// output.h -- manage the output file for gold -*- C++ -*- #ifndef GOLD_OUTPUT_H #define GOLD_OUTPUT_H #include <list> #include <vector> #include "elfcpp.h" #include "layout.h" #include "reloc-types.h" namespace gold { class General_options; class Object; class Symbol; class Output_file; class Output_section; class Target; template<int size, bool big_endian> class Sized_target; template<int size, bool big_endian> class Sized_relobj; // An abtract class for data which has to go into the output file. class Output_data { public: explicit Output_data(off_t data_size = 0) : address_(0), data_size_(data_size), offset_(-1) { } virtual ~Output_data(); // Return the address. This is only valid after Layout::finalize is // finished. uint64_t address() const { return this->address_; } // Return the size of the data. This must be valid after // Layout::finalize calls set_address, but need not be valid before // then. off_t data_size() const { return this->data_size_; } // Return the file offset. This is only valid after // Layout::finalize is finished. off_t offset() const { return this->offset_; } // Return the required alignment. uint64_t addralign() const { return this->do_addralign(); } // 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 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. This is called // during Layout::finalize. void set_address(uint64_t addr, off_t off); // 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 all sizes must // now be fixed. static void layout_complete() { Output_data::sizes_are_fixed = true; } 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 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 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(); } // Set the address and file offset of the data. This only needs to // be implemented if the child needs to know. The child class can // set its size in this call. virtual void do_set_address(uint64_t, off_t) { } // Functions that child classes may call. // Set the size of the data. void set_data_size(off_t data_size) { gold_assert(!Output_data::sizes_are_fixed); this->data_size_ = data_size; } // Return default alignment for a size--32 or 64. static uint64_t default_alignment(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 after we set the section addresses. static bool sizes_are_fixed; // Memory address in file (not always meaningful). uint64_t address_; // Size of data in file. off_t data_size_; // Offset within file. off_t offset_; }; // Output the section headers. class Output_section_headers : public Output_data { public: Output_section_headers(int size, bool big_endian, const Layout*, const Layout::Segment_list*, const Layout::Section_list*, const Stringpool*); // 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(this->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*); int size_; bool big_endian_; const Layout* layout_; const Layout::Segment_list* segment_list_; const Layout::Section_list* unattached_section_list_; const Stringpool* secnamepool_; }; // Output the segment headers. class Output_segment_headers : public Output_data { public: Output_segment_headers(int size, bool big_endian, const Layout::Segment_list& segment_list); // 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(this->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*); int size_; bool big_endian_; const Layout::Segment_list& segment_list_; }; // Output the ELF file header. class Output_file_header : public Output_data { public: Output_file_header(int size, bool big_endian, const General_options&, const Target*, const Symbol_table*, const Output_segment_headers*); // 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); // 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(this->size_); } // Set the address and offset--we only implement this for error // checking. void do_set_address(uint64_t, off_t off) const { gold_assert(off == 0); } 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*); int size_; bool big_endian_; const General_options& options_; const Target* target_; const Symbol_table* symtab_; const Output_segment_headers* segment_header_; const Output_section_headers* section_header_; const Output_section* shstrtab_; }; // 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) : Output_data(data_size), output_section_(NULL), addralign_(addralign) { } Output_section_data(uint64_t addralign) : Output_data(0), 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 output address is known. // OUTPUT_SECTION_ADDRESS is the address of the output section which // this is a part of. If this function returns true, it sets // *POUTPUT to the output address. virtual bool output_address(const Relobj* object, unsigned int shndx, off_t offset, uint64_t output_section_address, uint64_t *poutput) const { return this->do_output_address(object, shndx, offset, output_section_address, poutput); } 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_address. virtual bool do_output_address(const Relobj*, unsigned int, off_t, uint64_t, uint64_t*) const { return false; } // Return the required alignment. uint64_t do_addralign() const { return this->addralign_; } // Return the section index of the output section. unsigned int do_out_shndx() const; // Set the alignment. void set_addralign(uint64_t addralign) { this->addralign_ = addralign; } private: // The output section for this section. const Output_section* output_section_; // The required alignment. uint64_t addralign_; }; // 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), data_(data) { } Output_data_const(const char* p, off_t len, uint64_t addralign) : Output_section_data(len, addralign), data_(p, len) { } Output_data_const(const unsigned char* p, off_t len, uint64_t addralign) : Output_section_data(len, addralign), data_(reinterpret_cast<const char*>(p), len) { } // Add more data. void add_data(const