// output.cc -- manage the output file for gold // Copyright 2006, 2007 Free Software Foundation, Inc. // Written by Ian Lance Taylor <iant@google.com>. // 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 <cstdlib> #include <cerrno> #include <fcntl.h> #include <unistd.h> #include <sys/mman.h> #include <sys/stat.h> #include <algorithm> #include "libiberty.h" // for unlink_if_ordinary() #include "parameters.h" #include "object.h" #include "symtab.h" #include "reloc.h" #include "merge.h" #include "output.h" namespace gold { // Output_data variables. bool Output_data::sizes_are_fixed; // Output_data methods. Output_data::~Output_data() { } // Set the address and offset. void Output_data::set_address(uint64_t addr, off_t off) { this->address_ = addr; this->offset_ = off; // Let the child class know. this->do_set_address(addr, off); } // Return the default alignment for a size--32 or 64. uint64_t Output_data::default_alignment(int size) { if (size == 32) return 4; else if (size == 64) return 8; else gold_unreachable(); } // Output_section_header methods. This currently assumes that the // segment and section lists are complete at construction time. Output_section_headers::Output_section_headers( const Layout* layout, const Layout::Segment_list* segment_list, const Layout::Section_list* unattached_section_list, const Stringpool* secnamepool) : layout_(layout), segment_list_(segment_list), unattached_section_list_(unattached_section_list), secnamepool_(secnamepool) { // Count all the sections. Start with 1 for the null section. off_t count = 1; for (Layout::Segment_list::const_iterator p = segment_list->begin(); p != segment_list->end(); ++p) if ((*p)->type() == elfcpp::PT_LOAD) count += (*p)->output_section_count(); count += unattached_section_list->size(); const int size = parameters->get_size(); int shdr_size; if (size == 32) shdr_size = elfcpp::Elf_sizes<32>::shdr_size; else if (size == 64) shdr_size = elfcpp::Elf_sizes<64>::shdr_size; else gold_unreachable(); this->set_data_size(count * shdr_size); } // Write out the section headers. void Output_section_headers::do_write(Output_file* of) { if (parameters->get_size() == 32) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_32_BIG this->do_sized_write<32, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_32_LITTLE this->do_sized_write<32, false>(of); #else gold_unreachable(); #endif } } else if (parameters->get_size() == 64) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_64_BIG this->do_sized_write<64, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_64_LITTLE this->do_sized_write<64, false>(of); #else gold_unreachable(); #endif } } else gold_unreachable(); } template<int size, bool big_endian> void Output_section_headers::do_sized_write(Output_file* of) { off_t all_shdrs_size = this->data_size(); unsigned char* view = of->get_output_view(this->offset(), all_shdrs_size); const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size; unsigned char* v = view; { typename elfcpp::Shdr_write<size, big_endian> oshdr(v); oshdr.put_sh_name(0); oshdr.put_sh_type(elfcpp::SHT_NULL); oshdr.put_sh_flags(0); oshdr.put_sh_addr(0); oshdr.put_sh_offset(0); oshdr.put_sh_size(0); oshdr.put_sh_link(0); oshdr.put_sh_info(0); oshdr.put_sh_addralign(0); oshdr.put_sh_entsize(0); } v += shdr_size; unsigned shndx = 1; for (Layout::Segment_list::const_iterator p = this->segment_list_->begin(); p != this->segment_list_->end(); ++p) v = (*p)->write_section_headers SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( this->layout_, this->secnamepool_, v, &shndx SELECT_SIZE_ENDIAN(size, big_endian)); for (Layout::Section_list::const_iterator p = this->unattached_section_list_->begin(); p != this->unattached_section_list_->end(); ++p) { gold_assert(shndx == (*p)->out_shndx()); elfcpp::Shdr_write<size, big_endian> oshdr(v); (*p)->write_header(this->layout_, this->secnamepool_, &oshdr); v += shdr_size; ++shndx; } of->write_output_view(this->offset(), all_shdrs_size, view); } // Output_segment_header methods. Output_segment_headers::Output_segment_headers( const Layout::Segment_list& segment_list) : segment_list_(segment_list) { const int size = parameters->get_size(); int phdr_size; if (size == 32) phdr_size = elfcpp::Elf_sizes<32>::phdr_size; else if (size == 64) phdr_size = elfcpp::Elf_sizes<64>::phdr_size; else gold_unreachable(); this->set_data_size(segment_list.size() * phdr_size); } void Output_segment_headers::do_write(Output_file* of) { if (parameters->get_size() == 32) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_32_BIG this->do_sized_write<32, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_32_LITTLE this->do_sized_write<32, false>(of); #else gold_unreachable(); #endif } } else if (parameters->get_size() == 64) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_64_BIG this->do_sized_write<64, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_64_LITTLE this->do_sized_write<64, false>(of); #else gold_unreachable(); #endif } } else gold_unreachable(); } template<int size, bool big_endian> void Output_segment_headers::do_sized_write(Output_file* of) { const int phdr_size = elfcpp::Elf_sizes<size>::phdr_size; off_t all_phdrs_size = this->segment_list_.size() * phdr_size; unsigned char* view = of->get_output_view(this->offset(), all_phdrs_size); unsigned char* v = view; for (Layout::Segment_list::const_iterator p = this->segment_list_.begin(); p != this->segment_list_.end(); ++p) { elfcpp::Phdr_write<size, big_endian> ophdr(v); (*p)->write_header(&ophdr); v += phdr_size; } of->write_output_view(this->offset(), all_phdrs_size, view); } // Output_file_header methods. Output_file_header::Output_file_header(const Target* target, const Symbol_table* symtab, const Output_segment_headers* osh) : target_(target), symtab_(symtab), segment_header_(osh), section_header_(NULL), shstrtab_(NULL) { const int size = parameters->get_size(); int ehdr_size; if (size == 32) ehdr_size = elfcpp::Elf_sizes<32>::ehdr_size; else if (size == 64) ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size; else gold_unreachable(); this->set_data_size(ehdr_size); } // Set the section table information for a file header. void Output_file_header::set_section_info(const Output_section_headers* shdrs, const Output_section* shstrtab) { this->section_header_ = shdrs; this->shstrtab_ = shstrtab; } // Write out the file header. void Output_file_header::do_write(Output_file* of) { if (parameters->get_size() == 32) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_32_BIG this->do_sized_write<32, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_32_LITTLE this->do_sized_write<32, false>(of); #else gold_unreachable(); #endif } } else if (parameters->get_size() == 64) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_64_BIG this->do_sized_write<64, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_64_LITTLE this->do_sized_write<64, false>(of); #else gold_unreachable(); #endif } } else gold_unreachable(); } // Write out the file header with appropriate size and endianess. template<int size, bool big_endian> void Output_file_header::do_sized_write(Output_file* of) { gold_assert(this->offset() == 0); int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size; unsigned char* view = of->get_output_view(0, ehdr_size); elfcpp::Ehdr_write<size, big_endian> oehdr(view); unsigned char e_ident[elfcpp::EI_NIDENT]; memset(e_ident, 0, elfcpp::EI_NIDENT); e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0; e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1; e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2; e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3; if (size == 32) e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32; else if (size == 64) e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64; else gold_unreachable(); e_ident[elfcpp::EI_DATA] = (big_endian ? elfcpp::ELFDATA2MSB : elfcpp::ELFDATA2LSB); e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT; // FIXME: Some targets may need to set EI_OSABI and EI_ABIVERSION. oehdr.put_e_ident(e_ident); elfcpp::ET e_type; // FIXME: ET_DYN. if (parameters->output_is_object()) e_type = elfcpp::ET_REL; else e_type = elfcpp::ET_EXEC; oehdr.put_e_type(e_type); oehdr.put_e_machine(this->target_->machine_code()); oehdr.put_e_version(elfcpp::EV_CURRENT); // FIXME: Need to support -e, and target specific entry symbol. Symbol* sym = this->symtab_->lookup("_start"); typename Sized_symbol<size>::Value_type v; if (sym == NULL) v = 0; else { Sized_symbol<size>* ssym; ssym = this->symtab_->get_sized_symbol SELECT_SIZE_NAME(size) ( sym SELECT_SIZE(size)); v = ssym->value(); } oehdr.put_e_entry(v); oehdr.put_e_phoff(this->segment_header_->offset()); oehdr.put_e_shoff(this->section_header_->offset()); // FIXME: The target needs to set the flags. oehdr.put_e_flags(0); oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size); oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size); oehdr.put_e_phnum(this->segment_header_->data_size() / elfcpp::Elf_sizes<size>::phdr_size); oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size); oehdr.put_e_shnum(this->section_header_->data_size() / elfcpp::Elf_sizes<size>::shdr_size); oehdr.put_e_shstrndx(this->shstrtab_->out_shndx()); of->write_output_view(0, ehdr_size, view); } // Output_data_const methods. void Output_data_const::do_write(Output_file* of) { of->write(this->offset(), this->data_.data(), this->data_.size()); } // Output_data_const_buffer methods. void Output_data_const_buffer::do_write(Output_file* of) { of->write(this->offset(), this->p_, this->data_size()); } // Output_section_data methods. // Record the output section, and set the entry size and such. void Output_section_data::set_output_section(Output_section* os) { gold_assert(this->output_section_ == NULL); this->output_section_ = os; this->do_adjust_output_section(os); } // Return the section index of the output section. unsigned int Output_section_data::do_out_shndx() const { gold_assert(this->output_section_ != NULL); return this->output_section_->out_shndx(); } // Output_data_strtab methods. // Set the address. We don't actually care about the address, but we // do set our final size. void Output_data_strtab::do_set_address(uint64_t, off_t) { this->strtab_->set_string_offsets(); this->set_data_size(this->strtab_->get_strtab_size()); } // Write out a string table. void Output_data_strtab::do_write(Output_file* of) { this->strtab_->write(of, this->offset()); } // Output_reloc methods. // Get the symbol index of a