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// output.h -- manage the output file for gold -*- C++ -*- // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc. // Written by Ian Lance Taylor <iant@google.com>. // This file is part of gold. // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 3 of the License, or // (at your option) any later version. // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, // MA 02110-1301, USA. #ifndef GOLD_OUTPUT_H #define GOLD_OUTPUT_H #include <list> #include <vector> #include "elfcpp.h" #include "mapfile.h" #include "layout.h" #include "reloc-types.h" namespace gold { class General_options; class Object; class Symbol; class Output_file; class Output_merge_base; class Output_section; class Relocatable_relocs; class Target; template<int size, bool big_endian> class Sized_target; template<int size, bool big_endian> class Sized_relobj; // This class specifies an input section. It is used as a key type // for maps. class Input_section_specifier { public: Input_section_specifier(const Relobj* relobj, unsigned int shndx) : relobj_(relobj), shndx_(shndx) { } // Return Relobj of this. const Relobj* relobj() const { return this->relobj_; } // Return section index of this. unsigned int shndx() const { return this->shndx_; } // Whether this equals to another specifier ISS. bool eq(const Input_section_specifier& iss) const { return this->relobj_ == iss.relobj_ && this->shndx_ == iss.shndx_; } // Compute a hash value of this. size_t hash_value() const { return this->string_hash(this->relobj_->name().c_str()) ^ this->shndx_; } // Functors for containers. struct equal_to { bool operator()(const Input_section_specifier& iss1, const Input_section_specifier& iss2) const { return iss1.eq(iss2); } }; struct hash { size_t operator()(const Input_section_specifier& iss) const { return iss.hash_value(); } }; private: // For portability, we use our own string hash function instead of assuming // __gnu_cxx::hash or std::tr1::hash is available. This is the same hash // function used in Stringpool_template::string_hash. static size_t string_hash(const char* s) { size_t h = 5381; while (*s != '\0') h = h * 33 + *s++; return h; } // An object. const Relobj* relobj_; // A section index. unsigned int shndx_; }; // An abtract class for data which has to go into the output file. class Output_data { public: explicit Output_data() : address_(0), data_size_(0), offset_(-1), is_address_valid_(false), is_data_size_valid_(false), is_offset_valid_(false), is_data_size_fixed_(false), dynamic_reloc_count_(0) { } virtual ~Output_data(); // Return the address. For allocated sections, this is only valid // after Layout::finalize is finished. uint64_t address() const { gold_assert(this->is_address_valid_); return this->address_; } // Return the size of the data. For allocated sections, this must // be valid after Layout::finalize calls set_address, but need not // be valid before then. off_t data_size() const { gold_assert(this->is_data_size_valid_); return this->data_size_; } // Return true if data size is fixed. bool is_data_size_fixed() const { return this->is_data_size_fixed_; } // Return the file offset. This is only valid after // Layout::finalize is finished. For some non-allocated sections, // it may not be valid until near the end of the link. off_t offset() const { gold_assert(this->is_offset_valid_); return this->offset_; } // Reset the address and file offset. This essentially disables the // sanity testing about duplicate and unknown settings. void reset_address_and_file_offset() { this->is_address_valid_ = false; this->is_offset_valid_ = false; if (!this->is_data_size_fixed_) this->is_data_size_valid_ = false; this->do_reset_address_and_file_offset(); } // Return true if address and file offset already have reset values. In // other words, calling reset_address_and_file_offset will not change them. bool address_and_file_offset_have_reset_values() const { return this->do_address_and_file_offset_have_reset_values(); } // Return the required alignment. uint64_t addralign() const { return this->do_addralign(); } // Return whether this has a load address. bool has_load_address() const { return this->do_has_load_address(); } // Return the load address. uint64_t load_address() const { return this->do_load_address(); } // Return whether this is an Output_section. bool is_section() const { return this->do_is_section(); } // Return whether this is an Output_section of the specified type. bool is_section_type(elfcpp::Elf_Word stt) const { return this->do_is_section_type(stt); } // Return whether this is an Output_section with the specified flag // set. bool is_section_flag_set(elfcpp::Elf_Xword shf) const { return this->do_is_section_flag_set(shf); } // Return the output section that this goes in, if there is one. Output_section* output_section() { return this->do_output_section(); } // Return the output section index, if there is an output section. unsigned int out_shndx() const { return this->do_out_shndx(); } // Set the output section index, if this is an output section. void set_out_shndx(unsigned int shndx) { this->do_set_out_shndx(shndx); } // Set the address and file offset of this data, and finalize the // size of the data. This is called during Layout::finalize for // allocated sections. void set_address_and_file_offset(uint64_t addr, off_t off) { this->set_address(addr); this->set_file_offset(off); this->finalize_data_size(); } // Set the address. void set_address(uint64_t addr) { gold_assert(!this->is_address_valid_); this->address_ = addr; this->is_address_valid_ = true; } // Set the file offset. void set_file_offset(off_t off) { gold_assert(!this->is_offset_valid_); this->offset_ = off; this->is_offset_valid_ = true; } // Finalize the data size. void finalize_data_size() { if (!this->is_data_size_valid_) { // Tell the child class to set the data size. this->set_final_data_size(); gold_assert(this->is_data_size_valid_); } } // Set the TLS offset. Called only for SHT_TLS sections. void set_tls_offset(uint64_t tls_base) { this->do_set_tls_offset(tls_base); } // Return the TLS offset, relative to the base of the TLS segment. // Valid only for SHT_TLS sections. uint64_t tls_offset() const { return this->do_tls_offset(); } // Write the data to the output file. This is called after // Layout::finalize is complete. void write(Output_file* file) { this->do_write(file); } // This is called by Layout::finalize to note that the sizes of // allocated sections must now be fixed. static void layout_complete() { Output_data::allocated_sizes_are_fixed = true; } // Used to check that layout has been done. static bool is_layout_complete() { return Output_data::allocated_sizes_are_fixed; } // Count the number of dynamic relocations applied to this section. void add_dynamic_reloc() { ++this->dynamic_reloc_count_; } // Return the number of dynamic relocations applied to this section. unsigned int dynamic_reloc_count() const { return this->dynamic_reloc_count_; } // Whether the address is valid. bool is_address_valid() const { return this->is_address_valid_; } // Whether the file offset is valid. bool is_offset_valid() const { return this->is_offset_valid_; } // Whether the data size is valid. bool is_data_size_valid() const { return this->is_data_size_valid_; } // Print information to the map file. void print_to_mapfile(Mapfile* mapfile) const { return this->do_print_to_mapfile(mapfile); } protected: // Functions that child classes may or in some cases must implement. // Write the data to the output file. virtual void do_write(Output_file*) = 0; // Return the required alignment. virtual uint64_t do_addralign() const = 0; // Return whether this has a load address. virtual bool do_has_load_address() const { return false; } // Return the load address. virtual uint64_t do_load_address() const { gold_unreachable(); } // Return whether this is an Output_section. virtual bool do_is_section() const { return false; } // Return whether this is an Output_section of the specified type. // This only needs to be implement by Output_section. virtual bool do_is_section_type(elfcpp::Elf_Word) const { return false; } // Return whether this is an Output_section with the specific flag // set. This only needs to be implemented by Output_section. virtual bool do_is_section_flag_set(elfcpp::Elf_Xword) const { return false; } // Return the output section, if there is one. virtual Output_section* do_output_section() { return NULL; } // Return the output section index, if there is an output section. virtual unsigned int do_out_shndx() const { gold_unreachable(); } // Set the output section index, if this is an output section. virtual void do_set_out_shndx(unsigned int) { gold_unreachable(); } // This is a hook for derived classes to set the data size. This is // called by finalize_data_size, normally called during // Layout::finalize, when the section address is set. virtual void set_final_data_size() { gold_unreachable(); } // A hook for resetting the address and file offset. virtual void do_reset_address_and_file_offset() { } // Return true if address and file offset already have reset values. In // other words, calling reset_address_and_file_offset will not change them. // A child class overriding do_reset_address_and_file_offset may need to // also override this. virtual bool do_address_and_file_offset_have_reset_values() const { return !this->is_address_valid_ && !this->is_offset_valid_; } // Set the TLS offset. Called only for SHT_TLS sections. virtual void do_set_tls_offset(uint64_t) { gold_unreachable(); } // Return the TLS offset, relative to the base of the TLS segment. // Valid only for SHT_TLS sections. virtual uint64_t do_tls_offset() const { gold_unreachable(); } // Print to the map file. This only needs to be implemented by // classes which may appear in a PT_LOAD segment. virtual void do_print_to_mapfile(Mapfile*) const { gold_unreachable(); } // Functions that child classes may call. // Reset the address. The Output_section class needs this when an // SHF_ALLOC input section is added to an output section which was // formerly not SHF_ALLOC. void mark_address_invalid() { this->is_address_valid_ = false; } // Set the size of the data. void set_data_size(off_t data_size) { gold_assert(!this->is_data_size_valid_ && !this->is_data_size_fixed_); this->data_size_ = data_size; this->is_data_size_valid_ = true; } // Fix the data size. Once it is fixed, it cannot be changed // and the data size remains always valid. void fix_data_size() { gold_assert(this->is_data_size_valid_); this->is_data_size_fixed_ = true; } // Get the current data size--this is for the convenience of // sections which build up their size over time. off_t current_data_size_for_child() const { return this->data_size_; } // Set the current data size--this is for the convenience of // sections which build up their size over time. void set_current_data_size_for_child(off_t data_size) { gold_assert(!this->is_data_size_valid_); this->data_size_ = data_size; } // Return default alignment for the target size. static uint64_t default_alignment(); // Return default alignment for a specified size--32 or 64. static uint64_t default_alignment_for_size(int size); private: Output_data(const Output_data&); Output_data& operator=(const Output_data&); // This is used for verification, to make sure that we don't try to // change any sizes of allocated sections after we set the section // addresses. static bool allocated_sizes_are_fixed; // Memory address in output file. uint64_t address_; // Size of data in output file. off_t data_size_; // File offset of contents in output file. off_t offset_; // Whether address_ is valid. bool is_address_valid_; // Whether data_size_ is valid. bool is_data_size_valid_; // Whether offset_ is valid. bool is_offset_valid_; // Whether data size is fixed. bool is_data_size_fixed_; // Count of dynamic relocations applied to this section. unsigned int dynamic_reloc_count_; }; // Output the section headers. class Output_section_headers : public Output_data { public: Output_section_headers(const Layout*, const Layout::Segment_list*, const Layout::Section_list*, const Layout::Section_list*, const Stringpool*, const Output_section*); protected: // Write the data to the file. void do_write(Output_file*); // Return the required alignment. uint64_t do_addralign() const { return