// output.cc -- manage the output file for gold // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012 // Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 3 of the License, or // (at your option) any later version. // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, // MA 02110-1301, USA. #include "gold.h" #include #include #include #include #include #include #include #ifdef HAVE_SYS_MMAN_H #include #endif #include "libiberty.h" #include "dwarf.h" #include "parameters.h" #include "object.h" #include "symtab.h" #include "reloc.h" #include "merge.h" #include "descriptors.h" #include "layout.h" #include "output.h" // For systems without mmap support. #ifndef HAVE_MMAP # define mmap gold_mmap # define munmap gold_munmap # define mremap gold_mremap # ifndef MAP_FAILED # define MAP_FAILED (reinterpret_cast(-1)) # endif # ifndef PROT_READ # define PROT_READ 0 # endif # ifndef PROT_WRITE # define PROT_WRITE 0 # endif # ifndef MAP_PRIVATE # define MAP_PRIVATE 0 # endif # ifndef MAP_ANONYMOUS # define MAP_ANONYMOUS 0 # endif # ifndef MAP_SHARED # define MAP_SHARED 0 # endif # ifndef ENOSYS # define ENOSYS EINVAL # endif static void * gold_mmap(void *, size_t, int, int, int, off_t) { errno = ENOSYS; return MAP_FAILED; } static int gold_munmap(void *, size_t) { errno = ENOSYS; return -1; } static void * gold_mremap(void *, size_t, size_t, int) { errno = ENOSYS; return MAP_FAILED; } #endif #if defined(HAVE_MMAP) && !defined(HAVE_MREMAP) # define mremap gold_mremap extern "C" void *gold_mremap(void *, size_t, size_t, int); #endif // Some BSD systems still use MAP_ANON instead of MAP_ANONYMOUS #ifndef MAP_ANONYMOUS # define MAP_ANONYMOUS MAP_ANON #endif #ifndef MREMAP_MAYMOVE # define MREMAP_MAYMOVE 1 #endif // Mingw does not have S_ISLNK. #ifndef S_ISLNK # define S_ISLNK(mode) 0 #endif namespace gold { // A wrapper around posix_fallocate. If we don't have posix_fallocate, // or the --no-posix-fallocate option is set, we try the fallocate // system call directly. If that fails, we use ftruncate to set // the file size and hope that there is enough disk space. static int gold_fallocate(int o, off_t offset, off_t len) { #ifdef HAVE_POSIX_FALLOCATE if (parameters->options().posix_fallocate()) return ::posix_fallocate(o, offset, len); #endif // defined(HAVE_POSIX_FALLOCATE) #ifdef HAVE_FALLOCATE if (::fallocate(o, 0, offset, len) == 0) return 0; #endif // defined(HAVE_FALLOCATE) if (::ftruncate(o, offset + len) < 0) return errno; return 0; } // 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 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::shdr_size; unsigned char* v = view; { typename elfcpp::Shdr_write 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::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); size_t segment_count = this->segment_list_->size(); oshdr.put_sh_info(segment_count >= elfcpp::PN_XNUM ? segment_count : 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(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 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 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) { this->set_current_data_size_for_child(this->do_size()); } 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 void Output_segment_headers::do_sized_write(Output_file* of) { const int phdr_size = elfcpp::Elf_sizes::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 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) : target_(target), symtab_(symtab), segment_header_(osh), section_header_(NULL), shstrtab_(NULL) { 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 endianness. template void Output_file_header::do_sized_write(Output_file* of) { gold_assert(this->offset() == 0); int ehdr_size = elfcpp::Elf_sizes::ehdr_size; unsigned char* view = of->get_output_view(0, ehdr_size); elfcpp::Ehdr_write 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()); 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()); oehdr.put_e_flags(this->target_->processor_specific_flags()); oehdr.put_e_ehsize(elfcpp::Elf_sizes::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::phdr_size); size_t phnum = (this->segment_header_->data_size() / elfcpp::Elf_sizes::phdr_size); if (phnum > elfcpp::PN_XNUM) phnum = elfcpp::PN_XNUM; oehdr.put_e_phnum(phnum); } oehdr.put_e_shentsize(elfcpp::Elf_sizes::shdr_size); size_t section_count = (this->section_header_->data_size() / elfcpp::Elf_sizes::shdr_size); if (section_count < elfcpp::SHN_LORESERVE) oehdr.put_e_shnum(this->section_header_->data_size() / elfcpp::Elf_sizes::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. template typename elfcpp::Elf_types::Elf_Addr Output_file_header::entry() { const bool should_issue_warning = (parameters->options().entry() != NULL && !parameters->options().relocatable() && !parameters->options().shared()); const char* entry = parameters->entry(); Symbol* sym = this->symtab_->lookup(entry); typename Sized_symbol::Value_type v; if (sym != NULL) { Sized_symbol* ssym; ssym = this->symtab_->get_sized_symbol(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 Output_reloc::Output_reloc( Symbol* gsym, unsigned int type, Output_data* od, Address address, bool is_relative, bool is_symbolless, bool use_plt_offset) : address_(address), local_sym_index_(GSYM_CODE), type_(type), is_relative_(is_relative), is_symbolless_(is_symbolless), is_section_symbol_(false), use_plt_offset_(use_plt_offset), 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 Output_reloc::Output_reloc( Symbol* gsym, unsigned int type, Sized_relobj* relobj, unsigned int shndx, Address address, bool is_relative, bool is_symbolless, bool use_plt_offset) : address_(address), local_sym_index_(GSYM_CODE), type_(type), is_relative_(is_relative), is_symbolless_(is_symbolless), is_section_symbol_(false), use_plt_offset_(use_plt_offset), 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 Output_reloc::Output_reloc( Sized_relobj* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address, bool is_relative, bool is_symbolless, bool is_section_symbol, bool use_plt_offset) : address_(address), local_sym_index_(local_sym_index), type_(type), is_relative_(is_relative), is_symbolless_(is_symbolless), is_section_symbol_(is_section_symbol), use_plt_offset_(use_plt_offset), 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 Output_reloc::Output_reloc( Sized_relobj* relobj, unsigned int local_sym_index, unsigned int type, unsigned int shndx, Address address, bool is_relative, bool is_symbolless, bool is_section_symbol, bool use_plt_offset) : address_(address), local_sym_index_(local_sym_index), type_(type), is_relative_(is_relative), is_symbolless_(is_symbolless), is_section_symbol_(is_section_symbol), use_plt_offset_(use_plt_offset), 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 Output_reloc::Output_reloc( Output_section* os, unsigned int type, Output_data* od, Address address, bool is_relative) : address_(address), local_sym_index_(SECTION_CODE), type_(type), is_relative_(is_relative), is_symbolless_(is_relative), is_section_symbol_(true), use_plt_offset_(false), 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 Output_reloc::Output_reloc( Output_section* os, unsigned int type, Sized_relobj* relobj, unsigned int shndx, Address address, bool is_relative) : address_(address), local_sym_index_(SECTION_CODE), type_(type), is_relative_(is_relative), is_symbolless_(is_relative), is_section_symbol_(true), use_plt_offset_(false), 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(); } // An absolute relocation. template Output_reloc::Output_reloc( unsigned int type, Output_data* od, Address address) : address_(address), local_sym_index_(0), type_(type), is_relative_(false), is_symbolless_(false), is_section_symbol_(false), use_plt_offset_(false), shndx_(INVALID_CODE) { // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.relobj = NULL; this->u2_.od = od; } template Output_reloc::Output_reloc( unsigned int type, Sized_relobj* relobj, unsigned int shndx, Address address) : address_(address), local_sym_index_(0), type_(type), is_relative_(false), is_symbolless_(false), is_section_symbol_(false), use_plt_offset_(false), shndx_(shndx) { gold_assert(shndx != INVALID_CODE); // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.relobj = NULL; this->u2_.relobj = relobj; } // A target specific relocation. template Output_reloc::Output_reloc( unsigned int type, void* arg, Output_data* od, Address address) : address_(address), local_sym_index_(TARGET_CODE), type_(type), is_relative_(false), is_symbolless_(false), is_section_symbol_(false), use_plt_offset_(false), shndx_(INVALID_CODE) { // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.arg = arg; this->u2_.od = od; } template Output_reloc::Output_reloc( unsigned int type, void* arg, Sized_relobj* relobj, unsigned int shndx, Address address) : address_(address), local_sym_index_(TARGET_CODE), type_(type), is_relative_(false), is_symbolless_(false), is_section_symbol_(false), use_plt_offset_(false), shndx_(shndx) { gold_assert(shndx != INVALID_CODE); // this->type_ is a bitfield; make sure TYPE fits. gold_assert(this->type_ == type); this->u1_.arg = arg; this->u2_.relobj = relobj; } // Record