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// output.cc -- manage the output file for gold // Copyright 2006, 2007, 2008, 2009 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 <cstring> #include <cerrno> #include <fcntl.h> #include <unistd.h> #include <sys/mman.h> #include <sys/stat.h> #include <algorithm> #include "libiberty.h" #include "parameters.h" #include "object.h" #include "symtab.h" #include "reloc.h" #include "merge.h" #include "descriptors.h" #include "output.h" // Some BSD systems still use MAP_ANON instead of MAP_ANONYMOUS #ifndef MAP_ANONYMOUS # define MAP_ANONYMOUS MAP_ANON #endif #ifndef HAVE_POSIX_FALLOCATE // A dummy, non general, version of posix_fallocate. Here we just set // the file size and hope that there is enough disk space. FIXME: We // could allocate disk space by walking block by block and writing a // zero byte into each block. static int posix_fallocate(int o, off_t offset, off_t len) { return ftruncate(o, offset + len); } #endif // !defined(HAVE_POSIX_FALLOCATE) namespace gold { // Output_data variables. bool Output_data::allocated_sizes_are_fixed; // Output_data methods. Output_data::~Output_data() { } // Return the default alignment for the target size. uint64_t Output_data::default_alignment() { return Output_data::default_alignment_for_size( parameters->target().get_size()); } // Return the default alignment for a size--32 or 64. uint64_t Output_data::default_alignment_for_size(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* section_list, const Layout::Section_list* unattached_section_list, const Stringpool* secnamepool, const Output_section* shstrtab_section) : layout_(layout), segment_list_(segment_list), section_list_(section_list), unattached_section_list_(unattached_section_list), secnamepool_(secnamepool), shstrtab_section_(shstrtab_section) { } // Compute the current data size. off_t Output_section_headers::do_size() const { // Count all the sections. Start with 1 for the null section. off_t count = 1; if (!parameters->options().relocatable()) { for (Layout::Segment_list::const_iterator p = this->segment_list_->begin(); p != this->segment_list_->end(); ++p) if ((*p)->type() == elfcpp::PT_LOAD) count += (*p)->output_section_count(); } else { for (Layout::Section_list::const_iterator p = this->section_list_->begin(); p != this->section_list_->end(); ++p) if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0) ++count; } count += this->unattached_section_list_->size(); const int size = parameters->target().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(); return count * shdr_size; } // Write out the section headers. void Output_section_headers::do_write(Output_file* of) { switch (parameters->size_and_endianness()) { #ifdef HAVE_TARGET_32_LITTLE case Parameters::TARGET_32_LITTLE: this->do_sized_write<32, false>(of); break; #endif #ifdef HAVE_TARGET_32_BIG case Parameters::TARGET_32_BIG: this->do_sized_write<32, true>(of); break; #endif #ifdef HAVE_TARGET_64_LITTLE case Parameters::TARGET_64_LITTLE: this->do_sized_write<64, false>(of); break; #endif #ifdef HAVE_TARGET_64_BIG case Parameters::TARGET_64_BIG: this->do_sized_write<64, true>(of); break; #endif default: 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); size_t section_count = (this->data_size() / elfcpp::Elf_sizes<size>::shdr_size); if (section_count < elfcpp::SHN_LORESERVE) oshdr.put_sh_size(0); else oshdr.put_sh_size(section_count); unsigned int shstrndx = this->shstrtab_section_->out_shndx(); if (shstrndx < elfcpp::SHN_LORESERVE) oshdr.put_sh_link(0); else oshdr.put_sh_link(shstrndx); oshdr.put_sh_info(0); oshdr.put_sh_addralign(0); oshdr.put_sh_entsize(0); } v += shdr_size; unsigned int shndx = 1; if (!parameters->options().relocatable()) { for (Layout::Segment_list::const_iterator p = this->segment_list_->begin(); p != this->segment_list_->end(); ++p) v = (*p)->write_section_headers<size, big_endian>(this->layout_, this->secnamepool_, v, &shndx); } else { for (Layout::Section_list::const_iterator p = this->section_list_->begin(); p != this->section_list_->end(); ++p) { // We do unallocated sections below, except that group // sections have to come first. if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0 && (*p)->type() != elfcpp::SHT_GROUP) continue; 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; } } for (Layout::Section_list::const_iterator p = this->unattached_section_list_->begin(); p != this->unattached_section_list_->end(); ++p) { // For a relocatable link, we did unallocated group sections // above, since they have to come first. if ((*p)->type() == elfcpp::SHT_GROUP && parameters->options().relocatable()) continue; 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) { } void Output_segment_headers::do_write(Output_file* of) { switch (parameters->size_and_endianness()) { #ifdef HAVE_TARGET_32_LITTLE case Parameters::TARGET_32_LITTLE: this->do_sized_write<32, false>(of); break; #endif #ifdef HAVE_TARGET_32_BIG case Parameters::TARGET_32_BIG: this->do_sized_write<32, true>(of); break; #endif #ifdef HAVE_TARGET_64_LITTLE case Parameters::TARGET_64_LITTLE: this->do_sized_write<64, false>(of); break; #endif #ifdef HAVE_TARGET_64_BIG case Parameters::TARGET_64_BIG: this->do_sized_write<64, true>(of); break; #endif default: 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; gold_assert(all_phdrs_size == this->data_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; } gold_assert(v - view == all_phdrs_size); of->write_output_view(this->offset(), all_phdrs_size, view); } off_t Output_segment_headers::do_size() const { const int size = parameters->target().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(); return this->segment_list_.size() * phdr_size; } // Output_file_header methods. Output_file_header::Output_file_header(const Target* target, const Symbol_table* symtab, const Output_segment_headers* osh, const char* entry) : target_(target), symtab_(symtab), segment_header_(osh), section_header_(NULL), shstrtab_(NULL), entry_(entry) { this->set_data_size(this->do_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) { gold_assert(this->offset() == 0); switch (parameters->size_and_endianness()) { #ifdef HAVE_TARGET_32_LITTLE case Parameters::TARGET_32_LITTLE: this->do_sized_write<32, false>(of); break; #endif #ifdef HAVE_TARGET_32_BIG case Parameters::TARGET_32_BIG: this->do_sized_write<32, true>(of); break; #endif #ifdef HAVE_TARGET_64_LITTLE case Parameters::TARGET_64_LITTLE: this->do_sized_write<64, false>(of); break; #endif #ifdef HAVE_TARGET_64_BIG case Parameters::TARGET_64_BIG: this->do_sized_write<64, true>(of); break; #endif default: 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; oehdr.put_e_ident(e_ident); elfcpp::ET e_type; if (parameters->options().relocatable()) e_type = elfcpp::ET_REL; else if (parameters->options().output_is_position_independent()) e_type = elfcpp::ET_DYN; 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); oehdr.put_e_entry(this->entry<size>()); if (this->segment_header_ == NULL) oehdr.put_e_phoff(0); else 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); if (this->segment_header_ == NULL) { oehdr.put_e_phentsize(0); oehdr.put_e_phnum(0); } else { 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); size_t section_count = (this->section_header_->data_size() / elfcpp::Elf_sizes<size>::shdr_size); if (section_count < elfcpp::SHN_LORESERVE) oehdr.put_e_shnum(this->section_header_->data_size() / elfcpp::Elf_sizes<size>::shdr_size); else oehdr.put_e_shnum(0); unsigned int shstrndx = this->shstrtab_->out_shndx(); if (shstrndx < elfcpp::SHN_LORESERVE) oehdr.put_e_shstrndx(this->shstrtab_->out_shndx()); else oehdr.put_e_shstrndx(elfcpp::SHN_XINDEX); // Let the target adjust the ELF header, e.g., to set EI_OSABI in // the e_ident field. parameters->target().adjust_elf_header(view, ehdr_size); of->write_output_view(0, ehdr_size, view); } // Return the value to use for the entry address. THIS->ENTRY_ is the // symbol specified on the command line, if any. template<int size> typename elfcpp::Elf_types<size>::Elf_Addr Output_file_header::entry() { const bool should_issue_warning = (this->entry_ != NULL && !parameters->options().relocatable() && !parameters->options().shared()); // FIXME: Need to support target specific entry symbol. const char* entry = this->entry_; if (entry == NULL) entry = "_start"; Symbol* sym = this->symtab_->lookup(entry); typename Sized_symbol<size>::Value_type v; if (sym != NULL) { Sized_symbol<size>* ssym; ssym = this->symtab_->get_sized_symbol<size>(sym); if (!ssym->is_defined() && should_issue_warning) gold_warning("entry symbol '%s' exists but is not defined", entry); v = ssym->value(); } else { // We couldn't find the entry symbol. See if we can parse it as // a number. This supports, e.g., -e 0x1000. char* endptr; v = strtoull(entry, &endptr, 0); if (*endptr != '\0') { if (should_issue_warning) gold_warning("cannot find entry symbol '%s'", entry); v = 0; } } return v; } // Compute the current data size. off_t Output_file_header::do_size() const { const int size = parameters->target().get_size(); if (size == 32) return elfcpp::Elf_sizes<32>::ehdr_size; else if (size == 64) return elfcpp::Elf_sizes<64>::ehdr_size; else gold_unreachable(); } // 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(); } // Set the alignment, which means we may need to update the alignment // of the output section. void Output_section_data::set_addralign(uint64_t addralign) { this->addralign_ = addralign; if (this->output_section_ != NULL && this->output_section_->addralign() < addralign) this->output_section_->set_addralign(addralign); } // Output_data_strtab methods. // Set the final data size. void Output_data_strtab::set_final_data_size() { 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. // A reloc against a global symbol. template<bool dynamic, int size, bool big_endian> Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc( Symbol* gsym, unsigned int type, Output_data* od, Address address, bool is_relative) : address_(address), local_sym_index_(GSYM_CODE), type_(type), is_relative_(is_relative), is_section_symbol_(false), shndx_(INVALID_CODE) { // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.gsym = gsym; this->u2_.od = od; if (dynamic) this->set_needs_dynsym_index(); } template<bool dynamic, int size, bool big_endian> Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc( Symbol* gsym, unsigned int type, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, bool is_relative) : address_(address), local_sym_index_(GSYM_CODE), type_(type), is_relative_(is_relative), is_section_symbol_(false), shndx_(shndx) { gold_assert(shndx != INVALID_CODE); // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.gsym = gsym; this->u2_.relobj = relobj; if (dynamic) this->set_needs_dynsym_index(); } // A reloc against a local symbol. template<bool dynamic, int size, bool big_endian> Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc( Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address, bool is_relative, bool is_section_symbol) : address_(address), local_sym_index_(local_sym_index), type_(type), is_relative_(is_relative), is_section_symbol_(is_section_symbol), shndx_(INVALID_CODE) { gold_assert(local_sym_index != GSYM_CODE && local_sym_index != INVALID_CODE); // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.relobj = relobj; this->u2_.od = od; if (dynamic) this->set_needs_dynsym_index(); } template<bool dynamic, int size, bool big_endian> Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc( Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, unsigned int shndx, Address address, bool is_relative, bool is_section_symbol) : address_(address), local_sym_index_(local_sym_index), type_(type), is_relative_(is_relative), is_section_symbol_(is_section_symbol), shndx_(shndx) { gold_assert(local_sym_index != GSYM_CODE && local_sym_index != INVALID_CODE); gold_assert(shndx != INVALID_CODE); // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.relobj = relobj; this->u2_.relobj = relobj; if (dynamic) this->set_needs_dynsym_index(); } // A reloc against the STT_SECTION symbol of an output section. template<bool dynamic, int size, bool big_endian> Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc( Output_section* os, unsigned int type, Output_data* od, Address address) : address_(address), local_sym_index_(SECTION_CODE), type_(type), is_relative_(false), is_section_symbol_(true), shndx_(INVALID_CODE) { // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.os = os; this->u2_.od = od; if (dynamic) this->set_needs_dynsym_index(); else os->set_needs_symtab_index(); } template<bool dynamic, int size, bool big_endian> Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::Output_reloc( Output_section* os, unsigned int type, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address) : address_(address), local_sym_index_(SECTION_CODE), type_(type), is_relative_(false), is_section_symbol_(true), shndx_(shndx) { gold_assert(shndx != INVALID_CODE); // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.os = os; this->u2_.relobj = relobj; if (dynamic) this->set_needs_dynsym_index(); else os->set_needs_symtab_index(); } // Record that we need a dynamic symbol index for this relocation. template<bool dynamic, int size, bool big_endian> void Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>:: set_needs_dynsym_index() { if (this->is_relative_) return; switch (this->local_sym_index_) { case INVALID_CODE: gold_unreachable(); case GSYM_CODE: this->u1_.gsym->set_needs_dynsym_entry(); break; case SECTION_CODE: this->u1_.os->set_needs_dynsym_index(); break; case 0: break; default: { const unsigned int lsi = this->local_sym_index_; if (!this->is_section_symbol_) this->u1_.relobj->set_needs_output_dynsym_entry(lsi); else this->u1_.relobj->output_section(lsi)->set_needs_dynsym_index(); } break; } } // 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; case 0: // Relocations without symbols use a symbol index of 0. index = 0; break; default: { const unsigned int lsi = this->local_sym_index_; if (!this->is_section_symbol_) { if (dynamic) index = this->u1_.relobj->dynsym_index(lsi); else index = this->u1_.relobj->symtab_index(lsi); } else { Output_section* os = this->u1_.relobj->output_section(lsi); gold_assert(os != NULL); if (dynamic) index = os->dynsym_index(); else index = os->symtab_index(); } } break; } gold_assert(index != -1U); return index; } // For a local section symbol, get the address of the offset ADDEND // within the input section. template<bool dynamic, int size, bool big_endian> typename elfcpp::Elf_types<size>::Elf_Addr Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>:: local_section_offset(Addend addend) const { gold_assert(this->local_sym_index_ != GSYM_CODE && this->local_sym_index_ != SECTION_CODE && this->local_sym_index_ != INVALID_CODE && this->is_section_symbol_); const unsigned int lsi = this->local_sym_index_; Output_section* os = this->u1_.relobj->output_section(lsi); gold_assert(os != NULL); Address offset = this->u1_.relobj->get_output_section_offset(lsi); if (offset != invalid_address) return offset + addend; // This is a merge section. offset = os->output_address(this->u1_.relobj, lsi, addend); gold_assert(offset != invalid_address); return offset; } // Get the output address of a relocation. template<bool dynamic, int size, bool big_endian> typename elfcpp::Elf_types<size>::Elf_Addr Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_address() const { Address address = this->address_; if (this->shndx_ != INVALID_CODE) { Output_section* os = this->u2_.relobj->output_section(this->shndx_); gold_assert(os != NULL); Address off = this->u2_.relobj->get_output_section_offset(this->shndx_); if (off != invalid_address) address += os->address() + off; else { address = os->output_address(this->u2_.relobj, this->shndx_, address); gold_assert(address != invalid_address); } } else if (this->u2_.od != NULL) address += this->u2_.od->address(); return address; } // 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 { wr->put_r_offset(this->get_address()); unsigned int sym_index = this->is_relative_ ? 0 : this->get_symbol_index(); wr->put_r_info(elfcpp::elf_r_info<size>(sym_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); } // Get the value of the symbol referred to by a Rel relocation. template<bool dynamic, int size, bool big_endian> typename elfcpp::Elf_types<size>::Elf_Addr Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::symbol_value( Addend addend) const { if (this->local_sym_index_ == GSYM_CODE) { const Sized_symbol<size>* sym; sym = static_cast<const Sized_symbol<size>*>(this->u1_.gsym); return sym->value() + addend; } gold_assert(this->local_sym_index_ != SECTION_CODE && this->local_sym_index_ != INVALID_CODE && !this->is_section_symbol_); const unsigned int lsi = this->local_sym_index_; const Symbol_value<size>* symval = this->u1_.relobj->local_symbol(lsi); return symval->value(this->u1_.relobj, addend); } // Reloc comparison. This function sorts the dynamic relocs for the // benefit of the dynamic linker. First we sort all relative relocs // to the front. Among relative relocs, we sort by output address. // Among non-relative relocs, we sort by symbol index, then by output // address. template<bool dynamic, int size, bool big_endian> int Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>:: compare(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>& r2) const { if (this->is_relative_) { if (!r2.is_relative_) return -1; // Otherwise sort by reloc address below. } else if (r2.is_relative_) return 1; else { unsigned int sym1 = this->get_symbol_index(); unsigned int sym2 = r2.get_symbol_index(); if (sym1 < sym2) return -1; else if (sym1 > sym2) return 1; // Otherwise sort by reloc address. } section_offset_type addr1 = this->get_address(); section_offset_type addr2 = r2.get_address(); if (addr1 < addr2) return -1; else if (addr1 > addr2) return 1; // Final tie breaker, in order to generate the same output on any // host: reloc type. unsigned int type1 = this->type_; unsigned int type2 = r2.type_; if (type1 < type2) return -1; else if (type1 > type2) return 1; // These relocs appear to be exactly the same. return 0; } // 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); Addend addend = this->addend_; if (this->rel_.is_relative()) addend = this->rel_.symbol_value(addend); else if (this->rel_.is_local_section_symbol()) addend = this->rel_.local_section_offset(addend); orel.put_r_addend(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); if (this->sort_relocs_) { gold_assert(dynamic); std::sort(this->relocs_.begin(), this->relocs_.end(), Sort_relocs_comparison()); } 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(); } // Class Output_relocatable_relocs. template<int sh_type, int size, bool big_endian> void Output_relocatable_relocs<sh_type, size, big_endian>::set_final_data_size() { this->set_data_size(this->rr_->output_reloc_count() * Reloc_types<sh_type, size, big_endian>::reloc_size); } // class Output_data_group. template<int size, bool big_endian> Output_data_group<size, big_endian>::Output_data_group( Sized_relobj<size, big_endian>* relobj, section_size_type entry_count, elfcpp::Elf_Word flags, std::vector<unsigned int>* input_shndxes) : Output_section_data(entry_count * 4, 4, false), relobj_(relobj), flags_(flags) { this->input_shndxes_.swap(*input_shndxes); } // Write out the section group, which means translating the section // indexes to apply to the output file. template<int size, bool big_endian> void Output_data_group<size, big_endian>::do_write(Output_file* of) { const off_t off = this->offset(); const section_size_type oview_size = convert_to_section_size_type(this->data_size()); unsigned char* const oview = of->get_output_view(off, oview_size); elfcpp::Elf_Word* contents = reinterpret_cast<elfcpp::Elf_Word*>(oview); elfcpp::Swap<32, big_endian>::writeval(contents, this->flags_); ++contents; for (std::vector<unsigned int>::const_iterator p = this->input_shndxes_.begin(); p != this->input_shndxes_.end(); ++p, ++contents) { Output_section* os = this->relobj_->output_section(*p); unsigned int output_shndx; if (os != NULL) output_shndx = os->out_shndx(); else { this->relobj_->error(_("section group retained but " "group element discarded")); output_shndx = 0; } elfcpp::Swap<32, big_endian>::writeval(contents, output_shndx); } size_t wrote = reinterpret_cast<unsigned char*>(contents) - oview; gold_assert(wrote == oview_size); of->write_output_view(off, oview_size, oview); // We no longer need this information. this->input_shndxes_.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: { // If the symbol is resolved locally, we need to write out the // link-time value, which will be relocated dynamically by a // RELATIVE relocation. Symbol* gsym = this->u_.gsym; 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: { const unsigned int lsi = this->local_sym_index_; const Symbol_value<size>* symval = this->u_.object->local_symbol(lsi); val = symval->value(this->u_.object, 0); } 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, unsigned int got_type) { if (gsym->has_got_offset(got_type)) return false; this->entries_.push_back(Got_entry(gsym)); this->set_got_size(); gsym->set_got_offset(got_type, this->last_got_offset()); return true; } // Add an entry for a global symbol to the GOT, and add a dynamic // relocation of type R_TYPE for the GOT entry. template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_global_with_rel( Symbol* gsym, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type) { if (gsym->has_got_offset(got_type)) return; this->entries_.push_back(Got_entry()); this->set_got_size(); unsigned int got_offset = this->last_got_offset(); gsym->set_got_offset(got_type, got_offset); rel_dyn->add_global(gsym, r_type, this, got_offset); } template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_global_with_rela( Symbol* gsym, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type) { if (gsym->has_got_offset(got_type)) return; this->entries_.push_back(Got_entry()); this->set_got_size(); unsigned int got_offset = this->last_got_offset(); gsym->set_got_offset(got_type, got_offset); rela_dyn->add_global(gsym, r_type, this, got_offset, 0); } // Add a pair of entries for a global symbol to the GOT, and add // dynamic relocations of type R_TYPE_1 and R_TYPE_2, respectively. // If R_TYPE_2 == 0, add the second entry with no