// object.h -- support for an object file for linking in gold -*- C++ -*- // Copyright (C) 2006-2014 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // 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 #include #include "elfcpp.h" #include "elfcpp_file.h" #include "fileread.h" #include "target.h" #include "archive.h" namespace gold { class General_options; class Task; class Cref; class Layout; class Output_data; class Output_section; class Output_file; class Output_symtab_xindex; class Pluginobj; class Dynobj; class Object_merge_map; class Relocatable_relocs; struct Symbols_data; template class Stringpool_template; // Data to pass from read_symbols() to add_symbols(). struct Read_symbols_data { Read_symbols_data() : section_headers(NULL), section_names(NULL), symbols(NULL), symbol_names(NULL), versym(NULL), verdef(NULL), verneed(NULL) { } ~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; elfcpp::STT enclosing_symbol_type; }; // Data about a single relocation section. This is read in // read_relocs and processed in scan_relocs. struct Section_relocs { Section_relocs() : contents(NULL) { } ~Section_relocs() { delete this->contents; } // 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; // Whether the data section is allocated (has the SHF_ALLOC flag set). bool is_data_section_allocated; }; // Relocations in an object file. This is read in read_relocs and // processed in scan_relocs. struct Read_relocs_data { Read_relocs_data() : local_symbols(NULL) { } ~Read_relocs_data() { delete this->local_symbols; } typedef std::vector Relocs_list; // The relocations. Relocs_list relocs; // The local symbols. File_view* local_symbols; }; // The Xindex class manages section indexes for objects with more than // 0xff00 sections. class Xindex { public: Xindex(int large_shndx_offset) : large_shndx_offset_(large_shndx_offset), symtab_xindex_() { } // Initialize the symtab_xindex_ array, given the object and the // section index of the symbol table to use. template void initialize_symtab_xindex(Object*, unsigned int symtab_shndx); // Read in the symtab_xindex_ array, given its section index. // PSHDRS may optionally point to the section headers. template void read_symtab_xindex(Object*, unsigned int xindex_shndx, const unsigned char* pshdrs); // Symbol SYMNDX in OBJECT has a section of SHN_XINDEX; return the // real section index. unsigned int sym_xindex_to_shndx(Object* object, unsigned int symndx); private: // The type of the array giving the real section index for symbols // whose st_shndx field holds SHN_XINDEX. typedef std::vector Symtab_xindex; // Adjust a section index if necessary. This should only be called // for ordinary section indexes. unsigned int adjust_shndx(unsigned int shndx) { if (shndx >= elfcpp::SHN_LORESERVE) shndx += this->large_shndx_offset_; return shndx; } // Adjust to apply to large section indexes. int large_shndx_offset_; // The data from the SHT_SYMTAB_SHNDX section. Symtab_xindex symtab_xindex_; }; // A GOT offset list. A symbol may have more than one GOT offset // (e.g., when mixing modules compiled with two different TLS models), // but will usually have at most one. GOT_TYPE identifies the type of // GOT entry; its values are specific to each target. class Got_offset_list { public: Got_offset_list() : got_type_(-1U), got_offset_(0), got_next_(NULL) { } Got_offset_list(unsigned int got_type, unsigned int got_offset) : got_type_(got_type), got_offset_(got_offset), got_next_(NULL) { } ~Got_offset_list() { if (this->got_next_ != NULL) { delete this->got_next_; this->got_next_ = NULL; } } // Initialize the fields to their default values. void init() { this->got_type_ = -1U; this->got_offset_ = 0; this->got_next_ = NULL; } // Set the offset for the GOT entry of type GOT_TYPE. void set_offset(unsigned int got_type, unsigned int got_offset) { if (this->got_type_ == -1U) { this->got_type_ = got_type; this->got_offset_ = got_offset; } else { for (Got_offset_list* g = this; g != NULL; g = g->got_next_) { if (g->got_type_ == got_type) { g->got_offset_ = got_offset; return; } } Got_offset_list* g = new Got_offset_list(got_type, got_offset); g->got_next_ = this->got_next_; this->got_next_ = g; } } // Return the offset for a GOT entry of type GOT_TYPE. unsigned int get_offset(unsigned int got_type) const { for (const Got_offset_list* g = this; g != NULL; g = g->got_next_) { if (g->got_type_ == got_type) return g->got_offset_; } return -1U; } // Return a pointer to the list, or NULL if the list is empty. const Got_offset_list* get_list() const { if (this->got_type_ == -1U) return NULL; return this; } // Abstract visitor class for iterating over GOT offsets. class Visitor { public: Visitor() { } virtual ~Visitor() { } virtual void visit(unsigned int, unsigned int) = 0; }; // Loop over all GOT offset entries, calling a visitor class V for each. void for_all_got_offsets(Visitor* v) const { if (this->got_type_ == -1U) return; for (const Got_offset_list* g = this; g != NULL; g = g->got_next_) v->visit(g->got_type_, g->got_offset_); } private: unsigned int got_type_; unsigned int got_offset_; Got_offset_list* got_next_; }; // Type for mapping section index to uncompressed size and contents. struct Compressed_section_info { section_size_type size; const unsigned char* contents; }; typedef std::map Compressed_section_map; template Compressed_section_map* build_compressed_section_map(const unsigned char* pshdrs, unsigned int shnum, const char* names, section_size_type names_size, Object* obj, bool decompress_if_needed); // 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: typedef std::vector Symbols; // 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), is_needed_(false), uses_split_stack_(false), has_no_split_stack_(false), no_export_(false), is_in_system_directory_(false), as_needed_(false), xindex_(NULL), compressed_sections_(NULL) { if (input_file != NULL) { input_file->file().add_object(); this->is_in_system_directory_ = input_file->is_in_system_directory(); this->as_needed_ = input_file->options().as_needed(); } } virtual ~Object() { if (this->input_file_ != NULL) this->input_file_->file().remove_object(); } // Return the name of the object as we would report it to the user. 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 whether this object is needed--true if it is a dynamic // object which defines some symbol referenced by a regular object. // We keep the flag here rather than in Dynobj for convenience when // setting it. bool is_needed() const { return this->is_needed_; } // Record that this object is needed. void set_is_needed() { this->is_needed_ = true; } // Return whether this object was compiled with -fsplit-stack. bool uses_split_stack() const { return this->uses_split_stack_; } // Return whether this object contains any functions compiled with // the no_split_stack attribute. bool has_no_split_stack() const { return this->has_no_split_stack_; } // Returns NULL for Objects that are not dynamic objects. This method // is overridden in the Dynobj class. Dynobj* dynobj() { return this->do_dynobj(); } // Returns NULL for Objects that are not plugin objects. This method // is overridden in the Pluginobj class. Pluginobj* pluginobj() { return this->do_pluginobj(); } // Get the file. We pass on const-ness. Input_file* input_file() { gold_assert(this->input_file_ != NULL); return this->input_file_; } const Input_file* input_file() const { gold_assert(this->input_file_ != NULL); return this->input_file_; } // Lock the underlying file. void lock(const Task* t) { if (this->input_file_ != NULL) this->input_file_->file().lock(t); } // Unlock the underlying file. void unlock(const Task* t) { if (this->input_file_ != NULL) this->input_file()->file().unlock(t); } // Return