| // object.h -- support for an object file for linking in 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_OBJECT_H |
| #define GOLD_OBJECT_H |
| |
| #include <string> |
| #include <vector> |
| |
| #include "elfcpp.h" |
| #include "elfcpp_file.h" |
| #include "fileread.h" |
| #include "target.h" |
| |
| namespace gold |
| { |
| |
| class General_options; |
| class Task; |
| class Layout; |
| class Output_section; |
| class Output_file; |
| class Dynobj; |
| class Object_merge_map; |
| class Relocatable_relocs; |
| |
| template<typename Stringpool_char> |
| class Stringpool_template; |
| |
| // Data to pass from read_symbols() to add_symbols(). |
| |
| struct Read_symbols_data |
| { |
| // Section headers. |
| File_view* section_headers; |
| // Section names. |
| File_view* section_names; |
| // Size of section name data in bytes. |
| section_size_type section_names_size; |
| // Symbol data. |
| File_view* symbols; |
| // Size of symbol data in bytes. |
| section_size_type symbols_size; |
| // Offset of external symbols within symbol data. This structure |
| // sometimes contains only external symbols, in which case this will |
| // be zero. Sometimes it contains all symbols. |
| section_offset_type external_symbols_offset; |
| // Symbol names. |
| File_view* symbol_names; |
| // Size of symbol name data in bytes. |
| section_size_type symbol_names_size; |
| |
| // Version information. This is only used on dynamic objects. |
| // Version symbol data (from SHT_GNU_versym section). |
| File_view* versym; |
| section_size_type versym_size; |
| // Version definition data (from SHT_GNU_verdef section). |
| File_view* verdef; |
| section_size_type verdef_size; |
| unsigned int verdef_info; |
| // Needed version data (from SHT_GNU_verneed section). |
| File_view* verneed; |
| section_size_type verneed_size; |
| unsigned int verneed_info; |
| }; |
| |
| // Information used to print error messages. |
| |
| struct Symbol_location_info |
| { |
| std::string source_file; |
| std::string enclosing_symbol_name; |
| int line_number; |
| }; |
| |
| // Data about a single relocation section. This is read in |
| // read_relocs and processed in scan_relocs. |
| |
| struct Section_relocs |
| { |
| // Index of reloc section. |
| unsigned int reloc_shndx; |
| // Index of section that relocs apply to. |
| unsigned int data_shndx; |
| // Contents of reloc section. |
| File_view* contents; |
| // Reloc section type. |
| unsigned int sh_type; |
| // Number of reloc entries. |
| size_t reloc_count; |
| // Output section. |
| Output_section* output_section; |
| // Whether this section has special handling for offsets. |
| bool needs_special_offset_handling; |
| }; |
| |
| // Relocations in an object file. This is read in read_relocs and |
| // processed in scan_relocs. |
| |
| struct Read_relocs_data |
| { |
| typedef std::vector<Section_relocs> Relocs_list; |
| // The relocations. |
| Relocs_list relocs; |
| // The local symbols. |
| File_view* local_symbols; |
| }; |
| |
| // Object is an abstract base class which represents either a 32-bit |
| // or a 64-bit input object. This can be a regular object file |
| // (ET_REL) or a shared object (ET_DYN). |
| |
| class Object |
| { |
| public: |
| // NAME is the name of the object as we would report it to the user |
| // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is |
| // used to read the file. OFFSET is the offset within the input |
| // file--0 for a .o or .so file, something else for a .a file. |
| Object(const std::string& name, Input_file* input_file, bool is_dynamic, |
| off_t offset = 0) |
| : name_(name), input_file_(input_file), offset_(offset), shnum_(-1U), |
| is_dynamic_(is_dynamic), target_(NULL) |
| { input_file->file().add_object(); } |
| |
| virtual ~Object() |
| { this->input_file_->file().remove_object(); } |
| |
| // Return the name of the object as we would report it to the tuser. |
| const std::string& |
| name() const |
| { return this->name_; } |
| |
| // Get the offset into the file. |
| off_t |
| offset() const |
| { return this->offset_; } |
| |
| // Return whether this is a dynamic object. |
| bool |
| is_dynamic() const |
| { return this->is_dynamic_; } |
| |
| // Return the target structure associated with this object. |
| Target* |
| target() const |
| { return this->target_; } |
| |
| // Lock the underlying file. |
| void |
| lock(const Task* t) |
| { this->input_file()->file().lock(t); } |
| |
| // Unlock the underlying file. |
| void |
| unlock(const Task* t) |
| { this->input_file()->file().unlock(t); } |
| |
| // Return whether the underlying file is locked. |
| bool |
| is_locked() const |
| { return this->input_file()->file().is_locked(); } |
| |
| // Return the token, so that the task can be queued. |
| Task_token* |
| token() |
| { return this->input_file()->file().token(); } |
| |
| // Release the underlying file. |
| void |
| release() |
| { this->input_file_->file().release(); } |
| |
| // Return whether we should just read symbols from this file. |
| bool |
| just_symbols() const |
| { return this->input_file()->just_symbols(); } |
| |
| // Return the sized target structure associated with this object. |
| // This is like the target method but it returns a pointer of |
| // appropriate checked type. |
| template<int size, bool big_endian> |
| Sized_target<size, big_endian>* |
| sized_target(ACCEPT_SIZE_ENDIAN_ONLY) const; |
| |
| // Get the number of sections. |
| unsigned int |
| shnum() const |
| { return this->shnum_; } |
| |
| // Return a view of the contents of a section. Set *PLEN to the |
| // size. CACHE is a hint as in File_read::get_view. |
| const unsigned char* |
| section_contents(unsigned int shndx, section_size_type* plen, bool cache); |
| |
| // Return the size of a section given a section index. |
| uint64_t |
| section_size(unsigned int shndx) |
| { return this->do_section_size(shndx); } |
| |
| // Return the name of a section given a section index. |
| std::string |
| section_name(unsigned int shndx) |
| { return this->do_section_name(shndx); } |