std::string& add) { this->data_.append(add); this->set_data_size(this->data_.size()); } // Write the data to the output file. void do_write(Output_file*); 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) : Output_section_data(len, addralign), p_(p) { } // Write the data the output file. void do_write(Output_file*); private: const unsigned char* p_; }; // A place holder for data written out via some other mechanism. class Output_data_space : public Output_section_data { public: Output_data_space(off_t data_size, uint64_t addralign) : Output_section_data(data_size, addralign) { } explicit Output_data_space(uint64_t addralign) : Output_section_data(addralign) { } // Set the size. void set_space_size(off_t space_size) { this->set_data_size(space_size); } // Set the alignment. void set_space_alignment(uint64_t align) { this->set_addralign(align); } // Write out the data--this must be handled elsewhere. void do_write(Output_file*) { } }; // 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) { } // This is called to set the address and file offset. Here we make // sure that the Stringpool is finalized. void do_set_address(uint64_t, off_t); // Write out the data. void do_write(Output_file*); 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, 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; // 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) { } // A reloc against a global symbol. Output_reloc(Symbol* gsym, unsigned int type, Output_data* od, Address address) : address_(address), local_sym_index_(GSYM_CODE), type_(type), shndx_(INVALID_CODE) { this->u1_.gsym = gsym; this->u2_.od = od; } Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj, unsigned int shndx, Address address) : address_(address), local_sym_index_(GSYM_CODE), type_(type), shndx_(shndx) { gold_assert(shndx != INVALID_CODE); this->u1_.gsym = gsym; this->u2_.relobj = relobj; } // 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) : address_(address), local_sym_index_(local_sym_index), type_(type), shndx_(INVALID_CODE) { gold_assert(local_sym_index != GSYM_CODE && local_sym_index != INVALID_CODE); this->u1_.relobj = relobj; this->u2_.od = od; } Output_reloc(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, unsigned int shndx, Address address) : address_(address), local_sym_index_(local_sym_index), type_(type), shndx_(shndx) { gold_assert(local_sym_index != GSYM_CODE && local_sym_index != INVALID_CODE); gold_assert(shndx != INVALID_CODE); this->u1_.relobj = relobj; this->u2_.relobj = relobj; } // A reloc against the STT_SECTION symbol of an output section. Output_reloc(Output_section* os, unsigned int type, Output_data* od, Address address) : address_(address), local_sym_index_(SECTION_CODE), type_(type), shndx_(INVALID_CODE) { this->u1_.os = os; this->u2_.od = od; } Output_reloc(Output_section* os, unsigned int type, Relobj* relobj, unsigned int shndx, Address address) : address_(address), local_sym_index_(SECTION_CODE), type_(type), shndx_(shndx) { gold_assert(shndx != INVALID_CODE); this->u1_.os = os; this->u2_.relobj = relobj; } // 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; private: // Return the symbol index. We can't do a double template // specialization, so we do a secondary template here. unsigned int get_symbol_index() 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, 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, the symbol. If this is NULL, it indicates // a relocation against the undefined 0 symbol. Symbol* gsym; // For a relocation against an output section, the output section. Output_section* os; } u1_; union { // If shndx_ is not INVALID CODE, the object which holds the input // section being used to specify the reloc address. Relobj* relobj; // If 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_; // For a local symbol, the local symbol index. This is GSYM_CODE // for a global symbol, or INVALID_CODE for an uninitialized value. unsigned int local_sym_index_; // The reloc type--a processor specific code. unsigned int type_; // 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) : rel_(gsym, type, od, address), addend_(addend) { } Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj, unsigned int shndx, Address address, Addend addend) : rel_(gsym, type, relobj, shndx, address), 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) : rel_(relobj, local_sym_index, type, od, address), 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) : rel_(relobj, local_sym_index, type, shndx, address), 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, Relobj* 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; 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 { 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() : Output_section_data(Output_data::default_alignment(size)) { } // Write out the data. void do_write(Output_file*); protected: // Set the entry size and the link. void do_adjust_output_section(Output_section *os); // Add a relocation entry. void add(const Output_reloc_type& reloc) { this->relocs_.push_back(reloc); this->set_data_size(this->relocs_.size() * reloc_size); } private: typedef std::vector<Output_reloc_type> Relocs; Relocs 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() : Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian>() { } // Add a reloc against a global symbol. void add_global(Symbol* gsym, unsigned int type, Output_data* od, Address address) { this->add(Output_reloc_type(gsym, type, od, address)); } void add_global(Symbol* gsym, unsigned int type, Relobj* relobj, unsigned int shndx, Address address) { this->add(Output_reloc_type(gsym, type, relobj, shndx, address)); } // 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(Output_reloc_type(relobj, local_sym_index, type, od, address)); } void add_local(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, unsigned int shndx, Address