whether the underlying file is locked. bool is_locked() const { return this->input_file_ != NULL && this->input_file_->file().is_locked(); } // Return the token, so that the task can be queued. Task_token* token() { if (this->input_file_ == NULL) return NULL; return this->input_file()->file().token(); } // Release the underlying file. void release() { if (this->input_file_ != NULL) 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 whether this is an incremental object. bool is_incremental() const { return this->do_is_incremental(); } // Return the last modified time of the file. Timespec get_mtime() { return this->do_get_mtime(); } // 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); // Adjust a symbol's section index as needed. SYMNDX is the index // of the symbol and SHNDX is the symbol's section from // get_st_shndx. This returns the section index. It sets // *IS_ORDINARY to indicate whether this is a normal section index, // rather than a special code between SHN_LORESERVE and // SHN_HIRESERVE. unsigned int adjust_sym_shndx(unsigned int symndx, unsigned int shndx, bool* is_ordinary) { if (shndx < elfcpp::SHN_LORESERVE) *is_ordinary = true; else if (shndx == elfcpp::SHN_XINDEX) { if (this->xindex_ == NULL) this->xindex_ = this->do_initialize_xindex(); shndx = this->xindex_->sym_xindex_to_shndx(this, symndx); *is_ordinary = true; } else *is_ordinary = false; return shndx; } // 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) const { 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 entsize given a section index. uint64_t section_entsize(unsigned int shndx) { return this->do_section_entsize(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); } // Return the output section given a section index. Output_section* output_section(unsigned int shndx) const { return this->do_output_section(shndx); } // Given a section index, return its address. // The return value will be -1U if the section is specially mapped, // such as a merge section. uint64_t output_section_address(unsigned int shndx) { return this->do_output_section_address(shndx); } // Given a section index, return the offset in the Output_section. // The return value will be -1U if the section is specially mapped, // such as a merge section. uint64_t output_section_offset(unsigned int shndx) const { return this->do_output_section_offset(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, Layout *layout) { this->do_add_symbols(symtab, sd, layout); } // Add symbol information to the global symbol table. Archive::Should_include should_include_member(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd, std::string* why) { return this->do_should_include_member(symtab, layout, sd, why); } // Iterate over global symbols, calling a visitor class V for each. void for_all_global_symbols(Read_symbols_data* sd, Library_base::Symbol_visitor_base* v) { return this->do_for_all_global_symbols(sd, v); } // Iterate over local symbols, calling a visitor class V for each GOT offset // associated with a local symbol. void for_all_local_got_entries(Got_offset_list::Visitor* v) const { this->do_for_all_local_got_entries(v); } // 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, 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, true)); } // Get a view into the underlying file. const unsigned char* get_view(off_t start, section_size_type size, bool aligned, bool cache) { return this->input_file()->file().get_view(this->offset_, start, size, aligned, cache); } // Get a lasting view into the underlying file. File_view* get_lasting_view(off_t start, section_size_type size, bool aligned, bool cache) { return this->input_file()->file().get_lasting_view(this->offset_, start, size, aligned, cache); } // Read data from the underlying file. void read(off_t start, section_size_type size, void* p) { 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() { if (this->input_file_ != NULL) this->input_file_->file().clear_view_cache_marks(); } // Get the number of global symbols defined by this object, and the // number of the symbols whose final definition came from this // object. void get_global_symbol_counts(const Symbol_table* symtab, size_t* defined, size_t* used) const { this->do_get_global_symbol_counts(symtab, defined, used); } // Get the symbols defined in this object. const Symbols* get_global_symbols() const { return this->do_get_global_symbols(); } // Set flag that this object was found in a system directory. void set_is_in_system_directory() { this->is_in_system_directory_ = true; } // Return whether this object was found in a system directory. bool is_in_system_directory() const { return this->is_in_system_directory_; } // Set flag that this object was linked with --as-needed. void set_as_needed() { this->as_needed_ = true; } // Return whether this object was linked with --as-needed. bool as_needed() const { return this->as_needed_; } // Return whether we found this object by searching a directory. bool searched_for() const { return this->input_file()->will_search_for(); } bool no_export() const { return this->no_export_; } void set_no_export(bool value) { this->no_export_ = value; } bool section_is_compressed(unsigned int shndx, section_size_type* uncompressed_size) const { if (this->compressed_sections_ == NULL) return false; Compressed_section_map::const_iterator p = this->compressed_sections_->find(shndx); if (p != this->compressed_sections_->end()) { if (uncompressed_size != NULL) *uncompressed_size = p->second.size; return true; } return false; } // Return a view of the decompressed contents of a section. Set *PLEN // to the size. Set *IS_NEW to true if the contents need to be freed // by the caller. const unsigned char* decompressed_section_contents(unsigned int shndx, section_size_type* plen, bool* is_cached); // Discard any buffers of decompressed sections. This is done // at the end of the Add_symbols task. void discard_decompressed_sections(); // Return the index of the first incremental relocation for symbol SYMNDX. unsigned int get_incremental_reloc_base(unsigned int symndx) const { return this->do_get_incremental_reloc_base(symndx); } // Return the number of incremental relocations for symbol SYMNDX. unsigned int get_incremental_reloc_count(unsigned int symndx) const { return this->do_get_incremental_reloc_count(symndx); } protected: // Returns NULL for Objects that are not dynamic objects. This method // is overridden in the Dynobj class. virtual Dynobj* do_dynobj() { return NULL; } // Returns NULL for Objects that are not plugin objects. This method // is overridden in the Pluginobj class. virtual Pluginobj* do_pluginobj() { return NULL; } // Return TRUE if this is an incremental (unchanged) input file. // We return FALSE by default; the incremental object classes // override this method. virtual bool do_is_incremental() const { return false; } // Return the last modified time of the file. This method may be // overridden for subclasses that don't use an actual file (e.g., // Incremental objects). virtual Timespec do_get_mtime() { return this->input_file()->file().get_mtime(); } // 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*, Layout*) = 0; virtual Archive::Should_include do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*, std::string* why) = 0; // Iterate over global symbols, calling a visitor class V for each. virtual void do_for_all_global_symbols(Read_symbols_data* sd, Library_base::Symbol_visitor_base* v) = 0; // Iterate over local symbols, calling a visitor class V for each GOT offset // associated with a local symbol. virtual void do_for_all_local_got_entries(Got_offset_list::Visitor* v) const = 0; // Return the location of the contents of a section. Implemented by // child class. virtual const unsigned char* do_section_contents(unsigned int shndx, section_size_type* plen, bool cache) = 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) const = 0; // Get section flags--implemented by child class. virtual uint64_t do_section_flags(unsigned int shndx) = 0; // Get section entsize--implemented by child class. virtual uint64_t do_section_entsize(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; // Return the output section given a section index--implemented // by child class. virtual Output_section* do_output_section(unsigned int) const { gold_unreachable(); } // Get the address of a section--implemented by child class. virtual uint64_t do_output_section_address(unsigned int) { gold_unreachable(); } // Get the offset of a section--implemented by child class. virtual uint64_t do_output_section_offset(unsigned int) const { gold_unreachable(); } // Return the Xindex structure to use. virtual Xindex* do_initialize_xindex() = 0; // Implement get_global_symbol_counts--implemented by child class. virtual void do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const = 0; virtual const Symbols* do_get_global_symbols() const = 0; // Set the number of sections. void set_shnum(int shnum) { this->shnum_ = shnum; } // Functions used by both Sized_relobj_file and Sized_dynobj. // Read the section data into a Read_symbols_data object. template void read_section_data(elfcpp::Elf_file*, Read_symbols_data*); // Find the section header with the given NAME. If HDR is non-NULL // then it is a section header returned from a previous call to this // function and the next section header with the same name will be // returned. template const unsigned char* find_shdr(const unsigned char* pshdrs, const char* name, const char* names, section_size_type names_size, const unsigned char* hdr) const; // Let the child class initialize the xindex object directly. void set_xindex(Xindex* xindex) { gold_assert(this->xindex_ == NULL); this->xindex_ = xindex; } // 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*); // If NAME is the name of the special section which indicates that // this object was compiled with -fsplit-stack, mark it accordingly, // and return true. Otherwise return false. bool handle_split_stack_section(const char* name); // Discard any buffers of decompressed sections. This is done // at the end of the Add_symbols task. virtual void do_discard_decompressed_sections() { } // Return the index of the first incremental relocation for symbol SYMNDX-- // implemented by child class. virtual unsigned int do_get_incremental_reloc_base(unsigned int) const { gold_unreachable(); } // Return the number of incremental relocations for symbol SYMNDX-- // implemented by child class. virtual unsigned int do_get_incremental_reloc_count(unsigned int) const { gold_unreachable(); } void set_compressed_sections(Compressed_section_map* compressed_sections) { this->compressed_sections_ = compressed_sections; } Compressed_section_map* compressed_sections() { return this->compressed_sections_; } 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_ : 1; // Whether this object is needed. This is only set for dynamic // objects, and means that the object defined a symbol which was // used by a reference from a regular object. bool is_needed_ : 1; // Whether this object was compiled with -fsplit-stack. bool uses_split_stack_ : 1; // Whether this object contains any functions compiled with the // no_split_stack attribute. bool has_no_split_stack_ : 1; // True if exclude this object from automatic symbol export. // This is used only for archive objects. bool no_export_ : 1; // True if the object was found in a system directory. bool is_in_system_directory_ : 1; // True if the object was linked with --as-needed. bool as_needed_ : 1; // Many sections for objects with more than SHN_LORESERVE sections. Xindex* xindex_; // For compressed debug sections, map section index to uncompressed size // and contents. Compressed_section_map* compressed_sections_; }; // A regular object (ET_REL). This is an abstract base class itself. // The implementation is the template class Sized_relobj_file. class Relobj : public Object { public: Relobj(const std::string& name, Input_file* input_file, off_t offset = 0) : Object(name, input_file, false, offset), output_sections_(), map_to_relocatable_relocs_(NULL), object_merge_map_(NULL), relocs_must_follow_section_writes_(false), sd_(NULL), reloc_counts_(NULL), reloc_bases_(NULL), first_dyn_reloc_(0), dyn_reloc_count_(0) { } // During garbage collection, the Read_symbols_data pass for // each object is stored as layout needs to be done after // reloc processing. Symbols_data* get_symbols_data() { return this->sd_; } // Decides which section names have to be included in the worklist // as roots. bool is_section_name_included(const char* name); void copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd, unsigned int section_header_size); void set_symbols_data(Symbols_data* sd) { this->sd_ = sd; } // During garbage collection, the Read_relocs pass for all objects // is done before scanning the relocs. In that case, this->rd_ is // used to store the information from Read_relocs for each object. // This data is also used to compute the list of relevant sections. Read_relocs_data* get_relocs_data() { return this->rd_; } void set_relocs_data(Read_relocs_data* rd) { this->rd_ = rd; } virtual bool is_output_section_offset_invalid(unsigned int shndx) const = 0; // Read the relocs. void read_relocs(Read_relocs_data* rd) { return this->do_read_relocs(rd); } // Process the relocs, during garbage collection only. void gc_process_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd) { return this->do_gc_process_relocs(symtab, layout, rd); } // Scan the relocs and adjust the symbol table. void scan_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd) { return this->do_scan_relocs(symtab, layout, rd); } // Return the value of the local symbol whose index is SYMNDX, plus // ADDEND. ADDEND is passed in so that we can correctly handle the // section symbol for a merge section. uint64_t local_symbol_value(unsigned int symndx, uint64_t addend) const { return this->do_local_symbol_value(symndx, addend); } // Return the PLT offset for a local symbol. It is an error to call // this if it doesn't have one. unsigned int local_plt_offset(unsigned int symndx) const { return this->do_local_plt_offset(symndx); } // Return whether the local symbol SYMNDX has a GOT offset of type // GOT_TYPE. bool local_has_got_offset(unsigned int symndx, unsigned int got_type) const { return this->do_local_has_got_offset(symndx, got_type); } // Return the GOT offset of type GOT_TYPE of the local symbol // SYMNDX. It is an error to call this if the symbol does not have // a GOT offset of the specified type. unsigned int local_got_offset(unsigned int symndx, unsigned int got_type) const { return this->do_local_got_offset(symndx, got_type); } // Set the GOT offset with type GOT_TYPE of the local symbol SYMNDX // to GOT_OFFSET. void set_local_got_offset(unsigned int symndx, unsigned int got_type, unsigned int got_offset) { this->do_set_local_got_offset(symndx, got_type, got_offset); } // Return whether the local symbol SYMNDX is a TLS symbol. bool local_is_tls(unsigned int symndx) const { return this->do_local_is_tls(symndx); } // The number of local symbols in the input symbol table. virtual unsigned int local_symbol_count() const { return this->do_local_symbol_count(); } // The number of local symbols in the output symbol table. virtual unsigned int output_local_symbol_count() const { return this->do_output_local_symbol_count(); } // The file offset for local symbols in the output symbol table. virtual