relocation. template<bool dynamic, int size, bool big_endian> unsigned int Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index() const { unsigned int index; switch (this->local_sym_index_) { case INVALID_CODE: gold_unreachable(); case GSYM_CODE: if (this->u1_.gsym == NULL) index = 0; else if (dynamic) index = this->u1_.gsym->dynsym_index(); else index = this->u1_.gsym->symtab_index(); break; case SECTION_CODE: if (dynamic) index = this->u1_.os->dynsym_index(); else index = this->u1_.os->symtab_index(); break; default: if (dynamic) { // FIXME: It seems that some targets may need to generate // dynamic relocations against local symbols for some // reasons. This will have to be addressed at some point. gold_unreachable(); } else index = this->u1_.relobj->symtab_index(this->local_sym_index_); break; } gold_assert(index != -1U); return index; } // Write out the offset and info fields of a Rel or Rela relocation // entry. template<bool dynamic, int size, bool big_endian> template<typename Write_rel> void Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write_rel( Write_rel* wr) const { Address address = this->address_; if (this->shndx_ != INVALID_CODE) { off_t off; Output_section* os = this->u2_.relobj->output_section(this->shndx_, &off); gold_assert(os != NULL); address += os->address() + off; } else if (this->u2_.od != NULL) address += this->u2_.od->address(); wr->put_r_offset(address); wr->put_r_info(elfcpp::elf_r_info<size>(this->get_symbol_index(), this->type_)); } // Write out a Rel relocation. template<bool dynamic, int size, bool big_endian> void Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write( unsigned char* pov) const { elfcpp::Rel_write<size, big_endian> orel(pov); this->write_rel(&orel); } // Write out a Rela relocation. template<bool dynamic, int size, bool big_endian> void Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>::write( unsigned char* pov) const { elfcpp::Rela_write<size, big_endian> orel(pov); this->rel_.write_rel(&orel); orel.put_r_addend(this->addend_); } // Output_data_reloc_base methods. // Adjust the output section. template<int sh_type, bool dynamic, int size, bool big_endian> void Output_data_reloc_base<sh_type, dynamic, size, big_endian> ::do_adjust_output_section(Output_section* os) { if (sh_type == elfcpp::SHT_REL) os->set_entsize(elfcpp::Elf_sizes<size>::rel_size); else if (sh_type == elfcpp::SHT_RELA) os->set_entsize(elfcpp::Elf_sizes<size>::rela_size); else gold_unreachable(); if (dynamic) os->set_should_link_to_dynsym(); else os->set_should_link_to_symtab(); } // Write out relocation data. template<int sh_type, bool dynamic, int size, bool big_endian> void Output_data_reloc_base<sh_type, dynamic, size, big_endian>::do_write( Output_file* of) { const off_t off = this->offset(); const off_t oview_size = this->data_size(); unsigned char* const oview = of->get_output_view(off, oview_size); unsigned char* pov = oview; for (typename Relocs::const_iterator p = this->relocs_.begin(); p != this->relocs_.end(); ++p) { p->write(pov); pov += reloc_size; } gold_assert(pov - oview == oview_size); of->write_output_view(off, oview_size, oview); // We no longer need the relocation entries. this->relocs_.clear(); } // Output_data_got::Got_entry methods. // Write out the entry. template<int size, bool big_endian> void Output_data_got<size, big_endian>::Got_entry::write(unsigned char* pov) const { Valtype val = 0; switch (this->local_sym_index_) { case GSYM_CODE: { Symbol* gsym = this->u_.gsym; // If the symbol is resolved locally, we need to write out its // value. Otherwise we just write zero. The target code is // responsible for creating a relocation entry to fill in the // value at runtime. if (gsym->final_value_is_known()) { Sized_symbol<size>* sgsym; // This cast is a bit ugly. We don't want to put a // virtual method in Symbol, because we want Symbol to be // as small as possible. sgsym = static_cast<Sized_symbol<size>*>(gsym); val = sgsym->value(); } } break; case CONSTANT_CODE: val = this->u_.constant; break; default: val = this->u_.object->local_symbol_value(this->local_sym_index_); break; } elfcpp::Swap<size, big_endian>::writeval(pov, val); } // Output_data_got methods. // Add an entry for a global symbol to the GOT. This returns true if // this is a new GOT entry, false if the symbol already had a GOT // entry. template<int size, bool big_endian> bool Output_data_got<size, big_endian>::add_global(Symbol* gsym) { if (gsym->has_got_offset()) return false; this->entries_.push_back(Got_entry(gsym)); this->set_got_size(); gsym->set_got_offset(this->last_got_offset()); return true; } // Add an entry for a local symbol to the GOT. This returns true if // this is a new GOT entry, false if the symbol already has a GOT // entry. template<int size, bool big_endian> bool Output_data_got<size, big_endian>::add_local( Sized_relobj<size, big_endian>* object, unsigned int symndx) { if (object->local_has_got_offset(symndx)) return false; this->entries_.push_back(Got_entry(object, symndx)); this->set_got_size(); object->set_local_got_offset(symndx, this->last_got_offset()); return true; } // Write out the GOT. template<int size, bool big_endian> void Output_data_got<size, big_endian>::do_write(Output_file* of) { const int add = size / 8; const off_t off = this->offset(); const off_t oview_size = this->data_size(); unsigned char* const oview = of->get_output_view(off, oview_size); unsigned char* pov = oview; for (typename Got_entries::const_iterator p = this->entries_.begin(); p != this->entries_.end(); ++p) { p->write(pov); pov += add; } gold_assert(pov - oview == oview_size); of->write_output_view(off, oview_size, oview); // We no longer need the GOT entries. this->entries_.clear(); } // Output_data_dynamic::Dynamic_entry methods. // Write out the entry. template<int size, bool big_endian> void Output_data_dynamic::Dynamic_entry::write( unsigned char* pov, const Stringpool* pool ACCEPT_SIZE_ENDIAN) const { typename elfcpp::Elf_types<size>::Elf_WXword val; switch (this->classification_) { case DYNAMIC_NUMBER: val = this->u_.val; break; case DYNAMIC_SECTION_ADDRESS: val = this->u_.od->address(); break; case DYNAMIC_SECTION_SIZE: val = this->u_.od->data_size(); break; case DYNAMIC_SYMBOL: { const Sized_symbol<size>* s = static_cast<const Sized_symbol<size>*>(this->u_.sym); val = s->value(); } break; case DYNAMIC_STRING: val = pool->get_offset(this->u_.str); break; default: gold_unreachable(); } elfcpp::Dyn_write<size, big_endian> dw(pov); dw.put_d_tag(this->tag_); dw.put_d_val(val); } // Output_data_dynamic methods. // Adjust the output section to set the entry size. void Output_data_dynamic::do_adjust_output_section(Output_section* os) { if (parameters->get_size() == 32) os->set_entsize(elfcpp::Elf_sizes<32>::dyn_size); else if (parameters->get_size() == 64) os->set_entsize(elfcpp::Elf_sizes<64>::dyn_size); else gold_unreachable(); } // Set the final data size. void Output_data_dynamic::do_set_address(uint64_t, off_t) { // Add the terminating entry. this->add_constant(elfcpp::DT_NULL, 0); int dyn_size; if (parameters->get_size() == 32) dyn_size = elfcpp::Elf_sizes<32>::dyn_size; else if (parameters->get_size() == 64) dyn_size = elfcpp::Elf_sizes<64>::dyn_size; else gold_unreachable(); this->set_data_size(this->entries_.size() * dyn_size); } // Write out the dynamic entries. void Output_data_dynamic::do_write(Output_file* of) { if (parameters->get_size() == 32) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_32_BIG this->sized_write<32, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_32_LITTLE this->sized_write<32, false>(of); #else gold_unreachable(); #endif } } else if (parameters->get_size() == 64) { if (parameters->is_big_endian()) { #ifdef HAVE_TARGET_64_BIG this->sized_write<64, true>(of); #else gold_unreachable(); #endif } else { #ifdef HAVE_TARGET_64_LITTLE this->sized_write<64, false>(of); #else gold_unreachable(); #endif } } else gold_unreachable(); } template<int size, bool big_endian> void Output_data_dynamic::sized_write(Output_file* of) { const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size; const off_t offset = this->offset(); const off_t oview_size = this->data_size(); unsigned char* const oview = of->get_output_view(offset, oview_size); unsigned char* pov = oview; for (typename Dynamic_entries::const_iterator p = this->entries_.begin(); p != this->entries_.end(); ++p) { p->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)( pov, this->pool_ SELECT_SIZE_ENDIAN(size, big_endian)); pov += dyn_size; } gold_assert(pov - oview == oview_size); of->write_output_view(offset, oview_size, oview); // We no longer need the dynamic entries. this->entries_.clear(); } // Output_section::Input_section methods. // Return the data size. For an input section we store the size here. // For an Output_section_data, we have to ask it for the size. off_t Output_section::Input_section::data_size() const { if (this->is_input_section()) return this->u1_.data_size; else return this->u2_.posd->data_size(); } // Set the address and file offset. void Output_section::Input_section::set_address(uint64_t addr, off_t off, off_t secoff) { if (this->is_input_section()) this->u2_.object->set_section_offset(this->shndx_, off - secoff); else this->u2_.posd->set_address(addr, off); } // Try to turn an input address into an output address. bool Output_section::Input_section::output_address(const Relobj* object, unsigned int shndx, off_t offset, uint64_t output_section_address, uint64_t *poutput) const { if (!this->is_input_section()) return this->u2_.posd->output_address(object, shndx, offset, output_section_address, poutput); else { if (this->shndx_ != shndx || this->u2_.object != object) return false; off_t output_offset; Output_section* os = object->output_section(shndx, &output_offset); gold_assert(os != NULL); *poutput = output_section_address + output_offset + offset; return true; } } // Write out the data. We don't have to do anything for an input // section--they are handled via Object::relocate--but this is where // we write out the data for an Output_section_data. void Output_section::Input_section::write(Output_file* of) { if (!this->is_input_section()) this->u2_.posd->write(of); } // Output_section methods. // Construct an Output_section. NAME will point into a Stringpool. Output_section::Output_section(const