that we need a dynamic symbol index for this relocation. template void Output_reloc:: set_needs_dynsym_index() { if (this->is_symbolless_) 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 TARGET_CODE: // The target must take care of this if necessary. break; case 0: break; default: { const unsigned int lsi = this->local_sym_index_; Sized_relobj_file* relobj = this->u1_.relobj->sized_relobj(); gold_assert(relobj != NULL); if (!this->is_section_symbol_) relobj->set_needs_output_dynsym_entry(lsi); else relobj->output_section(lsi)->set_needs_dynsym_index(); } break; } } // Get the symbol index of a relocation. template unsigned int Output_reloc::get_symbol_index() const { unsigned int index; if (this->is_symbolless_) return 0; 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 TARGET_CODE: index = parameters->target().reloc_symbol_index(this->u1_.arg, this->type_); break; case 0: // Relocations without symbols use a symbol index of 0. index = 0; break; default: { const unsigned int lsi = this->local_sym_index_; Sized_relobj_file* relobj = this->u1_.relobj->sized_relobj(); gold_assert(relobj != NULL); if (!this->is_section_symbol_) { if (dynamic) index = relobj->dynsym_index(lsi); else index = relobj->symtab_index(lsi); } else { Output_section* os = 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 typename elfcpp::Elf_types::Elf_Addr Output_reloc:: local_section_offset(Addend addend) const { gold_assert(this->local_sym_index_ != GSYM_CODE && this->local_sym_index_ != SECTION_CODE && this->local_sym_index_ != TARGET_CODE && this->local_sym_index_ != INVALID_CODE && this->local_sym_index_ != 0 && 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. Sized_relobj_file* relobj = this->u1_.relobj->sized_relobj(); gold_assert(relobj != NULL); offset = os->output_address(relobj, lsi, addend); gold_assert(offset != invalid_address); return offset; } // Get the output address of a relocation. template typename elfcpp::Elf_types::Elf_Addr Output_reloc::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 { Sized_relobj_file* relobj = this->u2_.relobj->sized_relobj(); gold_assert(relobj != NULL); address = os->output_address(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 template void Output_reloc::write_rel( Write_rel* wr) const { wr->put_r_offset(this->get_address()); unsigned int sym_index = this->get_symbol_index(); wr->put_r_info(elfcpp::elf_r_info(sym_index, this->type_)); } // Write out a Rel relocation. template void Output_reloc::write( unsigned char* pov) const { elfcpp::Rel_write orel(pov); this->write_rel(&orel); } // Get the value of the symbol referred to by a Rel relocation. template typename elfcpp::Elf_types::Elf_Addr Output_reloc::symbol_value( Addend addend) const { if (this->local_sym_index_ == GSYM_CODE) { const Sized_symbol* sym; sym = static_cast*>(this->u1_.gsym); if (this->use_plt_offset_ && sym->has_plt_offset()) { uint64_t plt_address = parameters->target().plt_address_for_global(sym); return plt_address + sym->plt_offset(); } else return sym->value() + addend; } if (this->local_sym_index_ == SECTION_CODE) { gold_assert(!this->use_plt_offset_); return this->u1_.os->address() + addend; } gold_assert(this->local_sym_index_ != TARGET_CODE && this->local_sym_index_ != INVALID_CODE && this->local_sym_index_ != 0 && !this->is_section_symbol_); const unsigned int lsi = this->local_sym_index_; Sized_relobj_file* relobj = this->u1_.relobj->sized_relobj(); gold_assert(relobj != NULL); if (this->use_plt_offset_) { uint64_t plt_address = parameters->target().plt_address_for_local(relobj, lsi); return plt_address + relobj->local_plt_offset(lsi); } const Symbol_value* symval = relobj->local_symbol(lsi); return symval->value(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 int Output_reloc:: compare(const Output_reloc& 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 void Output_reloc::write( unsigned char* pov) const { elfcpp::Rela_write orel(pov); this->rel_.write_rel(&orel); Addend addend = this->addend_; if (this->rel_.is_target_specific()) addend = parameters->target().reloc_addend(this->rel_.target_arg(), this->rel_.type(), addend); else if (this->rel_.is_symbolless()) 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 void Output_data_reloc_base ::do_adjust_output_section(Output_section* os) { if (sh_type == elfcpp::SHT_REL) os->set_entsize(elfcpp::Elf_sizes::rel_size); else if (sh_type == elfcpp::SHT_RELA) os->set_entsize(elfcpp::Elf_sizes::rela_size); else gold_unreachable(); // A STT_GNU_IFUNC symbol may require a IRELATIVE reloc when doing a // static link. The backends will generate a dynamic reloc section // to hold this. In that case we don't want to link to the dynsym // section, because there isn't one. if (!dynamic) os->set_should_link_to_symtab(); else if (parameters->doing_static_link()) ; else os->set_should_link_to_dynsym(); } // Write out relocation data. template void Output_data_reloc_base::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 void Output_relocatable_relocs::set_final_data_size() { this->set_data_size(this->rr_->output_reloc_count() * Reloc_types::reloc_size); } // class Output_data_group. template Output_data_group::Output_data_group( Sized_relobj_file* relobj, section_size_type entry_count, elfcpp::Elf_Word flags, std::vector* 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 void Output_data_group::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(oview); elfcpp::Swap<32, big_endian>::writeval(contents, this->flags_); ++contents; for (std::vector::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(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 void Output_data_got::Got_entry::write( unsigned int got_indx, 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; if (this->use_plt_or_tls_offset_ && gsym->has_plt_offset()) val = (parameters->target().plt_address_for_global(gsym) + gsym->plt_offset()); else { switch (parameters->size_and_endianness()) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) case Parameters::TARGET_32_LITTLE: case Parameters::TARGET_32_BIG: { // This cast is ugly. We don't want to put a // virtual method in Symbol, because we want Symbol // to be as small as possible. Sized_symbol<32>::Value_type v; v = static_cast*>(gsym)->value(); val = convert_types::Value_type>(v); } break; #endif #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) case Parameters::TARGET_64_LITTLE: case Parameters::TARGET_64_BIG: { Sized_symbol<64>::Value_type v; v = static_cast*>(gsym)->value(); val = convert_types::Value_type>(v); } break; #endif default: gold_unreachable(); } if (this->use_plt_or_tls_offset_ && gsym->type() == elfcpp::STT_TLS) val += parameters->target().tls_offset_for_global(gsym, got_indx); } } break; case CONSTANT_CODE: val = this->u_.constant; break; case RESERVED_CODE: // If we're doing an incremental update, don't touch this GOT entry. if (parameters->incremental_update()) return; val = this->u_.constant; break; default: { const Relobj* object = this->u_.object; const unsigned int lsi = this->local_sym_index_; bool is_tls = object->local_is_tls(lsi); if (this->use_plt_or_tls_offset_ && !is_tls) { uint64_t plt_address = parameters->target().plt_address_for_local(object, lsi); val = plt_address + object->local_plt_offset(lsi); } else { uint64_t lval = object->local_symbol_value(lsi, 0); val = convert_types(lval); if (this->use_plt_or_tls_offset_ && is_tls) val += parameters->target().tls_offset_for_local(object, lsi, got_indx); } } break; } elfcpp::Swap::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 bool Output_data_got::add_global( Symbol* gsym, unsigned int got_type) { if (gsym->has_got_offset(got_type)) return false; unsigned int got_offset = this->add_got_entry(Got_entry(gsym, false)); gsym->set_got_offset(got_type, got_offset); return true; } // Like add_global, but use the PLT offset. template bool Output_data_got::add_global_plt(Symbol* gsym, unsigned int got_type) { if (gsym->has_got_offset(got_type)) return false; unsigned int got_offset = this->add_got_entry(Got_entry(gsym, true)); gsym->set_got_offset(got_type, 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 void Output_data_got::add_global_with_rel( Symbol* gsym, unsigned int got_type, Output_data_reloc_generic* rel_dyn, unsigned int r_type) { if (gsym->has_got_offset(got_type)) return; unsigned int got_offset = this->add_got_entry(Got_entry()); gsym->set_got_offset(got_type, got_offset); rel_dyn->add_global_generic(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 void Output_data_got::add_global_pair_with_rel( Symbol* gsym, unsigned int got_type, Output_data_reloc_generic* rel_dyn, unsigned int r_type_1, unsigned int r_type_2) { if (gsym->has_got_offset(got_type)) return; unsigned int got_offset = this->add_got_entry_pair(Got_entry(), Got_entry()); gsym->set_got_offset(got_type, got_offset); rel_dyn->add_global_generic(gsym, r_type_1, this, got_offset, 0); if (r_type_2 != 0) rel_dyn->add_global_generic(gsym, r_type_2, this, got_offset + got_size / 8, 0); } // 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 bool Output_data_got::add_local( Relobj* object, unsigned int symndx, unsigned int got_type) { if (object->local_has_got_offset(symndx, got_type)) return false; unsigned int got_offset = this->add_got_entry(Got_entry(object, symndx, false)); object->set_local_got_offset(symndx, got_type, got_offset); return true; } // Like add_local, but use the PLT offset. template bool Output_data_got::add_local_plt( Relobj* object, unsigned int symndx, unsigned int got_type) { if (object->local_has_got_offset(symndx, got_type)) return false; unsigned int got_offset = this->add_got_entry(Got_entry(object, symndx, true)); object->set_local_got_offset(symndx, got_type, 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 void Output_data_got::add_local_with_rel( Relobj* object, unsigned int symndx, unsigned int got_type, Output_data_reloc_generic* rel_dyn, unsigned int r_type) { if (object->local_has_got_offset(symndx, got_type)) return; unsigned int got_offset = this->add_got_entry(Got_entry()); object->set_local_got_offset(symndx, got_type, got_offset); rel_dyn->add_local_generic(object, symndx, r_type, this, got_offset, 0); } // Add a pair of entries for a local symbol to the GOT, and add // a dynamic relocation of type R_TYPE using the section symbol of // the output section to which input section SHNDX maps, on the first. // The first got entry will have a value of zero, the second the // value of the local symbol. template void Output_data_got::add_local_pair_with_rel( Relobj* object, unsigned int symndx, unsigned int shndx, unsigned int got_type, Output_data_reloc_generic* rel_dyn, unsigned int r_type) { if (object->local_has_got_offset(symndx, got_type)) return; unsigned int got_offset = this->add_got_entry_pair(Got_entry(), Got_entry(object, symndx, false)); object->set_local_got_offset(symndx, got_type, got_offset); Output_section* os = object->output_section(shndx); rel_dyn->add_output_section_generic(os, r_type, this, got_offset, 0); } // Add a pair of entries for a local symbol to the GOT, and add // a dynamic relocation of type R_TYPE using STN_UNDEF on the first. // The first got entry will have a value of zero, the second the // value of the local symbol offset by Target::tls_offset_for_local. template void Output_data_got::add_local_tls_pair( Relobj* object, unsigned int symndx, unsigned int got_type, Output_data_reloc_generic* rel_dyn, unsigned int r_type) { if (object->local_has_got_offset(symndx, got_type)) return; unsigned int got_offset = this->add_got_entry_pair(Got_entry(), Got_entry(object, symndx, true)); object->set_local_got_offset(symndx, got_type, got_offset); rel_dyn->add_local_generic(object, 0, r_type, this, got_offset, 0); } // Reserve a slot in the GOT for a local symbol or the second slot of a pair. template void Output_data_got::reserve_local( unsigned int i, Relobj* object, unsigned int sym_index, unsigned int got_type) { this->do_reserve_slot(i); object->set_local_got_offset(sym_index, got_type, this->got_offset(i)); } // Reserve a slot in the GOT for a global symbol. template void Output_data_got::reserve_global( unsigned int i, Symbol* gsym, unsigned int got_type) { this->do_reserve_slot(i); gsym->set_got_offset(got_type, this->got_offset(i)); } // Write out the GOT. template void Output_data_got::do_write(Output_file* of) { const int add = got_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 (unsigned int i = 0; i < this->entries_.size(); ++i) { this->entries_[i].write(i, 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(); } // Create a new GOT entry and return its offset. template unsigned int Output_data_got::add_got_entry(Got_entry got_entry) { if (!this->is_data_size_valid()) { this->entries_.push_back(got_entry); this->set_got_size(); return this->last_got_offset(); } else { // For an incremental update, find an available slot. off_t got_offset = this->free_list_.allocate(got_size / 8, got_size / 8, 0); if (got_offset == -1) gold_fallback(_("out of patch space (GOT);" " relink with --incremental-full")); unsigned int got_index = got_offset / (got_size / 8); gold_assert(got_index < this->entries_.size()); this->entries_[got_index] = got_entry; return static_cast(got_offset); } } // Create a pair of new GOT entries and return the offset of the first. template unsigned int Output_data_got::add_got_entry_pair( Got_entry got_entry_1, Got_entry got_entry_2) { if (!this->is_data_size_valid()) { unsigned int got_offset; this->entries_.push_back(got_entry_1); got_offset = this->last_got_offset(); this->entries_.push_back(got_entry_2); this->set_got_size(); return got_offset; } else { // For an incremental update, find an available pair of slots. off_t got_offset = this->free_list_.allocate(2 * got_size / 8, got_size / 8, 0); if (got_offset == -1) gold_fallback(_("out of patch space (GOT);" " relink with --incremental-full")); unsigned int got_index = got_offset / (got_size / 8); gold_assert(got_index < this->entries_.size()); this->entries_[got_index] = got_entry_1; this->entries_[got_index + 1] = got_entry_2; return static_cast(got_offset); } } // Replace GOT entry I with a new value. template void Output_data_got::replace_got_entry( unsigned int i, Got_entry got_entry) { gold_assert(i < this->entries_.size()); this->entries_[i] = got_entry; } // Output_data_dynamic::Dynamic_entry methods. // Write out the entry. template void Output_data_dynamic::Dynamic_entry::write( unsigned char* pov, const Stringpool* pool) const { typename elfcpp::Elf_types::Elf_WXword val; switch (this->offset_) { case DYNAMIC_NUMBER: val = this->u_.val; break; case DYNAMIC_SECTION_SIZE: val = this->u_.od->data_size(); if (this->od2 != NULL) val += this->od2->data_size(); break; case DYNAMIC_SYMBOL: { const Sized_symbol* s = static_cast*>(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 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_.back().tag() != elfcpp::DT_NULL) { int extra = parameters->options().spare_dynamic_tags(); for (int i = 0; i < extra; ++i) this->add_constant(elfcpp::DT_NULL, 0); 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 void Output_data_dynamic::sized_write(Output_file* of) { const int dyn_size = elfcpp::Elf_sizes::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(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(oview); else this->endian_do_write(oview); of->write_output_view(offset, oview_size, oview); // We no longer need the data. this->entries_.clear(); } template 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_fill_debug_info methods. // Return the minimum size needed for a dummy compilation unit header. size_t Output_fill_debug_info::do_minimum_hole_size() const { // Compile unit header fields: unit_length, version, debug_abbrev_offset, // address_size. const size_t len = 4 + 2 + 4 + 1; // For type units, add type_signature, type_offset. if (this->is_debug_types_) return len + 8 + 4; return len; } // Write a dummy compilation unit header to fill a hole in the // .debug_info or .debug_types section. void Output_fill_debug_info::do_write(Output_file* of, off_t off, size_t len) const { gold_debug(DEBUG_INCREMENTAL, "fill_debug_info(%08lx, %08lx)", static_cast(off), static_cast(len)); gold_assert(len >= this->do_minimum_hole_size()); unsigned char* const oview = of->get_output_view(off, len); unsigned char* pov = oview; // Write header fields: unit_length, version, debug_abbrev_offset, // address_size. if (this->is_big_endian()) { elfcpp::Swap_unaligned<32, true>::writeval(pov, len - 4); elfcpp::Swap_unaligned<16, true>::writeval(pov + 4, this->version); elfcpp::Swap_unaligned<32, true>::writeval(pov + 6, 0); } else { elfcpp::Swap_unaligned<32, false>::writeval(pov, len - 4); elfcpp::Swap_unaligned<16, false>::writeval(pov + 4, this->version); elfcpp::Swap_unaligned<32, false>::writeval(pov + 6, 0); } pov += 4 + 2 + 4; *pov++ = 4; // For type units, the additional header fields -- type_signature, // type_offset -- can be filled with zeroes. // Fill the remainder of the free space with zeroes. The first // zero should tell the consumer there are no DIEs to read in this // compilation unit. if (pov < oview + len) memset(pov, 0, oview + len - pov); of->write_output_view(off, len, oview); } // Output_fill_debug_line methods. // Return the minimum size needed for a dummy line number program header. size_t Output_fill_debug_line::do_minimum_hole_size() const { // Line number program header fields: unit_length, version, header_length, // minimum_instruction_length, default_is_stmt, line_base, line_range, // opcode_base, standard_opcode_lengths[], include_directories, filenames. const size_t len = 4 + 2 + 4 + this->header_length; return len; } // Write a dummy line number program header to fill a hole in the // .debug_line section. void Output_fill_debug_line::do_write(Output_file* of, off_t off, size_t len) const { gold_debug(DEBUG_INCREMENTAL, "fill_debug_line(%08lx, %08lx)", static_cast(off), static_cast(len)); gold_assert(len >= this->do_minimum_hole_size()); unsigned char* const oview = of->get_output_view(off, len); unsigned char* pov = oview; // Write header fields: unit_length, version, header_length, // minimum_instruction_length, default_is_stmt, line_base, line_range, // opcode_base, standard_opcode_lengths[], include_directories, filenames. // We