off_t local_symbol_offset() const { return this->do_local_symbol_offset(); } // 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* pool, Stringpool_template* 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, Symbol_table* symtab) { return this->do_finalize_local_symbols(index, off, symtab); } // 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); } // Record a dynamic relocation against an input section from this object. void add_dyn_reloc(unsigned int index) { if (this->dyn_reloc_count_ == 0) this->first_dyn_reloc_ = index; ++this->dyn_reloc_count_; } // Return the index of the first dynamic relocation. unsigned int first_dyn_reloc() const { return this->first_dyn_reloc_; } // Return the count of dynamic relocations. unsigned int dyn_reloc_count() const { return this->dyn_reloc_count_; } // Relocate the input sections and write out the local symbols. void relocate(const Symbol_table* symtab, const Layout* layout, Output_file* of) { return this->do_relocate(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->output_sections_.size()); return this->output_sections_[shndx] != NULL; } // The output section of the input section with index SHNDX. // This is only used currently to remove a section from the link in // relaxation. void set_output_section(unsigned int shndx, Output_section* os) { gold_assert(shndx < this->output_sections_.size()); this->output_sections_[shndx] = os; } // Set the offset of an input section within its output section. void set_section_offset(unsigned int shndx, uint64_t off) { this->do_set_section_offset(shndx, 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]; } // Layout sections whose layout was deferred while waiting for // input files from a plugin. void layout_deferred_sections(Layout* layout) { this->do_layout_deferred_sections(layout); } // Return the index of the first incremental relocation for symbol SYMNDX. virtual unsigned int do_get_incremental_reloc_base(unsigned int symndx) const { return this->reloc_bases_[symndx]; } // Return the number of incremental relocations for symbol SYMNDX. virtual unsigned int do_get_incremental_reloc_count(unsigned int symndx) const { return this->reloc_counts_[symndx]; } // Return the word size of the object file. int elfsize() const { return this->do_elfsize(); } // Return TRUE if this is a big-endian object file. bool is_big_endian() const { return this->do_is_big_endian(); } protected: // The output section to be used for each input section, indexed by // the input section number. The output section is NULL if the // input section is to be discarded. typedef std::vector Output_sections; // Read the relocs--implemented by child class. virtual void do_read_relocs(Read_relocs_data*) = 0; // Process the relocs--implemented by child class. virtual void do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0; // Scan the relocs--implemented by child class. virtual void do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0; // Return the value of a local symbol. virtual uint64_t do_local_symbol_value(unsigned int symndx, uint64_t addend) const = 0; // Return the PLT offset of a local symbol. virtual unsigned int do_local_plt_offset(unsigned int symndx) const = 0; // Return whether a local symbol has a GOT offset of a given type. virtual bool do_local_has_got_offset(unsigned int symndx, unsigned int got_type) const = 0; // Return the GOT offset of a given type of a local symbol. virtual unsigned int do_local_got_offset(unsigned int symndx, unsigned int got_type) const = 0; // Set the GOT offset with a given type for a local symbol. virtual void do_set_local_got_offset(unsigned int symndx, unsigned int got_type, unsigned int got_offset) = 0; // Return whether local symbol SYMNDX is a TLS symbol. virtual bool do_local_is_tls(unsigned int symndx) const = 0; // Return the number of local symbols--implemented by child class. virtual unsigned int do_local_symbol_count() const = 0; // Return the number of output local symbols--implemented by child class. virtual unsigned int do_output_local_symbol_count() const = 0; // Return the file offset for local symbols--implemented by child class. virtual off_t do_local_symbol_offset() const = 0; // Count local symbols--implemented by child class. virtual void do_count_local_symbols(Stringpool_template*, Stringpool_template*) = 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, Symbol_table*) = 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 Symbol_table* symtab, const Layout*, Output_file* of) = 0; // Set the offset of a section--implemented by child class. virtual void do_set_section_offset(unsigned int shndx, uint64_t off) = 0; // Layout sections whose layout was deferred while waiting for // input files from a plugin--implemented by child class. virtual void do_layout_deferred_sections(Layout*) = 0; // Given a section index, return the corresponding Output_section. // The return value will be NULL if the section is not included in // the link. Output_section* do_output_section(unsigned int shndx) const { gold_assert(shndx < this->output_sections_.size()); return this->output_sections_[shndx]; } // Return the vector mapping input sections to output sections. Output_sections& output_sections() { return this->output_sections_; } const Output_sections& output_sections() const { return this->output_sections_; } // Set the size of the relocatable relocs array. void size_relocatable_relocs() { this->map_to_relocatable_relocs_ = new std::vector(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; } // Allocate the array for counting incremental relocations. void allocate_incremental_reloc_counts() { unsigned int nsyms = this->do_get_global_symbols()->size(); this->reloc_counts_ = new unsigned int[nsyms]; gold_assert(this->reloc_counts_ != NULL); memset(this->reloc_counts_, 0, nsyms * sizeof(unsigned int)); } // Record a relocation in this object referencing global symbol SYMNDX. // Used for tracking incremental link information. void count_incremental_reloc(unsigned int symndx) { unsigned int nsyms = this->do_get_global_symbols()->size(); gold_assert(symndx < nsyms); gold_assert(this->reloc_counts_ != NULL); ++this->reloc_counts_[symndx]; } // Finalize the incremental relocation information. void finalize_incremental_relocs(Layout* layout, bool clear_counts); // Return the index of the next relocation to be written for global symbol // SYMNDX. Only valid after finalize_incremental_relocs() has been called. unsigned int next_incremental_reloc_index(unsigned int symndx) { unsigned int nsyms = this->do_get_global_symbols()->size(); gold_assert(this->reloc_counts_ != NULL); gold_assert(this->reloc_bases_ != NULL); gold_assert(symndx < nsyms); unsigned int counter = this->reloc_counts_[symndx]++; return this->reloc_bases_[symndx] + counter; } // Return the word size of the object file-- // implemented by child class. virtual int do_elfsize() const = 0; // Return TRUE if this is a big-endian object file-- // implemented by child class. virtual bool do_is_big_endian() const = 0; private: // Mapping from input sections to output section. Output_sections output_sections_; // Mapping from input section index to the information recorded for // the relocations. This is only used for a relocatable link. std::vector* 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_; // Used to store the relocs data computed by the Read_relocs pass. // Used during garbage collection of unused sections. Read_relocs_data* rd_; // Used to store the symbols data computed by the Read_symbols pass. // Again used during garbage collection when laying out referenced // sections. gold::Symbols_data* sd_; // Per-symbol counts of relocations, for incremental links. unsigned int* reloc_counts_; // Per-symbol