| |
| // Return the section flags given a section index. |
| uint64_t |
| section_flags(unsigned int shndx) |
| { return this->do_section_flags(shndx); } |
| |
| // Return the section address given a section index. |
| uint64_t |
| section_address(unsigned int shndx) |
| { return this->do_section_address(shndx); } |
| |
| // Return the section type given a section index. |
| unsigned int |
| section_type(unsigned int shndx) |
| { return this->do_section_type(shndx); } |
| |
| // Return the section link field given a section index. |
| unsigned int |
| section_link(unsigned int shndx) |
| { return this->do_section_link(shndx); } |
| |
| // Return the section info field given a section index. |
| unsigned int |
| section_info(unsigned int shndx) |
| { return this->do_section_info(shndx); } |
| |
| // Return the required section alignment given a section index. |
| uint64_t |
| section_addralign(unsigned int shndx) |
| { return this->do_section_addralign(shndx); } |
| |
| // Read the symbol information. |
| void |
| read_symbols(Read_symbols_data* sd) |
| { return this->do_read_symbols(sd); } |
| |
| // Pass sections which should be included in the link to the Layout |
| // object, and record where the sections go in the output file. |
| void |
| layout(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd) |
| { this->do_layout(symtab, layout, sd); } |
| |
| // Add symbol information to the global symbol table. |
| void |
| add_symbols(Symbol_table* symtab, Read_symbols_data* sd) |
| { this->do_add_symbols(symtab, sd); } |
| |
| // Functions and types for the elfcpp::Elf_file interface. This |
| // permit us to use Object as the File template parameter for |
| // elfcpp::Elf_file. |
| |
| // The View class is returned by view. It must support a single |
| // method, data(). This is trivial, because get_view does what we |
| // need. |
| class View |
| { |
| public: |
| View(const unsigned char* p) |
| : p_(p) |
| { } |
| |
| const unsigned char* |
| data() const |
| { return this->p_; } |
| |
| private: |
| const unsigned char* p_; |
| }; |
| |
| // Return a View. |
| View |
| view(off_t file_offset, section_size_type data_size) |
| { return View(this->get_view(file_offset, data_size, true)); } |
| |
| // Report an error. |
| void |
| error(const char* format, ...) const ATTRIBUTE_PRINTF_2; |
| |
| // A location in the file. |
| struct Location |
| { |
| off_t file_offset; |
| off_t data_size; |
| |
| Location(off_t fo, section_size_type ds) |
| : file_offset(fo), data_size(ds) |
| { } |
| }; |
| |
| // Get a View given a Location. |
| View view(Location loc) |
| { return View(this->get_view(loc.file_offset, loc.data_size, true)); } |
| |
| // Get a view into the underlying file. |
| const unsigned char* |
| get_view(off_t start, section_size_type size, bool cache) |
| { |
| return this->input_file()->file().get_view(start + this->offset_, size, |
| cache); |
| } |
| |
| // Get a lasting view into the underlying file. |
| File_view* |
| get_lasting_view(off_t start, section_size_type size, bool cache) |
| { |
| return this->input_file()->file().get_lasting_view(start + this->offset_, |
| size, cache); |
| } |
| |
| // Read data from the underlying file. |
| void |
| read(off_t start, section_size_type size, void* p) const |
| { this->input_file()->file().read(start + this->offset_, size, p); } |
| |
| // Read multiple data from the underlying file. |
| void |
| read_multiple(const File_read::Read_multiple& rm) |
| { this->input_file()->file().read_multiple(this->offset_, rm); } |
| |
| // Stop caching views in the underlying file. |
| void |
| clear_view_cache_marks() |
| { this->input_file()->file().clear_view_cache_marks(); } |
| |
| protected: |
| // Read the symbols--implemented by child class. |
| virtual void |
| do_read_symbols(Read_symbols_data*) = 0; |
| |
| // Lay out sections--implemented by child class. |
| virtual void |
| do_layout(Symbol_table*, Layout*, Read_symbols_data*) = 0; |
| |
| // Add symbol information to the global symbol table--implemented by |
| // child class. |
| virtual void |
| do_add_symbols(Symbol_table*, Read_symbols_data*) = 0; |
| |
| // Return the location of the contents of a section. Implemented by |
| // child class. |
| virtual Location |
| do_section_contents(unsigned int shndx) = 0; |
| |
| // Get the size of a section--implemented by child class. |
| virtual uint64_t |
| do_section_size(unsigned int shndx) = 0; |
| |
| // Get the name of a section--implemented by child class. |
| virtual std::string |
| do_section_name(unsigned int shndx) = 0; |
| |
| // Get section flags--implemented by child class. |
| virtual uint64_t |
| do_section_flags(unsigned int shndx) = 0; |
| |
| // Get section address--implemented by child class. |
| virtual uint64_t |
| do_section_address(unsigned int shndx) = 0; |
| |
| // Get section type--implemented by child class. |
| virtual unsigned int |
| do_section_type(unsigned int shndx) = 0; |
| |
| // Get section link field--implemented by child class. |
| virtual unsigned int |
| do_section_link(unsigned int shndx) = 0; |
| |
| // Get section info field--implemented by child class. |
| virtual unsigned int |
| do_section_info(unsigned int shndx) = 0; |
| |
| // Get section alignment--implemented by child class. |
| virtual uint64_t |
| do_section_addralign(unsigned int shndx) = 0; |
| |
| // Get the file. We pass on const-ness. |
| Input_file* |
| input_file() |
| { return this->input_file_; } |
| |
| const Input_file* |
| input_file() const |
| { return this->input_file_; } |
| |
| // Set the target. |
| void |
| set_target(int machine, int size, bool big_endian, int osabi, |
| int abiversion); |
| |
| // Set the number of sections. |
| void |
| set_shnum(int shnum) |
| { this->shnum_ = shnum; } |
| |
| // Functions used by both Sized_relobj and Sized_dynobj. |
| |
| // Read the section data into a Read_symbols_data object. |
| template<int size, bool big_endian> |
| void |
| read_section_data(elfcpp::Elf_file<size, big_endian, Object>*, |
| Read_symbols_data*); |
