| // reloc.h -- relocate input files for gold -*- C++ -*- |
| |
| #ifndef GOLD_RELOC_H |
| #define GOLD_RELOC_H |
| |
| #include <byteswap.h> |
| |
| #include "workqueue.h" |
| |
| namespace gold |
| { |
| |
| class General_options; |
| class Relobj; |
| class Read_relocs_data; |
| class Stringpool; |
| class Symbol; |
| class Layout; |
| |
| template<int size> |
| class Sized_symbol; |
| |
| 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. |
| |
| Is_runnable_type |
| is_runnable(Workqueue*); |
| |
| Task_locker* |
| locks(Workqueue*); |
| |
| void |
| run(Workqueue*); |
| |
| 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. |
| |
| Is_runnable_type |
| is_runnable(Workqueue*); |
| |
| Task_locker* |
| locks(Workqueue*); |
| |
| void |
| run(Workqueue*); |
| |
| private: |
| class Scan_relocs_locker; |
| |
| 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* final_blocker) |
| : options_(options), symtab_(symtab), layout_(layout), object_(object), |
| of_(of), final_blocker_(final_blocker) |
| { } |
| |
| // The standard Task methods. |
| |
| Is_runnable_type |
| is_runnable(Workqueue*); |
| |
| Task_locker* |
| locks(Workqueue*); |
| |
| void |
| run(Workqueue*); |
| |
| private: |
| class Relocate_locker; |
| |
| const General_options& options_; |
| const Symbol_table* symtab_; |
| const Layout* layout_; |
| Relobj* object_; |
| Output_file* of_; |
| 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 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); |
| } |
| |
| typedef Relocate_functions<size, big_endian> This; |
| |
| public: |
| // Do a simple 8-bit REL relocation with the addend in the object |
| // file data. |
| static inline void |
| rel8(unsigned char* view, unsigned char value) |
| { |
| This::template rel<8>(view, value); |
| } |
| |
| // Do a simple 8-bit PC relative relocation with the addend in the |
| // object file data. |
| 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); |
| } |
| |
| // Do a simple 16-bit REL relocation with the addend in the object |
| // file data. |
| static inline void |
| rel16(unsigned char* view, elfcpp::Elf_Half value) |
| { |
| This::template rel<16>(view, value); |
| } |
| |
| // Do a simple 32-bit PC relative REL relocation with the addend in |
| // the object file data. |
| static inline void |
| pcrel16(unsigned char* view, elfcpp::Elf_Word value, |
| typename elfcpp::Elf_types<size>::Elf_Addr address) |
| { |
| This::template pcrel<16>(view, value, 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); |
| } |
| |
| // 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); |
| } |
| |
| // 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); |
| } |
| |
| // 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); |
| } |
| }; |
| |
| // 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, |
| const elfcpp::Rel<size, big_endian>&); |
| |
| // Save a Rela against SYM for possible emission later. |
| void |
| save(Symbol* sym, Relobj*, unsigned int shndx, |
| 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, |
| Address address, Addend addend) |
| : sym_(sym), reloc_type_(reloc_type), relobj_(relobj), |
| shndx_(shndx), 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_; |
| 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_; |
| }; |
| |
| } // End namespace gold. |
| |
| #endif // !defined(GOLD_RELOC_H) |