set the header_length field to cover the entire hole, so the // line number program is empty. if (this->is_big_endian()) { elfcpp::Swap_unaligned<32, true>::writeval(pov, len - 4); elfcpp::Swap_unaligned<16, true>::writeval(pov + 4, this->version); elfcpp::Swap_unaligned<32, true>::writeval(pov + 6, len - (4 + 2 + 4)); } else { elfcpp::Swap_unaligned<32, false>::writeval(pov, len - 4); elfcpp::Swap_unaligned<16, false>::writeval(pov + 4, this->version); elfcpp::Swap_unaligned<32, false>::writeval(pov + 6, len - (4 + 2 + 4)); } pov += 4 + 2 + 4; *pov++ = 1; // minimum_instruction_length *pov++ = 0; // default_is_stmt *pov++ = 0; // line_base *pov++ = 5; // line_range *pov++ = 13; // opcode_base *pov++ = 0; // standard_opcode_lengths[1] *pov++ = 1; // standard_opcode_lengths[2] *pov++ = 1; // standard_opcode_lengths[3] *pov++ = 1; // standard_opcode_lengths[4] *pov++ = 1; // standard_opcode_lengths[5] *pov++ = 0; // standard_opcode_lengths[6] *pov++ = 0; // standard_opcode_lengths[7] *pov++ = 0; // standard_opcode_lengths[8] *pov++ = 1; // standard_opcode_lengths[9] *pov++ = 0; // standard_opcode_lengths[10] *pov++ = 0; // standard_opcode_lengths[11] *pov++ = 1; // standard_opcode_lengths[12] *pov++ = 0; // include_directories (empty) *pov++ = 0; // filenames (empty) // Some consumers don't check the header_length field, and simply // start reading the line number program immediately following the // header. For those consumers, we fill the remainder of the free // space with DW_LNS_set_basic_block opcodes. These are effectively // no-ops: the resulting line table program will not create any rows. if (pov < oview + len) memset(pov, elfcpp::DW_LNS_set_basic_block, oview + len - pov); of->write_output_view(off, len, oview); } // Output_section::Input_section methods. // Return the current 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::current_data_size() const { if (this->is_input_section()) return this->u1_.data_size; else { this->u2_.posd->pre_finalize_data_size(); return this->u2_.posd->current_data_size(); } } // 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(); } // Return the object for an input section. Relobj* Output_section::Input_section::relobj() const { if (this->is_input_section()) return this->u2_.object; else if (this->is_merge_section()) { gold_assert(this->u2_.pomb->first_relobj() != NULL); return this->u2_.pomb->first_relobj(); } else if (this->is_relaxed_input_section()) return this->u2_.poris->relobj(); else gold_unreachable(); } // Return the input section index for an input section. unsigned int Output_section::Input_section::shndx() const { if (this->is_input_section()) return this->shndx_; else if (this->is_merge_section()) { gold_assert(this->u2_.pomb->first_relobj() != NULL); return this->u2_.pomb->first_shndx(); } else if (this->is_relaxed_input_section()) return this->u2_.poris->shndx(); else gold_unreachable(); } // 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), order_(ORDER_INVALID), 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), input_section_order_specified_(false), may_sort_attached_input_sections_(false), must_sort_attached_input_sections_(false), attached_input_sections_are_sorted_(false), is_relro_(false), is_small_section_(false), is_large_section_(false), generate_code_fills_at_write_(false), is_entsize_zero_(false), section_offsets_need_adjustment_(false), is_noload_(false), always_keeps_input_sections_(false), has_fixed_layout_(false), is_patch_space_allowed_(false), is_unique_segment_(false), tls_offset_(0), extra_segment_flags_(0), segment_alignment_(0), checkpoint_(NULL), lookup_maps_(new Output_section_lookup_maps), free_list_(), free_space_fill_(NULL), patch_space_(0) { // 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->is_entsize_zero_) ; else if (this->entsize_ == 0) this->entsize_ = v; else if (this->entsize_ != v) { this->entsize_ = 0; this->is_entsize_zero_ = 1; } } // 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 off_t Output_section::add_input_section(Layout* layout, Sized_relobj_file* object, unsigned int shndx, const char* secname, const elfcpp::Shdr& 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(addralign), secname); addralign = 1; } if (addralign > this->addralign_) this->addralign_ = addralign; typename elfcpp::Elf_types::Elf_WXword sh_flags = shdr.get_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; } this->update_flags_for_input_section(sh_flags); this->set_entsize(entsize); // 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. // FIXME: Need to handle merge sections during incremental update. if ((sh_flags & elfcpp::SHF_MERGE) != 0 && reloc_shndx == 0 && shdr.get_sh_size() > 0 && !parameters->incremental()) { // Keep information about merged input sections for rebuilding fast // lookup maps if we have sections-script or we do relaxation. bool keeps_input_sections = (this->always_keeps_input_sections_ || have_sections_script || parameters->target().may_relax()); if (this->add_merge_input_section(object, shndx, sh_flags, entsize, addralign, keeps_input_sections)) { // Tell the relocation routines that they need to call the // output_offset method to determine the final address. return -1; } } section_size_type input_section_size = shdr.get_sh_size(); section_size_type uncompressed_size; if (object->section_is_compressed(shndx, &uncompressed_size)) input_section_size = uncompressed_size; off_t offset_in_section; off_t aligned_offset_in_section; if (this->has_fixed_layout()) { // For incremental updates, find a chunk of unused space in the section. offset_in_section = this->free_list_.allocate(input_section_size, addralign, 0); if (offset_in_section == -1) gold_fallback(_("out of patch space in section %s; " "relink with --incremental-full"), this->name()); aligned_offset_in_section = offset_in_section; } else { offset_in_section = this->current_data_size_for_child(); aligned_offset_in_section = align_address(offset_in_section, addralign); this->set_current_data_size_for_child(aligned_offset_in_section + input_section_size); } // 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. Also, if we are // sorting input sections we must delay fill generation. 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() || layout->is_section_ordering_specified())) { 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)); } } // 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 the // --section-ordering-file option is used to specify the order of // sections, we need to keep track of sections. if (this->always_keeps_input_sections_ || 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() || layout->is_section_ordering_specified()) { Input_section isecn(object, shndx, input_section_size, addralign); /* If section ordering is requested by specifying a ordering file, using --section-ordering-file, match the section name with a pattern. */ if (parameters->options().section_ordering_file()) { unsigned int section_order_index = layout->find_section_order_index(std::string(secname)); if (section_order_index != 0) { isecn.set_section_order_index(section_order_index); this->set_input_section_order_specified(); } } if (this->has_fixed_layout()) { // For incremental updates, finalize the address and offset now. uint64_t addr = this->address(); isecn.set_address_and_file_offset(addr + aligned_offset_in_section, aligned_offset_in_section, this->offset()); } this->input_sections_.push_back(isecn); } 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; if (this->has_fixed_layout()) { // For incremental updates, find a chunk of unused space. offset_in_section = this->free_list_.allocate(posd->data_size(), posd->addralign(), 0); if (offset_in_section == -1) gold_fallback(_("out of patch space in section %s; " "relink with --incremental-full"), this->name()); // Finalize the address and offset now. uint64_t addr = this->address(); off_t offset = this->offset(); posd->set_address_and_file_offset(addr + offset_in_section, offset + offset_in_section); } else { 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()); } } else if (this->has_fixed_layout()) { // For incremental updates, arrange for the data to have a fixed layout. // This will mean that additions to the data must be allocated from // free space within the containing output section. uint64_t addr = this->address(); posd->set_address(addr); posd->set_file_offset(0); // FIXME: This should eventually be unreachable. // gold_unreachable(); } } // Add a relaxed input section. void Output_section::add_relaxed_input_section(Layout* layout, Output_relaxed_input_section* poris, const std::string& name) { Input_section inp(poris); // If the --section-ordering-file option is used to specify the order of // sections, we need to keep track of sections. if (layout->is_section_ordering_specified()) { unsigned int section_order_index = layout->find_section_order_index(name); if (section_order_index != 0) { inp.set_section_order_index(section_order_index); this->set_input_section_order_specified(); } } this->add_output_section_data(&inp); if (this->lookup_maps_->is_valid()) this->lookup_maps_->add_relaxed_input_section(poris->relobj(), poris->shndx(), 