// reloc.h -- relocate input files 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_RELOC_H #define GOLD_RELOC_H #include <vector> #ifdef HAVE_BYTESWAP_H #include <byteswap.h> #endif #include "elfcpp.h" #include "workqueue.h" namespace gold { class General_options; class Object; class Relobj; class Read_relocs_data; class Symbol; class Layout; class Output_data; class Output_section; template<int size> class Sized_symbol; template<int size, bool big_endian> class Sized_relobj; template<int size> class Symbol_value; template<int sh_type, bool dynamic, int size, bool big_endian> class Output_data_reloc; // A class to read the relocations for an object file, and then queue // up a task to see if they require any GOT/PLT/COPY relocations in // the symbol table. class Read_relocs : public Task { public: // SYMTAB_LOCK is used to lock the symbol table. BLOCKER should be // unblocked when the Scan_relocs task completes. Read_relocs(Symbol_table* symtab, Layout* layout, Relobj* object, Task_token* symtab_lock, Task_token* blocker) : symtab_(symtab), layout_(layout), object_(object), symtab_lock_(symtab_lock), blocker_(blocker) { } // The standard Task methods. Task_token* is_runnable(); void locks(Task_locker*); void run(Workqueue*); std::string get_name() const; private: Symbol_table* symtab_; Layout* layout_; Relobj* object_; Task_token* symtab_lock_; Task_token* blocker_; }; // Process the relocs to figure out which sections are garbage. // Very similar to scan relocs. class Gc_process_relocs : public Task { public: // SYMTAB_LOCK is used to lock the symbol table. BLOCKER should be // unblocked when the task completes. Gc_process_relocs(Symbol_table* symtab, Layout* layout, Relobj* object, Read_relocs_data* rd, Task_token* symtab_lock, Task_token* blocker) : symtab_(symtab), layout_(layout), object_(object), rd_(rd), symtab_lock_(symtab_lock), blocker_(blocker) { } // The standard Task methods. Task_token* is_runnable(); void locks(Task_locker*); void run(Workqueue*); std::string get_name() const; private: Symbol_table* symtab_; Layout* layout_; Relobj* object_; Read_relocs_data* rd_; Task_token* symtab_lock_; Task_token* blocker_; }; // Scan the relocations for an object to see if they require any // GOT/PLT/COPY relocations. class Scan_relocs : public Task { public: // SYMTAB_LOCK is used to lock the symbol table. BLOCKER should be // unblocked when the task completes. Scan_relocs(Symbol_table* symtab, Layout* layout, Relobj* object, Read_relocs_data* rd, Task_token* symtab_lock, Task_token* blocker) : symtab_(symtab), layout_(layout), object_(object), rd_(rd), symtab_lock_(symtab_lock), blocker_(blocker) { } // The standard Task methods. Task_token* is_runnable(); void locks(Task_locker*); void run(Workqueue*); std::string get_name() const; private: Symbol_table* symtab_; Layout* layout_; Relobj* object_; Read_relocs_data* rd_; Task_token* symtab_lock_; Task_token* blocker_; }; // A class to perform all the relocations for an object file. class Relocate_task : public Task { public: Relocate_task(const Symbol_table* symtab, const Layout* layout, Relobj* object, Output_file* of, Task_token* input_sections_blocker, Task_token* output_sections_blocker, Task_token* final_blocker) : symtab_(symtab), layout_(layout), object_(object), of_(of), input_sections_blocker_(input_sections_blocker), output_sections_blocker_(output_sections_blocker), final_blocker_(final_blocker) { } // The standard Task methods. Task_token* is_runnable(); void locks(Task_locker*); void run(Workqueue*); std::string get_name() const; private: const Symbol_table* symtab_; const Layout* layout_; Relobj* object_; Output_file* of_; Task_token* input_sections_blocker_; Task_token* output_sections_blocker_; Task_token* final_blocker_; }; // During a relocatable link, this class records how relocations // should be handled for a single input reloc section. An instance of // this class is created while scanning relocs, and it is used while // processing relocs. class Relocatable_relocs { public: // We use a vector of unsigned char to indicate how the input relocs // should be handled. Each element is one of the following values. // We create this vector when we initially scan the relocations. enum Reloc_strategy { // Copy the input reloc. Don't modify it other than updating the // r_offset field and the r_sym part of the r_info field. RELOC_COPY, // Copy the input reloc which is against an STT_SECTION symbol. // Update the r_offset and