char* name, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags) : name_(name), addralign_(0), entsize_(0), link_section_(NULL), link_(0), info_section_(NULL), info_(0), type_(type), flags_(flags), out_shndx_(0), symtab_index_(0), dynsym_index_(0), input_sections_(), first_input_offset_(0), fills_(), needs_symtab_index_(false), needs_dynsym_index_(false), should_link_to_symtab_(false), should_link_to_dynsym_(false) { } Output_section::~Output_section() { } // Set the entry size. void Output_section::set_entsize(uint64_t v) { if (this->entsize_ == 0) this->entsize_ = v; else gold_assert(this->entsize_ == v); } // Add the input section SHNDX, with header SHDR, named SECNAME, in // OBJECT, to the Output_section. Return the offset of the input // section within the output section. We don't always keep track of // input sections for an Output_section. Instead, each Object keeps // track of the Output_section for each of its input sections. template<int size, bool big_endian> off_t Output_section::add_input_section(Relobj* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<size, big_endian>& shdr) { elfcpp::Elf_Xword addralign = shdr.get_sh_addralign(); if ((addralign & (addralign - 1)) != 0) { object->error(_("invalid alignment %lu for section \"%s\""), static_cast<unsigned long>(addralign), secname); addralign = 1; } if (addralign > this->addralign_) this->addralign_ = addralign; // If this is a SHF_MERGE section, we pass all the input sections to // a Output_data_merge. if ((shdr.get_sh_flags() & elfcpp::SHF_MERGE) != 0) { if (this->add_merge_input_section(object, shndx, shdr.get_sh_flags(), shdr.get_sh_entsize(), addralign)) { // Tell the relocation routines that they need to call the // output_address method to determine the final address. return -1; } } off_t offset_in_section = this->data_size(); off_t aligned_offset_in_section = align_address(offset_in_section, addralign); if (aligned_offset_in_section > offset_in_section && (shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0 && object->target()->has_code_fill()) { // We need to add some fill data. Using fill_list_ when // possible is an optimization, since we will often have fill // sections without input sections. off_t fill_len = aligned_offset_in_section - offset_in_section; if (this->input_sections_.empty()) this->fills_.push_back(Fill(offset_in_section, fill_len)); else { // FIXME: When relaxing, the size needs to adjust to // maintain a constant alignment. std::string fill_data(object->target()->code_fill(fill_len)); Output_data_const* odc = new Output_data_const(fill_data, 1); this->input_sections_.push_back(Input_section(odc)); } } this->set_data_size(aligned_offset_in_section + shdr.get_sh_size()); // We need to keep track of this section if we are already keeping // track of sections, or if we are relaxing. FIXME: Add test for // relaxing. if (!this->input_sections_.empty()) this->input_sections_.push_back(Input_section(object, shndx, shdr.get_sh_size(), addralign)); return aligned_offset_in_section; } // Add arbitrary data to an output section. void Output_section::add_output_section_data(Output_section_data* posd) { Input_section inp(posd); this->add_output_section_data(&inp); } // Add arbitrary data to an output section by Input_section. void Output_section::add_output_section_data(Input_section* inp) { if (this->input_sections_.empty()) this->first_input_offset_ = this->data_size(); this->input_sections_.push_back(*inp); uint64_t addralign = inp->addralign(); if (addralign > this->addralign_) this->addralign_ = addralign; inp->set_output_section(this); } // Add a merge section to an output section. void Output_section::add_output_merge_section(Output_section_data* posd, bool is_string, uint64_t entsize) { Input_section inp(posd, is_string, entsize); this->add_output_section_data(&inp); } // Add an input section to a SHF_MERGE section. bool Output_section::add_merge_input_section(Relobj* object, unsigned int shndx, uint64_t flags, uint64_t entsize, uint64_t addralign) { // We only merge constants if the alignment is not more than the // entry size. This could be handled, but it's unusual. if (addralign > entsize) return false; bool is_string = (flags & elfcpp::SHF_STRINGS) != 0; Input_section_list::iterator p; for (p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) if (p->is_merge_section(is_string, entsize)) break; // We handle the actual constant merging in Output_merge_data or // Output_merge_string_data. if (p != this->input_sections_.end()) p->add_input_section(object, shndx); else { Output_section_data* posd; if (!is_string) posd = new Output_merge_data(entsize); else if (entsize == 1) posd = new Output_merge_string<char>(); else if (entsize == 2) posd = new Output_merge_string<uint16_t>(); else if (entsize == 4) posd = new Output_merge_string<uint32_t>(); else return false; this->add_output_merge_section(posd, is_string, entsize); posd->add_input_section(object, shndx); } return true; } // Return the output virtual address of OFFSET relative to the start // of input section SHNDX in object OBJECT. uint64_t Output_section::output_address(const Relobj* object, unsigned int shndx, off_t offset) const { uint64_t addr = this->address() + this->first_input_offset_; for (Input_section_list::const_iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { addr = align_address(addr, p->addralign()); uint64_t output; if (p->output_address(object, shndx, offset, addr, &output)) return