| |
| // If NAME is the name of a special .gnu.warning section, arrange |
| // for the warning to be issued. SHNDX is the section index. |
| // Return whether it is a warning section. |
| bool |
| handle_gnu_warning_section(const char* name, unsigned int shndx, |
| Symbol_table*); |
| |
| private: |
| // This class may not be copied. |
| Object(const Object&); |
| Object& operator=(const Object&); |
| |
| // Name of object as printed to user. |
| std::string name_; |
| // For reading the file. |
| Input_file* input_file_; |
| // Offset within the file--0 for an object file, non-0 for an |
| // archive. |
| off_t offset_; |
| // Number of input sections. |
| unsigned int shnum_; |
| // Whether this is a dynamic object. |
| bool is_dynamic_; |
| // Target functions--may be NULL if the target is not known. |
| Target* target_; |
| }; |
| |
| // Implement sized_target inline for efficiency. This approach breaks |
| // static type checking, but is made safe using asserts. |
| |
| template<int size, bool big_endian> |
| inline Sized_target<size, big_endian>* |
| Object::sized_target(ACCEPT_SIZE_ENDIAN_ONLY) const |
| { |
| gold_assert(this->target_->get_size() == size); |
| gold_assert(this->target_->is_big_endian() ? big_endian : !big_endian); |
| return static_cast<Sized_target<size, big_endian>*>(this->target_); |
| } |
| |
| // A regular object (ET_REL). This is an abstract base class itself. |
| // The implementation is the template class Sized_relobj. |
| |
| class Relobj : public Object |
| { |
| public: |
| Relobj(const std::string& name, Input_file* input_file, off_t offset = 0) |
| : Object(name, input_file, false, offset), |
| map_to_output_(), |
| map_to_relocatable_relocs_(NULL), |
| object_merge_map_(NULL), |
| relocs_must_follow_section_writes_(false) |
| { } |
| |
| // Read the relocs. |
| void |
| read_relocs(Read_relocs_data* rd) |
| { return this->do_read_relocs(rd); } |
| |
| // Scan the relocs and adjust the symbol table. |
| void |
| scan_relocs(const General_options& options, Symbol_table* symtab, |
| Layout* layout, Read_relocs_data* rd) |
| { return this->do_scan_relocs(options, symtab, layout, rd); } |
| |
| // The number of local symbols in the input symbol table. |
| virtual unsigned int |
| local_symbol_count() const |
| { return this->do_local_symbol_count(); } |
| |
| // Initial local symbol processing: count the number of local symbols |
| // in the output symbol table and dynamic symbol table; add local symbol |
| // names to *POOL and *DYNPOOL. |
| void |
| count_local_symbols(Stringpool_template<char>* pool, |
| Stringpool_template<char>* dynpool) |
| { return this->do_count_local_symbols(pool, dynpool); } |
| |
| // Set the values of the local symbols, set the output symbol table |
| // indexes for the local variables, and set the offset where local |
| // symbol information will be stored. Returns the new local symbol index. |
| unsigned int |
| finalize_local_symbols(unsigned int index, off_t off) |
| { return this->do_finalize_local_symbols(index, off); } |
| |
| // Set the output dynamic symbol table indexes for the local variables. |
| unsigned int |
| set_local_dynsym_indexes(unsigned int index) |
| { return this->do_set_local_dynsym_indexes(index); } |
| |
| // Set the offset where local dynamic symbol information will be stored. |
| unsigned int |
| set_local_dynsym_offset(off_t off) |
| { return this->do_set_local_dynsym_offset(off); } |
| |
| // Relocate the input sections and write out the local symbols. |
| void |
| relocate(const General_options& options, const Symbol_table* symtab, |
| const Layout* layout, Output_file* of) |
| { return this->do_relocate(options, symtab, layout, of); } |
| |
| // Return whether an input section is being included in the link. |
| bool |
| is_section_included(unsigned int shndx) const |
| { |
| gold_assert(shndx < this->map_to_output_.size()); |
| return this->map_to_output_[shndx].output_section != NULL; |
| } |
| |
| // Return whether an input section requires special |
| // handling--whether it is not simply mapped from the input file to |
| // the output file. |
| bool |
| is_section_specially_mapped(unsigned int shndx) const |
| { |
| gold_assert(shndx < this->map_to_output_.size()); |
| return (this->map_to_output_[shndx].output_section != NULL |
| && this->map_to_output_[shndx].offset == -1); |
| } |
| |
| // Given a section index, return the corresponding Output_section |
| // (which will be NULL if the section is not included in the link) |
| // and set *POFF to the offset within that section. *POFF will be |
| // set to -1 if the section requires special handling. |
| inline Output_section* |
| output_section(unsigned int shndx, section_offset_type* poff) const; |
| |
| // Set the offset of an input section within its output section. |
| void |
| set_section_offset(unsigned int shndx, section_offset_type off) |
| { |
| gold_assert(shndx < this->map_to_output_.size()); |
| this->map_to_output_[shndx].offset = off; |
| } |
| |
| // Return true if we need to wait for output sections to be written |
| // before we can apply relocations. This is true if the object has |
| // any relocations for sections which require special handling, such |
| // as the exception frame section. |
| bool |
| relocs_must_follow_section_writes() const |
| { return this->relocs_must_follow_section_writes_; } |
| |
| // Return the object merge map. |
| Object_merge_map* |
| merge_map() const |
| { return this->object_merge_map_; } |
| |
| // Set the object merge map. |
| void |
| set_merge_map(Object_merge_map* object_merge_map) |
| { |
| gold_assert(this->object_merge_map_ == NULL); |
| this->object_merge_map_ = object_merge_map; |
| } |
| |
| // Record the relocatable reloc info for an input reloc section. |
| void |
| set_relocatable_relocs(unsigned int reloc_shndx, Relocatable_relocs* rr) |
| { |
| gold_assert(reloc_shndx < this->shnum()); |
| (*this->map_to_relocatable_relocs_)[reloc_shndx] = rr; |
| } |
| |
| // Get the relocatable reloc info for an input reloc section. |