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 keeps_input_sections) { 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. // Currently, we only invalidate the lookup maps in script processing // and relaxation. We should not have done either when we reach here. // So we assume that the lookup maps are valid to simply code. gold_assert(this->lookup_maps_->is_valid()); Merge_section_properties msp(is_string, entsize, addralign); Output_merge_base* pomb = this->lookup_maps_->find_merge_section(msp); bool is_new = false; if (pomb != NULL) { gold_assert(pomb->is_string() == is_string && pomb->entsize() == entsize && pomb->addralign() == addralign); } else { // Create a new Output_merge_data or Output_merge_string_data. if (!is_string) pomb = new Output_merge_data(entsize, addralign); else { switch (entsize) { case 1: pomb = new Output_merge_string(addralign); break; case 2: pomb = new Output_merge_string(addralign); break; case 4: pomb = new Output_merge_string(addralign); break; default: return false; } } // If we need to do script processing or relaxation, we need to keep // the original input sections to rebuild the fast lookup maps. if (keeps_input_sections) pomb->set_keeps_input_sections(); is_new = true; } if (pomb->add_input_section(object, shndx)) { // Add new merge section to this output section and link merge // section properties to new merge section in map. if (is_new) { this->add_output_merge_section(pomb, is_string, entsize); this->lookup_maps_->add_merge_section(msp, pomb); } // Add input section to new merge section and link input section to new // merge section in map. this->lookup_maps_->add_merge_input_section(object, shndx, pomb); return true; } else { // If add_input_section failed, delete new merge section to avoid // exporting empty merge sections in Output_section::get_input_section. if (is_new) delete pomb; return false; } } // 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()) { Section_id sid(is.relobj(), is.shndx()); (*relaxation_map)[sid] = i; } } } // Convert regular input sections in INPUT_SECTIONS into relaxed input // sections in RELAXED_SECTIONS. MAP is a prebuilt map from section id // indices of INPUT_SECTIONS. void Output_section::convert_input_sections_in_list_to_relaxed_sections( const std::vector& 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]; Section_id sid(poris->relobj(), poris->shndx()); Relaxation_map::const_iterator p = map.find(sid); gold_assert(p != map.end()); gold_assert((*input_sections)[p->second].is_input_section()); // Remember section order index of original input section // if it is set. Copy it to the relaxed input section. unsigned int soi = (*input_sections)[p->second].section_order_index(); (*input_sections)[p->second] = Input_section(poris); (*input_sections)[p->second].set_section_order_index(soi); } } // 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& 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 fast look-up map. if (this->lookup_maps_->is_valid()) for (size_t i = 0; i < relaxed_sections.size(); ++i) { Output_relaxed_input_section* poris = relaxed_sections[i]; this->lookup_maps_->add_relaxed_input_section(poris->relobj(), poris->shndx(), poris); } } // 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)); if ((flags & elfcpp::SHF_MERGE) == 0) this->flags_ &=~ elfcpp::SHF_MERGE; else { if (this->current_data_size_for_child() == 0) this->flags_ |= elfcpp::SHF_MERGE; } if ((flags & elfcpp::SHF_STRINGS) == 0) this->flags_ &=~ elfcpp::SHF_STRINGS; else { if (this->current_data_size_for_child() == 0) this->flags_ |= elfcpp::SHF_STRINGS; } } // 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 { if (!this->lookup_maps_->is_valid()) this->build_lookup_maps(); return this->lookup_maps_->find_merge_section(object, shndx); } // Build the lookup maps for merge and relaxed sections. This is needs // to be declared as a const methods so that it is callable with a const // Output_section pointer. The method only updates states of the maps. void Output_section::build_lookup_maps() const { this->lookup_maps_->clear(); for (Input_section_list::const_iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { if (p->is_merge_section()) { Output_merge_base* pomb = p->output_merge_base(); Merge_section_properties msp(pomb->is_string(), pomb->entsize(), pomb->addralign()); this->lookup_maps_->add_merge_section(msp, pomb); for (Output_merge_base::Input_sections::const_iterator is = pomb->input_sections_begin(); is != pomb->input_sections_end(); ++is) { const Const_section_id& csid = *is; this->lookup_maps_->add_merge_input_section(csid.first, csid.second, pomb); } } else if (p->is_relaxed_input_section()) { Output_relaxed_input_section* poris = p->relaxed_input_section(); this->lookup_maps_->add_relaxed_input_section(poris->relobj(), poris->shndx(), poris); } } } // Find an relaxed input section corresponding to an input section // in OBJECT with index SHNDX. const Output_relaxed_input_section* Output_section::find_relaxed_input_section(const Relobj* object, unsigned int shndx) const { if (!this->lookup_maps_->is_valid()) this->build_lookup_maps(); return this->lookup_maps_->find_relaxed_input_section(object, shndx); } // 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; } // Update the data size of an Output_section. void Output_section::update_data_size() { if (this->input_sections_.empty()) return; if (this->must_sort_attached_input_sections() || this->input_section_order_specified()) this->sort_attached_input_sections(); 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()); off += p->current_data_size(); } this->set_current_data_size_for_child(off); } // 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() { off_t data_size; if (this->input_sections_.empty()) data_size = this->current_data_size_for_child(); else { if (this->must_sort_attached_input_sections() || this->input_section_order_specified()) 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(); } data_size = off - startoff; } // For full incremental links, we want to allocate some patch space // in most sections for subsequent incremental updates. if (this->is_patch_space_allowed_ && parameters->incremental_full()) { double pct = parameters->options().incremental_patch(); size_t extra = static_cast(data_size * pct); if (this->free_space_fill_ != NULL && this->free_space_fill_->minimum_hole_size() > extra) extra = this->free_space_fill_->minimum_hole_size(); off_t new_size = align_address(data_size + extra, this->addralign()); this->patch_space_ = new_size - data_size; gold_debug(DEBUG_INCREMENTAL, "set_final_data_size: %08lx + %08lx: section %s", static_cast(data_size), static_cast(this->patch_space_), this->name()); data_size = new_size; } this->set_data_size(data_size); } // 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. This does not // apply to NOLOAD sections though. if (((this->flags_ & elfcpp::SHF_ALLOC) == 0) && !this->is_noload_) 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(); // Remove any patch space that was added in set_final_data_size. if (this->patch_space_ > 0) { this->set_current_data_size_for_child(this->current_data_size_for_child() - this->patch_space_); this->patch_space_ = 0; } } // 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 ".ctors.*", ".dtors.*", // ".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, bool must_sort_attached_input_sections) : 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_ && must_sort_attached_input_sections) { // 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(-1); Object* obj = (input_section.is_input_section() ? input_section.relobj() : input_section.relaxed_input_section()->relobj()); Task_lock_obj 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) != std::string::npos; } // Return the priority. Believe it or not, gcc encodes the priority // differently for .ctors/.dtors and .init_array/.fini_array // sections. unsigned int get_priority() const { gold_assert(this->section_has_name_); bool is_ctors; if (is_prefix_of(".ctors.", this->section_name_.c_str()) || is_prefix_of(".dtors.", this->section_name_.c_str())) is_ctors = true; else if (is_prefix_of(".init_array.", this->section_name_.c_str()) || is_prefix_of(".fini_array.", this->section_name_.c_str())) is_ctors = false; else return 0; char* end; unsigned long prio = strtoul((this->section_name_.c_str() + (is_ctors ? 7 : 12)), &end, 10); if (*end != '\0') return 0; else if (is_ctors) return 65535 - prio; else return prio; } // 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* file_name) const { return Layout::match_file_name(this->input_section_.relobj(), file_name); } // Returns 1 if THIS should appear before S in section order, -1 if S // appears before THIS and 0 if they are not comparable. int compare_section_ordering(const Input_section_sort_entry& s) const { unsigned int this_secn_index = this->input_section_.section_order_index(); unsigned int s_secn_index = s.input_section().section_order_index(); if (this_secn_index > 0 && s_secn_index > 0) { if (this_secn_index < s_secn_index) return 1; else if (this_secn_index > s_secn_index) return -1; } return 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. 