Output_data::default_alignment(); } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** section headers")); } // Set final data size. void set_final_data_size() { this->set_data_size(this->do_size()); } private: // Write the data to the file with the right size and endianness. template<int size, bool big_endian> void do_sized_write(Output_file*); // Compute data size. off_t do_size() const; 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_; }; // Output the segment headers. class Output_segment_headers : public Output_data { public: Output_segment_headers(const Layout::Segment_list& segment_list); protected: // Write the data to the file. void do_write(Output_file*); // Return the required alignment. uint64_t do_addralign() const { return Output_data::default_alignment(); } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** segment headers")); } // Set final data size. void set_final_data_size() { this->set_data_size(this->do_size()); } private: // Write the data to the file with the right size and endianness. template<int size, bool big_endian> void do_sized_write(Output_file*); // Compute the current size. off_t do_size() const; const Layout::Segment_list& segment_list_; }; // Output the ELF file header. class Output_file_header : public Output_data { public: Output_file_header(const Target*, const Symbol_table*, const Output_segment_headers*, const char* entry); // Add information about the section headers. We lay out the ELF // file header before we create the section headers. void set_section_info(const Output_section_headers*, const Output_section* shstrtab); protected: // Write the data to the file. void do_write(Output_file*); // Return the required alignment. uint64_t do_addralign() const { return Output_data::default_alignment(); } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** file header")); } // Set final data size. void set_final_data_size(void) { this->set_data_size(this->do_size()); } private: // Write the data to the file with the right size and endianness. template<int size, bool big_endian> void do_sized_write(Output_file*); // Return the value to use for the entry address. template<int size> typename elfcpp::Elf_types<size>::Elf_Addr entry(); // Compute the current data size. off_t do_size() const; const Target* target_; const Symbol_table* symtab_; const Output_segment_headers* segment_header_; const Output_section_headers* section_header_; const Output_section* shstrtab_; const char* entry_; }; // Output sections are mainly comprised of input sections. However, // there are cases where we have data to write out which is not in an // input section. Output_section_data is used in such cases. This is // an abstract base class. class Output_section_data : public Output_data { public: Output_section_data(off_t data_size, uint64_t addralign, bool is_data_size_fixed) : Output_data(), output_section_(NULL), addralign_(addralign) { this->set_data_size(data_size); if (is_data_size_fixed) this->fix_data_size(); } Output_section_data(uint64_t addralign) : Output_data(), output_section_(NULL), addralign_(addralign) { } // Return the output section. const Output_section* output_section() const { return this->output_section_; } // Record the output section. void set_output_section(Output_section* os); // Add an input section, for SHF_MERGE sections. This returns true // if the section was handled. bool add_input_section(Relobj* object, unsigned int shndx) { return this->do_add_input_section(object, shndx); } // Given an input OBJECT, an input section index SHNDX within that // object, and an OFFSET relative to the start of that input // section, return whether or not the corresponding offset within // the output section is known. If this function returns true, it // sets *POUTPUT to the output offset. The value -1 indicates that // this input offset is being discarded. bool output_offset(const Relobj* object, unsigned int shndx, section_offset_type offset, section_offset_type *poutput) const { return this->do_output_offset(object, shndx, offset, poutput); } // Return whether this is the merge section for the input section // SHNDX in OBJECT. This should return true when output_offset // would return true for some values of OFFSET. bool is_merge_section_for(const Relobj* object, unsigned int shndx) const { return this->do_is_merge_section_for(object, shndx); } // Write the contents to a buffer. This is used for sections which // require postprocessing, such as compression. void write_to_buffer(unsigned char* buffer) { this->do_write_to_buffer(buffer); } // Print merge stats to stderr. This should only be called for // SHF_MERGE sections. void print_merge_stats(const char* section_name) { this->do_print_merge_stats(section_name); } protected: // The child class must implement do_write. // The child class may implement specific adjustments to the output // section. virtual void do_adjust_output_section(Output_section*) { } // May be implemented by child class. Return true if the section // was handled. virtual bool do_add_input_section(Relobj*, unsigned int) { gold_unreachable(); } // The child class may implement output_offset. virtual bool do_output_offset(const Relobj*, unsigned int, section_offset_type, section_offset_type*) const { return false; } // The child class may implement is_merge_section_for. virtual bool do_is_merge_section_for(const Relobj*, unsigned int) const { return false; } // The child class may implement write_to_buffer. Most child // classes can not appear in a compressed section, and they do not // implement this. virtual void do_write_to_buffer(unsigned char*) { gold_unreachable(); } // Print merge statistics. virtual void do_print_merge_stats(const char*) { gold_unreachable(); } // Return the required alignment. uint64_t do_addralign() const { return this->addralign_; } // Return the output section. Output_section* do_output_section() { return this->output_section_; } // Return the section index of the output section. unsigned int do_out_shndx() const; // Set the alignment. void set_addralign(uint64_t addralign); private: // The output section for this section. Output_section* output_section_; // The required alignment. uint64_t addralign_; }; // Some Output_section_data classes build up their data step by step, // rather than all at once. This class provides an interface for // them. class Output_section_data_build : public Output_section_data { public: Output_section_data_build(uint64_t addralign) : Output_section_data(addralign) { } // Get the current data size. off_t current_data_size() const { return this->current_data_size_for_child(); } // Set the current data size. void set_current_data_size(off_t data_size) { this->set_current_data_size_for_child(data_size); } protected: // Set the final data size. virtual void set_final_data_size() { this->set_data_size(this->current_data_size_for_child()); } }; // A simple case of Output_data in which we have constant data to // output. class Output_data_const : public Output_section_data { public: Output_data_const(const std::string& data, uint64_t addralign) : Output_section_data(data.size(), addralign, true), data_(data) { } Output_data_const(const char* p, off_t len, uint64_t addralign) : Output_section_data(len, addralign, true), data_(p, len) { } Output_data_const(const unsigned char* p, off_t len, uint64_t addralign) : Output_section_data(len, addralign, true), data_(reinterpret_cast<const char*>(p), len) { } protected: // Write the data to the output file. void do_write(Output_file*); // Write the data to a buffer. void do_write_to_buffer(unsigned char* buffer) { memcpy(buffer, this->data_.data(), this->data_.size()); } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** fill")); } private: std::string data_; }; // Another version of Output_data with constant data, in which the // buffer is allocated by the caller. class Output_data_const_buffer : public Output_section_data { public: Output_data_const_buffer(const unsigned char* p, off_t len, uint64_t addralign, const char* map_name) : Output_section_data(len, addralign, true), p_(p), map_name_(map_name) { } protected: // Write the data the output file. void do_write(Output_file*); // Write the data to a buffer. void do_write_to_buffer(unsigned char* buffer) { memcpy(buffer, this->p_, this->data_size()); } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _(this->map_name_)); } private: // The data to output. const unsigned char* p_; // Name to use in a map file. Maps are a rarely used feature, but // the space usage is minor as aren't very many of these objects. const char* map_name_; }; // A place holder for a fixed amount of data written out via some // other mechanism. class Output_data_fixed_space : public Output_section_data { public: Output_data_fixed_space(off_t data_size, uint64_t addralign, const char* map_name) : Output_section_data(data_size, addralign, true), map_name_(map_name) { } protected: // Write out the data--the actual data must be written out // elsewhere. void do_write(Output_file*) { } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _(this->map_name_)); } private: // Name to use in a map file. Maps are a rarely used feature, but // the space usage is minor as aren't very many of these objects. const char* map_name_; }; // A place holder for variable sized data written out via some other // mechanism. class Output_data_space : public Output_section_data_build { public: explicit Output_data_space(uint64_t addralign, const char* map_name) : Output_section_data_build(addralign), map_name_(map_name) { } // Set the alignment. void set_space_alignment(uint64_t align) { this->set_addralign(align); } protected: // Write out the data--the actual data must be written out // elsewhere. void do_write(Output_file*) { } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _(this->map_name_)); } private: // Name to use in a map file. Maps are a rarely used feature, but // the space usage is minor as aren't very many of these objects. const char* map_name_; }; // Fill fixed space with zeroes. This is just like // Output_data_fixed_space, except that the map name is known. class Output_data_zero_fill : public Output_section_data { public: Output_data_zero_fill(off_t data_size, uint64_t addralign) : Output_section_data(data_size, addralign, true) { } protected: // There is no data to write out. void do_write(Output_file*) { } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, "** zero fill"); } }; // A string table which goes into an output section. class Output_data_strtab : public Output_section_data { public: Output_data_strtab(Stringpool* strtab) : Output_section_data(1), strtab_(strtab) { } protected: // This is called to set the address and file offset. Here we make // sure that the Stringpool is finalized. void set_final_data_size(); // Write out the data. void do_write(Output_file*); // Write the data to a buffer. void do_write_to_buffer(unsigned char* buffer) { this->strtab_->write_to_buffer(buffer, this->data_size()); } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** string table")); } private: Stringpool* strtab_; }; // This POD class is used to represent a single reloc in the output // file. This could be a private class within Output_data_reloc, but // the templatization is complex enough that I broke it out into a // separate class. The class is templatized on either elfcpp::SHT_REL // or elfcpp::SHT_RELA, and also on whether this is a dynamic // relocation or an ordinary relocation. // A relocation can be against a global symbol, a local symbol, a // local section symbol, an output section, or the undefined symbol at // index 0. We represent the latter by using a NULL global symbol. template<int sh_type, bool dynamic, int size, bool big_endian> class Output_reloc; template<bool dynamic, int size, bool big_endian> class Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian> { public: typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend; static const Address invalid_address = static_cast<Address>(0) - 1; // An uninitialized entry. We need this because we want to put // instances of this class into an STL container. Output_reloc() : local_sym_index_(INVALID_CODE) { } // We have a bunch of different constructors. They come in pairs // depending on how the address of the relocation is specified. It // can either be an offset in an Output_data or an offset in an // input