| Relocatable_relocs* |
| relocatable_relocs(unsigned int reloc_shndx) |
| { |
| gold_assert(reloc_shndx < this->shnum()); |
| return (*this->map_to_relocatable_relocs_)[reloc_shndx]; |
| } |
| |
| protected: |
| // What we need to know to map an input section to an output |
| // section. We keep an array of these, one for each input section, |
| // indexed by the input section number. |
| struct Map_to_output |
| { |
| // The output section. This is NULL if the input section is to be |
| // discarded. |
| Output_section* output_section; |
| // The offset within the output section. This is -1 if the |
| // section requires special handling. |
| section_offset_type offset; |
| }; |
| |
| // Read the relocs--implemented by child class. |
| virtual void |
| do_read_relocs(Read_relocs_data*) = 0; |
| |
| // Scan the relocs--implemented by child class. |
| virtual void |
| do_scan_relocs(const General_options&, Symbol_table*, Layout*, |
| Read_relocs_data*) = 0; |
| |
| // Return the number of local symbols--implemented by child class. |
| virtual unsigned int |
| do_local_symbol_count() const = 0; |
| |
| // Count local symbols--implemented by child class. |
| virtual void |
| do_count_local_symbols(Stringpool_template<char>*, |
| Stringpool_template<char>*) = 0; |
| |
| // Finalize the local symbols. Set the output symbol table indexes |
| // for the local variables, and set the offset where local symbol |
| // information will be stored. |
| virtual unsigned int |
| do_finalize_local_symbols(unsigned int, off_t) = 0; |
| |
| // Set the output dynamic symbol table indexes for the local variables. |
| virtual unsigned int |
| do_set_local_dynsym_indexes(unsigned int) = 0; |
| |
| // Set the offset where local dynamic symbol information will be stored. |
| virtual unsigned int |
| do_set_local_dynsym_offset(off_t) = 0; |
| |
| // Relocate the input sections and write out the local |
| // symbols--implemented by child class. |
| virtual void |
| do_relocate(const General_options& options, const Symbol_table* symtab, |
| const Layout*, Output_file* of) = 0; |
| |
| // Return the vector mapping input sections to output sections. |
| std::vector<Map_to_output>& |
| map_to_output() |
| { return this->map_to_output_; } |
| |
| const std::vector<Map_to_output>& |
| map_to_output() const |
| { return this->map_to_output_; } |
| |
| // Set the size of the relocatable relocs array. |
| void |
| size_relocatable_relocs() |
| { |
| this->map_to_relocatable_relocs_ = |
| new std::vector<Relocatable_relocs*>(this->shnum()); |
| } |
| |
| // Record that we must wait for the output sections to be written |
| // before applying relocations. |
| void |
| set_relocs_must_follow_section_writes() |
| { this->relocs_must_follow_section_writes_ = true; } |
| |
| private: |
| // Mapping from input sections to output section. |
| std::vector<Map_to_output> map_to_output_; |
| // Mapping from input section index to the information recorded for |
| // the relocations. This is only used for a relocatable link. |
| std::vector<Relocatable_relocs*>* map_to_relocatable_relocs_; |
| // Mappings for merge sections. This is managed by the code in the |
| // Merge_map class. |
| Object_merge_map* object_merge_map_; |
| // Whether we need to wait for output sections to be written before |
| // we can apply relocations. |
| bool relocs_must_follow_section_writes_; |
| }; |
| |
| // Implement Object::output_section inline for efficiency. |
| inline Output_section* |
| Relobj::output_section(unsigned int shndx, section_offset_type* poff) const |
| { |
| gold_assert(shndx < this->map_to_output_.size()); |
| const Map_to_output& mo(this->map_to_output_[shndx]); |
| *poff = mo.offset; |
| return mo.output_section; |
| } |
| |
| // This class is used to handle relocations against a section symbol |
| // in an SHF_MERGE section. For such a symbol, we need to know the |
| // addend of the relocation before we can determine the final value. |
| // The addend gives us the location in the input section, and we can |
| // determine how it is mapped to the output section. For a |
| // non-section symbol, we apply the addend to the final value of the |
| // symbol; that is done in finalize_local_symbols, and does not use |
| // this class. |
| |
| template<int size> |
| class Merged_symbol_value |
| { |
| public: |
| typedef typename elfcpp::Elf_types<size>::Elf_Addr Value; |
| |
| // We use a hash table to map offsets in the input section to output |
| // addresses. |
| typedef Unordered_map<section_offset_type, Value> Output_addresses; |
| |
| Merged_symbol_value(Value input_value, Value output_start_address) |
| : input_value_(input_value), output_start_address_(output_start_address), |
| output_addresses_() |
| { } |
| |
| // Initialize the hash table. |
| void |
| initialize_input_to_output_map(const Relobj*, unsigned int input_shndx); |
| |
| // Release the hash table to save space. |
| void |
| free_input_to_output_map() |
| { this->output_addresses_.clear(); } |
| |
| // Get the output value corresponding to an addend. The object and |
| // input section index are passed in because the caller will have |
| // them; otherwise we could store them here. |
| Value |
| value(const Relobj* object, unsigned int input_shndx, Value addend) const |
| { |
| Value input_offset = this->input_value_ + addend; |
| typename Output_addresses::const_iterator p = |
| this->output_addresses_.find(input_offset); |
| if (p != this->output_addresses_.end()) |
| return p->second; |
| |
| return this->value_from_output_section(object, input_shndx, input_offset); |
| } |
| |
| private: |
| // Get the output value for an input offset if we couldn't find it |
| // in the hash table. |
| Value |
| value_from_output_section(const Relobj*, unsigned int input_shndx, |
| Value input_offset) const; |
| |
| // The value of the section symbol in the input file. This is |
| // normally zero, but could in principle be something else. |
| Value input_value_; |
| // The start address of this merged section in the output file. |
