X-Git-Url: https://oss.titaniummirror.com/gitweb?p=msp430-binutils.git;a=blobdiff_plain;f=gold%2Fobject.cc;fp=gold%2Fobject.cc;h=e9826b08a206a60ea335435bf3724b1e06f88e7a;hp=0000000000000000000000000000000000000000;hb=d5da4f291af551c0b8b79e1d4a9b173d60e5c10e;hpb=7b5ea4fcdf2819e070665ab5610f8b48e3867c10 diff --git a/gold/object.cc b/gold/object.cc new file mode 100644 index 0000000..e9826b0 --- /dev/null +++ b/gold/object.cc @@ -0,0 +1,2460 @@ +// 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. + +// 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); + if (*plen == 0) + { + static const unsigned char empty[1] = { '\0' }; + return empty; + } + 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); + if (len == 0) + { + const char* warning = name + warn_prefix_len; + contents = reinterpret_cast(warning); + len = strlen(warning); + } + std::string warning(reinterpret_cast(contents), len); + symtab->add_warning(name + warn_prefix_len, this, warning); + return true; + } + return false; +} + +// If NAME is the name of the special section which indicates that +// this object was compiled with -fstack-split, mark it accordingly. + +bool +Object::handle_split_stack_section(const char* name) +{ + if (strcmp(name, ".note.GNU-split-stack") == 0) + { + this->uses_split_stack_ = true; + return true; + } + if (strcmp(name, ".note.GNU-no-split-stack") == 0) + { + this->has_no_split_stack_ = true; + 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_(), + has_eh_frame_(false), + discarded_eh_frame_shndx_(-1U) +{ +} + +template +Sized_relobj::~Sized_relobj() +{ +} + +// Set up an object file based on the file header. This sets up the +// section information. + +template +void +Sized_relobj::do_setup() +{ + 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; + bool is_comdat; + Kept_section* kept_section = NULL; + + if ((flags & elfcpp::GRP_COMDAT) == 0) + { + include_group = true; + is_comdat = false; + } + else + { + include_group = layout->find_or_add_kept_section(signature, + this, index, true, + true, &kept_section); + is_comdat = true; + } + + 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 shndx = + this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i)); + + if (relocate_group) + shndxes.push_back(shndx); + + if (shndx >= this->shnum()) + { + this->error(_("section %u in section group %u out of range"), + shndx, 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 (shndx < index) + this->error(_("invalid section group %u refers to earlier section %u"), + index, shndx); + + // Get the name of the member section. + typename This::Shdr member_shdr(shdrs + shndx * 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) + { + if (is_comdat) + kept_section->add_comdat_section(mname, shndx, + member_shdr.get_sh_size()); + } + else + { + (*omit)[shndx] = true; + + if (is_comdat) + { + Relobj* kept_object = kept_section->object(); + if (kept_section->is_comdat()) + { + // Find the corresponding kept section, and store + // that info in the discarded section table. + unsigned int kept_shndx; + uint64_t kept_size; + if (kept_section->find_comdat_section(mname, &kept_shndx, + &kept_size)) + { + // We don't keep a mapping for this section if + // it has a different size. The mapping is only + // used for relocation processing, and we don't + // want to treat the sections as similar if the + // sizes are different. Checking the section + // size is the approach used by the GNU linker. + if (kept_size == member_shdr.get_sh_size()) + this->set_kept_comdat_section(shndx, kept_object, + kept_shndx); + } + } + else + { + // The existing section is a linkonce section. Add + // a mapping if there is exactly one section in the + // group (which is true when COUNT == 2) and if it + // is the same size. + if (count == 2 + && (kept_section->linkonce_size() + == member_shdr.get_sh_size())) + this->set_kept_comdat_section(shndx, kept_object, + kept_section->shndx()); + } + } + } + } + + 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& shdr) +{ + typename elfcpp::Elf_types::Elf_WXword sh_size = shdr.get_sh_size(); + // 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); + Kept_section* kept1; + Kept_section* kept2; + bool include1 = layout->find_or_add_kept_section(sig1, this, index, false, + false, &kept1); + bool include2 = layout->find_or_add_kept_section(sig2, this, index, false, + true, &kept2); + + if (!include2) + { + // We are not including this section because we already saw the + // name of the section as a signature. This normally implies + // that the kept section is another linkonce section. If it is + // the same size, record it as the section which corresponds to + // this one. + if (kept2->object() != NULL + && !kept2->is_comdat() + && kept2->linkonce_size() == sh_size) + this->set_kept_comdat_section(index, kept2->object(), kept2->shndx()); + } + 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_shndx; + uint64_t kept_size; + if (kept1->object() != NULL + && kept1->is_comdat() + && kept1->find_single_comdat_section(&kept_shndx, &kept_size) + && kept_size == sh_size) + this->set_kept_comdat_section(index, kept1->object(), kept_shndx); + } + else + { + kept1->set_linkonce_size(sh_size); + kept2->set_linkonce_size(sh_size); + } + + 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) and identical code folding +// (--icf), 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 for +// --gc-sections 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 or is_icf_ready is false. It is then +// set to true after the garbage collection worklist or identical code +// folding is processed and the relevant sections to be kept 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()) + || (parameters->options().icf_enabled() + && !symtab->icf()->is_icf_ready())); + + bool is_gc_pass_two = ((parameters->options().gc_sections() + && symtab->gc()->is_worklist_ready()) + || (parameters->options().icf_enabled() + && symtab->icf()->is_icf_ready())); + + bool is_gc_or_icf = (parameters->options().gc_sections() + || parameters->options().icf_enabled()); + + // Both is_gc_pass_one and is_gc_pass_two should not be true. + gold_assert(!