section. // A reloc against a global symbol. Output_reloc(Symbol* gsym, unsigned int type, Output_data* od, Address address, bool is_relative); Output_reloc(Symbol* gsym, unsigned int type, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, bool is_relative); // A reloc against a local symbol or local section symbol. Output_reloc(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address, bool is_relative, bool is_section_symbol); Output_reloc(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, unsigned int shndx, Address address, bool is_relative, bool is_section_symbol); // A reloc against the STT_SECTION symbol of an output section. Output_reloc(Output_section* os, unsigned int type, Output_data* od, Address address); Output_reloc(Output_section* os, unsigned int type, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address); // Return TRUE if this is a RELATIVE relocation. bool is_relative() const { return this->is_relative_; } // Return whether this is against a local section symbol. bool is_local_section_symbol() const { return (this->local_sym_index_ != GSYM_CODE && this->local_sym_index_ != SECTION_CODE && this->local_sym_index_ != INVALID_CODE && this->is_section_symbol_); } // For a local section symbol, return the offset of the input // section within the output section. ADDEND is the addend being // applied to the input section. Address local_section_offset(Addend addend) const; // Get the value of the symbol referred to by a Rel relocation when // we are adding the given ADDEND. Address symbol_value(Addend addend) const; // Write the reloc entry to an output view. void write(unsigned char* pov) const; // Write the offset and info fields to Write_rel. template<typename Write_rel> void write_rel(Write_rel*) const; // This is used when sorting dynamic relocs. Return -1 to sort this // reloc before R2, 0 to sort the same as R2, 1 to sort after R2. int compare(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>& r2) const; // Return whether this reloc should be sorted before the argument // when sorting dynamic relocs. bool sort_before(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>& r2) const { return this->compare(r2) < 0; } private: // Record that we need a dynamic symbol index. void set_needs_dynsym_index(); // Return the symbol index. unsigned int get_symbol_index() const; // Return the output address. Address get_address() const; // Codes for local_sym_index_. enum { // Global symbol. GSYM_CODE = -1U, // Output section. SECTION_CODE = -2U, // Invalid uninitialized entry. INVALID_CODE = -3U }; union { // For a local symbol or local section symbol // (this->local_sym_index_ >= 0), the object. We will never // generate a relocation against a local symbol in a dynamic // object; that doesn't make sense. And our callers will always // be templatized, so we use Sized_relobj here. Sized_relobj<size, big_endian>* relobj; // For a global symbol (this->local_sym_index_ == GSYM_CODE, the // symbol. If this is NULL, it indicates a relocation against the // undefined 0 symbol. Symbol* gsym; // For a relocation against an output section // (this->local_sym_index_ == SECTION_CODE), the output section. Output_section* os; } u1_; union { // If this->shndx_ is not INVALID CODE, the object which holds the // input section being used to specify the reloc address. Sized_relobj<size, big_endian>* relobj; // If this->shndx_ is INVALID_CODE, the output data being used to // specify the reloc address. This may be NULL if the reloc // address is absolute. Output_data* od; } u2_; // The address offset within the input section or the Output_data. Address address_; // This is GSYM_CODE for a global symbol, or SECTION_CODE for a // relocation against an output section, or INVALID_CODE for an // uninitialized value. Otherwise, for a local symbol // (this->is_section_symbol_ is false), the local symbol index. For // a local section symbol (this->is_section_symbol_ is true), the // section index in the input file. unsigned int local_sym_index_; // The reloc type--a processor specific code. unsigned int type_ : 30; // True if the relocation is a RELATIVE relocation. bool is_relative_ : 1; // True if the relocation is against a section symbol. bool is_section_symbol_ : 1; // If the reloc address is an input section in an object, the // section index. This is INVALID_CODE if the reloc address is // specified in some other way. unsigned int shndx_; }; // The SHT_RELA version of Output_reloc<>. This is just derived from // the SHT_REL version of Output_reloc, but it adds an addend. template<bool dynamic, int size, bool big_endian> class Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian> { public: typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend; // An uninitialized entry. Output_reloc() : rel_() { } // A reloc against a global symbol. Output_reloc(Symbol* gsym, unsigned int type, Output_data* od, Address address, Addend addend, bool is_relative) : rel_(gsym, type, od, address, is_relative), addend_(addend) { } Output_reloc(Symbol* gsym, unsigned int type, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, Addend addend, bool is_relative) : rel_(gsym, type, relobj, shndx, address, is_relative), addend_(addend) { } // A reloc against a local symbol. Output_reloc(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address, Addend addend, bool is_relative, bool is_section_symbol) : rel_(relobj, local_sym_index, type, od, address, is_relative, is_section_symbol), addend_(addend) { } Output_reloc(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, unsigned int shndx, Address address, Addend addend, bool is_relative, bool is_section_symbol) : rel_(relobj, local_sym_index, type, shndx, address, is_relative, is_section_symbol), addend_(addend) { } // A reloc against the STT_SECTION symbol of an output section. Output_reloc(Output_section* os, unsigned int type, Output_data* od, Address address, Addend addend) : rel_(os, type, od, address), addend_(addend) { } Output_reloc(Output_section* os, unsigned int type, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, Addend addend) : rel_(os, type, relobj, shndx, address), addend_(addend) { } // Write the reloc entry to an output view. void write(unsigned char* pov) const; // Return whether this reloc should be sorted before the argument // when sorting dynamic relocs. bool sort_before(const Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>& r2) const { int i = this->rel_.compare(r2.rel_); if (i < 0) return true; else if (i > 0) return false; else return this->addend_ < r2.addend_; } private: // The basic reloc. Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian> rel_; // The addend. Addend addend_; }; // Output_data_reloc is used to manage a section containing relocs. // SH_TYPE is either elfcpp::SHT_REL or elfcpp::SHT_RELA. DYNAMIC // indicates whether this is a dynamic relocation or a normal // relocation. Output_data_reloc_base is a base class. // Output_data_reloc is the real class, which we specialize based on // the reloc type. template<int sh_type, bool dynamic, int size, bool big_endian> class Output_data_reloc_base : public Output_section_data_build { public: typedef Output_reloc<sh_type, dynamic, size, big_endian> Output_reloc_type; typedef typename Output_reloc_type::Address Address; static const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; // Construct the section. Output_data_reloc_base(bool sort_relocs) : Output_section_data_build(Output_data::default_alignment_for_size(size)), sort_relocs_(sort_relocs) { } protected: // Write out the data. void do_write(Output_file*); // Set the entry size and the link. void do_adjust_output_section(Output_section *os); // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, (dynamic ? _("** dynamic relocs") : _("** relocs"))); } // Add a relocation entry. void add(Output_data *od, const Output_reloc_type& reloc) { this->relocs_.push_back(reloc); this->set_current_data_size(this->relocs_.size() * reloc_size); od->add_dynamic_reloc(); } private: typedef std::vector<Output_reloc_type> Relocs; // The class used to sort the relocations. struct Sort_relocs_comparison { bool operator()(const Output_reloc_type& r1, const Output_reloc_type& r2) const { return r1.sort_before(r2); } }; // The relocations in this section. Relocs relocs_; // Whether to sort the relocations when writing them out, to make // the dynamic linker more efficient. bool sort_relocs_; }; // The class which callers actually create. template<int sh_type, bool dynamic, int size, bool big_endian> class Output_data_reloc; // The SHT_REL version of Output_data_reloc. template<bool dynamic, int size, bool big_endian> class Output_data_reloc<elfcpp::SHT_REL, dynamic, size, big_endian> : public Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian> { private: typedef Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian> Base; public: typedef typename Base::Output_reloc_type Output_reloc_type; typedef typename Output_reloc_type::Address Address; Output_data_reloc(bool sr) : Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian>(sr) { } // Add a reloc against a global symbol. void add_global(Symbol* gsym, unsigned int type, Output_data* od, Address address) { this->add(od, Output_reloc_type(gsym, type, od, address, false)); } void add_global(Symbol* gsym, unsigned int type, Output_data* od, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address) { this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address, false)); } // These are to simplify the Copy_relocs class. void add_global(Symbol* gsym, unsigned int type, Output_data* od, Address address, Address addend) { gold_assert(addend == 0); this->add_global(gsym, type, od, address); } void add_global(Symbol* gsym, unsigned int type, Output_data* od, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, Address addend) { gold_assert(addend == 0); this->add_global(gsym, type, od, relobj, shndx, address); } // Add a RELATIVE reloc against a global symbol. The final relocation // will not reference the symbol. void add_global_relative(Symbol* gsym, unsigned int type, Output_data* od, Address address) { this->add(od, Output_reloc_type(gsym, type, od, address, true)); } void add_global_relative(Symbol* gsym, unsigned int type, Output_data* od, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address) { this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address, true)); } // Add a reloc against a local symbol. void add_local(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address, false, false)); } void add_local(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, unsigned int shndx, Address address) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx, address, false, false)); } // Add a RELATIVE reloc against a local symbol. void add_local_relative(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address, true, false)); } void add_local_relative(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, unsigned int shndx, Address address) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx, address, true, false)); } // Add a reloc against a local section symbol. This will be // converted into a reloc against the STT_SECTION symbol of the // output section. void add_local_section(Sized_relobj<size, big_endian>* relobj, unsigned int input_shndx, unsigned int type, Output_data* od, Address address) { this->add(od, Output_reloc_type(relobj, input_shndx, type, od, address, false, true)); } void add_local_section(Sized_relobj<size, big_endian>* relobj, unsigned int input_shndx, unsigned int type, Output_data* od, unsigned int shndx, Address address) { this->add(od, Output_reloc_type(relobj, input_shndx, type, shndx, address, false, true)); } // A reloc against the STT_SECTION symbol of an output section. // OS is the Output_section that the relocation refers to; OD is // the Output_data object being relocated. void add_output_section(Output_section* os, unsigned int type, Output_data* od, Address address) { this->add(od, Output_reloc_type(os, type, od, address)); } void add_output_section(Output_section* os, unsigned int type, Output_data* od, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address) { this->add(od, Output_reloc_type(os, type, relobj, shndx, address)); } }; // The SHT_RELA version of Output_data_reloc. template<bool dynamic, int size, bool big_endian> class