output; addr += p->data_size(); } // If we get here, it means that we don't know the mapping for this // input section. This might happen in principle if // add_input_section were called before add_output_section_data. // But it should never actually happen. gold_unreachable(); } // Set the address of an Output_section. This is where we handle // setting the addresses of any Output_section_data objects. void Output_section::do_set_address(uint64_t address, off_t startoff) { if (this->input_sections_.empty()) return; off_t off = startoff + this->first_input_offset_; for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { off = align_address(off, p->addralign()); p->set_address(address + (off - startoff), off, startoff); off += p->data_size(); } this->set_data_size(off - startoff); } // Write the section header to *OSHDR. template<int size, bool big_endian> void Output_section::write_header(const Layout* layout, const Stringpool* secnamepool, elfcpp::Shdr_write<size, big_endian>* oshdr) const { oshdr->put_sh_name(secnamepool->get_offset(this->name_)); oshdr->put_sh_type(this->type_); oshdr->put_sh_flags(this->flags_); oshdr->put_sh_addr(this->address()); oshdr->put_sh_offset(this->offset()); oshdr->put_sh_size(this->data_size()); if (this->link_section_ != NULL) oshdr->put_sh_link(this->link_section_->out_shndx()); else if (this->should_link_to_symtab_) oshdr->put_sh_link(layout->symtab_section()->out_shndx()); else if (this->should_link_to_dynsym_) oshdr->put_sh_link(layout->dynsym_section()->out_shndx()); else oshdr->put_sh_link(this->link_); if (this->info_section_ != NULL) oshdr->put_sh_info(this->info_section_->out_shndx()); else oshdr->put_sh_info(this->info_); oshdr->put_sh_addralign(this->addralign_); oshdr->put_sh_entsize(this->entsize_); } // Write out the data. For input sections the data is written out by // Object::relocate, but we have to handle Output_section_data objects // here. void Output_section::do_write(Output_file* of) { off_t output_section_file_offset = this->offset(); for (Fill_list::iterator p = this->fills_.begin(); p != this->fills_.end(); ++p) { std::string fill_data(of->target()->code_fill(p->length())); of->write(output_section_file_offset + p->section_offset(), fill_data.data(), fill_data.size()); } for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) p->write(of); } // Output segment methods. Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags) : output_data_(), output_bss_(), vaddr_(0), paddr_(0), memsz_(0), align_(0), offset_(0), filesz_(0), type_(type), flags_(flags), is_align_known_(false) { } // Add an Output_section to an Output_segment. void Output_segment::add_output_section(Output_section* os, elfcpp::Elf_Word seg_flags, bool front) { gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0); gold_assert(!this->is_align_known_); // Update the segment flags. this->flags_ |= seg_flags; Output_segment::Output_data_list* pdl; if (os->type() == elfcpp::SHT_NOBITS) pdl = &this->output_bss_; else pdl = &this->output_data_; // So that PT_NOTE segments will work correctly, we need to ensure // that all SHT_NOTE sections are adjacent. This will normally // happen automatically, because all the SHT_NOTE input sections // will wind up in the same output section. However, it is possible // for multiple SHT_NOTE input sections to have different section // flags, and thus be in different output sections, but for the // different section flags to map into the same segment flags and // thus the same output segment. // Note that while there may be many input sections in an output // section, there are normally only a few output sections in an // output segment. This loop is expected to be fast. if (os->type() == elfcpp::SHT_NOTE && !pdl->empty()) { Output_segment::Output_data_list::iterator p = pdl->end(); do { --p; if ((*p)->is_section_type(elfcpp::SHT_NOTE)) { // We don't worry about the FRONT parameter. ++p; pdl->insert(p, os); return; } } while (p != pdl->begin()); } // Similarly, so that PT_TLS segments will work, we need to group // SHF_TLS sections. An SHF_TLS/SHT_NOBITS section is a special // case: we group the SHF_TLS/SHT_NOBITS sections right after the // SHF_TLS/SHT_PROGBITS sections. This lets us set up PT_TLS // correctly. if ((os->flags() & elfcpp::SHF_TLS) != 0 && !this->output_data_.empty()) { pdl = &this->output_data_; bool nobits = os->type() == elfcpp::SHT_NOBITS; bool sawtls = false; Output_segment::Output_data_list::iterator p = pdl->end(); do { --p; bool insert; if ((*p)->is_section_flag_set(elfcpp::SHF_TLS)) { sawtls = true; // Put a NOBITS section after the first TLS section. // But a PROGBITS section after the first TLS/PROGBITS // section. insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS); } else { // If we've gone past the TLS sections, but we've seen a // TLS section, then we need to insert this section now. insert = sawtls; } if (insert) { // We don't worry about the FRONT parameter. ++p; pdl->insert(p, os); return; } } while (p != pdl->begin()); // There are no TLS sections yet; put this one at the requested // location in the section list. } if (front) pdl->push_front(os); else pdl->push_back(os); } // Add an Output_data (which is not an Output_section) to