address) { this->add(Output_reloc_type(relobj, local_sym_index, type, shndx, address)); } // 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) { this->add(Output_reloc_type(os, type, od, address)); } void add_output_section(Output_section* os, unsigned int type, Relobj* relobj, unsigned int shndx, Address address) { this->add(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() : Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian>() { } // Add a reloc against a global symbol. void add_global(Symbol* gsym, unsigned int type, Output_data* od, Address address, Addend addend) { this->add(Output_reloc_type(gsym, type, od, address, addend)); } void add_global(Symbol* gsym, unsigned int type, Relobj* relobj, unsigned int shndx, Address address, Addend addend) { this->add(Output_reloc_type(gsym, type, relobj, shndx, address, addend)); } // 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(Output_reloc_type(relobj, local_sym_index, type, od, address, addend)); } void add_local(Sized_relobj<size, big_endian>* relobj, unsigned int local_sym_index, unsigned int type, unsigned int shndx, Address address, Addend addend) { this->add(Output_reloc_type(relobj, local_sym_index, type, shndx, address, addend)); } // 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(Output_reloc_type(os, type, od, address, addend)); } void add_output_section(Output_section* os, unsigned int type, Relobj* relobj, unsigned int shndx, Address address, Addend addend) { this->add(Output_reloc_type(os, type, relobj, shndx, address, addend)); } }; // 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 { public: typedef typename elfcpp::Elf_types<size>::Elf_Addr Valtype; Output_data_got(const General_options* options) : Output_section_data(Output_data::default_alignment(size)), options_(options), 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); // Add an entry for a local symbol to the GOT. This returns the // offset of the new entry from the start of the GOT. unsigned int add_local(Object* object, unsigned int sym_index) { this->entries_.push_back(Got_entry(object, sym_index)); this->set_got_size(); return this->last_got_offset(); } // 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(); } // Write out the GOT table. void do_write(Output_file*); 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(Object* 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(const General_options*, unsigned char* pov) const; private: enum { GSYM_CODE = -1U, CONSTANT_CODE = -2U }; union { // For a local symbol, the object. Object* 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_data_size(this->got_offset(this->entries_.size())); } // Options. const General_options* options_; // 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(const Target* target, Stringpool* pool) : Output_section_data(Output_data::default_alignment(target->get_size())), target_(target), 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 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, NULL))); } // Set the final data size. void do_set_address(uint64_t, off_t); // Write out the dynamic entries. void do_write(Output_file*); protected: // Adjust the output section to set the entry size. void do_adjust_output_section(Output_section*); 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), classification_(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), classification_(section_size ? DYNAMIC_SECTION_SIZE : DYNAMIC_SECTION_ADDRESS) { this->u_.od = od; } // Create an entry with the address of a symbol. Dynamic_entry(elfcpp::DT tag, const Symbol* sym) : tag_(tag), classification_(DYNAMIC_SYMBOL) { this->u_.sym = sym; } // Create an entry with a string. Dynamic_entry(elfcpp::DT tag, const char* str) : tag_(tag), classification_(DYNAMIC_STRING) { this->u_.str = str; } // Write the dynamic entry to an output view. template<int size, bool big_endian> void write(unsigned char* pov, const Stringpool* ACCEPT_SIZE_ENDIAN) const; private: enum Classification { // Number. DYNAMIC_NUMBER, // Section address. DYNAMIC_SECTION_ADDRESS, // Section size. DYNAMIC_SECTION_SIZE, // Symbol adress. DYNAMIC_SYMBOL, // String. DYNAMIC_STRING }; union { // For DYNAMIC_NUMBER. unsigned int val; // For DYNAMIC_SECTION_ADDRESS and DYNAMIC_SECTION_SIZE. 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 classification_; }; // 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 target. const Target* target_; // The entries. Dynamic_entries entries_; // The pool used for strings. Stringpool* pool_; }; // 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. Return the offset within the output section. template<int size, bool big_endian> off_t add_input_section(Relobj* object, unsigned int shndx, const char *name, const elfcpp::Shdr<size, big_endian>& shdr); // Add generated data POSD to this output section. void add_output_section_data(Output_section_data* posd); // 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_; } // Return the section index in the output file. unsigned int do_out_shndx() const { return this->out_shndx_; } // Set the output section index. void do_set_out_shndx(unsigned int shndx) { this->out_shndx_ = shndx; } // Return the entsize field. uint64_t entsize() const { return this->entsize_; } // Set the entsize field. void set_entsize(uint64_t v); // 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); return this->info_; } // Set the info field to the output section index of a section. void set_info_section(const Output_data* od) { gold_assert(this->info_ == 0); this->info_section_ = od; } // Set the info field to a constant. void set_info(unsigned int v) { gold_assert(this->info_section_ == NULL); this->info_ = v; } // Set the addralign field. void set_addralign(uint64_t v) { this->addralign_ = v; } // 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 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; // Set