Output_data_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian> : public Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian> { private: typedef Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian> Base; public: typedef typename Base::Output_reloc_type Output_reloc_type; typedef typename Output_reloc_type::Address Address; typedef typename Output_reloc_type::Addend Addend; Output_data_reloc(bool sr) : Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian>(sr) { } // Add a reloc against a global symbol. void add_global(Symbol* gsym, unsigned int type, Output_data* od, Address address, Addend addend) { this->add(od, Output_reloc_type(gsym, type, od, address, addend, false)); } void add_global(Symbol* gsym, unsigned int type, Output_data* od, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, Addend addend) { this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address, addend, false)); } // Add a RELATIVE reloc against a global symbol. The final output // relocation will not reference the symbol, but we must keep the symbol // information long enough to set the addend of the relocation correctly // when it is written. void add_global_relative(Symbol* gsym, unsigned int type, Output_data* od, Address address, Addend addend) { this->add(od, Output_reloc_type(gsym, type, od, address, addend, true)); } void add_global_relative(Symbol* gsym, unsigned int type, Output_data* od, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, Addend addend) { this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address, addend, true)); } // Add a reloc against a local symbol. void add_local(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address, Addend addend) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address, addend, false, false)); } void add_local(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, unsigned int shndx, Address address, Addend addend) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx, address, addend, false, false)); } // Add a RELATIVE reloc against a local symbol. void add_local_relative(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, Address address, Addend addend) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address, addend, true, false)); } void add_local_relative(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, Output_data* od, unsigned int shndx, Address address, Addend addend) { this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx, address, addend, true, false)); } // Add a reloc against a local section symbol. This will be // converted into a reloc against the STT_SECTION symbol of the // output section. void add_local_section(Sized_relobj<size, big_endian>* relobj, unsigned int input_shndx, unsigned int type, Output_data* od, Address address, Addend addend) { this->add(od, Output_reloc_type(relobj, input_shndx, type, od, address, addend, false, true)); } void add_local_section(Sized_relobj<size, big_endian>* relobj, unsigned int input_shndx, unsigned int type, Output_data* od, unsigned int shndx, Address address, Addend addend) { this->add(od, Output_reloc_type(relobj, input_shndx, type, shndx, address, addend, false, true)); } // A reloc against the STT_SECTION symbol of an output section. void add_output_section(Output_section* os, unsigned int type, Output_data* od, Address address, Addend addend) { this->add(os, Output_reloc_type(os, type, od, address, addend)); } void add_output_section(Output_section* os, unsigned int type, Sized_relobj<size, big_endian>* relobj, unsigned int shndx, Address address, Addend addend) { this->add(os, Output_reloc_type(os, type, relobj, shndx, address, addend)); } }; // Output_relocatable_relocs represents a relocation section in a // relocatable link. The actual data is written out in the target // hook relocate_for_relocatable. This just saves space for it. template<int sh_type, int size, bool big_endian> class Output_relocatable_relocs : public Output_section_data { public: Output_relocatable_relocs(Relocatable_relocs* rr) : Output_section_data(Output_data::default_alignment_for_size(size)), rr_(rr) { } void set_final_data_size(); // Write out the data. There is nothing to do here. void do_write(Output_file*) { } // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** relocs")); } private: // The relocs associated with this input section. Relocatable_relocs* rr_; }; // Handle a GROUP section. template<int size, bool big_endian> class Output_data_group : public Output_section_data { public: // The constructor clears *INPUT_SHNDXES. Output_data_group(Sized_relobj<size, big_endian>* relobj, section_size_type entry_count, elfcpp::Elf_Word flags, std::vector<unsigned int>* input_shndxes); void do_write(Output_file*); // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** group")); } // Set final data size. void set_final_data_size() { this->set_data_size((this->input_shndxes_.size() + 1) * 4); } private: // The input object. Sized_relobj<size, big_endian>* relobj_; // The group flag word. elfcpp::Elf_Word flags_; // The section indexes of the input sections in this group. std::vector<unsigned int> input_shndxes_; }; // Output_data_got is used to manage a GOT. Each entry in the GOT is // for one symbol--either a global symbol or a local symbol in an // object. The target specific code adds entries to the GOT as // needed. template<int size, bool big_endian> class Output_data_got : public Output_section_data_build { public: typedef typename elfcpp::Elf_types<size>::Elf_Addr Valtype; typedef Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian> Rel_dyn; typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian> Rela_dyn; Output_data_got() : Output_section_data_build(Output_data::default_alignment_for_size(size)), entries_() { } // Add an entry for a global symbol to the GOT. Return true if this // is a new GOT entry, false if the symbol was already in the GOT. bool add_global(Symbol* gsym, unsigned int got_type); // Add an entry for a global symbol to the GOT, and add a dynamic // relocation of type R_TYPE for the GOT entry. void add_global_with_rel(Symbol* gsym, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type); void add_global_with_rela(Symbol* gsym, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type); // 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. void add_global_pair_with_rel(Symbol* gsym, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type_1, unsigned int r_type_2); void add_global_pair_with_rela(Symbol* gsym, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type_1, unsigned int r_type_2); // 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. bool add_local(Sized_relobj<size, big_endian>* object, unsigned int sym_index, unsigned int got_type); // Add an entry for a local symbol to the GOT, and add a dynamic // relocation of type R_TYPE for the GOT entry. void add_local_with_rel(Sized_relobj<size, big_endian>* object, unsigned int sym_index, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type); void add_local_with_rela(Sized_relobj<size, big_endian>* object, unsigned int sym_index, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type); // Add a pair of entries for a local symbol to the GOT, and add // dynamic relocations of type R_TYPE_1 and R_TYPE_2, respectively. void add_local_pair_with_rel(Sized_relobj<size, big_endian>* object, unsigned int sym_index, unsigned int shndx, unsigned int got_type, Rel_dyn* rel_dyn, unsigned int r_type_1, unsigned int r_type_2); void add_local_pair_with_rela(Sized_relobj<size, big_endian>* object, unsigned int sym_index, unsigned int shndx, unsigned int got_type, Rela_dyn* rela_dyn, unsigned int r_type_1, unsigned int r_type_2); // Add a constant to the GOT. This returns the offset of the new // entry from the start of the GOT. unsigned int add_constant(Valtype constant) { this->entries_.push_back(Got_entry(constant)); this->set_got_size(); return this->last_got_offset(); } protected: // Write out the GOT table. void do_write(Output_file*); // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** GOT")); } private: // This POD class holds a single GOT entry. class Got_entry { public: // Create a zero entry. Got_entry() : local_sym_index_(CONSTANT_CODE) { this->u_.constant = 0; } // Create a global symbol entry. explicit Got_entry(Symbol* gsym) : local_sym_index_(GSYM_CODE) { this->u_.gsym = gsym; } // Create a local symbol entry. Got_entry(Sized_relobj<size, big_endian>* object, unsigned int local_sym_index) : local_sym_index_(local_sym_index) { gold_assert(local_sym_index != GSYM_CODE && local_sym_index != CONSTANT_CODE); this->u_.object = object; } // Create a constant entry. The constant is a host value--it will // be swapped, if necessary, when it is written out. explicit Got_entry(Valtype constant) : local_sym_index_(CONSTANT_CODE) { this->u_.constant = constant; } // Write the GOT entry to an output view. void write(unsigned char* pov) const; private: enum { GSYM_CODE = -1U, CONSTANT_CODE = -2U }; union { // For a local symbol, the object. Sized_relobj<size, big_endian>* object; // For a global symbol, the symbol. Symbol* gsym; // For a constant, the constant. Valtype constant; } u_; // For a local symbol, the local symbol index. This is GSYM_CODE // for a global symbol, or CONSTANT_CODE for a constant. unsigned int local_sym_index_; }; typedef std::vector<Got_entry> Got_entries; // Return the offset into the GOT of GOT entry I. unsigned int got_offset(unsigned int i) const { return i * (size / 8); } // Return the offset into the GOT of the last entry added. unsigned int last_got_offset() const { return this->got_offset(this->entries_.size() - 1); } // Set the size of the section. void set_got_size() { this->set_current_data_size(this->got_offset(this->entries_.size())); } // The list of GOT entries. Got_entries entries_; }; // Output_data_dynamic is used to hold the data in SHT_DYNAMIC // section. class Output_data_dynamic : public Output_section_data { public: Output_data_dynamic(Stringpool* pool) : Output_section_data(Output_data::default_alignment()), entries_(), pool_(pool) { } // Add a new dynamic entry with a fixed numeric value. void add_constant(elfcpp::DT tag, unsigned int val) { this->add_entry(Dynamic_entry(tag, val)); } // Add a new dynamic entry with the address of output data. void add_section_address(elfcpp::DT tag, const Output_data* od) { this->add_entry(Dynamic_entry(tag, od, false)); } // Add a new dynamic entry with the address of output data // plus a constant offset. void add_section_plus_offset(elfcpp::DT tag, const Output_data* od, unsigned int offset) { this->add_entry(Dynamic_entry(tag, od, offset)); } // Add a new dynamic entry with the size of output data. void add_section_size(elfcpp::DT tag, const Output_data* od) { this->add_entry(Dynamic_entry(tag, od, true)); } // Add a new dynamic entry with the address of a symbol. void add_symbol(elfcpp::DT tag, const Symbol* sym) { this->add_entry(Dynamic_entry(tag, sym)); } // Add a new dynamic entry with a string. void add_string(elfcpp::DT tag, const char* str) { this->add_entry(Dynamic_entry(tag, this->pool_->add(str, true, NULL))); } void add_string(elfcpp::DT tag, const std::string& str) { this->add_string(tag, str.c_str()); } protected: // Adjust the output section to set the entry size. void do_adjust_output_section(Output_section*); // Set the final data size. void set_final_data_size(); // Write out the dynamic entries. void do_write(Output_file*); // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** dynamic")); } private: // This POD class holds a single dynamic entry. class Dynamic_entry { public: // Create an entry with a fixed numeric value. Dynamic_entry(elfcpp::DT tag, unsigned int val) : tag_(tag), offset_(DYNAMIC_NUMBER) { this->u_.val = val; } // Create an entry with the size or address of a section. Dynamic_entry(elfcpp::DT tag, const Output_data* od, bool section_size) : tag_(tag), offset_(section_size ? DYNAMIC_SECTION_SIZE : DYNAMIC_SECTION_ADDRESS) { this->u_.od = od; } // Create an entry with the address of a section plus a constant offset. Dynamic_entry(elfcpp::DT tag, const Output_data* od, unsigned int offset) : tag_(tag), offset_(offset) { this->u_.od = od; } // Create an entry with the address of a symbol. Dynamic_entry(elfcpp::DT tag, const Symbol* sym) : tag_(tag), offset_(DYNAMIC_SYMBOL) { this->u_.sym = sym; } // Create an entry with a