r_sym part of the r_info field. Adjust // the addend by subtracting the value of the old local symbol and // adding the value of the new local symbol. The addend is in the // SHT_RELA reloc and the contents of the data section do not need // to be changed. RELOC_ADJUST_FOR_SECTION_RELA, // Like RELOC_ADJUST_FOR_SECTION_RELA but the addend should not be // adjusted. RELOC_ADJUST_FOR_SECTION_0, // Like RELOC_ADJUST_FOR_SECTION_RELA but the contents of the // section need to be changed. The number indicates the number of // bytes in the addend in the section contents. RELOC_ADJUST_FOR_SECTION_1, RELOC_ADJUST_FOR_SECTION_2, RELOC_ADJUST_FOR_SECTION_4, RELOC_ADJUST_FOR_SECTION_8, // Discard the input reloc--process it completely when relocating // the data section contents. RELOC_DISCARD, // An input reloc which is not discarded, but which requires // target specific processing in order to update it. RELOC_SPECIAL }; Relocatable_relocs() : reloc_strategies_(), output_reloc_count_(0), posd_(NULL) { } // Record the number of relocs. void set_reloc_count(size_t reloc_count) { this->reloc_strategies_.reserve(reloc_count); } // Record what to do for the next reloc. void set_next_reloc_strategy(Reloc_strategy strategy) { this->reloc_strategies_.push_back(static_cast<unsigned char>(strategy)); if (strategy != RELOC_DISCARD) ++this->output_reloc_count_; } // Record the Output_data associated with this reloc section. void set_output_data(Output_data* posd) { gold_assert(this->posd_ == NULL); this->posd_ = posd; } // Return the Output_data associated with this reloc section. Output_data* output_data() const { return this->posd_; } // Return what to do for reloc I. Reloc_strategy strategy(unsigned int i) const { gold_assert(i < this->reloc_strategies_.size()); return static_cast<Reloc_strategy>(this->reloc_strategies_[i]); } // Return the number of relocations to create in the output file. size_t output_reloc_count() const { return this->output_reloc_count_; } private: typedef std::vector<unsigned char> Reloc_strategies; // The strategies for the input reloc. There is one entry in this // vector for each relocation in the input section. Reloc_strategies reloc_strategies_; // The number of relocations to be created in the output file. size_t output_reloc_count_; // The output data structure associated with this relocation. Output_data* posd_; }; // Standard relocation routines which are used on many targets. Here // SIZE and BIG_ENDIAN refer to the target, not the relocation type. template<int size, bool big_endian> class Relocate_functions { private: // Do a simple relocation with the addend in the section contents. // VALSIZE is the size of the value. template<int valsize> static inline void rel(unsigned char* view, typename elfcpp::Swap<valsize, big_endian>::Valtype value) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value); } // Do a simple relocation using a Symbol_value with the addend in // the section contents. VALSIZE is the size of the value to // relocate. template<int valsize> static inline void rel(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); x = psymval->value(object, x); elfcpp::Swap<valsize, big_endian>::writeval(wv, x); } // Do a simple relocation with the addend in the relocation. // VALSIZE is the size of the value. template<int valsize> static inline void rela(unsigned char* view, typename elfcpp::Swap<valsize, big_endian>::Valtype value, typename elfcpp::Swap<valsize, big_endian>::Valtype addend) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); elfcpp::Swap<valsize, big_endian>::writeval(wv, value + addend); } // Do a simple relocation using a symbol value with the addend in // the relocation. VALSIZE is the size of the value. template<int valsize> static inline void rela(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, typename elfcpp::Swap<valsize, big_endian>::Valtype addend) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); Valtype x = psymval->value(object, addend); elfcpp::Swap<valsize, big_endian>::writeval(wv, x); } // Do a simple PC relative relocation with the addend in the section // contents. VALSIZE is the size of the value. template<int valsize> static inline void pcrel(unsigned char* view, typename elfcpp::Swap<valsize, big_endian>::Valtype value, typename elfcpp::Elf_types<size>::Elf_Addr address) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address); } // Do a simple PC relative relocation with a Symbol_value with the // addend in