base indexes of relocations, for incremental links. unsigned int* reloc_bases_; // Index of the first dynamic relocation for this object. unsigned int first_dyn_reloc_; // Count of dynamic relocations for this object. unsigned int dyn_reloc_count_; }; // 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 class Merged_symbol_value { public: typedef typename elfcpp::Elf_types::Elf_Addr Value; // We use a hash table to map offsets in the input section to output // addresses. typedef Unordered_map 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 { // This is a relocation against a section symbol. ADDEND is the // offset in the section. The result should be the start of some // merge area. If the object file wants something else, it should // use a regular symbol rather than a section symbol. // Unfortunately, PR 6658 shows a case in which the object file // refers to the section symbol, but uses a negative ADDEND to // compensate for a PC relative reloc. We can't handle the // general case. However, we can handle the special case of a // negative addend, by assuming that it refers to the start of the // section. Of course, that means that we have to guess when // ADDEND is negative. It is normal to see a 32-bit value here // even when the template parameter size is 64, as 64-bit object // file formats have 32-bit relocations. We know this is a merge // section, so we know it has to fit into memory. So we assume // that we won't see a value larger than a large 32-bit unsigned // value. This will break objects with very very large merge // sections; they probably break in other ways anyhow. Value input_offset = this->input_value_; if (addend < 0xffffff00) { input_offset += addend; addend = 0; } typename Output_addresses::const_iterator p = this->output_addresses_.find(input_offset); if (p != this->output_addresses_.end()) return p->second + addend; return (this->value_from_output_section(object, input_shndx, input_offset) + addend); } 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 class Symbol_value { public: typedef typename elfcpp::Elf_types::Elf_Addr Value; Symbol_value() : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0), is_ordinary_shndx_(false), is_section_symbol_(false), is_tls_symbol_(false), is_ifunc_symbol_(false), has_output_value_(true) { this->u_.value = 0; } ~Symbol_value() { if (!this->has_output_value_) delete this->u_.merged_symbol_value; } // 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 Value value(const Sized_relobj_file* object, Value addend) const { if (this->has_output_value_) return this->u_.value + addend; else { gold_assert(this->is_ordinary_shndx_); 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* 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_ && this->is_ordinary_shndx_); Merged_symbol_value* 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 and (in special cases) relocate_section. Value input_value() const { return this->u_.value; } // Return whether we have set the index in the output symbol table // yet. bool is_output_symtab_index_set() const { return (this->output_symtab_index_ != 0 && this->output_symtab_index_ != -2U); } // Return whether this symbol may be discarded from the normal // symbol table. bool may_be_discarded_from_output_symtab() const { gold_assert(!this->is_output_symtab_index_set()); return this->output_symtab_index_ != -2U; } // Return whether this symbol has an entry in the output symbol // table. bool has_output_symtab_entry() const { gold_assert(this->is_output_symtab_index_set()); return this->output_symtab_index_ != -1U; } // Return the index in the output symbol table. unsigned int output_symtab_index() const { gold_assert(this->is_output_symtab_index_set() && this->output_symtab_index_ != -1U); return this->output_symtab_index_; } // Set the index in the output symbol table. void set_output_symtab_index(unsigned int i) { gold_assert(!this->is_output_symtab_index_set()); gold_assert(i != 0 && i != -1U && i != -2U); 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; } // Record that this symbol must go into the output symbol table, // because it there is a relocation that uses it. void set_must_have_output_symtab_entry() { gold_assert(!this->is_output_symtab_index_set()); this->output_symtab_index_ = -2U; } // 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 dynamic symbol // table. bool needs_output_dynsym_entry() const { return this->output_dynsym_index_ != -1U; } // Return whether this symbol has an entry in the dynamic symbol // table. bool has_output_dynsym_entry() const { gold_assert(this->output_dynsym_index_ != 0); 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); gold_assert(i != 0 && i != -1U); 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, bool is_ordinary) { this->input_shndx_ = i; // input_shndx_ field is a bitfield, so make sure that the value // fits. gold_assert(this->input_shndx_ == i); this->is_ordinary_shndx_ = is_ordinary; } // Return the index of the input section in the input file. unsigned int input_shndx(bool* is_ordinary) const { *is_ordinary = this->is_ordinary_shndx_; 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_; } // Record that this is an IFUNC symbol. void set_is_ifunc_symbol() { this->is_ifunc_symbol_ = true; } // Return true if this is an IFUNC symbol. bool is_ifunc_symbol() const { return this->is_ifunc_symbol_; } // Return true if this has output value. bool has_output_value() const { return this->has_output_value_; } private: // The index of this local symbol in the output symbol table. This // will be 0 if no value has been assigned yet, and the symbol may // be omitted. This will be -1U if the symbol should not go into // the symbol table. This will be -2U if the symbol must go into // the symbol table, but no index has been assigned yet. unsigned int output_symtab_index_; // The index of this local symbol in the dynamic symbol table. This // will be -1U 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_ : 27; // Whether the section index is an ordinary index, not a special // value. bool is_ordinary_shndx_ : 1; // 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 is a STT_GNU_IFUNC symbol. bool is_ifunc_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* merged_symbol_value; } u_; }; // This type is used to modify relocations for -fsplit-stack. It is // indexed by relocation index, and means that the relocation at that // index should use the symbol from the vector, rather than the one // indicated by the relocation. class Reloc_symbol_changes { public: Reloc_symbol_changes(size_t count) : vec_(count, NULL) { } void set(size_t i, Symbol* sym) { this->vec_[i] = sym; } const Symbol* operator[](size_t i) const { return this->vec_[i]; } private: std::vector vec_; }; // Abstract base class for a regular object file, either a real object file // or an incremental (unchanged) object. This is size and endian specific. template class Sized_relobj : public Relobj { public: typedef typename elfcpp::Elf_types::Elf_Addr Address; typedef Relobj::Symbols Symbols; static const Address invalid_address = static_cast