string. Dynamic_entry(elfcpp::DT tag, const char* str) : tag_(tag), offset_(DYNAMIC_STRING) { this->u_.str = str; } // Return the tag of this entry. elfcpp::DT tag() const { return this->tag_; } // Write the dynamic entry to an output view. template<int size, bool big_endian> void write(unsigned char* pov, const Stringpool*) const; private: // Classification is encoded in the OFFSET field. enum Classification { // Section address. DYNAMIC_SECTION_ADDRESS = 0, // Number. DYNAMIC_NUMBER = -1U, // Section size. DYNAMIC_SECTION_SIZE = -2U, // Symbol adress. DYNAMIC_SYMBOL = -3U, // String. DYNAMIC_STRING = -4U // Any other value indicates a section address plus OFFSET. }; union { // For DYNAMIC_NUMBER. unsigned int val; // For DYNAMIC_SECTION_SIZE and section address plus OFFSET. const Output_data* od; // For DYNAMIC_SYMBOL. const Symbol* sym; // For DYNAMIC_STRING. const char* str; } u_; // The dynamic tag. elfcpp::DT tag_; // The type of entry (Classification) or offset within a section. unsigned int offset_; }; // Add an entry to the list. void add_entry(const Dynamic_entry& entry) { this->entries_.push_back(entry); } // Sized version of write function. template<int size, bool big_endian> void sized_write(Output_file* of); // The type of the list of entries. typedef std::vector<Dynamic_entry> Dynamic_entries; // The entries. Dynamic_entries entries_; // The pool used for strings. Stringpool* pool_; }; // Output_symtab_xindex is used to handle SHT_SYMTAB_SHNDX sections, // which may be required if the object file has more than // SHN_LORESERVE sections. class Output_symtab_xindex : public Output_section_data { public: Output_symtab_xindex(size_t symcount) : Output_section_data(symcount * 4, 4, true), entries_() { } // Add an entry: symbol number SYMNDX has section SHNDX. void add(unsigned int symndx, unsigned int shndx) { this->entries_.push_back(std::make_pair(symndx, shndx)); } protected: void do_write(Output_file*); // Write to a map file. void do_print_to_mapfile(Mapfile* mapfile) const { mapfile->print_output_data(this, _("** symtab xindex")); } private: template<bool big_endian> void endian_do_write(unsigned char*); // It is likely that most symbols will not require entries. Rather // than keep a vector for all symbols, we keep pairs of symbol index // and section index. typedef std::vector<std::pair<unsigned int, unsigned int> > Xindex_entries; // The entries we need. Xindex_entries entries_; }; // A relaxed input section. class Output_relaxed_input_section : public Output_section_data_build { public: // We would like to call relobj->section_addralign(shndx) to get the // alignment but we do not want the constructor to fail. So callers // are repsonsible for ensuring that. Output_relaxed_input_section(Relobj* relobj, unsigned int shndx, uint64_t addralign) : Output_section_data_build(addralign), relobj_(relobj), shndx_(shndx) { } // Return the Relobj of this relaxed input section. Relobj* relobj() const { return this->relobj_; } // Return the section index of this relaxed input section. unsigned int shndx() const { return this->shndx_; } private: Relobj* relobj_; unsigned int shndx_; }; // An output section. We don't expect to have too many output // sections, so we don't bother to do a template on the size. class Output_section : public Output_data { public: // Create an output section, giving the name, type, and flags. Output_section(const char* name, elfcpp::Elf_Word, elfcpp::Elf_Xword); virtual ~Output_section(); // Add a new input section SHNDX, named NAME, with header SHDR, from // object OBJECT. RELOC_SHNDX is the index of a relocation section // which applies to this section, or 0 if none, or -1 if more than // one. HAVE_SECTIONS_SCRIPT is true if we have a SECTIONS clause // in a linker script; in that case we need to keep track of input // sections associated with an output section. Return the offset // within the output section. template<int size, bool big_endian> off_t add_input_section(Sized_relobj<size, big_endian>* object, unsigned int shndx, const char *name, const elfcpp::Shdr<size, big_endian>& shdr, unsigned int reloc_shndx, bool have_sections_script); // Add generated data POSD to this output section. void add_output_section_data(Output_section_data* posd); // Add a relaxed input section PORIS to this output section. void add_relaxed_input_section(Output_relaxed_input_section* poris); // Return the section name. const char* name() const { return this->name_; } // Return the section type. elfcpp::Elf_Word type() const { return this->type_; } // Return the section flags. elfcpp::Elf_Xword flags() const { return this->flags_; } // Update the output section flags based on input section flags. void update_flags_for_input_section(elfcpp::Elf_Xword flags); // Return the entsize field. uint64_t entsize() const { return this->entsize_; } // Set the entsize field. void set_entsize(uint64_t v); // Set the load address. void set_load_address(uint64_t load_address) { this->load_address_ = load_address; this->has_load_address_ = true; } // Set the link field to the output section index of a section. void set_link_section(const Output_data* od) { gold_assert(this->link_ == 0 && !this->should_link_to_symtab_ && !this->should_link_to_dynsym_); this->link_section_ = od; } // Set the link field to a constant. void set_link(unsigned int v) { gold_assert(this->link_section_ == NULL && !this->should_link_to_symtab_ && !this->should_link_to_dynsym_); this->link_ = v; } // Record that this section should link to the normal symbol table. void set_should_link_to_symtab() { gold_assert(this->link_section_ == NULL && this->link_ == 0 && !this->should_link_to_dynsym_); this->should_link_to_symtab_ = true; } // Record that this section should link to the dynamic symbol table. void set_should_link_to_dynsym() { gold_assert(this->link_section_ == NULL && this->link_ == 0 && !this->should_link_to_symtab_); this->should_link_to_dynsym_ = true; } // Return the info field. unsigned int info() const { gold_assert(this->info_section_ == NULL && this->info_symndx_ == NULL); return this->info_; } // Set the info field to the output section index of a section. void set_info_section(const Output_section* os) { gold_assert((this->info_section_ == NULL || (this->info_section_ == os && this->info_uses_section_index_)) && this->info_symndx_ == NULL && this->info_ == 0); this->info_section_ = os; this->info_uses_section_index_= true; } // Set the info field to the symbol table index of a symbol. void set_info_symndx(const Symbol* sym) { gold_assert(this->info_section_ == NULL && (this->info_symndx_ == NULL || this->info_symndx_ == sym) && this->info_ == 0); this->info_symndx_ = sym; } // Set the info field to the symbol table index of a section symbol. void set_info_section_symndx(const Output_section* os) { gold_assert((this->info_section_ == NULL || (this->info_section_ == os && !this->info_uses_section_index_)) && this->info_symndx_ == NULL && this->info_ == 0); this->info_section_ = os; this->info_uses_section_index_ = false; } // Set the info field to a constant. void set_info(unsigned int v) { gold_assert(this->info_section_ == NULL && this->info_symndx_ == NULL && (this->info_ == 0 || this->info_ == v)); this->info_ = v; } // Set the addralign field. void set_addralign(uint64_t v) { this->addralign_ = v; } // Whether the output section index has been set. bool has_out_shndx() const { return this->out_shndx_ != -1U; } // Indicate that we need a symtab index. void set_needs_symtab_index() { this->needs_symtab_index_ = true; } // Return whether we need a symtab index. bool needs_symtab_index() const { return this->needs_symtab_index_; } // Get the symtab index. unsigned int symtab_index() const { gold_assert(this->symtab_index_ != 0); return this->symtab_index_; } // Set the symtab index. void set_symtab_index(unsigned int index) { gold_assert(index != 0); this->symtab_index_ = index; } // Indicate that we need a dynsym index. void set_needs_dynsym_index() { this->needs_dynsym_index_ = true; } // Return whether we need a dynsym index. bool needs_dynsym_index() const { return this->needs_dynsym_index_; } // Get the dynsym index. unsigned int dynsym_index() const { gold_assert(this->dynsym_index_ != 0); return this->dynsym_index_; } // Set the dynsym index. void set_dynsym_index(unsigned int index) { gold_assert(index != 0); this->dynsym_index_ = index; } // Return whether the input sections sections attachd to this output // section may require sorting. This is used to handle constructor // priorities compatibly with GNU ld. bool may_sort_attached_input_sections() const { return this->may_sort_attached_input_sections_; } // Record that the input sections attached to this output section // may require sorting. void set_may_sort_attached_input_sections() { this->may_sort_attached_input_sections_ = true; } // Return whether the input sections attached to this output section // require sorting. This is used to handle constructor priorities // compatibly with GNU ld. bool must_sort_attached_input_sections() const { return this->must_sort_attached_input_sections_; } // Record that the input sections attached to this output section // require sorting. void set_must_sort_attached_input_sections() { this->must_sort_attached_input_sections_ = true; } // Return whether this section holds relro data--data which has // dynamic relocations but which may be marked read-only after the // dynamic relocations have been completed. bool is_relro() const { return this->is_relro_; } // Record that this section holds relro data. void set_is_relro() { this->is_relro_ = true; } // Record that this section does not hold relro data. void clear_is_relro() { this->is_relro_ = false; } // True if this section holds relro local data--relro data for which // the dynamic relocations are all RELATIVE relocations. bool is_relro_local() const { return this->is_relro_local_; } // Record that this section holds relro local data. void set_is_relro_local() { this->is_relro_local_ = true; } // True if this is a small section: a section which holds small // variables. bool is_small_section() const { return this->is_small_section_; } // Record that this is a small section. void set_is_small_section() { this->is_small_section_ = true; } // True if this is a large section: a section which holds large // variables. bool is_large_section() const { return this->is_large_section_; } // Record that this is a large section. void set_is_large_section() { this->is_large_section_ = true; } // True if this is a large data (not BSS) section. bool is_large_data_section() { return this->is_large_section_ && this->type_ != elfcpp::SHT_NOBITS; } // True if this is the .interp section which goes into the PT_INTERP // segment. bool is_interp() const { return this->is_interp_; } // Record that this is the interp section. void set_is_interp() { this->is_interp_ = true; } // True if this is a section used by the dynamic linker. bool is_dynamic_linker_section() const { return this->is_dynamic_linker_section_; } // Record that this is a section used by the dynamic linker. void set_is_dynamic_linker_section() { this->is_dynamic_linker_section_ = true; } // Return whether this section should be written after all the input // sections are complete. bool after_input_sections() const { return this->after_input_sections_; } // Record that this section should be written after all the input // sections are complete. void set_after_input_sections() { this->after_input_sections_ = true; } // Return whether this section requires postprocessing after all // relocations have been applied. bool requires_postprocessing() const { return this->requires_postprocessing_; } // If a section requires postprocessing, return the buffer to use. unsigned char* postprocessing_buffer() const { gold_assert(this->postprocessing_buffer_ != NULL); return this->postprocessing_buffer_; } // If a section requires postprocessing, create the buffer to use. void create_postprocessing_buffer(); // If a section requires postprocessing, this is the size of the // buffer to which relocations should be applied. off_t postprocessing_buffer_size() const { return this->current_data_size_for_child(); } // Modify the section name. This is only permitted for an // unallocated section, and only before the size has been finalized. // Otherwise the name will not get into Layout::namepool_. void