relocation. template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_global_pair_with_rel( Symbol* gsym, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type_1, unsigned int r_type_2) { if (gsym->has_got_offset(got_type)) return; this->entries_.push_back(Got_entry()); unsigned int got_offset = this->last_got_offset(); gsym->set_got_offset(got_type, got_offset); rel_dyn->add_global(gsym, r_type_1, this, got_offset); this->entries_.push_back(Got_entry()); if (r_type_2 != 0) { got_offset = this->last_got_offset(); rel_dyn->add_global(gsym, r_type_2, this, got_offset); } this->set_got_size(); } template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_global_pair_with_rela( Symbol* gsym, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type_1, unsigned int r_type_2) { if (gsym->has_got_offset(got_type)) return; this->entries_.push_back(Got_entry()); unsigned int got_offset = this->last_got_offset(); gsym->set_got_offset(got_type, got_offset); rela_dyn->add_global(gsym, r_type_1, this, got_offset, 0); this->entries_.push_back(Got_entry()); if (r_type_2 != 0) { got_offset = this->last_got_offset(); rela_dyn->add_global(gsym, r_type_2, this, got_offset, 0); } this->set_got_size(); } // 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, unsigned int got_type) { if (object->local_has_got_offset(symndx, got_type)) return false; this->entries_.push_back(Got_entry(object, symndx)); this->set_got_size(); object->set_local_got_offset(symndx, got_type, this->last_got_offset()); return true; } // Add an entry for a local symbol to the GOT, and add a dynamic // relocation of type R_TYPE for the GOT entry. template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_local_with_rel( Sized_relobj<size, big_endian>* object, unsigned int symndx, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type) { if (object->local_has_got_offset(symndx, got_type)) return; this->entries_.push_back(Got_entry()); this->set_got_size(); unsigned int got_offset = this->last_got_offset(); object->set_local_got_offset(symndx, got_type, got_offset); rel_dyn->add_local(object, symndx, r_type, this, got_offset); } template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_local_with_rela( Sized_relobj<size, big_endian>* object, unsigned int symndx, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type) { if (object->local_has_got_offset(symndx, got_type)) return; this->entries_.push_back(Got_entry()); this->set_got_size(); unsigned int got_offset = this->last_got_offset(); object->set_local_got_offset(symndx, got_type, got_offset); rela_dyn->add_local(object, symndx, r_type, this, got_offset, 0); } // Add a pair of entries for a local symbol to the GOT, and add // dynamic relocations of type R_TYPE_1 and R_TYPE_2, respectively. // If R_TYPE_2 == 0, add the second entry with no relocation. template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_local_pair_with_rel( Sized_relobj<size, big_endian>* object, unsigned int symndx, unsigned int shndx, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type_1, unsigned int r_type_2) { if (object->local_has_got_offset(symndx, got_type)) return; this->entries_.push_back(Got_entry()); unsigned int got_offset = this->last_got_offset(); object->set_local_got_offset(symndx, got_type, got_offset); Output_section* os = object->output_section(shndx); rel_dyn->add_output_section(os, r_type_1, this, got_offset); this->entries_.push_back(Got_entry(object, symndx)); if (r_type_2 != 0) { got_offset = this->last_got_offset(); rel_dyn->add_output_section(os, r_type_2, this, got_offset); } this->set_got_size(); } template<int size, bool big_endian> void Output_data_got<size, big_endian>::add_local_pair_with_rela( Sized_relobj<size, big_endian>* object, unsigned int symndx, unsigned int shndx, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type_1, unsigned int r_type_2) { if (object->local_has_got_offset(symndx, got_type)) return; this->entries_.push_back(Got_entry()); unsigned int got_offset = this->last_got_offset(); object->set_local_got_offset(symndx, got_type, got_offset); Output_section* os = object->output_section(shndx); rela_dyn->add_output_section(os, r_type_1, this, got_offset, 0); this->entries_.push_back(Got_entry(object, symndx)); if (r_type_2 != 0) { got_offset = this->last_got_offset(); rela_dyn->add_output_section(os, r_type_2, this, got_offset, 0); } this->set_got_size(); } // 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) const { typename elfcpp::Elf_types<size>::Elf_WXword val; switch (this->offset_) { case DYNAMIC_NUMBER: val = this->u_.val; 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: val = this->u_.od->address() + this->offset_; break; } 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->target().get_size() == 32) os->set_entsize(elfcpp::Elf_sizes<32>::dyn_size); else if (parameters->target().get_size() == 64) os->set_entsize(elfcpp::Elf_sizes<64>::dyn_size); else gold_unreachable(); } // Set the final data size. void Output_data_dynamic::set_final_data_size() { // Add the terminating entry if it hasn't been added. // Because of relaxation, we can run this multiple times. if (this->entries_.empty() || this->entries_.rbegin()->tag() != elfcpp::DT_NULL) this->add_constant(elfcpp::DT_NULL, 0); int dyn_size; if (parameters->target().get_size() == 32) dyn_size = elfcpp::Elf_sizes<32>::dyn_size; else if (parameters->target().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) { switch (parameters->size_and_endianness()) { #ifdef HAVE_TARGET_32_LITTLE case Parameters::TARGET_32_LITTLE: this->sized_write<32, false>(of); break; #endif #ifdef HAVE_TARGET_32_BIG case Parameters::TARGET_32_BIG: this->sized_write<32, true>(of); break; #endif #ifdef HAVE_TARGET_64_LITTLE case Parameters::TARGET_64_LITTLE: this->sized_write<64, false>(of); break; #endif #ifdef HAVE_TARGET_64_BIG case Parameters::TARGET_64_BIG: this->sized_write<64, true>(of); break; #endif default: 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<size, big_endian>(pov, this->pool_); 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(); } // Class Output_symtab_xindex. void Output_symtab_xindex::do_write(Output_file* of) { 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); memset(oview, 0, oview_size); if (parameters->target().is_big_endian()) this->endian_do_write<true>(oview); else this->endian_do_write<false>(oview); of->write_output_view(offset, oview_size, oview); // We no longer need the data. this->entries_.clear(); } template<bool big_endian> void Output_symtab_xindex::endian_do_write(unsigned char* const oview) { for (Xindex_entries::const_iterator p = this->entries_.begin(); p != this->entries_.end(); ++p) { unsigned int symndx = p->first; gold_assert(symndx * 4 < this->data_size()); elfcpp::Swap<32, big_endian>::writeval(oview + symndx * 4, p->second); } } // 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_and_file_offset( uint64_t address, off_t file_offset, off_t section_file_offset) { if (this->is_input_section()) this->u2_.object->set_section_offset(this->shndx_, file_offset - section_file_offset); else this->u2_.posd->set_address_and_file_offset(address, file_offset); } // Reset the address and file offset. void Output_section::Input_section::reset_address_and_file_offset() { if (!this->is_input_section()) this->u2_.posd->reset_address_and_file_offset(); } // Finalize the data size. void Output_section::Input_section::finalize_data_size() { if (!this->is_input_section()) this->u2_.posd->finalize_data_size(); } // Try to turn an input offset into an output offset. We want to // return the output offset relative to the start of this // Input_section in the output section. inline bool Output_section::Input_section::output_offset( const Relobj* object, unsigned int shndx, section_offset_type offset, section_offset_type *poutput) const { if (!this->is_input_section()) return this->u2_.posd->output_offset(object, shndx, offset, poutput); else { if (this->shndx_ != shndx || this->u2_.object != object) return false; *poutput = offset; return true; } } // Return whether this is the merge section for the input section // SHNDX in OBJECT. inline bool Output_section::Input_section::is_merge_section_for(const Relobj* object, unsigned int shndx) const { if (this->is_input_section()) return false; return this->u2_.posd->is_merge_section_for(object, shndx); } // 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); } // Write the data to a buffer. As for write(), we don't have to do // anything for an input section. void Output_section::Input_section::write_to_buffer(unsigned char* buffer) { if (!this->is_input_section()) this->u2_.posd->write_to_buffer(buffer); } // Print to a map file. void Output_section::Input_section::print_to_mapfile(Mapfile* mapfile) const { switch (this->shndx_) { case OUTPUT_SECTION_CODE: case MERGE_DATA_SECTION_CODE: case MERGE_STRING_SECTION_CODE: this->u2_.posd->print_to_mapfile(mapfile); break; case RELAXED_INPUT_SECTION_CODE: { Output_relaxed_input_section* relaxed_section = this->relaxed_input_section(); mapfile->print_input_section(relaxed_section->relobj(), relaxed_section->shndx()); } break; default: mapfile->print_input_section(this->u2_.object, this->shndx_); break; } } // 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), load_address_(0), link_section_(NULL), link_(0), info_section_(NULL), info_symndx_(NULL), info_(0), type_(type), flags_(flags), out_shndx_(-1U), symtab_index_(0), dynsym_index_(0), input_sections_(), first_input_offset_(0), fills_(), postprocessing_buffer_(NULL), needs_symtab_index_(false), needs_dynsym_index_(false), should_link_to_symtab_(false), should_link_to_dynsym_(false), after_input_sections_(false), requires_postprocessing_(false), found_in_sections_clause_(false), has_load_address_(false), info_uses_section_index_(false), may_sort_attached_input_sections_(false), must_sort_attached_input_sections_(false), attached_input_sections_are_sorted_(false), is_relro_(false), is_relro_local_(false), is_small_section_(false), is_large_section_(false), is_interp_(false), is_dynamic_linker_section_(false), generate_code_fills_at_write_(false), tls_offset_(0), checkpoint_(NULL), merge_section_map_(), merge_section_by_properties_map_(), relaxed_input_section_map_(), is_relaxed_input_section_map_valid_(true) { // An unallocated section has no address. Forcing this means that // we don't need special treatment for symbols defined in debug // sections. if ((flags & elfcpp::SHF_ALLOC) == 0) this->set_address(0); } Output_section::~Output_section() { delete this->checkpoint_; } // 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. RELOC_SHNDX is the index of a // relocation section which applies to this section, or 0 if none, or // -1U if more than one. Return the offset of the input section // within the output section. Return -1 if the input section will // receive special handling. In the normal case 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. However, if HAVE_SECTIONS_SCRIPT is true, we do keep // track of input sections here; this is used when SECTIONS appears in // a linker script. template<int size, bool big_endian> off_t Output_section::add_input_section(Sized_relobj<size, big_endian>* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<size, big_endian>& shdr, unsigned int reloc_shndx, bool have_sections_script) { 