// target-select.h -- select a target for an object file -*- C++ -*- // Copyright (C) 2006-2014 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 3 of the License, or // (at your option) any later version. // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, // MA 02110-1301, USA. #ifndef GOLD_TARGET_SELECT_H #define GOLD_TARGET_SELECT_H #include #include "gold-threads.h" namespace gold { class Input_file; class Target; class Target_selector; // Used to set the target only once. class Set_target_once : public Once { public: Set_target_once(Target_selector* target_selector) : target_selector_(target_selector) { } protected: void do_run_once(void*); private: Target_selector* target_selector_; }; // We want to avoid a master list of targets, which implies using a // global constructor. And we also want the program to start up as // quickly as possible, which implies avoiding global constructors. // We compromise on a very simple global constructor. We use a target // selector, which specifies an ELF machine number and a recognition // function. We use global constructors to build a linked list of // target selectors--a simple pointer list, not a std::list. class Target_selector { public: // Create a target selector for a specific machine number, size (32 // or 64), and endianness. The machine number can be EM_NONE to // test for any machine number. BFD_NAME is the name of the target // used by the GNU linker, for backward compatibility; it may be // NULL. EMULATION is the name of the emulation used by the GNU // linker; it is similar to BFD_NAME. Target_selector(int machine, int size, bool is_big_endian, const char* bfd_name, const char* emulation); virtual ~Target_selector() { } // If we can handle this target, return a pointer to a target // structure. The size and endianness are known. Target* recognize(Input_file* input_file, off_t offset, int machine, int osabi, int abiversion) { return this->do_recognize(input_file, offset, machine, osabi, abiversion); } // If NAME matches the target, return a pointer to a target // structure. Target* recognize_by_bfd_name(const char* name) { return this->do_recognize_by_bfd_name(name); } // Push all supported BFD names onto the vector. This is only used // for help output. void supported_bfd_names(std::vector* names) { this->do_supported_bfd_names(names); } // If NAME matches the target emulation, return a pointer to a // target structure. Target* recognize_by_emulation(const char* name) { return this->do_recognize_by_emulation(name); } // Push all supported emulations onto the vector. This is only used // for help output. void supported_emulations(std::vector* names) { this->do_supported_emulations(names); } // Return the next Target_selector in the linked list. Target_selector* next() const { return this->next_; } // Return the machine number this selector is looking for. This can // be EM_NONE to match any machine number, in which case the // do_recognize hook will be responsible for matching the machine // number. int machine() const { return this->machine_; } // Return the size this is looking for (32 or 64). int get_size() const { return this->size_; } // Return the endianness this is looking for. bool is_big_endian() const { return this->is_big_endian_; } // Return the BFD name. This may return NULL, in which case the // do_recognize_by_bfd_name hook will be responsible for matching // the BFD name. const char* bfd_name() const { return this->bfd_name_; } // Return the emulation. This may return NULL, in which case the // do_recognize_by_emulation hook will be responsible for matching // the emulation. const char* emulation() const { return this->emulation_; } // The reverse mapping, for --print-output-format: if we // instantiated TARGET, return our BFD_NAME. If we did not // instantiate it, return NULL. const char* target_bfd_name(const Target* target) { return this->do_target_bfd_name(target); } protected: // Return an instance of the real target. This must be implemented // by the child class. virtual Target* do_instantiate_target() = 0; // Recognize an object file given a machine code, OSABI code, and // ELF version value. When this is called we already know that they // match the machine_, size_, and is_big_endian_ fields. The child // class may implement a different version of this to do additional // checks, or to check for multiple machine codes if the machine_ // field is EM_NONE. virtual Target* do_recognize(Input_file*, off_t, int, int, int) { return this->instantiate_target(); } // Recognize a target by name. When this is called we already know // that the name matches (or that the bfd_name_ field is NULL). The // child class may implement a different version of this to // recognize more than one name. virtual Target* do_recognize_by_bfd_name(const char*) { return this->instantiate_target(); } // Return a list of supported BFD names. The child class may // implement a different version of this to handle more than one // name. virtual void do_supported_bfd_names(std::vector* names) { gold_assert(this->bfd_name_ != NULL); names->push_back(this->bfd_name_); } // Recognize a target by emulation. When this is called we already // know that the name matches (or that the emulation_ field is // NULL). The child class may implement a different version of this // to recognize more than one emulation. virtual Target* do_recognize_by_emulation(const char*) { return this->instantiate_target(); } // Return a list of supported emulations. The child class may // implement a different version of this to handle more than one // emulation. virtual void do_supported_emulations(std::vector* emulations) { gold_assert(this->emulation_ != NULL); emulations->push_back(this->emulation_); } // Map from target to BFD name. virtual const char* do_target_bfd_name(const Target*); // Instantiate the target and return it. Target* instantiate_target(); // Return whether TARGET is the target we instantiated. bool is_our_target(const Target* target) { return target == this->instantiated_target_; } private: // Set the target. void set_target(); friend class Set_target_once; // ELF machine code. const int machine_; // Target size--32 or 64. const int size_; // Whether the target is big endian. const bool is_big_endian_; // BFD name of target, for compatibility. const char* const bfd_name_; // GNU linker emulation for this target, for compatibility. const char* const emulation_; // Next entry in list built at global constructor time. Target_selector* next_; // The singleton Target structure--this points to an instance of the // real implementation. Target* instantiated_target_; // Used to set the target only once. Set_target_once set_target_once_; }; // Select the target for an ELF file. extern Target* select_target(Input_file*, off_t, int machine, int size, bool big_endian, int osabi, int abiversion); // Select a target using a BFD name. extern Target* select_target_by_bfd_name(const char* name); // Select a target using a GNU linker emulation. extern Target* select_target_by_emulation(const char* name); // Fill in a vector with the list of supported targets. This returns // a list of BFD names. extern void supported_target_names(std::vector*); // Fill in a vector with the list of supported emulations. extern void supported_emulation_names(std::vector*); // Print the output format, for the --print-output-format option. extern void print_output_format(); } // End namespace gold. #endif // !defined(GOLD_TARGET_SELECT_H)