(0) - 1; Sized_relobj(const std::string& name, Input_file* input_file) : Relobj(name, input_file), local_got_offsets_(), section_offsets_() { } Sized_relobj(const std::string& name, Input_file* input_file, off_t offset) : Relobj(name, input_file, offset), local_got_offsets_(), section_offsets_() { } ~Sized_relobj() { } // If this is a regular object, return a pointer to the Sized_relobj_file // object. Otherwise, return NULL. virtual Sized_relobj_file* sized_relobj() { return NULL; } const virtual Sized_relobj_file* sized_relobj() const { return NULL; } // Checks if the offset of input section SHNDX within its output // section is invalid. bool is_output_section_offset_invalid(unsigned int shndx) const { return this->get_output_section_offset(shndx) == invalid_address; } // Get the offset of input section SHNDX within its output section. // This is -1 if the input section requires a special mapping, such // as a merge section. The output section can be found in the // output_sections_ field of the parent class Relobj. Address get_output_section_offset(unsigned int shndx) const { gold_assert(shndx < this->section_offsets_.size()); return this->section_offsets_[shndx]; } // Iterate over local symbols, calling a visitor class V for each GOT offset // associated with a local symbol. void do_for_all_local_got_entries(Got_offset_list::Visitor* v) const; protected: typedef Relobj::Output_sections Output_sections; // Clear the local symbol information. void clear_got_offsets() { this->local_got_offsets_.clear(); } // Return the vector of section offsets. std::vector
& section_offsets() { return this->section_offsets_; } // Get the address of an output section. uint64_t do_output_section_address(unsigned int shndx); // Get the offset of a section. uint64_t do_output_section_offset(unsigned int shndx) const { Address off = this->get_output_section_offset(shndx); if (off == invalid_address) return -1ULL; return off; } // Set the offset of a section. void do_set_section_offset(unsigned int shndx, uint64_t off) { gold_assert(shndx < this->section_offsets_.size()); this->section_offsets_[shndx] = (off == static_cast(-1) ? invalid_address : convert_types(off)); } // Return whether the local symbol SYMNDX has a GOT offset of type // GOT_TYPE. bool do_local_has_got_offset(unsigned int symndx, unsigned int got_type) const { Local_got_offsets::const_iterator p = this->local_got_offsets_.find(symndx); return (p != this->local_got_offsets_.end() && p->second->get_offset(got_type) != -1U); } // Return the GOT offset of type GOT_TYPE of the local symbol // SYMNDX. unsigned int do_local_got_offset(unsigned int symndx, unsigned int got_type) const { Local_got_offsets::const_iterator p = this->local_got_offsets_.find(symndx); gold_assert(p != this->local_got_offsets_.end()); unsigned int off = p->second->get_offset(got_type); gold_assert(off != -1U); return off; } // Set the GOT offset with type GOT_TYPE of the local symbol SYMNDX // to GOT_OFFSET. void do_set_local_got_offset(unsigned int symndx, unsigned int got_type, unsigned int got_offset) { Local_got_offsets::const_iterator p = this->local_got_offsets_.find(symndx); if (p != this->local_got_offsets_.end()) p->second->set_offset(got_type, got_offset); else { Got_offset_list* g = new Got_offset_list(got_type, got_offset); std::pair ins = this->local_got_offsets_.insert(std::make_pair(symndx, g)); gold_assert(ins.second); } } // Return the word size of the object file. virtual int do_elfsize() const { return size; } // Return TRUE if this is a big-endian object file. virtual bool do_is_big_endian() const { return big_endian; } private: // The GOT offsets of local symbols. This map also stores GOT offsets // for tp-relative offsets for TLS symbols. typedef Unordered_map Local_got_offsets; // GOT offsets for local non-TLS symbols, and tp-relative offsets // for TLS symbols, indexed by symbol number. Local_got_offsets local_got_offsets_; // For each input section, the offset of the input section in its // output section. This is INVALID_ADDRESS if the input section requires a // special mapping. std::vector
section_offsets_; }; // A regular object file. This is size and endian specific. template class Sized_relobj_file : public Sized_relobj { public: typedef typename elfcpp::Elf_types::Elf_Addr Address; typedef typename Sized_relobj::Symbols Symbols; typedef std::vector > Local_values; static const Address invalid_address = static_cast
(0) - 1; enum Compute_final_local_value_status { // No error. CFLV_OK, // An error occurred. CFLV_ERROR, // The local symbol has no output section. CFLV_DISCARDED }; Sized_relobj_file(const std::string& name, Input_file* input_file, off_t offset, const typename elfcpp::Ehdr&); ~Sized_relobj_file(); // Set up the object file based on TARGET. void setup() { this->do_setup(); } // Return a pointer to the Sized_relobj_file object. Sized_relobj_file* sized_relobj() { return this; } const Sized_relobj_file* sized_relobj() const { return this; } // Return the ELF file type. int e_type() const { return this->e_type_; } // Return the number of symbols. This is only valid after // Object::add_symbols has been called. unsigned int symbol_count() const { return this->local_symbol_count_ + this->symbols_.size(); } // 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. Set *IS_ORDINARY if this is an ordinary // section index, not a special code between SHN_LORESERVE and // SHN_HIRESERVE. 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, bool* is_ordinary); // Return a pointer to the Symbol_value structure which holds the // value of a local symbol. const Symbol_value* 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, bool* is_ordinary) const { gold_assert(sym < this->local_values_.size()); return this->local_values_[sym].input_shndx(is_ordinary); } // Record that local symbol SYM must be in the output symbol table. void set_must_have_output_symtab_entry(unsigned int sym) { gold_assert(sym < this->local_values_.size()); this->local_values_[sym].set_must_have_output_symtab_entry(); } // Record that local symbol SYM needs a dynamic symbol entry. 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 PLT offset. bool local_has_plt_offset(unsigned int symndx) const; // Set the PLT offset of the local symbol SYMNDX. void set_local_plt_offset(unsigned int symndx, unsigned int plt_offset); // Adjust this local symbol value. Return false if the symbol // should be discarded from the output file. bool adjust_local_symbol(Symbol_value* lv) const { return this->do_adjust_local_symbol(lv); } // 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); // Look for a kept section corresponding to the given discarded section, // and return its output address. This is used only for relocations in // debugging sections. Address map_to_kept_section(unsigned int shndx, bool* found) const; // Compute final local symbol value. R_SYM is the local symbol index. // LV_IN points to a local symbol value containing the input value. // LV_OUT points to a local symbol value storing the final output value, // which must not be a merged symbol value since before calling this // method to avoid memory leak. SYMTAB points to a symbol table. // // The method returns a status code at return. If the return status is // CFLV_OK, *LV_OUT contains the final value. If the return status is // CFLV_ERROR, *LV_OUT is 0. If the return status is CFLV_DISCARDED, // *LV_OUT is not modified. Compute_final_local_value_status compute_final_local_value(unsigned int r_sym, const Symbol_value* lv_in, Symbol_value* lv_out, const Symbol_table* symtab); // Return true if the layout for this object was deferred. bool is_deferred_layout() const { return this->is_deferred_layout_; } protected: typedef typename Sized_relobj::Output_sections Output_sections; // Set up. virtual void do_setup(); // Read the symbols. void do_read_symbols(Read_symbols_data*); // Read the symbols. This is common code for all target-specific // overrides of do_read_symbols. void base_read_symbols(Read_symbols_data*); // Return the value of a local symbol. uint64_t do_local_symbol_value(unsigned int symndx, uint64_t addend) const { const Symbol_value* symval = this->local_symbol(symndx); return symval->value(this, addend); } // Return the PLT offset for a local symbol. It is an error to call // this if it doesn't