// layout.h -- lay out output file sections for gold -*- C++ -*- #ifndef GOLD_LAYOUT_H #define GOLD_LAYOUT_H #include <list> #include <string> #include <utility> #include <vector> #include "workqueue.h" #include "object.h" #include "dynobj.h" #include "stringpool.h" namespace gold { class General_options; class Input_objects; class Symbol_table; class Output_section_data; class Output_section; class Output_section_headers; class Output_segment; class Output_data; class Output_data_dynamic; class Target; // This task function handles mapping the input sections to output // sections and laying them out in memory. class Layout_task_runner : public Task_function_runner { public: // OPTIONS is the command line options, INPUT_OBJECTS is the list of // input objects, SYMTAB is the symbol table, LAYOUT is the layout // object. Layout_task_runner(const General_options& options, const Input_objects* input_objects, Symbol_table* symtab, Layout* layout) : options_(options), input_objects_(input_objects), symtab_(symtab), layout_(layout) { } // Run the operation. void run(Workqueue*); private: Layout_task_runner(const Layout_task_runner&); Layout_task_runner& operator=(const Layout_task_runner&); const General_options& options_; const Input_objects* input_objects_; Symbol_table* symtab_; Layout* layout_; }; // This class handles the details of laying out input sections. class Layout { public: Layout(const General_options& options); // Given an input section SHNDX, named NAME, with data in SHDR, from // the object file OBJECT, return the output section where this // input section should go. Set *OFFSET to the offset within the // output section. template<int size, bool big_endian> Output_section* layout(Relobj *object, unsigned int shndx, const char* name, const elfcpp::Shdr<size, big_endian>& shdr, off_t* offset); // Add an Output_section_data to the layout. This is used for // special sections like the GOT section. void add_output_section_data(const char* name, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, Output_section_data*); // Create dynamic sections if necessary. void create_initial_dynamic_sections(const Input_objects*, Symbol_table*); // Return the Stringpool used for symbol names. const Stringpool* sympool() const { return &this->sympool_; } // Return the Stringpool used for dynamic symbol names and dynamic // tags. const Stringpool* dynpool() const { return &this->dynpool_; } // Return whether a section is a .gnu.linkonce section, given the // section name. static inline bool is_linkonce(const char* name) { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; } // Record the signature of a comdat section, and return whether to // include it in the link. The GROUP parameter is true for a // section group signature, false for a signature derived from a // .gnu.linkonce section. bool add_comdat(const char*, bool group); // Finalize the layout after all the input sections have been added. off_t finalize(const Input_objects*, Symbol_table*); // Return the TLS segment. This will return NULL if there isn't // one. Output_segment* tls_segment() const { return this->tls_segment_; } // Return the normal symbol table. Output_section* symtab_section() const { gold_assert(this->symtab_section_ != NULL); return this->symtab_section_; } // Return the dynamic symbol table. Output_section* dynsym_section() const { gold_assert(this->dynsym_section_ != NULL); return this->dynsym_section_; } // Return the dynamic tags. Output_data_dynamic* dynamic_data() const { return this->dynamic_data_; } // Write out data not associated with an input file or the symbol // table. void write_data(const Symbol_table*, const Target*, Output_file*) const; // Return an output section named NAME, or NULL if there is none. Output_section* find_output_section(const char* name) const; // Return an output segment of type TYPE, with segment flags SET set // and segment flags CLEAR clear. Return NULL if there is none. Output_segment* find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, elfcpp::Elf_Word clear) const; // The list of segments. typedef std::vector<Output_segment*> Segment_list; // The list of sections not attached to a segment. typedef std::vector<Output_section*> Section_list; // The list of information to write out which is not attached to // either a section or a segment. typedef std::vector<Output_data*> Data_list; private: Layout(const Layout&); Layout& operator=(const Layout&); // Mapping from .gnu.linkonce section names to output section names. struct Linkonce_mapping { const char* from; int fromlen; const char* to; int tolen; }; static const Linkonce_mapping linkonce_mapping[]; static const int linkonce_mapping_count; // Find the first read-only PT_LOAD segment, creating one if // necessary. Output_segment* find_first_load_seg(); // Create the output sections for the symbol table. void create_symtab_sections(int size, const Input_objects*, Symbol_table*, off_t*); // Create the .shstrtab section. Output_section* create_shstrtab(); // Create the section header table. Output_section_headers* create_shdrs(int size, bool big_endian, off_t*); // Create the dynamic symbol table. void create_dynamic_symtab(const Target*, Symbol_table*, Output_section** pdynstr, unsigned int* plocal_dynamic_count, std::vector<Symbol*>* pdynamic_symbols, Versions* versions); // Finish the .dynamic section and PT_DYNAMIC segment. void finish_dynamic_section(const Input_objects*, const Symbol_table*); // Create the .interp section and PT_INTERP segment. void create_interp(const