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Diffstat (limited to 'gold/target.h')
| -rw-r--r-- | gold/target.h | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/gold/target.h b/gold/target.h new file mode 100644 index 000000000000..9181a93193d5 --- /dev/null +++ b/gold/target.h @@ -0,0 +1,210 @@ +// target.h -- target support for gold -*- C++ -*- + +// The abstract class Target is the interface for target specific +// support. It defines abstract methods which each target must +// implement. Typically there will be one target per processor, but +// in some cases it may be necessary to have subclasses. + +// For speed and consistency we want to use inline functions to handle +// relocation processing. So besides implementations of the abstract +// methods, each target is expected to define a template +// specialization of the relocation functions. + +#ifndef GOLD_TARGET_H +#define GOLD_TARGET_H + +#include "elfcpp.h" + +namespace gold +{ + +class General_options; +class Object; +template<int size, bool big_endian> +class Sized_relobj; +template<int size, bool big_endian> +struct Relocate_info; +class Symbol; +template<int size> +class Sized_symbol; +class Symbol_table; + +// The abstract class for target specific handling. + +class Target +{ + public: + virtual ~Target() + { } + + // Return the bit size that this target implements. This should + // return 32 or 64. + int + get_size() const + { return this->pti_->size; } + + // Return whether this target is big-endian. + bool + is_big_endian() const + { return this->pti_->is_big_endian; } + + // Machine code to store in e_machine field of ELF header. + elfcpp::EM + machine_code() const + { return this->pti_->machine_code; } + + // Whether this target has a specific make_symbol function. + bool + has_make_symbol() const + { return this->pti_->has_make_symbol; } + + // Whether this target has a specific resolve function. + bool + has_resolve() const + { return this->pti_->has_resolve; } + + // Return the default name of the dynamic linker. + const char* + dynamic_linker() const + { return this->pti_->dynamic_linker; } + + // Return the default address to use for the text segment. + uint64_t + text_segment_address() const + { return this->pti_->text_segment_address; } + + // Return the ABI specified page size. + uint64_t + abi_pagesize() const + { return this->pti_->abi_pagesize; } + + // Return the common page size used on actual systems. + uint64_t + common_pagesize() const + { return this->pti_->common_pagesize; } + + // This is called to tell the target to complete any sections it is + // handling. After this all sections must have their final size. + void + finalize_sections(const General_options* options, Layout* layout) + { return this->do_finalize_sections(options, layout); } + + protected: + // This struct holds the constant information for a child class. We + // use a struct to avoid the overhead of virtual function calls for + // simple information. + struct Target_info + { + // Address size (32 or 64). + int size; + // Whether the target is big endian. + bool is_big_endian; + // The code to store in the e_machine field of the ELF header. + elfcpp::EM machine_code; + // Whether this target has a specific make_symbol function. + bool has_make_symbol; + // Whether this target has a specific resolve function. + bool has_resolve; + // The default dynamic linker name. + const char* dynamic_linker; + // The default text segment address. + uint64_t text_segment_address; + // The ABI specified page size. + uint64_t abi_pagesize; + // The common page size used by actual implementations. + uint64_t common_pagesize; + }; + + Target(const Target_info* pti) + : pti_(pti) + { } + + // Virtual function which may be implemented by the child class. + virtual void + do_finalize_sections(const General_options*, Layout*) + { } + + private: + Target(const Target&); + Target& operator=(const Target&); + + // The target information. + const Target_info* pti_; +}; + +// The abstract class for a specific size and endianness of target. +// Each actual target implementation class should derive from an +// instantiation of Sized_target. + +template<int size, bool big_endian> +class Sized_target : public Target +{ + public: + // Make a new symbol table entry for the target. This should be + // overridden by a target which needs additional information in the + // symbol table. This will only be called if has_make_symbol() + // returns true. + virtual Sized_symbol<size>* + make_symbol() const + { gold_unreachable(); } + + // Resolve a symbol for the target. This should be overridden by a + // target which needs to take special action. TO is the + // pre-existing symbol. SYM is the new symbol, seen in OBJECT. + // VERSION is the version of SYM. This will only be called if + // has_resolve() returns true. + virtual void + resolve(Symbol*, const elfcpp::Sym<size, big_endian>&, Object*, + const char*) + { gold_unreachable(); } + + // Scan the relocs for a section, and record any information + // required for the symbol. OPTIONS is the command line options. + // SYMTAB is the symbol table. OBJECT is the object in which the + // section appears. DATA_SHNDX is the section index that these + // relocs apply to. SH_TYPE is the type of the relocation section, + // SHT_REL or SHT_RELA. PRELOCS points to the relocation data. + // RELOC_COUNT is the number of relocs. LOCAL_SYMBOL_COUNT is the + // number of local symbols. PLOCAL_SYMBOLS points to the local + // symbol data from OBJECT. GLOBAL_SYMBOLS is the array of pointers + // to the global symbol table from OBJECT. + virtual void + scan_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<size, big_endian>* object, + unsigned int data_shndx, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + size_t local_symbol_count, + const unsigned char* plocal_symbols, + Symbol** global_symbols) = 0; + + // Relocate section data. SH_TYPE is the type of the relocation + // section, SHT_REL or SHT_RELA. PRELOCS points to the relocation + // information. RELOC_COUNT is the number of relocs. VIEW is a + // view into the output file holding the section contents, + // VIEW_ADDRESS is the virtual address of the view, and VIEW_SIZE is + // the size of the view. + virtual void + relocate_section(const Relocate_info<size, big_endian>*, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + unsigned char* view, + typename elfcpp::Elf_types<size>::Elf_Addr view_address, + off_t view_size) = 0; + + protected: + Sized_target(const Target::Target_info* pti) + : Target(pti) + { + gold_assert(pti->size == size); + gold_assert(pti->is_big_endian ? big_endian : !big_endian); + } +}; + +} // End namespace gold. + +#endif // !defined(GOLD_TARGET_H) |