| Value output_start_address_; |
| // A hash table which maps offsets in the input section to output |
| // addresses. This only maps specific offsets, not all offsets. |
| Output_addresses output_addresses_; |
| }; |
| |
| // This POD class is holds the value of a symbol. This is used for |
| // local symbols, and for all symbols during relocation processing. |
| // For special sections, such as SHF_MERGE sections, this calls a |
| // function to get the final symbol value. |
| |
| template<int size> |
| class Symbol_value |
| { |
| public: |
| typedef typename elfcpp::Elf_types<size>::Elf_Addr Value; |
| |
| Symbol_value() |
| : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0), |
| is_section_symbol_(false), is_tls_symbol_(false), |
| has_output_value_(true) |
| { this->u_.value = 0; } |
| |
| // Get the value of this symbol. OBJECT is the object in which this |
| // symbol is defined, and ADDEND is an addend to add to the value. |
| template<bool big_endian> |
| Value |
| value(const Sized_relobj<size, big_endian>* object, Value addend) const |
| { |
| if (this->has_output_value_) |
| return this->u_.value + addend; |
| else |
| return this->u_.merged_symbol_value->value(object, this->input_shndx_, |
| addend); |
| } |
| |
| // Set the value of this symbol in the output symbol table. |
| void |
| set_output_value(Value value) |
| { this->u_.value = value; } |
| |
| // For a section symbol in a merged section, we need more |
| // information. |
| void |
| set_merged_symbol_value(Merged_symbol_value<size>* msv) |
| { |
| gold_assert(this->is_section_symbol_); |
| this->has_output_value_ = false; |
| this->u_.merged_symbol_value = msv; |
| } |
| |
| // Initialize the input to output map for a section symbol in a |
| // merged section. We also initialize the value of a non-section |
| // symbol in a merged section. |
| void |
| initialize_input_to_output_map(const Relobj* object) |
| { |
| if (!this->has_output_value_) |
| { |
| gold_assert(this->is_section_symbol_); |
| Merged_symbol_value<size>* msv = this->u_.merged_symbol_value; |
| msv->initialize_input_to_output_map(object, this->input_shndx_); |
| } |
| } |
| |
| // Free the input to output map for a section symbol in a merged |
| // section. |
| void |
| free_input_to_output_map() |
| { |
| if (!this->has_output_value_) |
| this->u_.merged_symbol_value->free_input_to_output_map(); |
| } |
| |
| // Set the value of the symbol from the input file. This is only |
| // called by count_local_symbols, to communicate the value to |
| // finalize_local_symbols. |
| void |
| set_input_value(Value value) |
| { this->u_.value = value; } |
| |
| // Return the input value. This is only called by |
| // finalize_local_symbols. |
| Value |
| input_value() const |
| { return this->u_.value; } |
| |
| // Return whether this symbol should go into the output symbol |
| // table. |
| bool |
| needs_output_symtab_entry() const |
| { return this->output_symtab_index_ != -1U; } |
| |
| // Return the index in the output symbol table. |
| unsigned int |
| output_symtab_index() const |
| { |
| gold_assert(this->output_symtab_index_ != 0); |
| return this->output_symtab_index_; |
| } |
| |
| // Set the index in the output symbol table. |
| void |
| set_output_symtab_index(unsigned int i) |
| { |
| gold_assert(this->output_symtab_index_ == 0); |
| this->output_symtab_index_ = i; |
| } |
| |
| // Record that this symbol should not go into the output symbol |
| // table. |
| void |
| set_no_output_symtab_entry() |
| { |
| gold_assert(this->output_symtab_index_ == 0); |
| this->output_symtab_index_ = -1U; |
| } |
| |
| // Set the index in the output dynamic symbol table. |
| void |
| set_needs_output_dynsym_entry() |
| { |
| gold_assert(!this->is_section_symbol()); |
| this->output_dynsym_index_ = 0; |
| } |
| |
| // Return whether this symbol should go into the output symbol |
| // table. |
| bool |
| needs_output_dynsym_entry() const |
| { |
| return this->output_dynsym_index_ != -1U; |
| } |
| |
| // Record that this symbol should go into the dynamic symbol table. |
| void |
| set_output_dynsym_index(unsigned int i) |
| { |
| gold_assert(this->output_dynsym_index_ == 0); |
| this->output_dynsym_index_ = i; |
| } |
| |
| // Return the index in the output dynamic symbol table. |
| unsigned int |
| output_dynsym_index() const |
| { |
| gold_assert(this->output_dynsym_index_ != 0 |
| && this->output_dynsym_index_ != -1U); |
| return this->output_dynsym_index_; |
| } |
| |
| // Set the index of the input section in the input file. |
| void |
| set_input_shndx(unsigned int i) |
| { |
| this->input_shndx_ = i; |
| // input_shndx_ field is a bitfield, so make sure that the value |
| // fits. |
| gold_assert(this->input_shndx_ == i); |
| } |
| |
| // Return the index of the input section in the input file. |
| unsigned int |
| input_shndx() const |
| { return this->input_shndx_; } |
| |
| // Whether this is a section symbol. |
| bool |
| is_section_symbol() const |
| { return this->is_section_symbol_; } |
| |
| // Record that this is a section symbol. |
| void |
| set_is_section_symbol() |
| { |
| gold_assert(!this->needs_output_dynsym_entry()); |
| this->is_section_symbol_ = true; |
| } |
| |
| // Record that this is a TLS symbol. |
| void |
| set_is_tls_symbol() |
| { this->is_tls_symbol_ = true; } |
| |
| // Return TRUE if this is a TLS symbol. |
| bool |
| is_tls_symbol() const |
| { return this->is_tls_symbol_; } |
| |
| private: |
| // The index of this local symbol in the output symbol table. This |
| // will be -1 if the symbol should not go into the symbol table. |
| unsigned int output_symtab_index_; |
| // The index of this local symbol in the dynamic symbol table. This |
| // will be -1 if the symbol should not go into the symbol table. |
| unsigned int output_dynsym_index_; |
| // The section index in the input file in which this symbol is |
| // defined. |
| unsigned int input_shndx_ : 29; |
| // Whether this is a STT_SECTION symbol. |
| bool is_section_symbol_ : 1; |