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; typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags(); this->update_flags_for_input_section(sh_flags); uint64_t entsize = shdr.get_sh_entsize(); // .debug_str is a mergeable string section, but is not always so // marked by compilers. Mark manually here so we can optimize. if (strcmp(secname, ".debug_str") == 0) { sh_flags |= (elfcpp::SHF_MERGE | elfcpp::SHF_STRINGS); entsize = 1; } // If this is a SHF_MERGE section, we pass all the input sections to // a Output_data_merge. We don't try to handle relocations for such // a section. We don't try to handle empty merge sections--they // mess up the mappings, and are useless anyhow. if ((sh_flags & elfcpp::SHF_MERGE) != 0 && reloc_shndx == 0 && shdr.get_sh_size() > 0) { if (this->add_merge_input_section(object, shndx, sh_flags, entsize, addralign)) { // Tell the relocation routines that they need to call the // output_offset method to determine the final address. return -1; } } off_t offset_in_section = this->current_data_size_for_child(); off_t aligned_offset_in_section = align_address(offset_in_section, addralign); // Determine if we want to delay code-fill generation until the output // section is written. When the target is relaxing, we want to delay fill // generating to avoid adjusting them during relaxation. if (!this->generate_code_fills_at_write_ && !have_sections_script && (sh_flags & elfcpp::SHF_EXECINSTR) != 0 && parameters->target().has_code_fill() && parameters->target().may_relax()) { gold_assert(this->fills_.empty()); this->generate_code_fills_at_write_ = true; } if (aligned_offset_in_section > offset_in_section && !this->generate_code_fills_at_write_ && !have_sections_script && (sh_flags & elfcpp::SHF_EXECINSTR) != 0 && parameters->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 { std::string fill_data(parameters->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_current_data_size_for_child(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. Also, if this is a // section which requires sorting, or which may require sorting in // the future, we keep track of the sections. if (have_sections_script || !this->input_sections_.empty() || this->may_sort_attached_input_sections() || this->must_sort_attached_input_sections() || parameters->options().user_set_Map() || parameters->target().may_relax()) 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); if (posd->is_data_size_valid()) { off_t offset_in_section = this->current_data_size_for_child(); off_t aligned_offset_in_section = align_address(offset_in_section, posd->addralign()); this->set_current_data_size_for_child(aligned_offset_in_section + posd->data_size()); } } // Add a relaxed input section. void Output_section::add_relaxed_input_section(Output_relaxed_input_section* poris) { Input_section inp(poris); this->add_output_section_data(&inp); if (this->is_relaxed_input_section_map_valid_) { Input_section_specifier iss(poris->relobj(), poris->shndx()); this->relaxed_input_section_map_[iss] = poris; } // For a relaxed section, we use the current data size. Linker scripts // get all the input sections, including relaxed one from an output // section and add them back to them same output section to compute the // output section size. If we do not account for sizes of relaxed input // sections, an output section would be incorrectly sized. off_t offset_in_section = this->current_data_size_for_child(); off_t aligned_offset_in_section = align_address(offset_in_section, poris->addralign()); this->set_current_data_size_for_child(aligned_offset_in_section + poris->current_data_size()); } // 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->current_data_size_for_child(); 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) { bool is_string = (flags & elfcpp::SHF_STRINGS) != 0; // We only merge strings if the alignment is not more than the // character size. This could be handled, but it's unusual. if (is_string && addralign > entsize) return false; // We cannot restore merged input section states. gold_assert(this->checkpoint_ == NULL); // Look up merge sections by required properties. Merge_section_properties msp(is_string, entsize, addralign); Merge_section_by_properties_map::const_iterator p = this->merge_section_by_properties_map_.find(msp); if (p != this->merge_section_by_properties_map_.end()) { Output_merge_base* merge_section = p->second; merge_section->add_input_section(object, shndx); gold_assert(merge_section->is_string() == is_string && merge_section->entsize() == entsize && merge_section->addralign() == addralign); // Link input section to found merge section. Input_section_specifier iss(object, shndx); this->merge_section_map_[iss] = merge_section; return true; } // We handle the actual constant merging in Output_merge_data or // Output_merge_string_data. Output_merge_base* pomb; if (!is_string) pomb = new Output_merge_data(entsize, addralign); else { switch (entsize) { case 1: pomb = new Output_merge_string<char>(addralign); break; case 2: pomb = new Output_merge_string<uint16_t>(addralign); break; case 4: pomb = new Output_merge_string<uint32_t>(addralign); break; default: return false; } } // Add new merge section to this output section and link merge section // properties to new merge section in map. this->add_output_merge_section(pomb, is_string, entsize); this->merge_section_by_properties_map_[msp] = pomb; // Add input section to new merge section and link input section to new // merge section in map. pomb->add_input_section(object, shndx); Input_section_specifier iss(object, shndx); this->merge_section_map_[iss] = pomb; return true; } // Build a relaxation map to speed up relaxation of existing input sections. // Look up to the first LIMIT elements in INPUT_SECTIONS. void Output_section::build_relaxation_map( const Input_section_list& input_sections, size_t limit, Relaxation_map* relaxation_map) const { for (size_t i = 0; i < limit; ++i) { const Input_section& is(input_sections[i]); if (is.is_input_section() || is.is_relaxed_input_section()) { Input_section_specifier iss(is.relobj(), is.shndx()); (*relaxation_map)[iss] = i; } } } // Convert regular input sections in INPUT_SECTIONS into relaxed input // sections in RELAXED_SECTIONS. MAP is a prebuilt map from input section // specifier to indices of INPUT_SECTIONS. void Output_section::convert_input_sections_in_list_to_relaxed_sections( const std::vector<Output_relaxed_input_section*>& relaxed_sections, const Relaxation_map& map, Input_section_list* input_sections) { for (size_t i = 0; i < relaxed_sections.size(); ++i) { Output_relaxed_input_section* poris = relaxed_sections[i]; Input_section_specifier iss(poris->relobj(), poris->shndx()); Relaxation_map::const_iterator p = map.find(iss); gold_assert(p != map.end()); gold_assert((*input_sections)[p->second].is_input_section()); (*input_sections)[p->second] = Input_section(poris); } } // Convert regular input sections into relaxed input sections. RELAXED_SECTIONS // is a vector of pointers to Output_relaxed_input_section or its derived // classes. The relaxed sections must correspond to existing input sections. void Output_section::convert_input_sections_to_relaxed_sections( const std::vector<Output_relaxed_input_section*>& relaxed_sections) { gold_assert(parameters->target().may_relax()); // We want to make sure that restore_states does not undo the effect of // this. If there is no checkpoint active, just search the current // input section list and replace the sections there. If there is // a checkpoint, also replace the sections there. // By default, we look at the whole list. size_t limit = this->input_sections_.size(); if (this->checkpoint_ != NULL) { // Replace input sections with relaxed input section in the saved // copy of the input section list. if (this->checkpoint_->input_sections_saved()) { Relaxation_map map; this->build_relaxation_map( *(this->checkpoint_->input_sections()), this->checkpoint_->input_sections()->size(), &map); this->convert_input_sections_in_list_to_relaxed_sections( relaxed_sections, map, this->checkpoint_->input_sections()); } else { // We have not copied the input section list yet. Instead, just // look at the portion that would be saved. limit = this->checkpoint_->input_sections_size(); } } // Convert input sections in input_section_list. Relaxation_map map; this->build_relaxation_map(this->input_sections_, limit, &map); this->convert_input_sections_in_list_to_relaxed_sections( relaxed_sections, map, &this->input_sections_); } // Update the output section flags based on input section flags. void Output_section::update_flags_for_input_section(elfcpp::Elf_Xword flags) { // If we created the section with SHF_ALLOC clear, we set the // address. If we are now setting the SHF_ALLOC flag, we need to // undo that. if ((this->flags_ & elfcpp::SHF_ALLOC) == 0 && (flags & elfcpp::SHF_ALLOC) != 0) this->mark_address_invalid(); this->flags_ |= (flags & (elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR)); } // Find the merge section into which an input section with index SHNDX in // OBJECT has been added. Return NULL if none found. Output_section_data* Output_section::find_merge_section(const Relobj* object, unsigned int shndx) const { Input_section_specifier iss(object, shndx); Output_section_data_by_input_section_map::const_iterator p = this->merge_section_map_.find(iss); if (p != this->merge_section_map_.end()) { Output_section_data* posd = p->second; gold_assert(posd->is_merge_section_for(object, shndx)); return posd; } else return NULL; } // Find an relaxed input section corresponding to an input section // in OBJECT with index SHNDX. const Output_section_data* Output_section::find_relaxed_input_section(const Relobj* object, unsigned int shndx) const { // Be careful that the map may not be valid due to input section export // to scripts or a check-point restore. if (!this->is_relaxed_input_section_map_valid_) { // Rebuild the map as needed. this->relaxed_input_section_map_.clear(); for (Input_section_list::const_iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) if (p->is_relaxed_input_section()) { Input_section_specifier iss(p->relobj(), p->shndx()); this->relaxed_input_section_map_[iss] = p->relaxed_input_section(); } this->is_relaxed_input_section_map_valid_ = true; } Input_section_specifier iss(object, shndx); Output_section_data_by_input_section_map::const_iterator p = this->relaxed_input_section_map_.find(iss); if (p != this->relaxed_input_section_map_.end()) return p->second; else return NULL; } // Given an address OFFSET relative to the start of input section // SHNDX in OBJECT, return whether this address is being included in // the final link. This should only be called if SHNDX in OBJECT has // a special mapping. bool Output_section::is_input_address_mapped(const Relobj* object, unsigned int shndx, off_t offset) const { // Look at the Output_section_data_maps first. const Output_section_data* posd = this->find_merge_section(object, shndx); if (posd == NULL) posd = this->find_relaxed_input_section(object, shndx); if (posd != NULL) { section_offset_type output_offset; bool found = posd->output_offset(object, shndx, offset, &output_offset); gold_assert(found); return output_offset != -1; } // Fall back to the