have one. unsigned int do_local_plt_offset(unsigned int symndx) const; // Return whether local symbol SYMNDX is a TLS symbol. bool do_local_is_tls(unsigned int symndx) const { return this->local_symbol(symndx)->is_tls_symbol(); } // Return the number of local symbols. unsigned int do_local_symbol_count() const { return this->local_symbol_count_; } // Return the number of local symbols in the output symbol table. unsigned int do_output_local_symbol_count() const { return this->output_local_symbol_count_; } // Return the number of local symbols in the output symbol table. off_t do_local_symbol_offset() const { return this->local_symbol_offset_; } // Lay out the input sections. void do_layout(Symbol_table*, Layout*, Read_symbols_data*); // Layout sections whose layout was deferred while waiting for // input files from a plugin. void do_layout_deferred_sections(Layout*); // Add the symbols to the symbol table. void do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*); Archive::Should_include do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*, std::string* why); // Iterate over global symbols, calling a visitor class V for each. void do_for_all_global_symbols(Read_symbols_data* sd, Library_base::Symbol_visitor_base* v); // Read the relocs. void do_read_relocs(Read_relocs_data*); // Process the relocs to find list of referenced sections. Used only // during garbage collection. void do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*); // Scan the relocs and adjust the symbol table. void do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*); // Count the local symbols. void do_count_local_symbols(Stringpool_template*, Stringpool_template*); // Finalize the local symbols. unsigned int do_finalize_local_symbols(unsigned int, off_t, Symbol_table*); // 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 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) const { return this->elf_file_.section_name(shndx); } // Return the location of the contents of a section. const unsigned char* do_section_contents(unsigned int shndx, section_size_type* plen, bool cache) { Object::Location loc(this->elf_file_.section_contents(shndx)); *plen = convert_to_section_size_type(loc.data_size); if (*plen == 0) { static const unsigned char empty[1] = { '\0' }; return empty; } return this->get_view(loc.file_offset, *plen, true, cache); } // Return section flags. uint64_t do_section_flags(unsigned int shndx); // Return section entsize. uint64_t do_section_entsize(unsigned int 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); } // Return the Xindex structure to use. Xindex* do_initialize_xindex(); // Get symbol counts. void do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const; // Get the global symbols. const Symbols* do_get_global_symbols() const { return &this->symbols_; } // Adjust a section index if necessary. unsigned int adjust_shndx(unsigned int shndx) { if (shndx >= elfcpp::SHN_LORESERVE) shndx += this->elf_file_.large_shndx_offset(); return shndx; } // 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(); // Return symbol table section index. unsigned int symtab_shndx() const { return this->symtab_shndx_; } // Allow a child class to access the ELF file. elfcpp::Elf_file* elf_file() { return &this->elf_file_; } // Allow a child class to access the local values. Local_values* local_values() { return &this->local_values_; } // Views and sizes when relocating. struct View_size { unsigned char* view; typename elfcpp::Elf_types::Elf_Addr address; off_t offset; section_size_type view_size; bool is_input_output_view; bool is_postprocessing_view; bool is_ctors_reverse_view; }; typedef std::vector Views; // Stash away info for a number of special sections. // Return true if any of the sections found require local symbols to be read. virtual bool do_find_special_sections(Read_symbols_data* sd); // This may be overriden by a child class. virtual void do_relocate_sections(const Symbol_table* symtab, const Layout* layout, const unsigned char* pshdrs, Output_file* of, Views* pviews); // Adjust this local symbol value. Return false if the symbol // should be discarded from the output file. virtual bool do_adjust_local_symbol(Symbol_value*) const { return true; } // Allow a child to set output local symbol count. void set_output_local_symbol_count(unsigned int value) { this->output_local_symbol_count_ = value; } private: // For convenience. typedef Sized_relobj_file This; static const int ehdr_size = elfcpp::Elf_sizes::ehdr_size; static const int shdr_size = elfcpp::Elf_sizes::shdr_size; static const int sym_size = elfcpp::Elf_sizes::sym_size; typedef elfcpp::Shdr Shdr; // To keep track of discarded comdat sections, we need to map a member // section index to the object and section index of the corresponding // kept section. struct Kept_comdat_section { Kept_comdat_section(Relobj* a_object, unsigned int a_shndx) : object(a_object), shndx(a_shndx) { } Relobj* object; unsigned int shndx; }; typedef std::map Kept_comdat_section_table; // 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* 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 unsigned char*, const char*, section_size_type, std::vector*); // Whether to include a linkonce section in the link. bool include_linkonce_section(Layout*, unsigned int, const char*, const elfcpp::Shdr&); // Layout an input section. void layout_section(Layout* layout, unsigned int shndx, const char* name, const typename This::Shdr& shdr, unsigned int reloc_shndx, unsigned int reloc_type); // Layout an input .eh_frame section. void layout_eh_frame_section(Layout* layout, const unsigned char* symbols_data, section_size_type symbols_size, const unsigned char* symbol_names_data, section_size_type symbol_names_size, unsigned int shndx, const typename This::Shdr&, unsigned int reloc_shndx, unsigned int reloc_type); // Write section data to the output file. Record the views and // sizes in VIEWS for use when relocating. void write_sections(const Layout*, const unsigned char* pshdrs, Output_file*, Views*); // Relocate the sections in the output file. void relocate_sections(const Symbol_table* symtab, const Layout* layout, const unsigned char* pshdrs, Output_file* of, Views* pviews) { this->do_relocate_sections(symtab, layout, pshdrs, of, pviews); } // Reverse the words in a section. Used for .ctors sections mapped // to .init_array sections. void reverse_words(unsigned char*, section_size_type); // Scan the input relocations for --emit-relocs. void emit_relocs_scan(Symbol_table*, Layout*, const unsigned char* plocal_syms, const Read_relocs_data::Relocs_list::iterator&); // Scan the input relocations for --emit-relocs, templatized on the // type of the relocation section. template void emit_relocs_scan_reltype(Symbol_table*, Layout*, const unsigned char* plocal_syms, const Read_relocs_data::Relocs_list::iterator&, Relocatable_relocs*); // Scan the input relocations for --incremental. void incremental_relocs_scan(const Read_relocs_data::Relocs_list::iterator&); // Scan the input relocations for --incremental, templatized on the // type of the relocation section. template void incremental_relocs_scan_reltype( const Read_relocs_data::Relocs_list::iterator&); void incremental_relocs_write(const Relocate_info*, unsigned int sh_type, const unsigned char* prelocs, size_t reloc_count, Output_section*, Address output_offset, Output_file*); template void incremental_relocs_write_reltype(const Relocate_info*, const unsigned char* prelocs, size_t reloc_count, Output_section*, Address output_offset, Output_file*); // A type shared by split_stack_adjust_reltype and find_functions. typedef std::map Function_offsets; // Check for -fsplit-stack routines calling non-split-stack