| // Whether this is a STT_TLS symbol. |
| bool is_tls_symbol_ : 1; |
| // Whether this symbol has a value for the output file. This is |
| // normally set to true during Layout::finalize, by |
| // finalize_local_symbols. It will be false for a section symbol in |
| // a merge section, as for such symbols we can not determine the |
| // value to use in a relocation until we see the addend. |
| bool has_output_value_ : 1; |
| union |
| { |
| // This is used if has_output_value_ is true. Between |
| // count_local_symbols and finalize_local_symbols, this is the |
| // value in the input file. After finalize_local_symbols, it is |
| // the value in the output file. |
| Value value; |
| // This is used if has_output_value_ is false. It points to the |
| // information we need to get the value for a merge section. |
| Merged_symbol_value<size>* merged_symbol_value; |
| } u_; |
| }; |
| |
| // A regular object file. This is size and endian specific. |
| |
| template<int size, bool big_endian> |
| class Sized_relobj : public Relobj |
| { |
| public: |
| typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; |
| typedef std::vector<Symbol*> Symbols; |
| typedef std::vector<Symbol_value<size> > Local_values; |
| |
| Sized_relobj(const std::string& name, Input_file* input_file, off_t offset, |
| const typename elfcpp::Ehdr<size, big_endian>&); |
| |
| ~Sized_relobj(); |
| |
| // Set up the object file based on the ELF header. |
| void |
| setup(const typename elfcpp::Ehdr<size, big_endian>&); |
| |
| // If SYM is the index of a global symbol in the object file's |
| // symbol table, return the Symbol object. Otherwise, return NULL. |
| Symbol* |
| global_symbol(unsigned int sym) const |
| { |
| if (sym >= this->local_symbol_count_) |
| { |
| gold_assert(sym - this->local_symbol_count_ < this->symbols_.size()); |
| return this->symbols_[sym - this->local_symbol_count_]; |
| } |
| return NULL; |
| } |
| |
| // Return the section index of symbol SYM. Set *VALUE to its value |
| // in the object file. Note that for a symbol which is not defined |
| // in this object file, this will set *VALUE to 0 and return |
| // SHN_UNDEF; it will not return the final value of the symbol in |
| // the link. |
| unsigned int |
| symbol_section_and_value(unsigned int sym, Address* value); |
| |
| // Return a pointer to the Symbol_value structure which holds the |
| // value of a local symbol. |
| const Symbol_value<size>* |
| local_symbol(unsigned int sym) const |
| { |
| gold_assert(sym < this->local_values_.size()); |
| return &this->local_values_[sym]; |
| } |
| |
| // Return the index of local symbol SYM in the ordinary symbol |
| // table. A value of -1U means that the symbol is not being output. |
| unsigned int |
| symtab_index(unsigned int sym) const |
| { |
| gold_assert(sym < this->local_values_.size()); |
| return this->local_values_[sym].output_symtab_index(); |
| } |
| |
| // Return the index of local symbol SYM in the dynamic symbol |
| // table. A value of -1U means that the symbol is not being output. |
| unsigned int |
| dynsym_index(unsigned int sym) const |
| { |
| gold_assert(sym < this->local_values_.size()); |
| return this->local_values_[sym].output_dynsym_index(); |
| } |
| |
| // Return the input section index of local symbol SYM. |
| unsigned int |
| local_symbol_input_shndx(unsigned int sym) const |
| { |
| gold_assert(sym < this->local_values_.size()); |
| return this->local_values_[sym].input_shndx(); |
| } |
| |
| // Return the appropriate Sized_target structure. |
| Sized_target<size, big_endian>* |
| sized_target() |
| { |
| return this->Object::sized_target |
| SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( |
| SELECT_SIZE_ENDIAN_ONLY(size, big_endian)); |
| } |
| |
| // Return the value of the local symbol symndx. |
| Address |
| local_symbol_value(unsigned int symndx) const; |
| |
| void |
| set_needs_output_dynsym_entry(unsigned int sym) |
| { |
| gold_assert(sym < this->local_values_.size()); |
| this->local_values_[sym].set_needs_output_dynsym_entry(); |
| } |
| |
| // Return whether the local symbol SYMNDX has a GOT offset. |
| // For TLS symbols, the GOT entry will hold its tp-relative offset. |
| bool |
| local_has_got_offset(unsigned int symndx) const |
| { |
| return (this->local_got_offsets_.find(symndx) |
| != this->local_got_offsets_.end()); |
| } |
| |
| // Return the GOT offset of the local symbol SYMNDX. |
| unsigned int |
| local_got_offset(unsigned int symndx) const |
| { |
| Local_got_offsets::const_iterator p = |
| this->local_got_offsets_.find(symndx); |
| gold_assert(p != this->local_got_offsets_.end()); |
| return p->second; |
| } |
| |
| // Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET. |
| void |
| set_local_got_offset(unsigned int symndx, unsigned int got_offset) |
| { |
| std::pair<Local_got_offsets::iterator, bool> ins = |
| this->local_got_offsets_.insert(std::make_pair(symndx, got_offset)); |
| gold_assert(ins.second); |
| } |
| |
| // Return whether the local TLS symbol SYMNDX has a GOT offset. |
| // The GOT entry at this offset will contain a module index. If |
| // NEED_PAIR is true, a second entry immediately following the first |
| // will contain the dtv-relative offset. |
| bool |
| local_has_tls_got_offset(unsigned int symndx, bool need_pair) const |
| { |
| typename Local_tls_got_offsets::const_iterator p = |
| this->local_tls_got_offsets_.find(symndx); |
| if (p == this->local_tls_got_offsets_.end() |
| || (need_pair && !p->second.have_pair_)) |
| return false; |
| return true; |
| } |
| |
| // Return the offset of the GOT entry for the local TLS symbol SYMNDX. |
| // If NEED_PAIR is true, we need the offset of a pair of GOT entries; |
| // otherwise we need the offset of the GOT entry for the module index. |
| unsigned int |
| local_tls_got_offset(unsigned int symndx, bool need_pair) const |
| { |
| typename Local_tls_got_offsets::const_iterator p = |
| this->local_tls_got_offsets_.find(symndx); |
| gold_assert(p != this->local_tls_got_offsets_.end()); |