the section contents. VALSIZE is the size of the // value. template<int valsize> static inline void pcrel(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, typename elfcpp::Elf_types<size>::Elf_Addr address) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); x = psymval->value(object, x); elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address); } // Do a simple PC relative relocation with the addend in the // relocation. VALSIZE is the size of the value. template<int valsize> static inline void pcrela(unsigned char* view, typename elfcpp::Swap<valsize, big_endian>::Valtype value, typename elfcpp::Swap<valsize, big_endian>::Valtype addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); elfcpp::Swap<valsize, big_endian>::writeval(wv, value + addend - address); } // Do a simple PC relative relocation with a Symbol_value with the // addend in the relocation. VALSIZE is the size of the value. template<int valsize> static inline void pcrela(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, typename elfcpp::Swap<valsize, big_endian>::Valtype addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast<Valtype*>(view); Valtype x = psymval->value(object, addend); elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address); } typedef Relocate_functions<size, big_endian> This; public: // Do a simple 8-bit REL relocation with the addend in the section // contents. static inline void rel8(unsigned char* view, unsigned char value) { This::template rel<8>(view, value); } static inline void rel8(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval) { This::template rel<8>(view, object, psymval); } // Do an 8-bit RELA relocation with the addend in the relocation. static inline void rela8(unsigned char* view, unsigned char value, unsigned char addend) { This::template rela<8>(view, value, addend); } static inline void rela8(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, unsigned char addend) { This::template rela<8>(view, object, psymval, addend); } // Do a simple 8-bit PC relative relocation with the addend in the // section contents. static inline void pcrel8(unsigned char* view, unsigned char value, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<8>(view, value, address); } static inline void pcrel8(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<8>(view, object, psymval, address); } // Do a simple 8-bit PC relative RELA relocation with the addend in // the reloc. static inline void pcrela8(unsigned char* view, unsigned char value, unsigned char addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<8>(view, value, addend, address); } static inline void pcrela8(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, unsigned char addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<8>(view, object, psymval, addend, address); } // Do a simple 16-bit REL relocation with the addend in the section // contents. static inline void rel16(unsigned char* view, elfcpp::Elf_Half value) { This::template rel<16>(view, value); } static inline void rel16(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval) { This::template rel<16>(view, object, psymval); } // Do an 16-bit RELA relocation with the addend in the relocation. static inline void rela16(unsigned char* view, elfcpp::Elf_Half value, elfcpp::Elf_Half addend) { This::template rela<16>(view, value, addend); } static inline void rela16(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, elfcpp::Elf_Half addend) { This::template rela<16>(view, object, psymval, addend); } // Do a simple 16-bit PC relative REL relocation with the addend in // the section contents. static inline void pcrel16(unsigned char* view, elfcpp::Elf_Half value, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<16>(view, value, address); } static inline void pcrel16(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<16>(view, object, psymval, address); } // Do a simple 16-bit PC relative RELA relocation with the addend in // the reloc. static inline void pcrela16(unsigned char* view, elfcpp::Elf_Half value, elfcpp::Elf_Half addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<16>(view, value, addend, address); } static inline void pcrela16(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, elfcpp::Elf_Half addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<16>(view, object, psymval, addend, address); } // Do a simple 32-bit REL relocation with the addend in the section // contents. static inline void rel32(unsigned