slow look-up. for (Input_section_list::const_iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { section_offset_type output_offset; if (p->output_offset(object, shndx, offset, &output_offset)) return output_offset != -1; } // By default we assume that the address is mapped. This should // only be called after we have passed all sections to Layout. At // that point we should know what we are discarding. return true; } // Given an address OFFSET relative to the start of input section // SHNDX in object OBJECT, return the output offset relative to the // start of the input section in the output section. This should only // be called if SHNDX in OBJECT has a special mapping. section_offset_type Output_section::output_offset(const Relobj* object, unsigned int shndx, section_offset_type offset) const { // This can only be called meaningfully when we know the data size // of this. gold_assert(this->is_data_size_valid()); // Look at the Output_section_data_maps first. const Output_section_data* posd = this->find_merge_section(object, shndx); if (posd == NULL) posd = this->find_relaxed_input_section(object, shndx); if (posd != NULL) { section_offset_type output_offset; bool found = posd->output_offset(object, shndx, offset, &output_offset); gold_assert(found); return output_offset; } // Fall back to the slow look-up. for (Input_section_list::const_iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { section_offset_type output_offset; if (p->output_offset(object, shndx, offset, &output_offset)) return output_offset; } gold_unreachable(); } // 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_; // Look at the Output_section_data_maps first. const Output_section_data* posd = this->find_merge_section(object, shndx); if (posd == NULL) posd = this->find_relaxed_input_section(object, shndx); if (posd != NULL && posd->is_address_valid()) { section_offset_type output_offset; bool found = posd->output_offset(object, shndx, offset, &output_offset); gold_assert(found); return posd->address() + output_offset; } // Fall back to the slow look-up. for (Input_section_list::const_iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { addr = align_address(addr, p->addralign()); section_offset_type output_offset; if (p->output_offset(object, shndx, offset, &output_offset)) { if (output_offset == -1) return -1ULL; return addr + output_offset; } 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(); } // Find the output address of the start of the merged section for // input section SHNDX in object OBJECT. bool Output_section::find_starting_output_address(const Relobj* object, unsigned int shndx, uint64_t* paddr) const { // FIXME: This becomes a bottle-neck if we have many relaxed sections. // Looking up the merge section map does not always work as we sometimes // find a merge section without its address set. 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()); // It would be nice if we could use the existing output_offset // method to get the output offset of input offset 0. // Unfortunately we don't know for sure that input offset 0 is // mapped at all. if (p->is_merge_section_for(object, shndx)) { *paddr = addr; return true; } addr += p->data_size(); } // We couldn't find a merge output section for this input section. return false; } // Set the data size of an Output_section. This is where we handle // setting the addresses of any Output_section_data objects. void Output_section::set_final_data_size() { if (this->input_sections_.empty()) { this->set_data_size(this->current_data_size_for_child()); return; } if (this->must_sort_attached_input_sections()) this->sort_attached_input_sections(); uint64_t address = this->address(); off_t startoff = this->offset(); 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_and_file_offset(address + (off - startoff), off, startoff); off += p->data_size(); } this->set_data_size(off - startoff); } // Reset the address and file offset. void Output_section::do_reset_address_and_file_offset() { // An unallocated section has no address. Forcing this means that // we don't need special treatment for symbols defined in debug // sections. We do the same in the constructor. if ((this->flags_ & elfcpp::SHF_ALLOC) == 0) this->set_address(0); for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) p->reset_address_and_file_offset(); } // Return true if address and file offset have the values after reset. bool Output_section::do_address_and_file_offset_have_reset_values() const { if (this->is_offset_valid()) return false; // An unallocated section has address 0 after its construction or a reset. if ((this->flags_ & elfcpp::SHF_ALLOC) == 0) return this->is_address_valid() && this->address() == 0; else return !this->is_address_valid(); } // Set the TLS offset. Called only for SHT_TLS sections. void Output_section::do_set_tls_offset(uint64_t tls_base) { this->tls_offset_ = this->address() - tls_base; } // In a few cases we need to sort the input sections attached to an // output section. This is used to implement the type of constructor // priority ordering implemented by the GNU linker, in which the // priority becomes part of the section name and the sections are // sorted by name. We only do this for an output section if we see an // attached input section matching ".ctor.*", ".dtor.*", // ".init_array.*" or ".fini_array.*". class Output_section::Input_section_sort_entry { public: Input_section_sort_entry() : input_section_(), index_(-1U), section_has_name_(false), section_name_() { } Input_section_sort_entry(const Input_section& input_section, unsigned int index) : input_section_(input_section), index_(index), section_has_name_(input_section.is_input_section() || input_section.is_relaxed_input_section()) { if (this->section_has_name_) { // This is only called single-threaded from Layout::finalize, // so it is OK to lock. Unfortunately we have no way to pass // in a Task token. const Task* dummy_task = reinterpret_cast<const Task*>(-1); Object* obj = (input_section.is_input_section() ? input_section.relobj() : input_section.relaxed_input_section()->relobj()); Task_lock_obj<Object> tl(dummy_task, obj); // This is a slow operation, which should be cached in // Layout::layout if this becomes a speed problem. this->section_name_ = obj->section_name(input_section.shndx()); } } // Return the Input_section. const Input_section& input_section() const { gold_assert(this->index_ != -1U); return this->input_section_; } // The index of this entry in the original list. This is used to // make the sort stable. unsigned int index() const { gold_assert(this->index_ != -1U); return this->index_; } // Whether there is a section name. bool section_has_name() const { return this->section_has_name_; } // The section name. const std::string& section_name() const { gold_assert(this->section_has_name_); return this->section_name_; } // Return true if the section name has a priority. This is assumed // to be true if it has a dot after the initial dot. bool has_priority() const { gold_assert(this->section_has_name_); return this->section_name_.find('.', 1); } // Return true if this an input file whose base name matches // FILE_NAME. The base name must have an extension of ".o", and // must be exactly FILE_NAME.o or FILE_NAME, one character, ".o". // This is to match crtbegin.o as well as crtbeginS.o without // getting confused by other possibilities. Overall matching the // file name this way is a dreadful hack, but the GNU linker does it // in order to better support gcc, and we need to be compatible. bool match_file_name(const char* match_file_name) const { const std::string& file_name(this->input_section_.relobj()->name()); const char* base_name = lbasename(file_name.c_str()); size_t match_len = strlen(match_file_name); if (strncmp(base_name, match_file_name, match_len) != 0) return false; size_t base_len = strlen(base_name); if (base_len != match_len + 2 && base_len != match_len + 3) return false; return memcmp(base_name + base_len - 2, ".o", 2) == 0; } private: // The Input_section we are sorting. Input_section input_section_; // The index of this Input_section in the original list. unsigned int index_; // Whether this Input_section has a section name--it won't if this // is some random Output_section_data. bool section_has_name_; // The section name if there is one. std::string section_name_; }; // Return true if S1 should come before S2 in the output section. bool Output_section::Input_section_sort_compare::operator()( const Output_section::Input_section_sort_entry& s1, const Output_section::Input_section_sort_entry& s2) const { // crtbegin.o must come first. bool s1_begin = s1.match_file_name("crtbegin"); bool s2_begin = s2.match_file_name("crtbegin"); if (s1_begin || s2_begin) { if (!s1_begin) return false; if (!s2_begin) return true; return s1.index() < s2.index(); } // crtend.o must come last. bool s1_end = s1.match_file_name("crtend"); bool s2_end = s2.match_file_name("crtend"); if (s1_end || s2_end) { if (!s1_end) return true; if (!s2_end) return false; return s1.index() < s2.index(); } // We sort all the sections with no names to the end. if (!s1.section_has_name() || !s2.section_has_name()) { if (s1.section_has_name()) return true; if (s2.section_has_name()) return false; return s1.index() < s2.index(); } // A section with a priority follows a section without a priority. // The GNU linker does this for all but .init_array sections; until // further notice we'll assume that that is an mistake. bool s1_has_priority = s1.has_priority(); bool s2_has_priority = s2.has_priority(); if (s1_has_priority && !s2_has_priority) return false; if (!s1_has_priority && s2_has_priority) return true; // Otherwise we sort by name. int compare = s1.section_name().compare(s2.section_name()); if (compare != 0) return compare < 0; // Otherwise we keep the input order. return s1.index() < s2.index(); } // Sort the input sections attached to an output section. void Output_section::sort_attached_input_sections() { if (this->attached_input_sections_are_sorted_) return; if (this->checkpoint_ != NULL && !this->checkpoint_->input_sections_saved()) this->checkpoint_->save_input_sections(); // The only thing we know about an input section is the object and // the section index. We need the section name. Recomputing this // is slow but this is an unusual case. If this becomes a speed // problem we can cache the names as required in Layout::layout. // We start by building a larger vector holding a copy of each // Input_section, plus its current index in the list and its name. std::vector<Input_section_sort_entry> sort_list; unsigned int i = 0; for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p, ++i) sort_list.push_back(Input_section_sort_entry(*p, i)); // Sort the input sections. std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_compare()); // Copy the sorted input sections back to our list. this->input_sections_.clear(); for (std::vector<Input_section_sort_entry>::iterator p = sort_list.begin(); p != sort_list.end(); ++p) this->input_sections_.push_back(p->input_section()); // Remember that we sorted the input sections, since we might get // called again. this->attached_input_sections_are_sorted_ = true; } // 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_); elfcpp::Elf_Xword