the start of // a segment. void Output_segment::add_initial_output_data(Output_data* od) { gold_assert(!this->is_align_known_); this->output_data_.push_front(od); } // Return the maximum alignment of the Output_data in Output_segment. // Once we compute this, we prohibit new sections from being added. uint64_t Output_segment::addralign() { if (!this->is_align_known_) { uint64_t addralign; addralign = Output_segment::maximum_alignment(&this->output_data_); if (addralign > this->align_) this->align_ = addralign; addralign = Output_segment::maximum_alignment(&this->output_bss_); if (addralign > this->align_) this->align_ = addralign; this->is_align_known_ = true; } return this->align_; } // Return the maximum alignment of a list of Output_data. uint64_t Output_segment::maximum_alignment(const Output_data_list* pdl) { uint64_t ret = 0; for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) { uint64_t addralign = (*p)->addralign(); if (addralign > ret) ret = addralign; } return ret; } // Set the section addresses for an Output_segment. ADDR is the // address and *POFF is the file offset. Set the section indexes // starting with *PSHNDX. Return the address of the immediately // following segment. Update *POFF and *PSHNDX. uint64_t Output_segment::set_section_addresses(uint64_t addr, off_t* poff, unsigned int* pshndx) { gold_assert(this->type_ == elfcpp::PT_LOAD); this->vaddr_ = addr; this->paddr_ = addr; off_t orig_off = *poff; this->offset_ = orig_off; *poff = align_address(*poff, this->addralign()); addr = this->set_section_list_addresses(&this->output_data_, addr, poff, pshndx); this->filesz_ = *poff - orig_off; off_t off = *poff; uint64_t ret = this->set_section_list_addresses(&this->output_bss_, addr, poff, pshndx); this->memsz_ = *poff - orig_off; // Ignore the file offset adjustments made by the BSS Output_data // objects. *poff = off; return ret; } // Set the addresses and file offsets in a list of Output_data // structures. uint64_t Output_segment::set_section_list_addresses(Output_data_list* pdl, uint64_t addr, off_t* poff, unsigned int* pshndx) { off_t startoff = *poff; off_t off = startoff; for (Output_data_list::iterator p = pdl->begin(); p != pdl->end(); ++p) { off = align_address(off, (*p)->addralign()); (*p)->set_address(addr + (off - startoff), off); // Unless this is a PT_TLS segment, we want to ignore the size // of a SHF_TLS/SHT_NOBITS section. Such a section does not // affect the size of a PT_LOAD segment. if (this->type_ == elfcpp::PT_TLS || !(*p)->is_section_flag_set(elfcpp::SHF_TLS) || !(*p)->is_section_type(elfcpp::SHT_NOBITS)) off += (*p)->data_size(); if ((*p)->is_section()) { (*p)->set_out_shndx(*pshndx); ++*pshndx; } } *poff = off; return addr + (off - startoff); } // For a non-PT_LOAD segment, set the offset from the sections, if // any. void Output_segment::set_offset() { gold_assert(this->type_ != elfcpp::PT_LOAD); if (this->output_data_.empty() && this->output_bss_.empty()) { this->vaddr_ = 0; this->paddr_ = 0; this->memsz_ = 0; this->align_ = 0; this->offset_ = 0; this->filesz_ = 0; return; } const Output_data* first; if (this->output_data_.empty()) first = this->output_bss_.front(); else first = this->output_data_.front(); this->vaddr_ = first->address(); this->paddr_ = this->vaddr_; this->offset_ = first->offset(); if (this->output_data_.empty()) this->filesz_ = 0; else { const Output_data* last_data = this->output_data_.back(); this->filesz_ = (last_data->address() + last_data->data_size() - this->vaddr_); } const Output_data* last; if (this->output_bss_.empty()) last = this->output_data_.back(); else last = this->output_bss_.back(); this->memsz_ = (last->address() + last->data_size() - this->vaddr_); } // Return the number of Output_sections in an Output_segment. unsigned int Output_segment::output_section_count() const { return (this->output_section_count_list(&this->output_data_) + this->output_section_count_list(&this->output_bss_)); } // Return the number of Output_sections in an Output_data_list. unsigned int Output_segment::output_section_count_list(const Output_data_list* pdl) const { unsigned int count = 0; for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) { if ((*p)->is_section()) ++count; } return count; } // Write the segment data into *OPHDR. template<int size, bool big_endian> void Output_segment::write_header(elfcpp::Phdr_write<size, big_endian>* ophdr) { ophdr->put_p_type(this->type_); ophdr->put_p_offset(this->offset_); ophdr->put_p_vaddr(this->vaddr_); ophdr->put_p_paddr(this->paddr_); ophdr->put_p_filesz(this->filesz_); ophdr->put_p_memsz(this->memsz_); ophdr->put_p_flags(this->flags_); ophdr->put_p_align(this->addralign()); } // Write the section headers into V. template<int size, bool big_endian> unsigned char* Output_segment::write_section_headers(const Layout* layout, const Stringpool* secnamepool, unsigned char* v, unsigned int *pshndx ACCEPT_SIZE_ENDIAN) const { // Every section that is attached to a segment must be attached to a // PT_LOAD segment, so we only write out section headers for PT_LOAD // segments. if (this->type_ != elfcpp::PT_LOAD) return v; v = this->write_section_headers_list SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( layout, secnamepool, &this->output_data_, v, pshndx