routines. void split_stack_adjust(const Symbol_table*, const unsigned char* pshdrs, unsigned int sh_type, unsigned int shndx, const unsigned char* prelocs, size_t reloc_count, unsigned char* view, section_size_type view_size, Reloc_symbol_changes** reloc_map); template void split_stack_adjust_reltype(const Symbol_table*, const unsigned char* pshdrs, unsigned int shndx, const unsigned char* prelocs, size_t reloc_count, unsigned char* view, section_size_type view_size, Reloc_symbol_changes** reloc_map); // Find all functions in a section. void find_functions(const unsigned char* pshdrs, unsigned int shndx, Function_offsets*); // Write out the local symbols. void write_local_symbols(Output_file*, const Stringpool_template*, const Stringpool_template*, Output_symtab_xindex*, Output_symtab_xindex*, off_t); // Record a mapping from discarded section SHNDX to the corresponding // kept section. void set_kept_comdat_section(unsigned int shndx, Relobj* kept_object, unsigned int kept_shndx) { Kept_comdat_section kept(kept_object, kept_shndx); this->kept_comdat_sections_.insert(std::make_pair(shndx, kept)); } // Find the kept section corresponding to the discarded section // SHNDX. Return true if found. bool get_kept_comdat_section(unsigned int shndx, Relobj** kept_object, unsigned int* kept_shndx) const { typename Kept_comdat_section_table::const_iterator p = this->kept_comdat_sections_.find(shndx); if (p == this->kept_comdat_sections_.end()) return false; *kept_object = p->second.object; *kept_shndx = p->second.shndx; return true; } // Compute final local symbol value. R_SYM is the local symbol index. // LV_IN points to a local symbol value containing the input value. // LV_OUT points to a local symbol value storing the final output value, // which must not be a merged symbol value since before calling this // method to avoid memory leak. RELOCATABLE indicates whether we are // linking a relocatable output. OUT_SECTIONS is an array of output // sections. OUT_OFFSETS is an array of offsets of the sections. SYMTAB // points to a symbol table. // // The method returns a status code at return. If the return status is // CFLV_OK, *LV_OUT contains the final value. If the return status is // CFLV_ERROR, *LV_OUT is 0. If the return status is CFLV_DISCARDED, // *LV_OUT is not modified. inline Compute_final_local_value_status compute_final_local_value_internal(unsigned int r_sym, const Symbol_value* lv_in, Symbol_value* lv_out, bool relocatable, const Output_sections& out_sections, const std::vector
& out_offsets, const Symbol_table* symtab); // The PLT offsets of local symbols. typedef Unordered_map Local_plt_offsets; // Saved information for sections whose layout was deferred. struct Deferred_layout { static const int shdr_size = elfcpp::Elf_sizes::shdr_size; Deferred_layout(unsigned int shndx, const char* name, const unsigned char* pshdr, unsigned int reloc_shndx, unsigned int reloc_type) : shndx_(shndx), name_(name), reloc_shndx_(reloc_shndx), reloc_type_(reloc_type) { memcpy(this->shdr_data_, pshdr, shdr_size); } unsigned int shndx_; std::string name_; unsigned int reloc_shndx_; unsigned int reloc_type_; unsigned char shdr_data_[shdr_size]; }; // General access to the ELF file. elfcpp::Elf_file elf_file_; // Type of ELF file (ET_REL or ET_EXEC). ET_EXEC files are allowed // as input files only for the --just-symbols option. int e_type_; // 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_; // Number of symbols defined in object file itself. size_t defined_count_; // File offset for local symbols (relative to start of symbol table). off_t local_symbol_offset_; // File offset for local dynamic symbols (absolute). off_t local_dynsym_offset_; // Values of local symbols. Local_values local_values_; // PLT offsets for local symbols. Local_plt_offsets local_plt_offsets_; // Table mapping discarded comdat sections to corresponding kept sections. Kept_comdat_section_table kept_comdat_sections_; // Whether this object has a GNU style .eh_frame section. bool has_eh_frame_; // If this object has a GNU style .eh_frame section that is discarded in // output, record the index here. Otherwise it is -1U. unsigned int discarded_eh_frame_shndx_; // True if the layout of this object was deferred, waiting for plugin // replacement files. bool is_deferred_layout_; // The list of sections whose layout was deferred. std::vector deferred_layout_; // The list of relocation sections whose layout was deferred. std::vector deferred_layout_relocs_; }; // A class to manage the list of all objects. class Input_objects { public: Input_objects() : relobj_list_(), dynobj_list_(), sonames_(), cref_(NULL) { } // The type of the list of input relocateable objects. typedef std::vector Relobj_list; typedef Relobj_list::const_iterator Relobj_iterator; // The type of the list of input dynamic objects. typedef std::vector 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*); // Start processing an archive. void archive_start(Archive*); // Stop processing an archive. void archive_stop(Archive*); // 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; // Print symbol counts. void print_symbol_counts(const Symbol_table*) const; // Print a cross reference table. void print_cref(const Symbol_table*, FILE*) 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 non dynamic objects. int number_of_relobjs() const { return this->relobj_list_.size(); } // 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 sonames_; // Manage cross-references if requested. Cref* cref_; }; // Some of the information we pass to the relocation routines. We // group this together to avoid passing a dozen different arguments. template struct Relocate_info { // Symbol table. const Symbol_table* symtab; // Layout. const Layout* layout; // Object being relocated. Sized_relobj_file* object; // Section index of relocation section. unsigned int reloc_shndx; // Section header of relocation section. const unsigned char* reloc_shdr; // Section index of section being relocated. unsigned int data_shndx; // Section header of data section. const unsigned char* data_shdr; // 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; }; // This is used to represent a section in an object and is used as the // key type for various section maps. typedef std::pair Section_id; // This is similar to Section_id but is used when the section // pointers are const. typedef std::pair Const_section_id; // The hash value is based on the address of an object in memory during // linking. It is okay to use this for looking up sections but never use // this in an unordered container that we want to traverse in a repeatable // manner. struct Section_id_hash { size_t operator()(const Section_id& loc) const { return reinterpret_cast(loc.first) ^ loc.second; } }; struct Const_section_id_hash { size_t operator()(const Const_section_id& loc) const { return reinterpret_cast(loc.first) ^ loc.second; } }; // Return whether INPUT_FILE contains an ELF object start at file // offset OFFSET. This sets *START to point to a view of the start of // the file. It sets *READ_SIZE to the number of bytes in the view. extern bool is_elf_object(Input_file* input_file, off_t offset, const unsigned char** start, int* read_size); // Return an Object appropriate for the input file. P is BYTES long, // and holds the ELF header. If PUNCONFIGURED is not NULL, then if // this sees an object the linker is not configured to support, it // sets *PUNCONFIGURED to true and returns NULL without giving an // error message. extern Object* make_elf_object(const std::string& name, Input_file*, off_t offset, const unsigned char* p, section_offset_type bytes, bool* punconfigured); } // end namespace gold #endif // !defined(GOLD_OBJECT_H)