the address 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 the final addresses // here. void do_set_address(uint64_t, off_t); // 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. void do_write(Output_file*); // Return the address alignment--function required by parent class. uint64_t do_addralign() const { return this->addralign_; } // 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; } // 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; private: // 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); 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_(ffsll(static_cast<long long>(posd->addralign()))) { 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_(ffsll(static_cast<long long>(posd->addralign()))) { this->u1_.entsize = entsize; this->u2_.posd = posd; } // The required alignment. uint64_t addralign() const { return (this->p2align_ == 0 ? 0 : static_cast<uint64_t>(1) << (this->p2align_ - 1)); } // Return the required size. off_t data_size() const; // Return whether this is a merge section which matches the // parameters. bool is_merge_section(bool is_string, uint64_t entsize) const { return (this->shndx_ == (is_string ? MERGE_STRING_SECTION_CODE : MERGE_DATA_SECTION_CODE) && this->u1_.entsize == entsize); } // Set the output section. void set_output_section(Output_section* os) { gold_assert(!this->is_input_section()); this->u2_.posd->set_output_section(os); } // Set the address and file offset. This is called during // Layout::finalize. SECOFF is the file offset of the enclosing // section. void set_address(uint64_t addr, off_t off, off_t secoff); // 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 address is known. // OUTPUT_SECTION_ADDRESS is the address of the output section // which this is a part of. If this function returns true, it // sets *POUTPUT to the output address. bool output_address(const Relobj* object, unsigned int shndx, off_t offset, uint64_t output_section_address, uint64_t *poutput) const; // Write out the data. This does nothing for an input section. void write(Output_file*); 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 }; // 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); } // 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, 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; } u2_; }; typedef std::vector<Input_section> Input_section_list; // 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); // 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 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_data* info_section_; // If info_section_ is NULL, this is the section info field. unsigned int info_; // The section type. 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_; // 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; }; // 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. 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 maximum alignment of the Output_data. uint64_t addralign(); // Add an Output_section to this segment. void add_output_section(Output_section* os, elfcpp::Elf_Word seg_flags) { this->add_output_section(os, seg_flags, false); } // Add an Output_section to the start of this segment. void add_initial_output_section(Output_section* os, elfcpp::Elf_Word seg_flags) { this->add_output_section(os, seg_flags, true); } // Add an Output_data (which is not an Output_section) to the start // of this segment. void add_initial_output_data(Output_data*); // Set the address of the segment to ADDR and the offset to *POFF // (aligned if necessary), and set the addresses and offsets of all // contained output sections accordingly. Set the section indexes // of all contained output sections starting with *PSHNDX. 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(uint64_t addr, off_t* poff, unsigned int* pshndx); // Set the offset of this segment based on the section. This should // only be called for a non-PT_LOAD segment. void set_offset(); // Return the number of output sections. unsigned int output_section_count() 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 ACCEPT_SIZE_ENDIAN) const; private: Output_segment(const Output_segment&); Output_segment& operator=(const Output_segment&); typedef std::list<Output_data*> Output_data_list; // Add an Output_section to this segment, specifying front or back. void add_output_section(Output_section*, elfcpp::Elf_Word seg_flags, bool front); // Find the maximum alignment in an Output_data_list. static uint64_t maximum_alignment(const Output_data_list*); // Set the section addresses in an Output_data_list. uint64_t set_section_list_addresses(Output_data_list*, uint64_t addr, off_t* poff, unsigned int* pshndx); // Return the number of Output_sections in an Output_data_list. unsigned int output_section_count_list(const Output_data_list*) 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 ACCEPT_SIZE_ENDIAN) const; // 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 segment alignment. uint64_t 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 set align_. bool is_align_known_; }; // This class represents the output file. class Output_file { public: Output_file(const General_options& options); // Open the output file. FILE_SIZE is the final size of the file. void open(off_t file_size); // Close the output file and make sure there are no error. void close(); // 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, off_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, off_t size) { gold_assert(start >= 0 && size >= 0 && start + 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, off_t, unsigned char*) { } private: // General options. const General_options& options_; // File name. const char* name_; // File descriptor. int o_; // File size. off_t file_size_; // Base of file mapped into memory. unsigned char* base_; }; } // End namespace gold. #endif // !defined(GOLD_OUTPUT_H)