set_name(const char* newname) { gold_assert((this->flags_ & elfcpp::SHF_ALLOC) == 0); gold_assert(!this->is_data_size_valid()); this->name_ = newname; } // Return whether the offset OFFSET in the input section SHNDX in // object OBJECT is being included in the link. bool is_input_address_mapped(const Relobj* object, unsigned int shndx, off_t offset) const; // Return the offset within the output section of OFFSET relative to // the start of input section SHNDX in object OBJECT. section_offset_type output_offset(const Relobj* object, unsigned int shndx, section_offset_type offset) const; // Return the output virtual address of OFFSET relative to the start // of input section SHNDX in object OBJECT. uint64_t output_address(const Relobj* object, unsigned int shndx, off_t offset) const; // Look for the merged section for input section SHNDX in object // OBJECT. If found, return true, and set *ADDR to the address of // the start of the merged section. This is not necessary the // output offset corresponding to input offset 0 in the section, // since the section may be mapped arbitrarily. bool find_starting_output_address(const Relobj* object, unsigned int shndx, uint64_t* addr) const; // Record that this output section was found in the SECTIONS clause // of a linker script. void set_found_in_sections_clause() { this->found_in_sections_clause_ = true; } // Return whether this output section was found in the SECTIONS // clause of a linker script. bool found_in_sections_clause() const { return this->found_in_sections_clause_; } // Write the section header into *OPHDR. template<int size, bool big_endian> void write_header(const Layout*, const Stringpool*, elfcpp::Shdr_write<size, big_endian>*) const; // The next few calls are for linker script support. // We need to export the input sections to linker scripts. Previously // we export a pair of Relobj pointer and section index. We now need to // handle relaxed input sections as well. So we use this class. class Simple_input_section { private: static const unsigned int invalid_shndx = static_cast<unsigned int>(-1); public: Simple_input_section(Relobj *relobj, unsigned int shndx) : shndx_(shndx) { gold_assert(shndx != invalid_shndx); this->u_.relobj = relobj; } Simple_input_section(Output_relaxed_input_section* section) : shndx_(invalid_shndx) { this->u_.relaxed_input_section = section; } // Whether this is a relaxed section. bool is_relaxed_input_section() const { return this->shndx_ == invalid_shndx; } // Return object of an input section. Relobj* relobj() const { return ((this->shndx_ != invalid_shndx) ? this->u_.relobj : this->u_.relaxed_input_section->relobj()); } // Return index of an input section. unsigned int shndx() const { return ((this->shndx_ != invalid_shndx) ? this->shndx_ : this->u_.relaxed_input_section->shndx()); } // Return the Output_relaxed_input_section object of a relaxed section. Output_relaxed_input_section* relaxed_input_section() const { gold_assert(this->shndx_ == invalid_shndx); return this->u_.relaxed_input_section; } private: // Pointer to either an Relobj or an Output_relaxed_input_section. union { Relobj* relobj; Output_relaxed_input_section* relaxed_input_section; } u_; // Section index for an non-relaxed section or invalid_shndx for // a relaxed section. unsigned int shndx_; }; // Store the list of input sections for this Output_section into the // list passed in. This removes the input sections, leaving only // any Output_section_data elements. This returns the size of those // Output_section_data elements. ADDRESS is the address of this // output section. FILL is the fill value to use, in case there are // any spaces between the remaining Output_section_data elements. uint64_t get_input_sections(uint64_t address, const std::string& fill, std::list<Simple_input_section>*); // Add an input section from a script. void add_input_section_for_script(const Simple_input_section& input_section, off_t data_size, uint64_t addralign); // Set the current size of the output section. void set_current_data_size(off_t size) { this->set_current_data_size_for_child(size); } // Get the current size of the output section. off_t current_data_size() const { return this->current_data_size_for_child(); } // End of linker script support. // Save states before doing section layout. // This is used for relaxation. void save_states(); // Restore states prior to section layout. void restore_states(); // Convert existing input sections to relaxed input sections. void convert_input_sections_to_relaxed_sections( const std::vector<Output_relaxed_input_section*>& sections); // Print merge statistics to stderr. void print_merge_stats(); protected: // Return the output section--i.e., the object itself. Output_section* do_output_section() { return this; } // Return the section index in the output file. unsigned int do_out_shndx() const { gold_assert(this->out_shndx_ != -1U); return this->out_shndx_; } // Set the output section index. void do_set_out_shndx(unsigned int shndx) { gold_assert(this->out_shndx_ == -1U || this->out_shndx_ == shndx); this->out_shndx_ = shndx; } // Set the final data size of the Output_section. For a typical // Output_section, there is nothing to do, but if there are any // Output_section_data objects we need to set their final addresses // here. virtual void set_final_data_size(); // Reset the address and file offset. void do_reset_address_and_file_offset(); // Return true if address and file offset already have reset values. In // other words, calling reset_address_and_file_offset will not change them. bool do_address_and_file_offset_have_reset_values() const; // Write the data to the file. For a typical Output_section, this // does nothing: the data is written out by calling Object::Relocate // on each input object. But if there are any Output_section_data // objects we do need to write them out here. virtual void do_write(Output_file*); // Return the address alignment--function required by parent class. uint64_t do_addralign() const { return this->addralign_; } // Return whether there is a load address. bool do_has_load_address() const { return this->has_load_address_; } // Return the load address. uint64_t do_load_address() const { gold_assert(this->has_load_address_); return this->load_address_; } // Return whether this is an Output_section. bool do_is_section() const { return true; } // Return whether this is a section of the specified type. bool do_is_section_type(elfcpp::Elf_Word type) const { return this->type_ == type; } // Return whether the specified section flag is set. bool do_is_section_flag_set(elfcpp::Elf_Xword flag) const { return (this->flags_ & flag) != 0; } // Set the TLS offset. Called only for SHT_TLS sections. void do_set_tls_offset(uint64_t tls_base); // Return the TLS offset, relative to the base of the TLS segment. // Valid only for SHT_TLS sections. uint64_t do_tls_offset() const { return this->tls_offset_; } // This may be implemented by a child class. virtual void do_finalize_name(Layout*) { } // Print to the map file. virtual void do_print_to_mapfile(Mapfile*) const; // Record that this section requires postprocessing after all // relocations have been applied. This is called by a child class. void set_requires_postprocessing() { this->requires_postprocessing_ = true; this->after_input_sections_ = true; } // Write all the data of an Output_section into the postprocessing // buffer. void write_to_postprocessing_buffer(); // In some cases we need to keep a list of the input sections // associated with this output section. We only need the list if we // might have to change the offsets of the input section within the // output section after we add the input section. The ordinary // input sections will be written out when we process the object // file, and as such we don't need to track them here. We do need // to track Output_section_data objects here. We store instances of // this structure in a std::vector, so it must be a POD. There can // be many instances of this structure, so we use a union to save // some space. class Input_section { public: Input_section() : shndx_(0), p2align_(0) { this->u1_.data_size = 0; this->u2_.object = NULL; } // For an ordinary input section. Input_section(Relobj* object, unsigned int shndx, off_t data_size, uint64_t addralign) : shndx_(shndx), p2align_(ffsll(static_cast<long long>(addralign))) { gold_assert(shndx != OUTPUT_SECTION_CODE && shndx != MERGE_DATA_SECTION_CODE && shndx != MERGE_STRING_SECTION_CODE && shndx != RELAXED_INPUT_SECTION_CODE); this->u1_.data_size = data_size; this->u2_.object = object; } // For a non-merge output section. Input_section(Output_section_data* posd) : shndx_(OUTPUT_SECTION_CODE), p2align_(0) { this->u1_.data_size = 0; this->u2_.posd = posd; } // For a merge section. Input_section(Output_section_data* posd, bool is_string, uint64_t entsize) : shndx_(is_string ? MERGE_STRING_SECTION_CODE : MERGE_DATA_SECTION_CODE), p2align_(0) { this->u1_.entsize = entsize; this->u2_.posd = posd; } // For a relaxed input section. Input_section(Output_relaxed_input_section *psection) : shndx_(RELAXED_INPUT_SECTION_CODE), p2align_(0) { this->u1_.data_size = 0; this->u2_.poris = psection; } // The required alignment. uint64_t addralign() const { if (!this->is_input_section()) return this->u2_.posd->addralign(); return (this->p2align_ == 0 ? 0 : static_cast<uint64_t>(1) << (this->p2align_ - 1)); } // Return the required size. off_t data_size() const; // Whether this is an input section. bool is_input_section() const { return (this->shndx_ != OUTPUT_SECTION_CODE && this->shndx_ != MERGE_DATA_SECTION_CODE && this->shndx_ != MERGE_STRING_SECTION_CODE && this->shndx_ != RELAXED_INPUT_SECTION_CODE); } // Return whether this is a merge section which matches the // parameters. bool is_merge_section(bool is_string, uint64_t entsize, uint64_t addralign) const { return (this->shndx_ == (is_string ? MERGE_STRING_SECTION_CODE : MERGE_DATA_SECTION_CODE) && this->u1_.entsize == entsize && this->addralign() == addralign); } // Return whether this is a relaxed input section. bool is_relaxed_input_section() const { return this->shndx_ == RELAXED_INPUT_SECTION_CODE; } // Return whether this is a generic Output_section_data. bool is_output_section_data() const { return this->shndx_ == OUTPUT_SECTION_CODE; } // Return the object for an input section. Relobj* relobj() const { if (this->is_input_section()) return this->u2_.object; 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 shndx() const { if (this->is_input_section()) return this->shndx_; else if (this->is_relaxed_input_section()) return this->u2_.poris->shndx(); else gold_unreachable(); } // For non-input-sections, return the associated Output_section_data // object. Output_section_data* output_section_data() const { gold_assert(!this->is_input_section()); return this->u2_.posd; } // Return the Output_relaxed_input_section object. Output_relaxed_input_section* relaxed_input_section() const { gold_assert(this->is_relaxed_input_section()); return this->u2_.poris; } // Set the output section. void set_output_section(Output_section* os) { gold_assert(!this->is_input_section()); Output_section_data *posd = this->is_relaxed_input_section() ? this->u2_.poris : this->u2_.posd; posd->set_output_section(os); } // Set the address and file offset. This is called during // Layout::finalize. SECTION_FILE_OFFSET is the file offset of // the enclosing section. void set_address_and_file_offset(uint64_t address, off_t file_offset, off_t section_file_offset); // Reset the address and file offset. void reset_address_and_file_offset(); // Finalize the data size. void finalize_data_size(); // Add an input section, for SHF_MERGE sections. bool add_input_section(Relobj* object, unsigned int shndx) { gold_assert(this->shndx_ == MERGE_DATA_SECTION_CODE || this->shndx_ == MERGE_STRING_SECTION_CODE); return this->u2_.posd->add_input_section(object, shndx); } // Given an input OBJECT, an input section index SHNDX within that // object, and an OFFSET relative to the start of that input // section, return whether or not the output offset is known. If // this function returns true, it sets *POUTPUT to the offset in // the output section, relative to the start of the input section // in the output section. *POUTPUT may be different from OFFSET // for a merged section. bool output_offset(const