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; // Check if a section order exists for these sections through a section // ordering file. If sequence_num is 0, an order does not exist. int sequence_num = s1.compare_section_ordering(s2); if (sequence_num != 0) return sequence_num == 1; // 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(); } // Return true if S1 should come before S2 in an .init_array or .fini_array // output section. bool Output_section::Input_section_sort_init_fini_compare::operator()( const Output_section::Input_section_sort_entry& s1, const Output_section::Input_section_sort_entry& s2) const { // 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 without a priority follows a section with a priority. // This is the reverse of .ctors and .dtors sections. bool s1_has_priority = s1.has_priority(); bool s2_has_priority = s2.has_priority(); if (s1_has_priority && !s2_has_priority) return true; if (!s1_has_priority && s2_has_priority) return false; // .ctors and .dtors sections without priority come after // .init_array and .fini_array sections without priority. if (!s1_has_priority && (s1.section_name() == ".ctors" || s1.section_name() == ".dtors") && s1.section_name() != s2.section_name()) return false; if (!s2_has_priority && (s2.section_name() == ".ctors" || s2.section_name() == ".dtors") && s2.section_name() != s1.section_name()) return true; // Sort by priority if we can. if (s1_has_priority) { unsigned int s1_prio = s1.get_priority(); unsigned int s2_prio = s2.get_priority(); if (s1_prio < s2_prio) return true; else if (s1_prio > s2_prio) return false; } // Check if a section order exists for these sections through a section // ordering file. If sequence_num is 0, an order does not exist. int sequence_num = s1.compare_section_ordering(s2); if (sequence_num != 0) return sequence_num == 1; // 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(); } // Return true if S1 should come before S2. Sections that do not match // any pattern in the section ordering file are placed ahead of the sections // that match some pattern. bool Output_section::Input_section_sort_section_order_index_compare::operator()( const Output_section::Input_section_sort_entry& s1, const Output_section::Input_section_sort_entry& s2) const { unsigned int s1_secn_index = s1.input_section().section_order_index(); unsigned int s2_secn_index = s2.input_section().section_order_index(); // Keep input order if section ordering cannot determine order. if (s1_secn_index == s2_secn_index) return s1.index() < s2.index(); return s1_secn_index < s2_secn_index; } // This updates the section order index of input sections according to the // the order specified in the mapping from Section id to order index. void Output_section::update_section_layout( const Section_layout_order* order_map) { for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { if (p->is_input_section() || p->is_relaxed_input_section()) { Object* obj = (p->is_input_section() ? p->relobj() : p->relaxed_input_section()->relobj()); unsigned int shndx = p->shndx(); Section_layout_order::const_iterator it = order_map->find(Section_id(obj, shndx)); if (it == order_map->end()) continue; unsigned int section_order_index = it->second; if (section_order_index != 0) { p->set_section_order_index(section_order_index); this->set_input_section_order_specified(); } } } } // 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 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, this->must_sort_attached_input_sections())); // Sort the input sections. if (this->must_sort_attached_input_sections()) { if (this->type() == elfcpp::SHT_PREINIT_ARRAY || this->type() == elfcpp::SHT_INIT_ARRAY || this->type() == elfcpp::SHT_FINI_ARRAY) std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_init_fini_compare()); else std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_compare()); } else { gold_assert(this->input_section_order_specified()); std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_section_order_index_compare()); } // Copy the sorted input sections back to our list. this->input_sections_.clear(); for (std::vector::iterator p = sort_list.begin(); p != sort_list.end(); ++p) this->input_sections_.push_back(p->input_section()); sort_list.clear(); // 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 void Output_section::write_header(const Layout* layout, const Stringpool* secnamepool, elfcpp::Shdr_write* 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_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(); } // For incremental links, fill in unused chunks in debug sections // with dummy compilation unit headers. if (this->free_space_fill_ != NULL) { for (Free_list::Const_iterator p = this->free_list_.begin(); p != this->free_list_.end(); ++p) { off_t off = p->start_; size_t len = p->end_ - off; this->free_space_fill_->write(of, this->offset() + off, len); } if (this->patch_space_ > 0) { off_t off = this->current_data_size_for_child() - this->patch_space_; this->free_space_fill_->write(of, this->offset() + off, this->patch_space_); } } } // 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* input_sections) { if (this->checkpoint_ != NULL && !this->checkpoint_->input_sections_saved()) this->checkpoint_->save_input_sections(); // Invalidate fast look-up maps. this->lookup_maps_->invalidate(); 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() || p->is_relaxed_input_section() || p->is_merge_section()) input_sections->push_back(*p); 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 a script input section. SIS is an Output_section::Input_section, // which can be either a plain input section or a special input section like // a relaxed input section. For a special input section, its size must be // finalized. void Output_section::add_script_input_section(const Input_section& sis) { uint64_t data_size = sis.data_size(); uint64_t addralign = sis.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); this->input_sections_.push_back(sis); // Update fast lookup maps if necessary. if (this->lookup_maps_->is_valid()) { if (sis.is_merge_section()) { Output_merge_base* pomb = sis.output_merge_base(); Merge_section_properties msp(pomb->is_string(), pomb->entsize(), pomb->addralign()); this->lookup_maps_->add_merge_section(msp, pomb); for (Output_merge_base::Input_sections::const_iterator p = pomb->input_sections_begin(); p != pomb->input_sections_end(); ++p) this->lookup_maps_->add_merge_input_section(p->first, p->second, pomb); } else if (sis.is_relaxed_input_section()) { Output_relaxed_input_section* poris = sis.relaxed_input_section(); this->lookup_maps_->add_relaxed_input_section(poris->relobj(), poris->shndx(), poris); } } } // Save states for relaxation. 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::discard_states() { gold_assert(this->checkpoint_ != NULL); delete this->checkpoint_; this->checkpoint_ = NULL; gold_assert(this->fills_.empty()); // Simply invalidate the fast lookup maps since we do not keep // track of them. this->lookup_maps_->invalidate(); } 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 fast lookup maps since we do not keep // track of them. this->lookup_maps_->invalidate(); } // Update the section offsets of input sections in this. This is required if // relaxation causes some input sections to change sizes. void Output_section::adjust_section_offsets() { if (!this->section_offsets_need_adjustment_) return; off_t off = 0; for (Input_section_list::iterator p = this->input_sections_.begin(); p != this->input_sections_.end(); ++p) { off = align_address(off, p->addralign()); if (p->is_input_section()) p->relobj()->set_section_offset(p->shndx(), off); off += p->data_size(); } this->section_offsets_need_adjustment_ = 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_); } // Set a fixed layout for the section. Used for incremental update links. void Output_section::set_fixed_layout(uint64_t sh_addr, off_t sh_offset, off_t sh_size, uint64_t sh_addralign) { this->addralign_ = sh_addralign; this->set_current_data_size(sh_size); if ((this->flags_ & elfcpp::SHF_ALLOC) != 0) this->set_address(sh_addr); this->set_file_offset(sh_offset); this->finalize_data_size(); this->free_list_.init(sh_size, false); this->has_fixed_layout_ = true; } // Reserve space within the fixed layout for the section. Used for // incremental update links. void Output_section::reserve(uint64_t sh_offset, uint64_t sh_size) { this->free_list_.remove(sh_offset, sh_offset + sh_size); } // Allocate space from the free list for the section. Used for // incremental update links. off_t Output_section::allocate(off_t len, uint64_t addralign) { return this->free_list_.allocate(len, addralign, 0); } // Output segment methods. Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags) : 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), is_unique_segment_(false) { // The ELF ABI specifies that a PT_TLS segment always has PF_R as // the flags. if (type == elfcpp::PT_TLS) this->flags_ = elfcpp::PF_R; } // Add an Output_section to a PT_LOAD Output_segment. void Output_segment::add_output_section_to_load(Layout* layout, Output_section* os, elfcpp::Elf_Word seg_flags) { gold_assert(this->type() == elfcpp::PT_LOAD); 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()); this->update_flags_for_output_section(seg_flags); // We don't want to change the ordering if we have a linker script // with a SECTIONS clause. Output_section_order order = os->order(); if (layout->script_options()->saw_sections_clause()) order = static_cast(0); else gold_assert(order != ORDER_INVALID); this->output_lists_[order].push_back(os); } // Add an Output_section to a non-PT_LOAD Output_segment. void Output_segment::add_output_section_to_nonload(Output_section* os, elfcpp::Elf_Word seg_flags) { gold_assert(this->type() != elfcpp::PT_LOAD); gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0); gold_assert(!this->is_max_align_known_); this->update_flags_for_output_section(seg_flags); this->output_lists_[0].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) { for (int i = 0; i < static_cast(ORDER_MAX); ++i) { Output_data_list* pdl = &this->output_lists_[i]; for (Output_data_list::iterator p = pdl->begin(); p != pdl->end(); ++p) { if (*p == os) { pdl->erase(p); return; } } } gold_unreachable(); } // Add an Output_data (which need not be 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_); Output_data_list::iterator p = this->output_lists_[0].begin(); this->output_lists_[0].insert(p, od); } // Return true if this segment has any sections which hold actual // data, rather than being a BSS section. bool Output_segment::has_any_data_sections() const { for (int i = 0; i < static_cast(ORDER_MAX); ++i) { const Output_data_list* pdl = &this->output_lists_[i]; for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) { if (!(*p)->is_section()) return true; if ((*p)->output_section()->type() != elfcpp::SHT_NOBITS) return true; } } return false; } // Return whether the first data section (not counting TLS sections) // is a relro section. bool Output_segment::is_first_section_relro() const { for (int i = 0; i < static_cast(ORDER_MAX); ++i) { if (i == static_cast(ORDER_TLS_DATA) || i == static_cast(ORDER_TLS_BSS)) continue; const Output_data_list* pdl = &this->output_lists_[i]; if (!pdl->empty()) { Output_data* p = pdl->front(); return p->is_section() && p->output_section()->is_relro(); } } return false; } // Return the maximum alignment of the Output_data in Output_segment. uint64_t Output_segment::maximum_alignment() { if (!this->is_max_align_known_) { for (int i = 0; i < static_cast(ORDER_MAX); ++i) { const Output_data_list* pdl = &this->output_lists_[i]; uint64_t addralign = Output_segment::maximum_alignment_list(pdl); 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 whether this segment has any dynamic relocs. bool Output_segment::has_dynamic_reloc() const { for (int i = 0; i < static_cast(ORDER_MAX); ++i) if (this->has_dynamic_reloc_list(&this->output_lists_[i])) return true; return false; } // Return whether this Output_data_list has any dynamic relocs. bool Output_segment::has_dynamic_reloc_list(const Output_data_list* pdl) const { for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) if ((*p)->has_dynamic_reloc()) return true; return false; } // 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. // INCREASE_RELRO is the size of the portion of the first non-relro // section that should be included in the PT_GNU_RELRO segment. // If this segment has relro sections, and has been aligned for // that purpose, set *HAS_RELRO to TRUE. Return the address of // the immediately following segment. Update *HAS_RELRO, *POFF, // and *PSHNDX. uint64_t Output_segment::set_section_addresses(Layout* layout, bool reset, uint64_t addr, unsigned int* increase_relro, bool* has_relro, off_t* poff, unsigned int* pshndx) { gold_assert(this->type_ == elfcpp::PT_LOAD); uint64_t last_relro_pad = 0; off_t orig_off = *poff; bool in_tls = false; // If we have relro sections, we need to pad forward now so that the // relro sections plus INCREASE_RELRO end on an abi page boundary. if (parameters->options().relro() && this->is_first_section_relro() && (!this->are_addresses_set_ || reset)) { uint64_t relro_size = 0; off_t off = *poff; uint64_t max_align = 0; for (int i = 0; i <= static_cast(ORDER_RELRO_LAST); ++i) { Output_data_list* pdl = &this->output_lists_[i]; Output_data_list::iterator p; for (p = pdl->begin(); p != pdl->end(); ++p) { if (!(*p)->is_section()) break; uint64_t align = (*p)->addralign(); if (align > max_align) max_align = align; if ((*p)->is_section_flag_set(elfcpp::SHF_TLS)) in_tls = true; else if (in_tls) { // Align the first non-TLS section to the alignment // of the TLS segment. align = max_align; in_tls = false; } relro_size = align_address(relro_size, align); // Ignore the size of the .tbss section. if ((*p)->is_section_flag_set(elfcpp::SHF_TLS) && (*p)->is_section_type(elfcpp::SHT_NOBITS)) continue; if ((*p)->is_address_valid()) relro_size += (*p)->data_size(); else { // FIXME: This could be faster. (*p)->set_address_and_file_offset(addr + relro_size, off + relro_size); relro_size += (*p)->data_size(); (*p)->reset_address_and_file_offset(); } } if (p != pdl->end()) break; } relro_size += *increase_relro; // Pad the total relro size to a multiple of the maximum // section alignment seen. uint64_t aligned_size = align_address(relro_size, max_align); // Note the amount of padding added after the last relro section. last_relro_pad = aligned_size - relro_size; *has_relro = true; uint64_t page_align = parameters->target().abi_pagesize(); // Align to offset N such that (N + RELRO_SIZE) % PAGE_ALIGN == 0. uint64_t desired_align = page_align - (aligned_size % page_align); if (desired_align < *poff % page_align) *poff += page_align - *poff % page_align; *poff += desired_align - *poff % page_align; addr += *poff - orig_off; orig_off = *poff; } 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; } in_tls = false; this->offset_ = orig_off; off_t off = 0; uint64_t ret; for (int i = 0; i < static_cast(ORDER_MAX); ++i) { if (i == static_cast(ORDER_RELRO_LAST)) { *poff += last_relro_pad; addr += last_relro_pad; if (this->output_lists_[i].empty()) { // If there is nothing in the ORDER_RELRO_LAST list, // the padding will occur at the end of the relro // segment, and we need to add it to *INCREASE_RELRO. *increase_relro += last_relro_pad; } } addr = this->set_section_list_addresses(layout, reset, &this->output_lists_[i], addr, poff, pshndx, &in_tls); if (i < static_cast(ORDER_SMALL_BSS)) { this->filesz_ = *poff - orig_off; off = *poff; } ret = addr; } // 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); } 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(Layout* layout, bool reset, Output_data_list* pdl, uint64_t addr, off_t* poff, unsigned int* pshndx, bool* in_tls) { off_t startoff = *poff; // For incremental updates, we may allocate non-fixed sections from // free space in the file. This keeps track of the high-water mark. off_t maxoff = startoff; 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 doing an incremental update or 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 (!parameters->incremental_update()) { off = align_address(off, align); (*p)->set_address_and_file_offset(addr + (off - startoff), off); } else { // Incremental update: allocate file space from free list. (*p)->pre_finalize_data_size(); off_t current_size = (*p)->current_data_size(); off = layout->allocate(current_size, align, startoff); if (off == -1) { gold_assert((*p)->output_section() != NULL); gold_fallback(_("out of patch space for section %s; " "relink with --incremental-full"), (*p)->output_section()->name()); } (*p)->set_address_and_file_offset(addr + (off - startoff), off); if ((*p)->data_size() > current_size) { gold_assert((*p)->output_section() != NULL); gold_fallback(_("%s: section changed size; " "relink with --incremental-full"), (*p)->output_section()->name()); } } } else if (parameters->incremental_update()) { // For incremental updates, use the fixed offset for the // high-water mark computation. off = (*p)->offset(); } 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(addr + (off - startoff)); unsigned long long dot = static_cast((*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(); } if (parameters->incremental_update()) gold_debug(DEBUG_INCREMENTAL, "set_section_list_addresses: %08lx %08lx %s", static_cast(off), static_cast((*p)->data_size()), ((*p)->output_section() != NULL ? (*p)->output_section()->name() : "(special)")); // We want to ignore the size of a SHF_TLS SHT_NOBITS // section. Such a section does not affect the size of a // PT_LOAD segment. if (!(*p)->is_section_flag_set(elfcpp::SHF_TLS) || !