flags = this->flags_; if (this->info_section_ != NULL && this->info_uses_section_index_) flags |= elfcpp::SHF_INFO_LINK; oshdr->put_sh_flags(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_); elfcpp::Elf_Word info; if (this->info_section_ != NULL) { if (this->info_uses_section_index_) info = this->info_section_->out_shndx(); else info = this->info_section_->symtab_index(); } else if (this->info_symndx_ != NULL) info = this->info_symndx_->symtab_index(); else info = this->info_; oshdr->put_sh_info(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) { gold_assert(!this->requires_postprocessing()); // If the target performs relaxation, we delay filler generation until now. gold_assert(!this->generate_code_fills_at_write_ || this->fills_.empty()); 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(parameters->target().code_fill(p->length())); of->write(output_section_file_offset + p->section_offset(), fill_data.data(), fill_data.size()); } off_t off = this->offset() + this->first_input_offset_; for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { off_t aligned_off = align_address(off, p->addralign()); if (this->generate_code_fills_at_write_ && (off != aligned_off)) { size_t fill_len = aligned_off - off; std::string fill_data(parameters->target().code_fill(fill_len)); of->write(off, fill_data.data(), fill_data.size()); } p->write(of); off = aligned_off + p->data_size(); } } // If a section requires postprocessing, create the buffer to use. void Output_section::create_postprocessing_buffer() { gold_assert(this->requires_postprocessing()); if (this->postprocessing_buffer_ != NULL) return; if (!this->input_sections_.empty()) { off_t off = 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->finalize_data_size(); off += p->data_size(); } this->set_current_data_size_for_child(off); } off_t buffer_size = this->current_data_size_for_child(); this->postprocessing_buffer_ = new unsigned char[buffer_size]; } // Write all the data of an Output_section into the postprocessing // buffer. This is used for sections which require postprocessing, // such as compression. Input sections are handled by // Object::Relocate. void Output_section::write_to_postprocessing_buffer() { gold_assert(this->requires_postprocessing()); // If the target performs relaxation, we delay filler generation until now. gold_assert(!this->generate_code_fills_at_write_ || this->fills_.empty()); unsigned char* buffer = this->postprocessing_buffer(); for (Fill_list::iterator p = this->fills_.begin(); p != this->fills_.end(); ++p) { std::string fill_data(parameters->target().code_fill(p->length())); memcpy(buffer + p->section_offset(), fill_data.data(), fill_data.size()); } off_t off = this->first_input_offset_; for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { off_t aligned_off = align_address(off, p->addralign()); if (this->generate_code_fills_at_write_ && (off != aligned_off)) { size_t fill_len = aligned_off - off; std::string fill_data(parameters->target().code_fill(fill_len)); memcpy(buffer + off, fill_data.data(), fill_data.size()); } p->write_to_buffer(buffer + aligned_off); off = aligned_off + p->data_size(); } } // Get the input sections for linker script processing. We leave // behind the Output_section_data entries. Note that this may be // slightly incorrect for merge sections. We will leave them behind, // but it is possible that the script says that they should follow // some other input sections, as in: // .rodata { *(.rodata) *(.rodata.cst*) } // For that matter, we don't handle this correctly: // .rodata { foo.o(.rodata.cst*) *(.rodata.cst*) } // With luck this will never matter. uint64_t Output_section::get_input_sections( uint64_t address, const std::string& fill, std::list<Simple_input_section>* input_sections) { if (this->checkpoint_ != NULL && !this->checkpoint_->input_sections_saved()) this->checkpoint_->save_input_sections(); // Invalidate the relaxed input section map. this->is_relaxed_input_section_map_valid_ = false; uint64_t orig_address = address; address = align_address(address, this->addralign()); Input_section_list remaining; for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { if (p->is_input_section()) input_sections->push_back(Simple_input_section(p->relobj(), p->shndx())); else if (p->is_relaxed_input_section()) input_sections->push_back( Simple_input_section(p->relaxed_input_section())); else { uint64_t aligned_address = align_address(address, p->addralign()); if (aligned_address != address && !fill.empty()) { section_size_type length = convert_to_section_size_type(aligned_address - address); std::string this_fill; this_fill.reserve(length); while (this_fill.length() + fill.length() <= length) this_fill += fill; if (this_fill.length() < length) this_fill.append(fill, 0, length - this_fill.length()); Output_section_data* posd = new Output_data_const(this_fill, 0); remaining.push_back(Input_section(posd)); } address = aligned_address; remaining.push_back(*p); p->finalize_data_size(); address += p->data_size(); } } this->input_sections_.swap(remaining); this->first_input_offset_ = 0; uint64_t data_size = address - orig_address; this->set_current_data_size_for_child(data_size); return data_size; } // Add an input section from a script. void Output_section::add_input_section_for_script(const Simple_input_section& sis, off_t data_size, uint64_t addralign) { if (addralign > this->addralign_) this->addralign_ = addralign; off_t offset_in_section = this->current_data_size_for_child(); off_t aligned_offset_in_section = align_address(offset_in_section, addralign); this->set_current_data_size_for_child(aligned_offset_in_section + data_size); Input_section is = (sis.is_relaxed_input_section() ? Input_section(sis.relaxed_input_section()) : Input_section(sis.relobj(), sis.shndx(), data_size, addralign)); this->input_sections_.push_back(is); } // void Output_section::save_states() { gold_assert(this->checkpoint_ == NULL); Checkpoint_output_section* checkpoint = new Checkpoint_output_section(this->addralign_, this->flags_, this->input_sections_, this->first_input_offset_, this->attached_input_sections_are_sorted_); this->checkpoint_ = checkpoint; gold_assert(this->fills_.empty()); } void Output_section::restore_states() { gold_assert(this->checkpoint_ != NULL); Checkpoint_output_section* checkpoint = this->checkpoint_; this->addralign_ = checkpoint->addralign(); this->flags_ = checkpoint->flags(); this->first_input_offset_ = checkpoint->first_input_offset(); if (!checkpoint->input_sections_saved()) { // If we have not copied the input sections, just resize it. size_t old_size = checkpoint->input_sections_size(); gold_assert(this->input_sections_.size() >= old_size); this->input_sections_.resize(old_size); } else { // We need to copy the whole list. This is not efficient for // extremely large output with hundreads of thousands of input // objects. We may need to re-think how we should pass sections // to scripts. this->input_sections_ = *checkpoint->input_sections(); } this->attached_input_sections_are_sorted_ = checkpoint->attached_input_sections_are_sorted(); // Simply invalidate the relaxed input section map since we do not keep // track of it. this->is_relaxed_input_section_map_valid_ = false; } // Print to the map file. void Output_section::do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_section(this); for (Input_section_list::const_iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) p->print_to_mapfile(mapfile); } // Print stats for merge sections to stderr. void Output_section::print_merge_stats() { Input_section_list::iterator p; for (p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) p->print_merge_stats(this->name_); } // 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), max_align_(0), min_p_align_(0), offset_(0), filesz_(0), type_(type), flags_(flags), is_max_align_known_(false), are_addresses_set_(false), is_large_data_segment_(false) { } // Add an Output_section to an Output_segment. void Output_segment::add_output_section(Output_section* os, elfcpp::Elf_Word seg_flags, bool do_sort) { gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0); gold_assert(!this->is_max_align_known_); gold_assert(os->is_large_data_section() == this->is_large_data_segment()); gold_assert(this->type() == elfcpp::PT_LOAD || !do_sort); // 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_; // 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. The loops below are expected to be fast. // So that PT_NOTE segments will work correctly, we need to ensure // that all SHT_NOTE sections are adjacent. 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)) { ++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. SHF_TLS sections get added to both a PT_LOAD segment // and the PT_TLS segment; we do this grouping only for the PT_LOAD // segment. if (this->type_ != elfcpp::PT_TLS && (os->flags() & elfcpp::SHF_TLS) != 0) { pdl = &this->output_data_; if (!pdl->empty()) { bool nobits = os->type() == elfcpp::SHT_NOBITS; bool sawtls = false; Output_segment::Output_data_list::iterator p = pdl->end(); gold_assert(p != pdl->begin()); do { --p; bool insert; if ((*p)->is_section_flag_set(elfcpp::SHF_TLS)) { sawtls = true; // Put a NOBITS section after the first TLS section. // Put 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) { ++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. } // For the PT_GNU_RELRO segment, we need to group relro sections, // and we need to put them before any non-relro sections. Also, // relro local sections go before relro non-local sections. if (parameters->options().relro() && os->is_relro()) { gold_assert(pdl == &this->output_data_); Output_segment::Output_data_list::iterator p; for (p = pdl->begin(); p != pdl->end(); ++p) { if (!(*p)->is_section()) break; Output_section* pos = (*p)->output_section(); if (!pos->is_relro() || (os->is_relro_local() && !pos->is_relro_local())) break; } pdl->insert(p, os); return; } // Small data sections go at the end of the list of data sections. // If OS is not small, and there are small sections, we have to // insert it before the first small section. if (os->type() != elfcpp::SHT_NOBITS && !os->is_small_section() && !pdl->empty() && pdl->back()->is_section() && pdl->back()->output_section()->is_small_section()) { for (Output_segment::Output_data_list::iterator p = pdl->begin(); p != pdl->end(); ++p) { if ((*p)->is_section() && (*p)->output_section()->is_small_section()) { pdl->insert(p, os); return; } } gold_unreachable(); } // A small BSS section goes at the start of the BSS sections, after // other small BSS sections. if (os->type() == elfcpp::SHT_NOBITS && os->is_small_section()) { for (Output_segment::Output_data_list::iterator p = pdl->begin(); p != pdl->end(); ++p) { if (!(*p)->is_section() || !