Relobj* object, unsigned int shndx, section_offset_type offset, section_offset_type *poutput) const; // Return whether this is the merge section for the input section // SHNDX in OBJECT. bool is_merge_section_for(const Relobj* object, unsigned int shndx) const; // Write out the data. This does nothing for an input section. void write(Output_file*); // Write the data to a buffer. This does nothing for an input // section. void write_to_buffer(unsigned char*); // Print to a map file. void print_to_mapfile(Mapfile*) const; // Print statistics about merge sections to stderr. void print_merge_stats(const char* section_name) { if (this->shndx_ == MERGE_DATA_SECTION_CODE || this->shndx_ == MERGE_STRING_SECTION_CODE) this->u2_.posd->print_merge_stats(section_name); } private: // Code values which appear in shndx_. If the value is not one of // these codes, it is the input section index in the object file. enum { // An Output_section_data. OUTPUT_SECTION_CODE = -1U, // An Output_section_data for an SHF_MERGE section with // SHF_STRINGS not set. MERGE_DATA_SECTION_CODE = -2U, // An Output_section_data for an SHF_MERGE section with // SHF_STRINGS set. MERGE_STRING_SECTION_CODE = -3U, // An Output_section_data for a relaxed input section. RELAXED_INPUT_SECTION_CODE = -4U }; // For an ordinary input section, this is the section index in the // input file. For an Output_section_data, this is // OUTPUT_SECTION_CODE or MERGE_DATA_SECTION_CODE or // MERGE_STRING_SECTION_CODE. unsigned int shndx_; // The required alignment, stored as a power of 2. unsigned int p2align_; union { // For an ordinary input section, the section size. off_t data_size; // For OUTPUT_SECTION_CODE or RELAXED_INPUT_SECTION_CODE, this is not // used. For MERGE_DATA_SECTION_CODE or MERGE_STRING_SECTION_CODE, the // entity size. uint64_t entsize; } u1_; union { // For an ordinary input section, the object which holds the // input section. Relobj* object; // For OUTPUT_SECTION_CODE or MERGE_DATA_SECTION_CODE or // MERGE_STRING_SECTION_CODE, the data. Output_section_data* posd; // For RELAXED_INPUT_SECTION_CODE, the data. Output_relaxed_input_section* poris; } u2_; }; typedef std::vector<Input_section> Input_section_list; // Allow a child class to access the input sections. const Input_section_list& input_sections() const { return this->input_sections_; } private: // We only save enough information to undo the effects of section layout. class Checkpoint_output_section { public: Checkpoint_output_section(uint64_t addralign, elfcpp::Elf_Xword flags, const Input_section_list& input_sections, off_t first_input_offset, bool attached_input_sections_are_sorted) : addralign_(addralign), flags_(flags), input_sections_(input_sections), input_sections_size_(input_sections_.size()), input_sections_copy_(), first_input_offset_(first_input_offset), attached_input_sections_are_sorted_(attached_input_sections_are_sorted) { } virtual ~Checkpoint_output_section() { } // Return the address alignment. uint64_t addralign() const { return this->addralign_; } // Return the section flags. elfcpp::Elf_Xword flags() const { return this->flags_; } // Return a reference to the input section list copy. Input_section_list* input_sections() { return &this->input_sections_copy_; } // Return the size of input_sections at the time when checkpoint is // taken. size_t input_sections_size() const { return this->input_sections_size_; } // Whether input sections are copied. bool input_sections_saved() const { return this->input_sections_copy_.size() == this->input_sections_size_; } off_t first_input_offset() const { return this->first_input_offset_; } bool attached_input_sections_are_sorted() const { return this->attached_input_sections_are_sorted_; } // Save input sections. void save_input_sections() { this->input_sections_copy_.reserve(this->input_sections_size_); this->input_sections_copy_.clear(); Input_section_list::const_iterator p = this->input_sections_.begin(); gold_assert(this->input_sections_size_ >= this->input_sections_.size()); for(size_t i = 0; i < this->input_sections_size_ ; i++, ++p) this->input_sections_copy_.push_back(*p); } private: // The section alignment. uint64_t addralign_; // The section flags. elfcpp::Elf_Xword flags_; // Reference to the input sections to be checkpointed. const Input_section_list& input_sections_; // Size of the checkpointed portion of input_sections_; size_t input_sections_size_; // Copy of input sections. Input_section_list input_sections_copy_; // The offset of the first entry in input_sections_. off_t first_input_offset_; // True if the input sections attached to this output section have // already been sorted. bool attached_input_sections_are_sorted_; }; // This class is used to sort the input sections. class Input_section_sort_entry; // This is the sort comparison function. struct Input_section_sort_compare { bool operator()(const Input_section_sort_entry&, const Input_section_sort_entry&) const; }; // Fill data. This is used to fill in data between input sections. // It is also used for data statements (BYTE, WORD, etc.) in linker // scripts. When we have to keep track of the input sections, we // can use an Output_data_const, but we don't want to have to keep // track of input sections just to implement fills. class Fill { public: Fill(off_t section_offset, off_t length) : section_offset_(section_offset), length_(convert_to_section_size_type(length)) { } // Return section offset. off_t section_offset() const { return this->section_offset_; } // Return fill length. section_size_type length() const { return this->length_; } private: // The offset within the output section. off_t section_offset_; // The length of the space to fill. section_size_type length_; }; typedef std::vector<Fill> Fill_list; // This class describes properties of merge data sections. It is used // as a key type for maps. class Merge_section_properties { public: Merge_section_properties(bool is_string, uint64_t entsize, uint64_t addralign) : is_string_(is_string), entsize_(entsize), addralign_(addralign) { } // Whether this equals to another Merge_section_properties MSP. bool eq(const Merge_section_properties& msp) const { return ((this->is_string_ == msp.is_string_) && (this->entsize_ == msp.entsize_) && (this->addralign_ == msp.addralign_)); } // Compute a hash value for this using 64-bit FNV-1a hash. size_t hash_value() const { uint64_t h = 14695981039346656037ULL; // FNV offset basis. uint64_t prime = 1099511628211ULL; h = (h ^ static_cast<uint64_t>(this->is_string_)) * prime; h = (h ^ static_cast<uint64_t>(this->entsize_)) * prime; h = (h ^ static_cast<uint64_t>(this->addralign_)) * prime; return h; } // Functors for associative containers. struct equal_to { bool operator()(const Merge_section_properties& msp1, const Merge_section_properties& msp2) const { return msp1.eq(msp2); } }; struct hash { size_t operator()(const Merge_section_properties& msp) const { return msp.hash_value(); } }; private: // Whether this merge data section is for strings. bool is_string_; // Entsize of this merge data section. uint64_t entsize_; // Address alignment. uint64_t addralign_; }; // Map that link Merge_section_properties to Output_merge_base. typedef Unordered_map<Merge_section_properties, Output_merge_base*, Merge_section_properties::hash, Merge_section_properties::equal_to> Merge_section_by_properties_map; // Map that link Input_section_specifier to Output_section_data. typedef Unordered_map<Input_section_specifier, Output_section_data*, Input_section_specifier::hash, Input_section_specifier::equal_to> Output_section_data_by_input_section_map; // Map used during relaxation of existing sections. This map // an input section specifier to an input section list index. // We assume that Input_section_list is a vector. typedef Unordered_map<Input_section_specifier, size_t, Input_section_specifier::hash, Input_section_specifier::equal_to> Relaxation_map; // Add a new output section by Input_section. void add_output_section_data(Input_section*); // Add an SHF_MERGE input section. Returns true if the section was // handled. bool add_merge_input_section(Relobj* object, unsigned int shndx, uint64_t flags, uint64_t entsize, uint64_t addralign); // Add an output SHF_MERGE section POSD to this output section. // IS_STRING indicates whether it is a SHF_STRINGS section, and // ENTSIZE is the entity size. This returns the entry added to // input_sections_. void add_output_merge_section(Output_section_data* posd, bool is_string, uint64_t entsize); // Sort the attached input sections. void sort_attached_input_sections(); // 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* find_merge_section(const Relobj* object, unsigned int shndx) const; // Find a relaxed input section to an input section in OBJECT // with index SHNDX. Return NULL if none is found. const Output_section_data* find_relaxed_input_section(const Relobj* object, unsigned int shndx) const; // Build a relaxation map. void build_relaxation_map( const Input_section_list& input_sections, size_t limit, Relaxation_map* map) const; // Convert input sections in an input section list into relaxed sections. void convert_input_sections_in_list_to_relaxed_sections( const std::vector<Output_relaxed_input_section*>& relaxed_sections, const Relaxation_map& map, Input_section_list* input_sections); // Most of these fields are only valid after layout. // The name of the section. This will point into a Stringpool. const char* name_; // The section address is in the parent class. // The section alignment. uint64_t addralign_; // The section entry size. uint64_t entsize_; // The load address. This is only used when using a linker script // with a SECTIONS clause. The has_load_address_ field indicates // whether this field is valid. uint64_t load_address_; // The file offset is in the parent class. // Set the section link field to the index of this section. const Output_data* link_section_; // If link_section_ is NULL, this is the link field. unsigned int link_; // Set the section info field to the index of this section. const Output_section* info_section_; // If info_section_ is NULL, set the info field to the symbol table // index of this symbol. const Symbol* info_symndx_; // If info_section_ and info_symndx_ are NULL, this is the section // info field. unsigned int info_; // The section type. const elfcpp::Elf_Word type_; // The section flags. elfcpp::Elf_Xword flags_; // The section index. unsigned int out_shndx_; // If there is a STT_SECTION for this output section in the normal // symbol table, this is the symbol index. This starts out as zero. // It is initialized in Layout::finalize() to be the index, or -1U // if there isn't one. unsigned int symtab_index_; // If there is a STT_SECTION for this output section in the dynamic // symbol table, this is the symbol index. This starts out as zero. // It is initialized in Layout::finalize() to be the index, or -1U // if there isn't one. unsigned int dynsym_index_; // The input sections. This will be empty in cases where we don't // need to keep track of them. Input_section_list input_sections_; // The offset of the first entry in input_sections_. off_t first_input_offset_; // The fill data. This is separate from input_sections_ because we // often will need fill sections without needing to keep track of // input sections. Fill_list fills_; // If the section requires postprocessing, this buffer holds the // section contents during relocation. unsigned char* postprocessing_buffer_; // Whether this output section needs a STT_SECTION symbol in the // normal symbol table. This will be true if there is a relocation // which needs it. bool needs_symtab_index_ : 1; // Whether this output section needs a STT_SECTION symbol in the // dynamic symbol table. This will be true if there is a dynamic // relocation which needs it. bool needs_dynsym_index_ : 1; // Whether the link field of this output section should point to the // normal symbol table. bool should_link_to_symtab_ : 1; // Whether the link field of this output section should point to the // dynamic symbol table. bool should_link_to_dynsym_ : 1; // Whether this section should be written after all the input // sections are complete. bool after_input_sections_ : 1; // Whether this section requires post processing after all // relocations have been applied. bool requires_postprocessing_ : 1; // Whether an input