char* view, elfcpp::Elf_Word value) { This::template rel<32>(view, value); } static inline void rel32(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval) { This::template rel<32>(view, object, psymval); } // Do an 32-bit RELA relocation with the addend in the relocation. static inline void rela32(unsigned char* view, elfcpp::Elf_Word value, elfcpp::Elf_Word addend) { This::template rela<32>(view, value, addend); } static inline void rela32(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, elfcpp::Elf_Word addend) { This::template rela<32>(view, object, psymval, addend); } // Do a simple 32-bit PC relative REL relocation with the addend in // the section contents. static inline void pcrel32(unsigned char* view, elfcpp::Elf_Word value, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<32>(view, value, address); } static inline void pcrel32(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<32>(view, object, psymval, address); } // Do a simple 32-bit PC relative RELA relocation with the addend in // the relocation. static inline void pcrela32(unsigned char* view, elfcpp::Elf_Word value, elfcpp::Elf_Word addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<32>(view, value, addend, address); } static inline void pcrela32(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, elfcpp::Elf_Word addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<32>(view, object, psymval, addend, address); } // Do a simple 64-bit REL relocation with the addend in the section // contents. static inline void rel64(unsigned char* view, elfcpp::Elf_Xword value) { This::template rel<64>(view, value); } static inline void rel64(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval) { This::template rel<64>(view, object, psymval); } // Do a 64-bit RELA relocation with the addend in the relocation. static inline void rela64(unsigned char* view, elfcpp::Elf_Xword value, elfcpp::Elf_Xword addend) { This::template rela<64>(view, value, addend); } static inline void rela64(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, elfcpp::Elf_Xword addend) { This::template rela<64>(view, object, psymval, addend); } // Do a simple 64-bit PC relative REL relocation with the addend in // the section contents. static inline void pcrel64(unsigned char* view, elfcpp::Elf_Xword value, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<64>(view, value, address); } static inline void pcrel64(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrel<64>(view, object, psymval, address); } // Do a simple 64-bit PC relative RELA relocation with the addend in // the relocation. static inline void pcrela64(unsigned char* view, elfcpp::Elf_Xword value, elfcpp::Elf_Xword addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<64>(view, value, addend, address); } static inline void pcrela64(unsigned char* view, const Sized_relobj<size, big_endian>* object, const Symbol_value<size>* psymval, elfcpp::Elf_Xword addend, typename elfcpp::Elf_types<size>::Elf_Addr address) { This::template pcrela<64>(view, object, psymval, addend, address); } }; // Track relocations while reading a section. This lets you ask for // the relocation at a certain offset, and see how relocs occur // between points of interest. template<int size, bool big_endian> class Track_relocs { public: Track_relocs() : prelocs_(NULL), len_(0), pos_(0), reloc_size_(0) { } // Initialize the Track_relocs object. OBJECT is the object holding // the reloc section, RELOC_SHNDX is the section index of the reloc // section, and RELOC_TYPE is the type of the reloc section // (elfcpp::SHT_REL or elfcpp::SHT_RELA). This returns false if // something went wrong. bool initialize(Object* object, unsigned int reloc_shndx, unsigned int reloc_type); // Return the offset in the data section to which the next reloc // applies. THis returns -1 if there is no next reloc. off_t next_offset() const; // Return the symbol index of the next reloc. This returns -1U if // there is no next reloc. unsigned int next_symndx() const; // Advance to OFFSET within the data section, and return the number // of relocs which would be skipped. int advance(off_t offset); private: // The contents of the input object's reloc section. const unsigned char* prelocs_; // The length of the reloc section. section_size_type len_; // Our current position in the reloc section. section_size_type pos_; // The size of the relocs in the section. int reloc_size_; }; } // End namespace gold. #endif // !defined(GOLD_RELOC_H)