(*p)->output_section()->is_small_section()) { pdl->insert(p, os); return; } } } // A large BSS section goes at the end of the BSS sections, which // means that one that is not large must come before the first large // one. if (os->type() == elfcpp::SHT_NOBITS && !os->is_large_section() && !pdl->empty() && pdl->back()->is_section() && pdl->back()->output_section()->is_large_section()) { for (Output_segment::Output_data_list::iterator p = pdl->begin(); p != pdl->end(); ++p) { if ((*p)->is_section() && (*p)->output_section()->is_large_section()) { pdl->insert(p, os); return; } } gold_unreachable(); } // We do some further output section sorting in order to make the // generated program run more efficiently. We should only do this // when not using a linker script, so it is controled by the DO_SORT // parameter. if (do_sort) { // FreeBSD requires the .interp section to be in the first page // of the executable. That is a more efficient location anyhow // for any OS, since it means that the kernel will have the data // handy after it reads the program headers. if (os->is_interp() && !pdl->empty()) { pdl->insert(pdl->begin(), os); return; } // Put loadable non-writable notes immediately after the .interp // sections, so that the PT_NOTE segment is on the first page of // the executable. if (os->type() == elfcpp::SHT_NOTE && (os->flags() & elfcpp::SHF_WRITE) == 0 && !pdl->empty()) { Output_segment::Output_data_list::iterator p = pdl->begin(); if ((*p)->is_section() && (*p)->output_section()->is_interp()) ++p; pdl->insert(p, os); return; } // If this section is used by the dynamic linker, and it is not // writable, then put it first, after the .interp section and // any loadable notes. This makes it more likely that the // dynamic linker will have to read less data from the disk. if (os->is_dynamic_linker_section() && !pdl->empty() && (os->flags() & elfcpp::SHF_WRITE) == 0) { bool is_reloc = (os->type() == elfcpp::SHT_REL || os->type() == elfcpp::SHT_RELA); Output_segment::Output_data_list::iterator p = pdl->begin(); while (p != pdl->end() && (*p)->is_section() && ((*p)->output_section()->is_dynamic_linker_section() || (*p)->output_section()->type() == elfcpp::SHT_NOTE)) { // Put reloc sections after the other ones. Putting the // dynamic reloc sections first confuses BFD, notably // objcopy and strip. if (!is_reloc && ((*p)->output_section()->type() == elfcpp::SHT_REL || (*p)->output_section()->type() == elfcpp::SHT_RELA)) break; ++p; } pdl->insert(p, os); return; } } // If there were no constraints on the output section, just add it // to the end of the list. pdl->push_back(os); } // Remove an Output_section from this segment. It is an error if it // is not present. void Output_segment::remove_output_section(Output_section* os) { // We only need this for SHT_PROGBITS. gold_assert(os->type() == elfcpp::SHT_PROGBITS); for (Output_data_list::iterator p = this->output_data_.begin(); p != this->output_data_.end(); ++p) { if (*p == os) { this->output_data_.erase(p); return; } } gold_unreachable(); } // 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_max_align_known_); this->output_data_.push_front(od); } // Return whether the first data section is a relro section. bool Output_segment::is_first_section_relro() const { return (!this->output_data_.empty() && this->output_data_.front()->is_section() && this->output_data_.front()->output_section()->is_relro()); } // Return the maximum alignment of the Output_data in Output_segment. uint64_t Output_segment::maximum_alignment() { if (!this->is_max_align_known_) { uint64_t addralign; addralign = Output_segment::maximum_alignment_list(&this->output_data_); if (addralign > this->max_align_) this->max_align_ = addralign; addralign = Output_segment::maximum_alignment_list(&this->output_bss_); if (addralign > this->max_align_) this->max_align_ = addralign; // If -z relro is in effect, and the first section in this // segment is a relro section, then the segment must be aligned // to at least the common page size. This ensures that the // PT_GNU_RELRO segment will start at a page boundary. if (this->type_ == elfcpp::PT_LOAD && parameters->options().relro() && this->is_first_section_relro()) { addralign = parameters->target().common_pagesize(); if (addralign > this->max_align_) this->max_align_ = addralign; } this->is_max_align_known_ = true; } return this->max_align_; } // Return the maximum alignment of a list of Output_data. uint64_t Output_segment::maximum_alignment_list(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; } // Return the number of dynamic relocs applied to this segment. unsigned int Output_segment::dynamic_reloc_count() const { return (this->dynamic_reloc_count_list(&this->output_data_) + this->dynamic_reloc_count_list(&this->output_bss_)); } // Return the number of dynamic relocs applied to an Output_data_list. unsigned int Output_segment::dynamic_reloc_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) count += (*p)->dynamic_reloc_count(); return count; } // Set the section addresses for an Output_segment. If RESET is true, // reset the addresses first. 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(const Layout* layout, bool reset, uint64_t addr, off_t* poff, unsigned int* pshndx) { gold_assert(this->type_ == elfcpp::PT_LOAD); if (!reset && this->are_addresses_set_) { gold_assert(this->paddr_ == addr); addr = this->vaddr_; } else { this->vaddr_ = addr; this->paddr_ = addr; this->are_addresses_set_ = true; } bool in_tls = false; bool in_relro = (parameters->options().relro() && this->is_first_section_relro()); off_t orig_off = *poff; this->offset_ = orig_off; addr = this->set_section_list_addresses(layout, reset, &this->output_data_, addr, poff, pshndx, &in_tls, &in_relro); this->filesz_ = *poff - orig_off; off_t off = *poff; uint64_t ret = this->set_section_list_addresses(layout, reset, &this->output_bss_, addr, poff, pshndx, &in_tls, &in_relro); // If the last section was a TLS section, align upward to the // alignment of the TLS segment, so that the overall size of the TLS // segment is aligned. if (in_tls) { uint64_t segment_align = layout->tls_segment()->maximum_alignment(); *poff = align_address(*poff, segment_align); } // If all the sections were relro sections, align upward to the // common page size. if (in_relro) { uint64_t page_align = parameters->target().common_pagesize(); *poff = align_address(*poff, page_align); } 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(const Layout* layout, bool reset, Output_data_list* pdl, uint64_t addr, off_t* poff, unsigned int* pshndx, bool* in_tls, bool* in_relro) { off_t startoff = *poff; off_t off = startoff; for (Output_data_list::iterator p = pdl->begin(); p != pdl->end(); ++p) { if (reset) (*p)->reset_address_and_file_offset(); // When using a linker script the section will most likely // already have an address. if (!(*p)->is_address_valid()) { uint64_t align = (*p)->addralign(); if ((*p)->is_section_flag_set(elfcpp::SHF_TLS)) { // Give the first TLS section the alignment of the // entire TLS segment. Otherwise the TLS segment as a // whole may be misaligned. if (!*in_tls) { Output_segment* tls_segment = layout->tls_segment(); gold_assert(tls_segment != NULL); uint64_t segment_align = tls_segment->maximum_alignment(); gold_assert(segment_align >= align); align = segment_align; *in_tls = true; } } else { // If this is the first section after the TLS segment, // align it to at least the alignment of the TLS // segment, so that the size of the overall TLS segment // is aligned. if (*in_tls) { uint64_t segment_align = layout->tls_segment()->maximum_alignment(); if (segment_align > align) align = segment_align; *in_tls = false; } } // If this is a non-relro section after a relro section, // align it to a common page boundary so that the dynamic // linker has a page to mark as read-only. if (*in_relro && (!(*p)->is_section() || !(*p)->output_section()->is_relro())) { uint64_t page_align = parameters->target().common_pagesize(); if (page_align > align) align = page_align; *in_relro = false; } off = align_address(off, align); (*p)->set_address_and_file_offset(addr + (off - startoff), off); } else { // The script may have inserted a skip forward, but it // better not have moved backward. if ((*p)->address() >= addr + (off - startoff)) off += (*p)->address() - (addr + (off - startoff)); else { if (!layout->script_options()->saw_sections_clause()) gold_unreachable(); else { Output_section* os = (*p)->output_section(); // Cast to unsigned long long to avoid format warnings. unsigned long long previous_dot = static_cast<unsigned long long>(addr + (off - startoff)); unsigned long long dot = static_cast<unsigned long long>((*p)->address()); if (os == NULL) gold_error(_("dot moves backward in linker script " "from 0x%llx to 0x%llx"), previous_dot, dot); else gold_error(_("address of section '%s' moves backward " "from 0x%llx to 0x%llx"), os->name(), previous_dot, dot); } } (*p)->set_file_offset(off); (*p)->finalize_data_size(); } // We want to ignore the size of a SHF_TLS or SHT_NOBITS // section. Such a section does not affect the size of a // PT_LOAD segment. if (!(*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); gold_assert(!this->are_addresses_set_); if (this->output_data_.empty() && this->output_bss_.empty()) { this->vaddr_ = 0; this->paddr_ = 0; this->are_addresses_set_ = true; this->memsz_ = 0; this->min_p_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_ = (first->has_load_address() ? first->load_address() : this->vaddr_); this->are_addresses_set_ = true; 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_); // If this is a TLS segment, align the memory size. The code in // set_section_list ensures that the section after the TLS segment // is aligned to give us room. if (this->type_ == elfcpp::PT_TLS) { uint64_t segment_align = this->maximum_alignment(); gold_assert(this->vaddr_ == align_address(this->vaddr_, segment_align)); this->memsz_ = align_address(this->memsz_, segment_align); } // If this is a RELRO segment, align the memory size. The code in // set_section_list ensures that the section after the RELRO segment // is aligned to give us room. if (this->type_ == elfcpp::PT_GNU_RELRO) { uint64_t page_align = parameters->target().common_pagesize(); gold_assert(this->vaddr_ == align_address(this->vaddr_, page_align)); this->memsz_ = align_address(this->memsz_, page_align); } } // Set the TLS offsets of the sections in the PT_TLS segment. void Output_segment::set_tls_offsets() { gold_assert(this->type_ == elfcpp::PT_TLS); for (Output_data_list::iterator p = this->output_data_.begin(); p != this->output_data_.end(); ++p) (*p)->set_tls_offset(this->vaddr_); for (Output_data_list::iterator p = this->output_bss_.begin(); p != this->output_bss_.end(); ++p) (*p)->set_tls_offset(this->vaddr_); } // Return the address of the first section. uint64_t Output_segment::first_section_load_address() const { for (Output_data_list::const_iterator p = this->output_data_.begin(); p != this->output_data_.end(); ++p) if ((*p)->is_section()) return (*p)->has_load_address() ? (*p)->load_address() : (*p)->address(); for (Output_data_list::const_iterator p = this->output_bss_.begin(); p != this->output_bss_.end(); ++p) if ((*p)->is_section()) return (*p)->has_load_address() ? (*p)->load_address() : (*p)->address(); gold_unreachable(); } // 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; } // Return the section attached to the list segment with the lowest // load address. This is used when handling a PHDRS clause in a // linker script. Output_section* Output_segment::section_with_lowest_load_address() const { Output_section* found = NULL; uint64_t found_lma = 0; this->lowest_load_address_in_list(&this->output_data_, &found, &found_lma); Output_section* found_data = found; this->lowest_load_address_in_list(&this->output_bss_, &found, &found_lma); if (found != found_data && found_data != NULL) { gold_error(_("nobits section %s may not precede progbits section %s " "in same segment"), found->name(), found_data->name()); return NULL; } return found; } // Look through a list for a section with a lower load address. void Output_segment::lowest_load_address_in_list(const Output_data_list* pdl, Output_section** found, uint64_t* found_lma) const { for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) { if (!