SELECT_SIZE_ENDIAN(size, big_endian)); v = this->write_section_headers_list SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( layout, secnamepool, &this->output_bss_, v, pshndx SELECT_SIZE_ENDIAN(size, big_endian)); return v; } template<int size, bool big_endian> unsigned char* Output_segment::write_section_headers_list(const Layout* layout, const Stringpool* secnamepool, const Output_data_list* pdl, unsigned char* v, unsigned int* pshndx ACCEPT_SIZE_ENDIAN) const { const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size; for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) { if ((*p)->is_section()) { const Output_section* ps = static_cast<const Output_section*>(*p); gold_assert(*pshndx == ps->out_shndx()); elfcpp::Shdr_write<size, big_endian> oshdr(v); ps->write_header(layout, secnamepool, &oshdr); v += shdr_size; ++*pshndx; } } return v; } // Output_file methods. Output_file::Output_file(const General_options& options, Target* target) : options_(options), target_(target), name_(options.output_file_name()), o_(-1), file_size_(0), base_(NULL) { } // Open the output file. void Output_file::open(off_t file_size) { this->file_size_ = file_size; // Unlink the file first; otherwise the open() may fail if the file // is busy (e.g. it's an executable that's currently being executed). // // However, the linker may be part of a system where a zero-length // file is created for it to write to, with tight permissions (gcc // 2.95 did something like this). Unlinking the file would work // around those permission controls, so we only unlink if the file // has a non-zero size. We also unlink only regular files to avoid // trouble with directories/etc. // // If we fail, continue; this command is merely a best-effort attempt // to improve the odds for open(). struct stat s; if (::stat(this->name_, &s) == 0 && s.st_size != 0) unlink_if_ordinary(this->name_); int mode = parameters->output_is_object() ? 0666 : 0777; int o = ::open(this->name_, O_RDWR | O_CREAT | O_TRUNC, mode); if (o < 0) gold_fatal(_("%s: open: %s"), this->name_, strerror(errno)); this->o_ = o; // Write out one byte to make the file the right size. if (::lseek(o, file_size - 1, SEEK_SET) < 0) gold_fatal(_("%s: lseek: %s"), this->name_, strerror(errno)); char b = 0; if (::write(o, &b, 1) != 1) gold_fatal(_("%s: write: %s"), this->name_, strerror(errno)); // Map the file into memory. void* base = ::mmap(NULL, file_size, PROT_READ | PROT_WRITE, MAP_SHARED, o, 0); if (base == MAP_FAILED) gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno)); this->base_ = static_cast<unsigned char*>(base); } // Close the output file. void Output_file::close() { if (::munmap(this->base_, this->file_size_) < 0) gold_error(_("%s: munmap: %s"), this->name_, strerror(errno)); this->base_ = NULL; if (::close(this->o_) < 0) gold_error(_("%s: close: %s"), this->name_, strerror(errno)); this->o_ = -1; } // Instantiate the templates we need. We could use the configure // script to restrict this to only the ones for implemented targets. #ifdef HAVE_TARGET_32_LITTLE template off_t Output_section::add_input_section<32, false>( Relobj* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<32, false>& shdr); #endif #ifdef HAVE_TARGET_32_BIG template off_t Output_section::add_input_section<32, true>( Relobj* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<32, true>& shdr); #endif #ifdef HAVE_TARGET_64_LITTLE template off_t Output_section::add_input_section<64, false>( Relobj* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<64, false>& shdr); #endif #ifdef HAVE_TARGET_64_BIG template off_t Output_section::add_input_section<64, true>( Relobj* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<64, true>& shdr); #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc<elfcpp::SHT_REL, false, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc<elfcpp::SHT_REL, false, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc<elfcpp::SHT_REL, false, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc<elfcpp::SHT_REL, false, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc<elfcpp::SHT_REL, true, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc<elfcpp::SHT_REL, true, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc<elfcpp::SHT_REL, true, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc<elfcpp::SHT_REL, true, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc<elfcpp::SHT_RELA, false, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc<elfcpp::SHT_RELA, false, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc<elfcpp::SHT_RELA, false, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc<elfcpp::SHT_RELA, false, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc<elfcpp::SHT_RELA, true, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc<elfcpp::SHT_RELA, true, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc<elfcpp::SHT_RELA, true, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc<elfcpp::SHT_RELA, true, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_got<32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_got<32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_got<64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_got<64, true>; #endif } // End namespace gold.