| // reloc.h -- relocate input files for gold -*- C++ -*- |
| |
| // Copyright 2006, 2007 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> |
| #include <byteswap.h> |
| |
| #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_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(const General_options& options, Symbol_table* symtab, |
| Layout* layout, Relobj* object, Task_token* symtab_lock, |
| Task_token* blocker) |
| : options_(options), 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: |
| const General_options& options_; |
| Symbol_table* symtab_; |
| Layout* layout_; |
| Relobj* object_; |
| 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(const General_options& options, Symbol_table* symtab, |
| Layout* layout, Relobj* object, Read_relocs_data* rd, |
| Task_token* symtab_lock, Task_token* blocker) |
| : options_(options), 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: |
| const General_options& options_; |
| 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 General_options& options, 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) |
| : options_(options), 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 General_options& options_; |
| 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_; |
| }; |
| |
| // 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); } |
| }; |
| |
| // We try to avoid COPY relocations when possible. A COPY relocation |
| // may be required when an executable refers to a variable defined in |
| // a shared library. COPY relocations are problematic because they |
| // tie the executable to the exact size of the variable in the shared |
| // library. We can avoid them if all the references to the variable |
| // are in a writeable section. In that case we can simply use dynamic |
| // relocations. However, when scanning relocs, we don't know when we |
| // see the relocation whether we will be forced to use a COPY |
| // relocation or not. So we have to save the relocation during the |
| // reloc scanning, and then emit it as a dynamic relocation if |
| // necessary. This class implements that. It is used by the target |
| // specific code. |
| |
| template<int size, bool big_endian> |
| class Copy_relocs |
| { |
| public: |
| Copy_relocs() |
| : entries_() |
| { } |
| |
| // Return whether we need a COPY reloc for a reloc against GSYM, |
| // which is being applied to section SHNDX in OBJECT. |
| static bool |
| need_copy_reloc(const General_options*, Relobj* object, unsigned int shndx, |
| Sized_symbol<size>* gsym); |
| |
| // Save a Rel against SYM for possible emission later. SHNDX is the |
| // index of the section to which the reloc is being applied. |
| void |
| save(Symbol* sym, Relobj*, unsigned int shndx, |
| Output_section* output_section, const elfcpp::Rel<size, big_endian>&); |
| |
| // Save a Rela against SYM for possible emission later. |
| void |
| save(Symbol* sym, Relobj*, unsigned int shndx, |
| Output_section* output_section, const elfcpp::Rela<size, big_endian>&); |
| |
| // Return whether there are any relocs to emit. This also discards |
| // entries which need not be emitted. |
| bool |
| any_to_emit(); |
| |
| // Emit relocs for each symbol which did not get a COPY reloc (i.e., |
| // is still defined in the dynamic object). |
| template<int sh_type> |
| void |
| emit(Output_data_reloc<sh_type, true, size, big_endian>*); |
| |
| private: |
| typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; |
| typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend; |
| |
| // This POD class holds the entries we are saving. |
| class Copy_reloc_entry |
| { |
| public: |
| Copy_reloc_entry(Symbol* sym, unsigned int reloc_type, |
| Relobj* relobj, unsigned int shndx, |
| Output_section* output_section, |
| Address address, Addend addend) |
| : sym_(sym), reloc_type_(reloc_type), relobj_(relobj), |
| shndx_(shndx), output_section_(output_section), |
| address_(address), addend_(addend) |
| { } |
| |
| // Return whether we should emit this reloc. If we should not |
| // emit, we clear it. |
| bool |
| should_emit(); |
| |
| // Emit this reloc. |
| |
| void |
| emit(Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian>*); |
| |
| void |
| emit(Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>*); |
| |
| private: |
| Symbol* sym_; |
| unsigned int reloc_type_; |
| Relobj* relobj_; |
| unsigned int shndx_; |
| Output_section* output_section_; |
| Address address_; |
| Addend addend_; |
| }; |
| |
| // A list of relocs to be saved. |
| typedef std::vector<Copy_reloc_entry> Copy_reloc_entries; |
| |
| // The list of relocs we are saving. |
| Copy_reloc_entries entries_; |
| }; |
| |
| // 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) |