| gold_assert(!need_pair || p->second.have_pair_); |
| return p->second.got_offset_; |
| } |
| |
| // Set the offset of the GOT entry for the local TLS symbol SYMNDX |
| // to GOT_OFFSET. If HAVE_PAIR is true, we have a pair of GOT entries; |
| // otherwise, we have just a single entry for the module index. |
| void |
| set_local_tls_got_offset(unsigned int symndx, unsigned int got_offset, |
| bool have_pair) |
| { |
| typename Local_tls_got_offsets::iterator p = |
| this->local_tls_got_offsets_.find(symndx); |
| if (p != this->local_tls_got_offsets_.end()) |
| { |
| // An entry already existed for this symbol. This can happen |
| // if we see a relocation asking for the module index before |
| // a relocation asking for the pair. In that case, the original |
| // GOT entry will remain, but won't get used by any further |
| // relocations. |
| p->second.got_offset_ = got_offset; |
| gold_assert(have_pair); |
| p->second.have_pair_ = true; |
| } |
| else |
| { |
| std::pair<typename Local_tls_got_offsets::iterator, bool> ins = |
| this->local_tls_got_offsets_.insert( |
| std::make_pair(symndx, Tls_got_entry(got_offset, have_pair))); |
| gold_assert(ins.second); |
| } |
| } |
| |
| // Return the name of the symbol that spans the given offset in the |
| // specified section in this object. This is used only for error |
| // messages and is not particularly efficient. |
| bool |
| get_symbol_location_info(unsigned int shndx, off_t offset, |
| Symbol_location_info* info); |
| |
| protected: |
| // Read the symbols. |
| void |
| do_read_symbols(Read_symbols_data*); |
| |
| // Return the number of local symbols. |
| unsigned int |
| do_local_symbol_count() const |
| { return this->local_symbol_count_; } |
| |
| // Lay out the input sections. |
| void |
| do_layout(Symbol_table*, Layout*, Read_symbols_data*); |
| |
| // Add the symbols to the symbol table. |
| void |
| do_add_symbols(Symbol_table*, Read_symbols_data*); |
| |
| // Read the relocs. |
| void |
| do_read_relocs(Read_relocs_data*); |
| |
| // Scan the relocs and adjust the symbol table. |
| void |
| do_scan_relocs(const General_options&, Symbol_table*, Layout*, |
| Read_relocs_data*); |
| |
| // Count the local symbols. |
| void |
| do_count_local_symbols(Stringpool_template<char>*, |
| Stringpool_template<char>*); |
| |
| // Finalize the local symbols. |
| unsigned int |
| do_finalize_local_symbols(unsigned int, off_t); |
| |
| // Set the offset where local dynamic symbol information will be stored. |
| unsigned int |
| do_set_local_dynsym_indexes(unsigned int); |
| |
| // Set the offset where local dynamic symbol information will be stored. |
| unsigned int |
| do_set_local_dynsym_offset(off_t); |
| |
| // Relocate the input sections and write out the local symbols. |
| void |
| do_relocate(const General_options& options, const Symbol_table* symtab, |
| const Layout*, Output_file* of); |
| |
| // Get the size of a section. |
| uint64_t |
| do_section_size(unsigned int shndx) |
| { return this->elf_file_.section_size(shndx); } |
| |
| // Get the name of a section. |
| std::string |
| do_section_name(unsigned int shndx) |
| { return this->elf_file_.section_name(shndx); } |
| |
| // Return the location of the contents of a section. |
| Object::Location |
| do_section_contents(unsigned int shndx) |
| { return this->elf_file_.section_contents(shndx); } |
| |
| // Return section flags. |
| uint64_t |
| do_section_flags(unsigned int shndx) |
| { return this->elf_file_.section_flags(shndx); } |
| |
| // Return section address. |
| uint64_t |
| do_section_address(unsigned int shndx) |
| { return this->elf_file_.section_addr(shndx); } |
| |
| // Return section type. |
| unsigned int |
| do_section_type(unsigned int shndx) |
| { return this->elf_file_.section_type(shndx); } |
| |
| // Return the section link field. |
| unsigned int |
| do_section_link(unsigned int shndx) |
| { return this->elf_file_.section_link(shndx); } |
| |
| // Return the section info field. |
| unsigned int |
| do_section_info(unsigned int shndx) |
| { return this->elf_file_.section_info(shndx); } |
| |
| // Return the section alignment. |
| uint64_t |
| do_section_addralign(unsigned int shndx) |
| { return this->elf_file_.section_addralign(shndx); } |
| |
| private: |
| // For convenience. |
| typedef Sized_relobj<size, big_endian> This; |
| static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size; |
| static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size; |
| static const int sym_size = elfcpp::Elf_sizes<size>::sym_size; |
| typedef elfcpp::Shdr<size, big_endian> Shdr; |
| |
| // Find the SHT_SYMTAB section, given the section headers. |
| void |
| find_symtab(const unsigned char* pshdrs); |
| |
| // Return whether SHDR has the right flags for a GNU style exception |
| // frame section. |
| bool |
| check_eh_frame_flags(const elfcpp::Shdr<size, big_endian>* shdr) const; |
| |
| // Return whether there is a section named .eh_frame which might be |
| // a GNU style exception frame section. |
| bool |
| find_eh_frame(const unsigned char* pshdrs, const char* names, |
| section_size_type names_size) const; |
| |
| // Whether to include a section group in the link. |
| bool |
| include_section_group(Symbol_table*, Layout*, unsigned int, const char*, |
| const elfcpp::Shdr<size, big_endian>&, |
| std::vector<bool>*); |
| |
| // Whether to include a linkonce section in the link. |
| bool |
| include_linkonce_section(Layout*, const char*, |
| const elfcpp::Shdr<size, big_endian>&); |
| |
| // Views and sizes when relocating. |
| struct View_size |
| { |
| unsigned char* view; |
| typename elfcpp::Elf_types<size>::Elf_Addr address; |
| off_t offset; |
| section_size_type view_size; |
| bool is_input_output_view; |
| bool is_postprocessing_view; |
| }; |
| |
| typedef std::vector<View_size> Views; |
| |
| // Write section data to the output file. Record the views and |
| // sizes in VIEWS for use when relocating. |
| void |
| write_sections(const unsigned char* pshdrs, Output_file*, Views*); |
| |
| // Relocate the sections in the output file. |