(is_gc_pass_one && is_gc_pass_two)); + + 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 (is_gc_or_icf) + { + 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 = (is_gc_or_icf) + ? 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; + } + + // The .note.GNU-split-stack section is also special. It + // indicates that the object was compiled with + // -fsplit-stack. + if (this->handle_split_stack_section(name)) + { + if (!parameters->options().relocatable() + && !parameters->options().shared()) + 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 && parameters->options().gc_sections()) + { + 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 && parameters->options().gc_sections()) + { + // 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) + && symtab->gc()->is_section_garbage(this, i)) + { + 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; + } + } + + if (is_gc_pass_two && parameters->options().icf_enabled()) + { + if (out_sections[i] == NULL) + { + gold_assert(out_section_offsets[i] == invalid_address); + continue; + } + if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0) + && symtab->icf()->is_section_folded(this, i)) + { + if (parameters->options().print_icf_sections()) + { + Section_id folded = + symtab->icf()->get_folded_section(this, i); + Relobj* folded_obj = + reinterpret_cast(folded.first); + gold_info(_("%s: ICF folding section '%s' in file '%s'" + "into '%s' in file '%s'"), + program_name, this->section_name(i).c_str(), + this->name().c_str(), + folded_obj->section_name(folded.second).c_str(), + folded_obj->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 and Identical Code Folding is not + // turned on for relocatable code. + if (emit_relocs) + this->size_relocatable_relocs(); + + gold_assert(!(is_gc_or_icf) || 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) + { + // An object can contain at most one section holding exception + // frame information. + gold_assert(this->discarded_eh_frame_shndx_ == -1U); + this->discarded_eh_frame_shndx_ = i; + 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; + this->set_symbols_data(NULL); + } + 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; + bool discard_locals = parameters->options().discard_locals(); + 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) + || (shndx == this->discarded_eh_frame_shndx_)) + { + 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; + } + + // If --discard-locals option is used, discard all temporary local + // symbols. These symbols start with system-specific local label + // prefixes, typically .L for ELF system. We want to be compatible + // with GNU ld so here we essentially use the same check in + // bfd_is_local_label(). The code is different because we already + // know that: + // + // - the symbol is local and thus cannot have global or weak binding. + // - the symbol is not a section symbol. + // - the symbol has a name. + // + // We do not discard a symbol if it needs a dynamic symbol entry. + const char* name = pnames + sym.get_st_name(); + if (discard_locals + && sym.get_st_type() != elfcpp::STT_FILE + && !lv.needs_output_dynsym_entry() + && parameters->target().is_local_label_name(name)) + { + lv.set_no_output_symtab_entry(); + continue; + } + + // Discard the local symbol if -retain_symbols_file is specified + // and the local symbol is not in that file. + if (!parameters->options().should_retain_symbol(name)) + { + lv.set_no_output_symtab_entry(); + continue; + } + + // Add the symbol to the symbol table string pool. + 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, + Symbol_table* symtab) +{ + gold_assert(off == static_cast(align_address(off, size >> 3))); + + const unsigned int loccount = this->local_symbol_count_; + this->local_symbol_offset_ = off; + + const bool relocatable = parameters->options().relocatable(); + 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 || Symbol::is_common_shndx(shndx)) + 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]; + Address secoffset = out_offsets[shndx]; + if (symtab->is_section_folded(this, shndx)) + { + gold_assert (os == NULL && secoffset == invalid_address); + // Get the os of the section it is folded onto. + Section_id folded = symtab->icf()->get_folded_section(this, + shndx); + gold_assert(folded.first != NULL); + Sized_relobj* folded_obj = reinterpret_cast + *>(folded.first); + os = folded_obj->output_section(folded.second); + gold_assert(os != NULL); + secoffset = folded_obj->get_output_section_offset(folded.second); + gold_assert(secoffset != invalid_address); + } + + 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 (secoffset == invalid_address) + { + uint64_t