section was mapped to this output section // because of a SECTIONS clause in a linker script. bool found_in_sections_clause_ : 1; // Whether this section has an explicitly specified load address. bool has_load_address_ : 1; // True if the info_section_ field means the section index of the // section, false if it means the symbol index of the corresponding // section symbol. bool info_uses_section_index_ : 1; // True if the input sections attached to this output section may // need sorting. bool may_sort_attached_input_sections_ : 1; // True if the input sections attached to this output section must // be sorted. bool must_sort_attached_input_sections_ : 1; // True if the input sections attached to this output section have // already been sorted. bool attached_input_sections_are_sorted_ : 1; // True if this section holds relro data. bool is_relro_ : 1; // True if this section holds relro local data. bool is_relro_local_ : 1; // True if this is a small section. bool is_small_section_ : 1; // True if this is a large section. bool is_large_section_ : 1; // True if this is the .interp section going into the PT_INTERP // segment. bool is_interp_ : 1; // True if this is section is read by the dynamic linker. bool is_dynamic_linker_section_ : 1; // Whether code-fills are generated at write. bool generate_code_fills_at_write_ : 1; // For SHT_TLS sections, the offset of this section relative to the base // of the TLS segment. uint64_t tls_offset_; // Saved checkpoint. Checkpoint_output_section* checkpoint_; // Map from input sections to merge sections. Output_section_data_by_input_section_map merge_section_map_; // Map from merge section properties to merge_sections; Merge_section_by_properties_map merge_section_by_properties_map_; // Map from input sections to relaxed input sections. This is mutable // because it is updated lazily. We may need to update it in a // const qualified method. mutable Output_section_data_by_input_section_map relaxed_input_section_map_; // Whether relaxed_input_section_map_ is valid. mutable bool is_relaxed_input_section_map_valid_; }; // An output segment. PT_LOAD segments are built from collections of // output sections. Other segments typically point within PT_LOAD // segments, and are built directly as needed. // // NOTE: We want to use the copy constructor for this class. During // relaxation, we may try built the segments multiple times. We do // that by copying the original segment list before lay-out, doing // a trial lay-out and roll-back to the saved copied if we need to // to the lay-out again. class Output_segment { public: // Create an output segment, specifying the type and flags. Output_segment(elfcpp::Elf_Word, elfcpp::Elf_Word); // Return the virtual address. uint64_t vaddr() const { return this->vaddr_; } // Return the physical address. uint64_t paddr() const { return this->paddr_; } // Return the segment type. elfcpp::Elf_Word type() const { return this->type_; } // Return the segment flags. elfcpp::Elf_Word flags() const { return this->flags_; } // Return the memory size. uint64_t memsz() const { return this->memsz_; } // Return the file size. off_t filesz() const { return this->filesz_; } // Return the file offset. off_t offset() const { return this->offset_; } // Whether this is a segment created to hold large data sections. bool is_large_data_segment() const { return this->is_large_data_segment_; } // Record that this is a segment created to hold large data // sections. void set_is_large_data_segment() { this->is_large_data_segment_ = true; } // Return the maximum alignment of the Output_data. uint64_t maximum_alignment(); // Add the Output_section OS to this segment. SEG_FLAGS is the // segment flags to use. DO_SORT is true if we should sort the // placement of the input section for more efficient generated code. void add_output_section(Output_section* os, elfcpp::Elf_Word seg_flags, bool do_sort); // Remove an Output_section from this segment. It is an error if it // is not present. void remove_output_section(Output_section* os); // Add an Output_data (which is not an Output_section) to the start // of this segment. void add_initial_output_data(Output_data*); // Return true if this segment has any sections which hold actual // data, rather than being a BSS section. bool has_any_data_sections() const { return !this->output_data_.empty(); } // Return the number of dynamic relocations applied to this segment. unsigned int dynamic_reloc_count() const; // Return the address of the first section. uint64_t first_section_load_address() const; // Return whether the addresses have been set already. bool are_addresses_set() const { return this->are_addresses_set_; } // Set the addresses. void set_addresses(uint64_t vaddr, uint64_t paddr) { this->vaddr_ = vaddr; this->paddr_ = paddr; this->are_addresses_set_ = true; } // Set the segment flags. This is only used if we have a PHDRS // clause which explicitly specifies the flags. void set_flags(elfcpp::Elf_Word flags) { this->flags_ = flags; } // Set the address of the segment to ADDR and the offset to *POFF // and set the addresses and offsets of all contained output // sections accordingly. Set the section indexes of all contained // output sections starting with *PSHNDX. If RESET is true, first // reset the addresses of the contained sections. Return the // address of the immediately following segment. Update *POFF and // *PSHNDX. This should only be called for a PT_LOAD segment. uint64_t set_section_addresses(const Layout*, bool reset, uint64_t addr, off_t* poff, unsigned int* pshndx); // Set the minimum alignment of this segment. This may be adjusted // upward based on the section alignments. void set_minimum_p_align(uint64_t align) { this->min_p_align_ = align; } // Set the offset of this segment based on the section. This should // only be called for a non-PT_LOAD segment. void set_offset(); // Set the TLS offsets of the sections contained in the PT_TLS segment. void set_tls_offsets(); // Return the number of output sections. unsigned int output_section_count() const; // 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* section_with_lowest_load_address() const; // Write the segment header into *OPHDR. template<int size, bool big_endian> void write_header(elfcpp::Phdr_write<size, big_endian>*); // Write the section headers of associated sections into V. template<int size, bool big_endian> unsigned char* write_section_headers(const Layout*, const Stringpool*, unsigned char* v, unsigned int* pshndx) const; // Print the output sections in the map file. void print_sections_to_mapfile(Mapfile*) const; private: typedef std::list<Output_data*> Output_data_list; // Find the maximum alignment in an Output_data_list. static uint64_t maximum_alignment_list(const Output_data_list*); // Return whether the first data section is a relro section. bool is_first_section_relro() const; // Set the section addresses in an Output_data_list. uint64_t set_section_list_addresses(const Layout*, bool reset, Output_data_list*, uint64_t addr, off_t* poff, unsigned int* pshndx, bool* in_tls, bool* in_relro); // Return the number of Output_sections in an Output_data_list. unsigned int output_section_count_list(const Output_data_list*) const; // Return the number of dynamic relocs in an Output_data_list. unsigned int dynamic_reloc_count_list(const Output_data_list*) const; // Find the section with the lowest load address in an // Output_data_list. void lowest_load_address_in_list(const Output_data_list* pdl, Output_section** found, uint64_t* found_lma) const; // Write the section headers in the list into V. template<int size, bool big_endian> unsigned char* write_section_headers_list(const Layout*, const Stringpool*, const Output_data_list*, unsigned char* v, unsigned int* pshdx) const; // Print a section list to the mapfile. void print_section_list_to_mapfile(Mapfile*, const Output_data_list*) const; // NOTE: We want to use the copy constructor. Currently, shallow copy // works for us so we do not need to write our own copy constructor. // The list of output data with contents attached to this segment. Output_data_list output_data_; // The list of output data without contents attached to this segment. Output_data_list output_bss_; // The segment virtual address. uint64_t vaddr_; // The segment physical address. uint64_t paddr_; // The size of the segment in memory. uint64_t memsz_; // The maximum section alignment. The is_max_align_known_ field // indicates whether this has been finalized. uint64_t max_align_; // The required minimum value for the p_align field. This is used // for PT_LOAD segments. Note that this does not mean that // addresses should be aligned to this value; it means the p_paddr // and p_vaddr fields must be congruent modulo this value. For // non-PT_LOAD segments, the dynamic linker works more efficiently // if the p_align field has the more conventional value, although it // can align as needed. uint64_t min_p_align_; // The offset of the segment data within the file. off_t offset_; // The size of the segment data in the file. off_t filesz_; // The segment type; elfcpp::Elf_Word type_; // The segment flags. elfcpp::Elf_Word flags_; // Whether we have finalized max_align_. bool is_max_align_known_ : 1; // Whether vaddr and paddr were set by a linker script. bool are_addresses_set_ : 1; // Whether this segment holds large data sections. bool is_large_data_segment_ : 1; }; // This class represents the output file. class Output_file { public: Output_file(const char* name); // Indicate that this is a temporary file which should not be // output. void set_is_temporary() { this->is_temporary_ = true; } // Try to open an existing file. Returns false if the file doesn't // exist, has a size of 0 or can't be mmaped. This method is // thread-unsafe. bool open_for_modification(); // Open the output file. FILE_SIZE is the final size of the file. // If the file already exists, it is deleted/truncated. This method // is thread-unsafe. void open(off_t file_size); // Resize the output file. This method is thread-unsafe. void resize(off_t file_size); // Close the output file (flushing all buffered data) and make sure // there are no errors. This method is thread-unsafe. void close(); // Return the size of this file. off_t filesize() { return this->file_size_; } // We currently always use mmap which makes the view handling quite // simple. In the future we may support other approaches. // Write data to the output file. void write(off_t offset, const void* data, size_t len) { memcpy(this->base_ + offset, data, len); } // Get a buffer to use to write to the file, given the offset into // the file and the size. unsigned char* get_output_view(off_t start, size_t size) { gold_assert(start >= 0 && start + static_cast<off_t>(size) <= this->file_size_); return this->base_ + start; } // VIEW must have been returned by get_output_view. Write the // buffer to the file, passing in the offset and the size. void write_output_view(off_t, size_t, unsigned char*) { } // Get a read/write buffer. This is used when we want to write part // of the file, read it in, and write it again. unsigned char* get_input_output_view(off_t start, size_t size) { return this->get_output_view(start, size); } // Write a read/write buffer back to the file. void write_input_output_view(off_t, size_t, unsigned char*) { } // Get a read buffer. This is used when we just want to read part // of the file back it in. const unsigned char* get_input_view(off_t start, size_t size) { return this->get_output_view(start, size); } // Release a read bfufer. void free_input_view(off_t, size_t, const unsigned char*) { } private: // Map the file into memory or, if that fails, allocate anonymous // memory. void map(); // Allocate anonymous memory for the file. bool map_anonymous(); // Map the file into memory. bool map_no_anonymous(); // Unmap the file from memory (and flush to disk buffers). void unmap(); // File name. const char* name_; // File descriptor. int o_; // File size. off_t file_size_; // Base of file mapped into memory. unsigned char* base_; // True iff base_ points to a memory buffer rather than an output file. bool map_is_anonymous_; // True if this is a temporary file which should not be output. bool is_temporary_; }; } // End namespace gold. #endif // !defined(GOLD_OUTPUT_H)
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