifdef HAVE_TARGET_64_BIG template void Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*, Read_symbols_data*); #endif #ifdef HAVE_TARGET_32_LITTLE template class Sized_relobj<32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Sized_relobj<32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Sized_relobj<64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Sized_relobj<64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template struct Relocate_info<32, false>; #endif #ifdef HAVE_TARGET_32_BIG template struct Relocate_info<32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template struct Relocate_info<64, false>; #endif #ifdef HAVE_TARGET_64_BIG template struct Relocate_info<64, true>; #endif } // End namespace gold.