start; + + // This is a SHF_MERGE section or one which otherwise + // requires special handling. + if (shndx == this->discarded_eh_frame_shndx_) + { + // This local symbol belongs to a discarded .eh_frame + // section. Just treat it like the case in which + // os == NULL above. + gold_assert(this->has_eh_frame_); + continue; + } + else if (!lv.is_section_symbol()) + { + // This is not a section symbol. We can determine + // the final value now. + lv.set_output_value(os->output_address(this, shndx, + lv.input_value())); + } + else if (!os->find_starting_output_address(this, shndx, &start)) + { + // This is a section symbol, but apparently not one + // in a merged section. Just use the start of the + // output section. This happens with relocatable + // links when the input object has section symbols + // for arbitrary non-merge sections. + lv.set_output_value(os->address()); + } + else + { + // We have to consider the addend to determine the + // value to use in a relocation. START is the start + // of this input section. + 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() + + secoffset + + lv.input_value()); + else + lv.set_output_value((relocatable ? 0 : os->address()) + + secoffset + + 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_; +} + +// If Symbols_data is not NULL get the section flags from here otherwise +// get it from the file. + +template +uint64_t +Sized_relobj::do_section_flags(unsigned int shndx) +{ + Symbols_data* sd = this->get_symbols_data(); + if (sd != NULL) + { + const unsigned char* pshdrs = sd->section_headers_data + + This::shdr_size * shndx; + typename This::Shdr shdr(pshdrs); + return shdr.get_sh_flags(); + } + // If sd is NULL, read the section header from the file. + return this->elf_file_.section_flags(shndx); +} + +// Get the section's ent size from Symbols_data. Called by get_section_contents +// in icf.cc + +template +uint64_t +Sized_relobj::do_section_entsize(unsigned int shndx) +{ + Symbols_data* sd = this->get_symbols_data(); + gold_assert (sd != NULL); + + const unsigned char* pshdrs = sd->section_headers_data + + This::shdr_size * shndx; + typename This::Shdr shdr(pshdrs); + return shdr.get_sh_entsize(); +} + + +// 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 +{ + Relobj* kept_object; + unsigned int kept_shndx; + if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx)) + { + Sized_relobj* kept_relobj = + static_cast*>(kept_object); + Output_section* os = kept_relobj->output_section(kept_shndx); + Address offset = kept_relobj->get_output_section_offset(kept_shndx); + if (os != NULL && offset != invalid_address) + { + *found = true; + 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) +{ + // 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); + } + + // 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; +} + +// 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, + bool* punconfigured) +{ + Target* target = select_target(ehdr.get_e_machine(), size, big_endian, + ehdr.get_e_ident()[elfcpp::EI_OSABI], + ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]); + if (target == NULL) + gold_fatal(_("%s: unsupported ELF machine number %d"), + name.c_str(), ehdr.get_e_machine()); + + if (!parameters->target_valid()) + set_parameters_target(target); + else if (target != ¶meters->target()) + { + if (punconfigured != NULL) + *punconfigured = true; + else + gold_error(_("%s: incompatible target"), name.c_str()); + return NULL; + } + + return target->make_elf_object(name, input_file, offset, + ehdr); +} + +} // End anonymous namespace. + +namespace gold +{ + +// Return whether INPUT_FILE is an ELF object. + +bool +is_elf_object(Input_file* input_file, off_t offset, + const unsigned char** start, int *read_size) +{ + off_t filesize = input_file->file().filesize(); + int want = elfcpp::Elf_recognizer::max_header_size; + if (filesize - offset < want) + want = filesize - offset; + + const unsigned char* p = input_file->file().get_view(offset, 0, want, + true, false); + *start = p; + *read_size = want; + + return elfcpp::Elf_recognizer::is_elf_file(p, want); +} + +// 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, + bool* punconfigured) +{ + if (punconfigured != NULL) + *punconfigured = false; + + std::string error; + bool big_endian; + int size; + if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size, + &big_endian, &error)) + { + gold_error(_("%s: %s"), name.c_str(), error.c_str()); + return NULL; + } + + if (size == 32) + { + 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, punconfigured); +#else + if (punconfigured != NULL) + *punconfigured = true; + 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, punconfigured); +#else + if (punconfigured != NULL) + *punconfigured = true; + else + gold_error(_("%s: not configured to support " + "32-bit little-endian object"), + name.c_str()); + return NULL; +#endif + } + } + else if (size == 64) + { + 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, punconfigured); +#else + if (punconfigured != NULL) + *punconfigured = true; + 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, punconfigured); +#else + if (punconfigured != NULL) + *punconfigured = true; + else + gold_error(_("%s: not configured to support " + "64-bit little-endian object"), + name.c_str()); + return NULL; +#endif + } + } + else + gold_unreachable(); +} + +// 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.