(*p)->is_section_type(elfcpp::SHT_NOBITS)) off += (*p)->data_size(); if (off > maxoff) maxoff = off; if ((*p)->is_section()) { (*p)->set_out_shndx(*pshndx); ++*pshndx; } } *poff = maxoff; return addr + (maxoff - startoff); } // For a non-PT_LOAD segment, set the offset from the sections, if // any. Add INCREASE to the file size and the memory size. void Output_segment::set_offset(unsigned int increase) { gold_assert(this->type_ != elfcpp::PT_LOAD); gold_assert(!this->are_addresses_set_); // A non-load section only uses output_lists_[0]. Output_data_list* pdl = &this->output_lists_[0]; if (pdl->empty()) { gold_assert(increase == 0); 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; } // Find the first and last section by address. const Output_data* first = NULL; const Output_data* last_data = NULL; const Output_data* last_bss = NULL; for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) { if (first == NULL || (*p)->address() < first->address() || ((*p)->address() == first->address() && (*p)->data_size() < first->data_size())) first = *p; const Output_data** plast; if ((*p)->is_section() && (*p)->output_section()->type() == elfcpp::SHT_NOBITS) plast = &last_bss; else plast = &last_data; if (*plast == NULL || (*p)->address() > (*plast)->address() || ((*p)->address() == (*plast)->address() && (*p)->data_size() > (*plast)->data_size())) *plast = *p; } 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 (last_data == NULL) this->filesz_ = 0; else this->filesz_ = (last_data->address() + last_data->data_size() - this->vaddr_); const Output_data* last = last_bss != NULL ? last_bss : last_data; this->memsz_ = (last->address() + last->data_size() - this->vaddr_); this->filesz_ += increase; this->memsz_ += increase; // If this is a RELRO segment, verify that the segment ends at a // page boundary. if (this->type_ == elfcpp::PT_GNU_RELRO) { uint64_t page_align = parameters->target().abi_pagesize(); uint64_t segment_end = this->vaddr_ + this->memsz_; if (parameters->incremental_update()) { // The INCREASE_RELRO calculation is bypassed for an incremental // update, so we need to adjust the segment size manually here. segment_end = align_address(segment_end, page_align); this->memsz_ = segment_end - this->vaddr_; } else gold_assert(segment_end == align_address(segment_end, page_align)); } // 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); } } // 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_lists_[0].begin(); p != this->output_lists_[0].end(); ++p) (*p)->set_tls_offset(this->vaddr_); } // Return the first section. Output_section* Output_segment::first_section() const { for (int i = 0; i < static_cast(ORDER_MAX); ++i) { const Output_data_list* pdl = &this->output_lists_[i]; for (Output_data_list::const_iterator p = pdl->begin(); p != pdl->end(); ++p) { if ((*p)->is_section()) return (*p)->output_section(); } } gold_unreachable(); } // Return the number of Output_sections in an Output_segment. unsigned int Output_segment::output_section_count() const { unsigned int ret = 0; for (int i = 0; i < static_cast(ORDER_MAX); ++i) ret += this->output_section_count_list(&this->output_lists_[i]); return ret; } // 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; for (int i = 0; i < static_cast(ORDER_MAX); ++i) this->lowest_load_address_in_list(&this->output_lists_[i], &found, &found_lma); 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(*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 void Output_segment::write_header(elfcpp::Phdr_write* 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 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; for (int i = 0; i < static_cast(ORDER_MAX); ++i) { const Output_data_list* pdl = &this->output_lists_[i]; v = this->write_section_headers_list(layout, secnamepool, pdl, v, pshndx); } return v; } template 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::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(*p); gold_assert(*pshndx == ps->out_shndx()); elfcpp::Shdr_write 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; for (int i = 0; i < static_cast(ORDER_MAX); ++i) this->print_section_list_to_mapfile(mapfile, &this->output_lists_[i]); } // 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), map_is_allocated_(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. If BASE_NAME is not // NULL, open that file as the base for incremental linking, and // copy its contents to the new output file. This routine can // be called for incremental updates, in which case WRITABLE should // be true, or by the incremental-dump utility, in which case // WRITABLE should be false. bool Output_file::open_base_file(const char* base_name, bool writable) { // The name "-" means "stdout". if (strcmp(this->name_, "-") == 0) return false; bool use_base_file = base_name != NULL; if (!use_base_file) base_name = this->name_; else if (strcmp(base_name, this->name_) == 0) gold_fatal(_("%s: incremental base and output file name are the same"), base_name); // Don't bother opening files with a size of zero. struct stat s; if (::stat(base_name, &s) != 0) { gold_info(_("%s: stat: %s"), base_name, strerror(errno)); return false; } if (s.st_size == 0) { gold_info(_("%s: incremental base file is empty"), base_name); return false; } // If we're using a base file, we want to open it read-only. if (use_base_file) writable = false; int oflags = writable ? O_RDWR : O_RDONLY; int o = open_descriptor(-1, base_name, oflags, 0); if (o < 0) { gold_info(_("%s: open: %s"), base_name, strerror(errno)); return false; } // If the base file and the output file are different, open a // new output file and read the contents from the base file into // the newly-mapped region. if (use_base_file) { this->open(s.st_size); ssize_t bytes_to_read = s.st_size; unsigned char* p = this->base_; while (bytes_to_read > 0) { ssize_t len = ::read(o, p, bytes_to_read); if (len < 0) { gold_info(_("%s: read failed: %s"), base_name, strerror(errno)); return false; } if (len == 0) { gold_info(_("%s: file too short: read only %lld of %lld bytes"), base_name, static_cast(s.st_size - bytes_to_read), static_cast(s.st_size)); return false; } p += len; bytes_to_read -= len; } ::close(o); return true; } this->o_ = o; this->file_size_ = s.st_size; if (!this->map_no_anonymous(writable)) { 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; if (!this->map_is_allocated_) { base = ::mremap(this->base_, this->file_size_, file_size, MREMAP_MAYMOVE); if (base == MAP_FAILED) gold_fatal(_("%s: mremap: %s"), this->name_, strerror(errno)); } else { base = realloc(this->base_, file_size); if (base == NULL) gold_nomem(); if (file_size > this->file_size_) memset(static_cast(base) + this->file_size_, 0, file_size - this->file_size_); } this->base_ = static_cast(base); this->file_size_ = file_size; } else { this->unmap(); this->file_size_ = file_size; if (!this->map_no_anonymous(true)) 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) { base = malloc(this->file_size_); if (base == NULL) return false; memset(base, 0, this->file_size_); this->map_is_allocated_ = true; } this->base_ = static_cast(base); this->map_is_anonymous_ = true; return true; } // Map the file into memory. Return whether the mapping succeeded. // If WRITABLE is true, map with write access. bool Output_file::map_no_anonymous(bool writable) { 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 (writable) { int err = gold_fallocate(o, 0, this->file_size_); if (err != 0) gold_fatal(_("%s: %s"), this->name_, strerror(err)); } // Map the file into memory. int prot = PROT_READ; if (writable) prot |= PROT_WRITE; base = ::mmap(NULL, this->file_size_, prot, 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(base); return true; } // Map the file into memory. void Output_file::map() { if (parameters->options().mmap_output_file() && this->map_no_anonymous(true)) 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(this->file_size_), strerror(errno)); } // Unmap the file from memory. void Output_file::unmap() { if (this->map_is_anonymous_) { // We've already written out the data, so there is no reason to // waste time unmapping or freeing the memory. } else { 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>( Layout* layout, Sized_relobj_file<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>( Layout* layout, Sized_relobj_file<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>( Layout* layout, Sized_relobj_file<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>( Layout* layout, Sized_relobj_file<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; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_reloc; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_reloc; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_reloc; #endif #ifdef HAVE_TARGET_32_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_data_reloc; #endif #ifdef HAVE_TARGET_64_BIG template class Output_data_reloc; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_relocatable_relocs; #endif #ifdef HAVE_TARGET_32_BIG template class Output_relocatable_relocs; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_relocatable_relocs; #endif #ifdef HAVE_TARGET_64_BIG template class Output_relocatable_relocs; #endif #ifdef HAVE_TARGET_32_LITTLE template class Output_relocatable_relocs; #endif #ifdef HAVE_TARGET_32_BIG template class Output_relocatable_relocs; #endif #ifdef HAVE_TARGET_64_LITTLE template class Output_relocatable_relocs; #endif #ifdef HAVE_TARGET_64_BIG template class Output_relocatable_relocs; #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 template class Output_data_got<32, false>; template class Output_data_got<32, true>; template class Output_data_got<64, false>; template class Output_data_got<64, true>; } // End namespace gold.