(*p)->is_section()) continue; Output_section* os = static_cast<Output_section*>(*p); uint64_t lma = (os->has_load_address() ? os->load_address() : os->address()); if (*found == NULL || lma < *found_lma) { *found = os; *found_lma = lma; } } } // 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(std::max(this->min_p_align_, this->maximum_alignment())); } // 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) 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<size, big_endian>(layout, secnamepool, &this->output_data_, v, pshndx); v = this->write_section_headers_list<size, big_endian>(layout, secnamepool, &this->output_bss_, v, pshndx); 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) 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; } // Print the output sections to the map file. void Output_segment::print_sections_to_mapfile(Mapfile* mapfile) const { if (this->type() != elfcpp::PT_LOAD) return; this->print_section_list_to_mapfile(mapfile, &this->output_data_); this->print_section_list_to_mapfile(mapfile, &this->output_bss_); } // Print an output section list to the map file. void Output_segment::print_section_list_to_mapfile(Mapfile* mapfile, const Output_data_list* pdl) const { for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) (*p)->print_to_mapfile(mapfile); } // Output_file methods. Output_file::Output_file(const char* name) : name_(name), o_(-1), file_size_(0), base_(NULL), map_is_anonymous_(false), is_temporary_(false) { } // Try to open an existing file. Returns false if the file doesn't // exist, has a size of 0 or can't be mmapped. bool Output_file::open_for_modification() { // The name "-" means "stdout". if (strcmp(this->name_, "-") == 0) return false; // Don't bother opening files with a size of zero. struct stat s; if (::stat(this->name_, &s) != 0 || s.st_size == 0) return false; int o = open_descriptor(-1, this->name_, O_RDWR, 0); if (o < 0) gold_fatal(_("%s: open: %s"), this->name_, strerror(errno)); this->o_ = o; this->file_size_ = s.st_size; // If the file can't be mmapped, copying the content to an anonymous // map will probably negate the performance benefits of incremental // linking. This could be helped by using views and loading only // the necessary parts, but this is not supported as of now. if (!this->map_no_anonymous()) { release_descriptor(o, true); this->o_ = -1; this->file_size_ = 0; return false; } return true; } // 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(). // We let the name "-" mean "stdout" if (!this->is_temporary_) { if (strcmp(this->name_, "-") == 0) this->o_ = STDOUT_FILENO; else { struct stat s; if (::stat(this->name_, &s) == 0 && (S_ISREG (s.st_mode) || S_ISLNK (s.st_mode))) { if (s.st_size != 0) ::unlink(this->name_); else if (!parameters->options().relocatable()) { // If we don't unlink the existing file, add execute // permission where read permissions already exist // and where the umask permits. int mask = ::umask(0); ::umask(mask); s.st_mode |= (s.st_mode & 0444) >> 2; ::chmod(this->name_, s.st_mode & ~mask); } } int mode = parameters->options().relocatable() ? 0666 : 0777; int o = open_descriptor(-1, this->name_, O_RDWR | O_CREAT | O_TRUNC, mode); if (o < 0) gold_fatal(_("%s: open: %s"), this->name_, strerror(errno)); this->o_ = o; } } this->map(); } // Resize the output file. void Output_file::resize(off_t file_size) { // If the mmap is mapping an anonymous memory buffer, this is easy: // just mremap to the new size. If it's mapping to a file, we want // to unmap to flush to the file, then remap after growing the file. if (this->map_is_anonymous_) { void* base = ::mremap(this->base_, this->file_size_, file_size, MREMAP_MAYMOVE); if (base == MAP_FAILED) gold_fatal(_("%s: mremap: %s"), this->name_, strerror(errno)); this->base_ = static_cast<unsigned char*>(base); this->file_size_ = file_size; } else { this->unmap(); this->file_size_ = file_size; if (!this->map_no_anonymous()) gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno)); } } // Map an anonymous block of memory which will later be written to the // file. Return whether the map succeeded. bool Output_file::map_anonymous() { void* base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (base != MAP_FAILED) { this->map_is_anonymous_ = true; this->base_ = static_cast<unsigned char*>(base); return true; } return false; } // Map the file into memory. Return whether the mapping succeeded. bool Output_file::map_no_anonymous() { const int o = this->o_; // If the output file is not a regular file, don't try to mmap it; // instead, we'll mmap a block of memory (an anonymous buffer), and // then later write the buffer to the file. void* base; struct stat statbuf; if (o == STDOUT_FILENO || o == STDERR_FILENO || ::fstat(o, &statbuf) != 0 || !S_ISREG(statbuf.st_mode) || this->is_temporary_) return false; // Ensure that we have disk space available for the file. If we // don't do this, it is possible that we will call munmap, close, // and exit with dirty buffers still in the cache with no assigned // disk blocks. If the disk is out of space at that point, the // output file will wind up incomplete, but we will have already // exited. The alternative to fallocate would be to use fdatasync, // but that would be a more significant performance hit. if (::posix_fallocate(o, 0, this->file_size_) < 0) gold_fatal(_("%s: %s"), this->name_, strerror(errno)); // Map the file into memory. base = ::mmap(NULL, this->file_size_, PROT_READ | PROT_WRITE, MAP_SHARED, o, 0); // The mmap call might fail because of file system issues: the file // system might not support mmap at all, or it might not support // mmap with PROT_WRITE. if (base == MAP_FAILED) return false; this->map_is_anonymous_ = false; this->base_ = static_cast<unsigned char*>(base); return true; } // Map the file into memory. void Output_file::map() { if (this->map_no_anonymous()) return; // The mmap call might fail because of file system issues: the file // system might not support mmap at all, or it might not support // mmap with PROT_WRITE. I'm not sure which errno values we will // see in all cases, so if the mmap fails for any reason and we // don't care about file contents, try for an anonymous map. if (this->map_anonymous()) return; gold_fatal(_("%s: mmap: failed to allocate %lu bytes for output file: %s"), this->name_, static_cast<unsigned long>(this->file_size_), strerror(errno)); } // Unmap the file from memory. void Output_file::unmap() { if (::munmap(this->base_, this->file_size_) < 0) gold_error(_("%s: munmap: %s"), this->name_, strerror(errno)); this->base_ = NULL; } // Close the output file. void Output_file::close() { // If the map isn't file-backed, we need to write it now. if (this->map_is_anonymous_ && !this->is_temporary_) { size_t bytes_to_write = this->file_size_; size_t offset = 0; while (bytes_to_write > 0) { ssize_t bytes_written = ::write(this->o_, this->base_ + offset, bytes_to_write); if (bytes_written == 0) gold_error(_("%s: write: unexpected 0 return-value"), this->name_); else if (bytes_written < 0) gold_error(_("%s: write: %s"), this->name_, strerror(errno)); else { bytes_to_write -= bytes_written; offset += bytes_written; } } } this->unmap(); // We don't close stdout or stderr if (this->o_ != STDOUT_FILENO && this->o_ != STDERR_FILENO && !this->is_temporary_) 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>( Sized_relobj<32, false>* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<32, false>& shdr, unsigned int reloc_shndx, bool have_sections_script); #endif #ifdef HAVE_TARGET_32_BIG template off_t Output_section::add_input_section<32, true>( Sized_relobj<32, true>* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<32, true>& shdr, unsigned int reloc_shndx, bool have_sections_script); #endif #ifdef HAVE_TARGET_64_LITTLE template off_t Output_section::add_input_section<64, false>( Sized_relobj<64, false>* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<64, false>& shdr, unsigned int reloc_shndx, bool have_sections_script); #endif #ifdef HAVE_TARGET_64_BIG template off_t Output_section::add_input_section<64, true>( Sized_relobj<64, true>* object, unsigned int shndx, const char* secname, const elfcpp::Shdr<64, true>& shdr, unsigned int reloc_shndx, bool have_sections_script); #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_reloc<elfcpp::SHT_REL, false, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc<elfcpp::SHT_REL, false, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc<elfcpp::SHT_REL, false, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc<elfcpp::SHT_REL, false, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_reloc<elfcpp::SHT_REL, true, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc<elfcpp::SHT_REL, true, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc<elfcpp::SHT_REL, true, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc<elfcpp::SHT_REL, true, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_reloc<elfcpp::SHT_RELA, false, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc<elfcpp::SHT_RELA, false, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc<elfcpp::SHT_RELA, false, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc<elfcpp::SHT_RELA, false, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_reloc<elfcpp::SHT_RELA, true, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc<elfcpp::SHT_RELA, true, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc<elfcpp::SHT_RELA, true, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc<elfcpp::SHT_RELA, true, 64, true>; #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_relocatable_relocs<elfcpp::SHT_REL, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_relocatable_relocs<elfcpp::SHT_REL, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_relocatable_relocs<elfcpp::SHT_REL, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_relocatable_relocs<elfcpp::SHT_REL, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_relocatable_relocs<elfcpp::SHT_RELA, 32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_relocatable_relocs<elfcpp::SHT_RELA, 32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_relocatable_relocs<elfcpp::SHT_RELA, 64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_relocatable_relocs<elfcpp::SHT_RELA, 64, true>; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_group<32, false>; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_group<32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_group<64, false>; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_group<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.
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