| void |
| relocate_sections(const General_options& options, const Symbol_table*, |
| const Layout*, const unsigned char* pshdrs, Views*); |
| |
| // Initialize input to output maps for section symbols in merged |
| // sections. |
| void |
| initialize_input_to_output_maps(); |
| |
| // Free the input to output maps for section symbols in merged |
| // sections. |
| void |
| free_input_to_output_maps(); |
| |
| // Write out the local symbols. |
| void |
| write_local_symbols(Output_file*, |
| const Stringpool_template<char>*, |
| const Stringpool_template<char>*); |
| |
| // Clear the local symbol information. |
| void |
| clear_local_symbols() |
| { |
| this->local_values_.clear(); |
| this->local_got_offsets_.clear(); |
| this->local_tls_got_offsets_.clear(); |
| } |
| |
| // The GOT offsets of local symbols. This map also stores GOT offsets |
| // for tp-relative offsets for TLS symbols. |
| typedef Unordered_map<unsigned int, unsigned int> Local_got_offsets; |
| |
| // The TLS GOT offsets of local symbols. The map stores the offsets |
| // for either a single GOT entry that holds the module index of a TLS |
| // symbol, or a pair of GOT entries containing the module index and |
| // dtv-relative offset. |
| struct Tls_got_entry |
| { |
| Tls_got_entry(int got_offset, bool have_pair) |
| : got_offset_(got_offset), |
| have_pair_(have_pair) |
| { } |
| int got_offset_; |
| bool have_pair_; |
| }; |
| typedef Unordered_map<unsigned int, Tls_got_entry> Local_tls_got_offsets; |
| |
| // General access to the ELF file. |
| elfcpp::Elf_file<size, big_endian, Object> elf_file_; |
| // Index of SHT_SYMTAB section. |
| unsigned int symtab_shndx_; |
| // The number of local symbols. |
| unsigned int local_symbol_count_; |
| // The number of local symbols which go into the output file. |
| unsigned int output_local_symbol_count_; |
| // The number of local symbols which go into the output file's dynamic |
| // symbol table. |
| unsigned int output_local_dynsym_count_; |
| // The entries in the symbol table for the external symbols. |
| Symbols symbols_; |
| // File offset for local symbols. |
| off_t local_symbol_offset_; |
| // File offset for local dynamic symbols. |
| off_t local_dynsym_offset_; |
| // Values of local symbols. |
| Local_values local_values_; |
| // GOT offsets for local non-TLS symbols, and tp-relative offsets |
| // for TLS symbols, indexed by symbol number. |
| Local_got_offsets local_got_offsets_; |
| // GOT offsets for local TLS symbols, indexed by symbol number |
| // and GOT entry type. |
| Local_tls_got_offsets local_tls_got_offsets_; |
| // Whether this object has a GNU style .eh_frame section. |
| bool has_eh_frame_; |
| }; |
| |
| // A class to manage the list of all objects. |
| |
| class Input_objects |
| { |
| public: |
| Input_objects() |
| : relobj_list_(), dynobj_list_(), sonames_(), system_library_directory_() |
| { } |
| |
| // The type of the list of input relocateable objects. |
| typedef std::vector<Relobj*> Relobj_list; |
| typedef Relobj_list::const_iterator Relobj_iterator; |
| |
| // The type of the list of input dynamic objects. |
| typedef std::vector<Dynobj*> Dynobj_list; |
| typedef Dynobj_list::const_iterator Dynobj_iterator; |
| |
| // Add an object to the list. Return true if all is well, or false |
| // if this object should be ignored. |
| bool |
| add_object(Object*); |
| |
| // For each dynamic object, check whether we've seen all of its |
| // explicit dependencies. |
| void |
| check_dynamic_dependencies() const; |
| |
| // Return whether an object was found in the system library |
| // directory. |
| bool |
| found_in_system_library_directory(const Object*) const; |
| |
| // Iterate over all regular objects. |
| |
| Relobj_iterator |
| relobj_begin() const |
| { return this->relobj_list_.begin(); } |
| |
| Relobj_iterator |
| relobj_end() const |
| { return this->relobj_list_.end(); } |
| |
| // Iterate over all dynamic objects. |
| |
| Dynobj_iterator |
| dynobj_begin() const |
| { return this->dynobj_list_.begin(); } |
| |
| Dynobj_iterator |
| dynobj_end() const |
| { return this->dynobj_list_.end(); } |
| |
| // Return whether we have seen any dynamic objects. |
| bool |
| any_dynamic() const |
| { return !this->dynobj_list_.empty(); } |
| |
| // Return the number of input objects. |
| int |
| number_of_input_objects() const |
| { return this->relobj_list_.size() + this->dynobj_list_.size(); } |
| |
| private: |
| Input_objects(const Input_objects&); |
| Input_objects& operator=(const Input_objects&); |
| |
| // The list of ordinary objects included in the link. |
| Relobj_list relobj_list_; |
| // The list of dynamic objects included in the link. |
| Dynobj_list dynobj_list_; |
| // SONAMEs that we have seen. |
| Unordered_set<std::string> sonames_; |
| // The directory in which we find the libc.so. |
| std::string system_library_directory_; |
| }; |
| |
| // Some of the information we pass to the relocation routines. We |
| // group this together to avoid passing a dozen different arguments. |
| |
| template<int size, bool big_endian> |
| struct Relocate_info |
| { |
| // Command line options. |
| const General_options* options; |
| // Symbol table. |
| const Symbol_table* symtab; |
| // Layout. |
| const Layout* layout; |
| // Object being relocated. |
| Sized_relobj<size, big_endian>* object; |
| // Section index of relocation section. |
| unsigned int reloc_shndx; |
| // Section index of section being relocated. |
| unsigned int data_shndx; |
| |
| // Return a string showing the location of a relocation. This is |
| // only used for error messages. |
| std::string |
| location(size_t relnum, off_t reloffset) const; |
| }; |
| |
| // Return an Object appropriate for the input file. P is BYTES long, |
| // and holds the ELF header. |
| |
| extern Object* |
| make_elf_object(const std::string& name, Input_file*, |
| off_t offset, const unsigned char* p, |
| section_offset_type bytes); |
| |
| } // end namespace gold |
| |
| #endif // !defined(GOLD_OBJECT_H) |