Target* target); // Create the version sections. void create_version_sections(const Target*, const Versions*, unsigned int local_symcount, const std::vector<Symbol*>& dynamic_symbols, const Output_section* dynstr); template<int size, bool big_endian> void sized_create_version_sections(const Versions* versions, unsigned int local_symcount, const std::vector<Symbol*>& dynamic_symbols, const Output_section* dynstr ACCEPT_SIZE_ENDIAN); // Return whether to include this section in the link. template<int size, bool big_endian> bool include_section(Object* object, const char* name, const elfcpp::Shdr<size, big_endian>&); // Return the output section name to use given an input section // name. Set *PLEN to the length of the name. *PLEN must be // initialized to the length of NAME. static const char* output_section_name(const char* name, size_t* plen); // Return the output section name to use for a linkonce section // name. PLEN is as for output_section_name. static const char* linkonce_output_name(const char* name, size_t* plen); // Return the output section for NAME, TYPE and FLAGS. Output_section* get_output_section(const char* name, Stringpool::Key name_key, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags); // Create a new Output_section. Output_section* make_output_section(const char* name, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags); // Set the final file offsets of all the segments. off_t set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx); // Set the final file offsets and section indexes of all the // sections not associated with a segment. off_t set_section_offsets(off_t, unsigned int *pshndx); // Return whether SEG1 comes before SEG2 in the output file. static bool segment_precedes(const Output_segment* seg1, const Output_segment* seg2); // Map from section flags to segment flags. static elfcpp::Elf_Word section_flags_to_segment(elfcpp::Elf_Xword flags); // A mapping used for group signatures. typedef Unordered_map<std::string, bool> Signatures; // Mapping from input section name/type/flags to output section. We // use canonicalized strings here. typedef std::pair<Stringpool::Key, std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key; struct Hash_key { size_t operator()(const Key& k) const; }; typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map; // A comparison class for segments. struct Compare_segments { bool operator()(const Output_segment* seg1, const Output_segment* seg2) { return Layout::segment_precedes(seg1, seg2); } }; // A reference to the options on the command line. const General_options& options_; // The output section names. Stringpool namepool_; // The output symbol names. Stringpool sympool_; // The dynamic strings, if needed. Stringpool dynpool_; // The list of group sections and linkonce sections which we have seen. Signatures signatures_; // The mapping from input section name/type/flags to output sections. Section_name_map section_name_map_; // The list of output segments. Segment_list segment_list_; // The list of output sections. Section_list section_list_; // The list of output sections which are not attached to any output // segment. Section_list unattached_section_list_; // The list of unattached Output_data objects which require special // handling because they are not Output_sections. Data_list special_output_list_; // A pointer to the PT_TLS segment if there is one. Output_segment* tls_segment_; // The SHT_SYMTAB output section. Output_section* symtab_section_; // The SHT_DYNSYM output section if there is one. Output_section* dynsym_section_; // The SHT_DYNAMIC output section if there is one. Output_section* dynamic_section_; // The dynamic data which goes into dynamic_section_. Output_data_dynamic* dynamic_data_; }; // This task handles writing out data which is not part of a section // or segment. class Write_data_task : public Task { public: Write_data_task(const Layout* layout, const Symbol_table* symtab, const Target* target, Output_file* of, Task_token* final_blocker) : layout_(layout), symtab_(symtab), target_(target), of_(of), final_blocker_(final_blocker) { } // The standard Task methods. Is_runnable_type is_runnable(Workqueue*); Task_locker* locks(Workqueue*); void run(Workqueue*); private: const Layout* layout_; const Symbol_table* symtab_; const Target* target_; Output_file* of_; Task_token* final_blocker_; }; // This task handles writing out the global symbols. class Write_symbols_task : public Task { public: Write_symbols_task(const Symbol_table* symtab, const Target* target, const Stringpool* sympool, const Stringpool* dynpool, Output_file* of, Task_token* final_blocker) : symtab_(symtab), target_(target), sympool_(sympool), dynpool_(dynpool), of_(of), final_blocker_(final_blocker) { } // The standard Task methods. Is_runnable_type is_runnable(Workqueue*); Task_locker* locks(Workqueue*); void run(Workqueue*); private: const Symbol_table* symtab_; const Target* target_; const Stringpool* sympool_; const Stringpool* dynpool_; Output_file* of_; Task_token* final_blocker_; }; // This task function handles closing the file. class Close_task_runner : public Task_function_runner { public: Close_task_runner(Output_file* of) : of_(of) { } // Run the operation. void run(Workqueue*); private: Output_file* of_; }; // A small helper function to align an address. inline uint64_t align_address(uint64_t address, uint64_t addralign) { if (addralign != 0) address = (address + addralign - 1) &~ (addralign - 1); return address; } } // End namespace gold. #endif // !defined(GOLD_LAYOUT_H)